root/drivers/pwm/core.c 
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Generic pwmlib implementation
 *
 * Copyright (C) 2011 Sascha Hauer <s.hauer@pengutronix.de>
 * Copyright (C) 2011-2012 Avionic Design GmbH
 */

#define DEFAULT_SYMBOL_NAMESPACE "PWM"

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/pwm.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>

#include <dt-bindings/pwm/pwm.h>

#include <uapi/linux/pwm.h>

#define CREATE_TRACE_POINTS
#include <trace/events/pwm.h>

#define PWM_MINOR_COUNT 256

/* protects access to pwm_chips */
static DEFINE_MUTEX(pwm_lock);

static DEFINE_IDR(pwm_chips);

static void pwmchip_lock(struct pwm_chip *chip)
{
        if (chip->atomic)
                spin_lock(&chip->atomic_lock);
        else
                mutex_lock(&chip->nonatomic_lock);
}

static void pwmchip_unlock(struct pwm_chip *chip)
{
        if (chip->atomic)
                spin_unlock(&chip->atomic_lock);
        else
                mutex_unlock(&chip->nonatomic_lock);
}

DEFINE_GUARD(pwmchip, struct pwm_chip *, pwmchip_lock(_T), pwmchip_unlock(_T))

static bool pwm_wf_valid(const struct pwm_waveform *wf)
{
        /*
         * For now restrict waveforms to period_length_ns <= S64_MAX to provide
         * some space for future extensions. One possibility is to simplify
         * representing waveforms with inverted polarity using negative values
         * somehow.
         */
        if (wf->period_length_ns > S64_MAX)
                return false;

        if (wf->duty_length_ns > wf->period_length_ns)
                return false;

        /*
         * .duty_offset_ns is supposed to be smaller than .period_length_ns, apart
         * from the corner case .duty_offset_ns == 0 && .period_length_ns == 0.
         */
        if (wf->duty_offset_ns && wf->duty_offset_ns >= wf->period_length_ns)
                return false;

        return true;
}

static void pwm_wf2state(const struct pwm_waveform *wf, struct pwm_state *state)
{
        if (wf->period_length_ns) {
                if (wf->duty_length_ns + wf->duty_offset_ns < wf->period_length_ns)
                        *state = (struct pwm_state){
                                .enabled = true,
                                .polarity = PWM_POLARITY_NORMAL,
                                .period = wf->period_length_ns,
                                .duty_cycle = wf->duty_length_ns,
                        };
                else
                        *state = (struct pwm_state){
                                .enabled = true,
                                .polarity = PWM_POLARITY_INVERSED,
                                .period = wf->period_length_ns,
                                .duty_cycle = wf->period_length_ns - wf->duty_length_ns,
                        };
        } else {
                *state = (struct pwm_state){
                        .enabled = false,
                };
        }
}

static void pwm_state2wf(const struct pwm_state *state, struct pwm_waveform *wf)
{
        if (state->enabled) {
                if (state->polarity == PWM_POLARITY_NORMAL)
                        *wf = (struct pwm_waveform){
                                .period_length_ns = state->period,
                                .duty_length_ns = state->duty_cycle,
                                .duty_offset_ns = 0,
                        };
                else
                        *wf = (struct pwm_waveform){
                                .period_length_ns = state->period,
                                .duty_length_ns = state->period - state->duty_cycle,
                                .duty_offset_ns = state->duty_cycle,
                        };
        } else {
                *wf = (struct pwm_waveform){
                        .period_length_ns = 0,
                };
        }
}

static int pwmwfcmp(const struct pwm_waveform *a, const struct pwm_waveform *b)
{
        if (a->period_length_ns > b->period_length_ns)
                return 1;

        if (a->period_length_ns < b->period_length_ns)
                return -1;

        if (a->duty_length_ns > b->duty_length_ns)
                return 1;

        if (a->duty_length_ns < b->duty_length_ns)
                return -1;

        if (a->duty_offset_ns > b->duty_offset_ns)
                return 1;

        if (a->duty_offset_ns < b->duty_offset_ns)
                return -1;

        return 0;
}

static bool pwm_check_rounding(const struct pwm_waveform *wf,
                               const struct pwm_waveform *wf_rounded)
{
        if (!wf->period_length_ns)
                return true;

        if (wf->period_length_ns < wf_rounded->period_length_ns)
                return false;

        if (wf->duty_length_ns < wf_rounded->duty_length_ns)
                return false;

        if (wf->duty_offset_ns < wf_rounded->duty_offset_ns)
                return false;

        return true;
}

static int __pwm_round_waveform_tohw(struct pwm_chip *chip, struct pwm_device *pwm,
                                     const struct pwm_waveform *wf, void *wfhw)
{
        const struct pwm_ops *ops = chip->ops;
        int ret;

        ret = ops->round_waveform_tohw(chip, pwm, wf, wfhw);
        trace_pwm_round_waveform_tohw(pwm, wf, wfhw, ret);

        return ret;
}

static int __pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
                                       const void *wfhw, struct pwm_waveform *wf)
{
        const struct pwm_ops *ops = chip->ops;
        int ret;

        ret = ops->round_waveform_fromhw(chip, pwm, wfhw, wf);
        trace_pwm_round_waveform_fromhw(pwm, wfhw, wf, ret);

        return ret;
}

static int __pwm_read_waveform(struct pwm_chip *chip, struct pwm_device *pwm, void *wfhw)
{
        const struct pwm_ops *ops = chip->ops;
        int ret;

        ret = ops->read_waveform(chip, pwm, wfhw);
        trace_pwm_read_waveform(pwm, wfhw, ret);

        return ret;
}

static int __pwm_write_waveform(struct pwm_chip *chip, struct pwm_device *pwm, const void *wfhw)
{
        const struct pwm_ops *ops = chip->ops;
        int ret;

        ret = ops->write_waveform(chip, pwm, wfhw);
        trace_pwm_write_waveform(pwm, wfhw, ret);

        return ret;
}

/**
 * pwm_round_waveform_might_sleep - Query hardware capabilities
 * Cannot be used in atomic context.
 * @pwm: PWM device
 * @wf: waveform to round and output parameter
 *
 * Typically a given waveform cannot be implemented exactly by hardware, e.g.
 * because hardware only supports coarse period resolution or no duty_offset.
 * This function returns the actually implemented waveform if you pass @wf to
 * pwm_set_waveform_might_sleep() now.
 *
 * Note however that the world doesn't stop turning when you call it, so when
 * doing::
 *
 *   pwm_round_waveform_might_sleep(mypwm, &wf);
 *   pwm_set_waveform_might_sleep(mypwm, &wf, true);
 *
 * the latter might fail, e.g. because an input clock changed its rate between
 * these two calls and the waveform determined by
 * pwm_round_waveform_might_sleep() cannot be implemented any more.
 *
 * Usually all values passed in @wf are rounded down to the nearest possible
 * value (in the order period_length_ns, duty_length_ns and then
 * duty_offset_ns). Only if this isn't possible, a value might grow. See the
 * documentation for pwm_set_waveform_might_sleep() for a more formal
 * description.
 *
 * Returns: 0 on success, 1 if at least one value had to be rounded up or a
 * negative errno.
 * Context: May sleep.
 */
int pwm_round_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf)
{
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;
        struct pwm_waveform wf_req = *wf;
        char wfhw[PWM_WFHWSIZE];
        int ret_tohw, ret_fromhw;

        BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw);

        if (!pwmchip_supports_waveform(chip))
                return -EOPNOTSUPP;

        if (!pwm_wf_valid(wf))
                return -EINVAL;

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, wfhw);
        if (ret_tohw < 0)
                return ret_tohw;

        if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw > 1)
                dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_tohw: requested %llu/%llu [+%llu], return value %d\n",
                        wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_tohw);

        ret_fromhw = __pwm_round_waveform_fromhw(chip, pwm, wfhw, wf);
        if (ret_fromhw < 0)
                return ret_fromhw;

        if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_fromhw > 0)
                dev_err(&chip->dev, "Unexpected return value from __pwm_round_waveform_fromhw: requested %llu/%llu [+%llu], return value %d\n",
                        wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns, ret_fromhw);

        if (IS_ENABLED(CONFIG_PWM_DEBUG) &&
            (ret_tohw == 0) != pwm_check_rounding(&wf_req, wf))
                dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu], ret: %d\n",
                        wf_req.duty_length_ns, wf_req.period_length_ns, wf_req.duty_offset_ns,
                        wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns, ret_tohw);

        return ret_tohw;
}
EXPORT_SYMBOL_GPL(pwm_round_waveform_might_sleep);

/**
 * pwm_get_waveform_might_sleep - Query hardware about current configuration
 * Cannot be used in atomic context.
 * @pwm: PWM device
 * @wf: output parameter
 *
 * Stores the current configuration of the PWM in @wf. Note this is the
 * equivalent of pwm_get_state_hw() (and not pwm_get_state()) for pwm_waveform.
 *
 * Returns: 0 on success or a negative errno
 * Context: May sleep.
 */
int pwm_get_waveform_might_sleep(struct pwm_device *pwm, struct pwm_waveform *wf)
{
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;
        char wfhw[PWM_WFHWSIZE];
        int err;

        BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw);

        if (!pwmchip_supports_waveform(chip) || !ops->read_waveform)
                return -EOPNOTSUPP;

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        err = __pwm_read_waveform(chip, pwm, &wfhw);
        if (err)
                return err;

        return __pwm_round_waveform_fromhw(chip, pwm, &wfhw, wf);
}
EXPORT_SYMBOL_GPL(pwm_get_waveform_might_sleep);

/* Called with the pwmchip lock held */
static int __pwm_set_waveform(struct pwm_device *pwm,
                              const struct pwm_waveform *wf,
                              bool exact)
{
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;
        char wfhw[PWM_WFHWSIZE];
        struct pwm_waveform wf_rounded;
        int err, ret_tohw;

        BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw);

        if (!pwmchip_supports_waveform(chip))
                return -EOPNOTSUPP;

        if (!pwm_wf_valid(wf))
                return -EINVAL;

        ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
        if (ret_tohw < 0)
                return ret_tohw;

        if ((IS_ENABLED(CONFIG_PWM_DEBUG) || exact) && wf->period_length_ns) {
                err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
                if (err)
                        return err;

                if (IS_ENABLED(CONFIG_PWM_DEBUG) && (ret_tohw == 0) != pwm_check_rounding(wf, &wf_rounded))
                        dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu], ret: %d\n",
                                wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
                                wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns, ret_tohw);

                if (exact && pwmwfcmp(wf, &wf_rounded)) {
                        dev_dbg(&chip->dev, "Requested no rounding, but %llu/%llu [+%llu] -> %llu/%llu [+%llu]\n",
                                wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
                                wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);

                        return 1;
                }
        }

        err = __pwm_write_waveform(chip, pwm, &wfhw);
        if (err)
                return err;

        /* update .state */
        pwm_wf2state(wf, &pwm->state);

        if (IS_ENABLED(CONFIG_PWM_DEBUG) && ops->read_waveform && wf->period_length_ns) {
                struct pwm_waveform wf_set;

                err = __pwm_read_waveform(chip, pwm, &wfhw);
                if (err)
                        /* maybe ignore? */
                        return err;

                err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_set);
                if (err)
                        /* maybe ignore? */
                        return err;

                if (pwmwfcmp(&wf_set, &wf_rounded) != 0)
                        dev_err(&chip->dev,
                                "Unexpected setting: requested %llu/%llu [+%llu], expected %llu/%llu [+%llu], set %llu/%llu [+%llu]\n",
                                wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
                                wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns,
                                wf_set.duty_length_ns, wf_set.period_length_ns, wf_set.duty_offset_ns);
        }

        return ret_tohw;
}

/**
 * pwm_set_waveform_might_sleep - Apply a new waveform
 * Cannot be used in atomic context.
 * @pwm: PWM device
 * @wf: The waveform to apply
 * @exact: If true no rounding is allowed
 *
 * Typically a requested waveform cannot be implemented exactly, e.g. because
 * you requested .period_length_ns = 100 ns, but the hardware can only set
 * periods that are a multiple of 8.5 ns. With that hardware passing @exact =
 * true results in pwm_set_waveform_might_sleep() failing and returning -EDOM.
 * If @exact = false you get a period of 93.5 ns (i.e. the biggest period not
 * bigger than the requested value).
 * Note that even with @exact = true, some rounding by less than 1 ns is
 * possible/needed. In the above example requesting .period_length_ns = 94 and
 * @exact = true, you get the hardware configured with period = 93.5 ns.
 *
 * Let C be the set of possible hardware configurations for a given PWM device,
 * consisting of tuples (p, d, o) where p is the period length, d is the duty
 * length and o the duty offset.
 *
 * The following algorithm is implemented to pick the hardware setting
 * (p, d, o) ∈ C for a given request (p', d', o') with @exact = false::
 *
 *   p = max( { ṗ | ∃ ḋ, ȯ : (ṗ, ḋ, ȯ) ∈ C ∧ ṗ ≤ p' } ∪ { min({ ṗ | ∃ ḋ, ȯ : (ṗ, ḋ, ȯ) ∈ C }) })
 *   d = max( { ḋ | ∃ ȯ : (p, ḋ, ȯ) ∈ C ∧ ḋ ≤ d' } ∪ { min({ ḋ | ∃ ȯ : (p, ḋ, ȯ) ∈ C }) })
 *   o = max( { ȯ | (p, d, ȯ) ∈ C ∧ ȯ ≤ o' } ∪ { min({ ȯ | (p, d, ȯ) ∈ C }) })
 *
 * In words: The chosen period length is the maximal possible period length not
 * bigger than the requested period length and if that doesn't exist, the
 * minimal period length. The chosen duty length is the maximal possible duty
 * length that is compatible with the chosen period length and isn't bigger than
 * the requested duty length. Again if such a value doesn't exist, the minimal
 * duty length compatible with the chosen period is picked. After that the duty
 * offset compatible with the chosen period and duty length is chosen in the
 * same way.
 *
 * Returns: 0 on success, -EDOM if setting failed due to the exact waveform not
 * being possible (if @exact), or a different negative errno on failure.
 * Context: May sleep.
 */
int pwm_set_waveform_might_sleep(struct pwm_device *pwm,
                                 const struct pwm_waveform *wf, bool exact)
{
        struct pwm_chip *chip = pwm->chip;
        int err;

        might_sleep();

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) {
                /*
                 * Catch any drivers that have been marked as atomic but
                 * that will sleep anyway.
                 */
                non_block_start();
                err = __pwm_set_waveform(pwm, wf, exact);
                non_block_end();
        } else {
                err = __pwm_set_waveform(pwm, wf, exact);
        }

        /*
         * map err == 1 to -EDOM for exact requests and 0 for !exact ones. Also
         * make sure that -EDOM is only returned in exactly that case. Note that
         * __pwm_set_waveform() should never return -EDOM which justifies the
         * unlikely().
         */
        if (unlikely(err == -EDOM))
                err = -EINVAL;
        else if (exact && err == 1)
                err = -EDOM;
        else if (err == 1)
                err = 0;

        return err;
}
EXPORT_SYMBOL_GPL(pwm_set_waveform_might_sleep);

static void pwm_apply_debug(struct pwm_device *pwm,
                            const struct pwm_state *state)
{
        struct pwm_state *last = &pwm->last;
        struct pwm_chip *chip = pwm->chip;
        struct pwm_state s1 = { 0 }, s2 = { 0 };
        int err;

        if (!IS_ENABLED(CONFIG_PWM_DEBUG))
                return;

        /* No reasonable diagnosis possible without .get_state() */
        if (!chip->ops->get_state)
                return;

        /*
         * If a disabled PWM was requested the result is unspecified, so nothing
         * to check.
         */
        if (!state->enabled)
                return;

        /*
         * *state was just applied. Read out the hardware state and do some
         * checks.
         */

        err = chip->ops->get_state(chip, pwm, &s1);
        trace_pwm_get(pwm, &s1, err);
        if (err)
                /* If that failed there isn't much to debug */
                return;

        /*
         * If the PWM was disabled that's maybe strange but there is nothing
         * that can be sensibly checked then. So return early.
         */
        if (!s1.enabled)
                return;

        /*
         * The lowlevel driver either ignored .polarity (which is a bug) or as
         * best effort inverted .polarity and fixed .duty_cycle respectively.
         * Undo this inversion and fixup for further tests.
         */
        if (s1.polarity != state->polarity) {
                s2.polarity = state->polarity;
                s2.duty_cycle = s1.period - s1.duty_cycle;
                s2.period = s1.period;
                s2.enabled = true;
        } else {
                s2 = s1;
        }

        if (s2.polarity != state->polarity &&
            s2.duty_cycle < s2.period)
                dev_warn(pwmchip_parent(chip), ".apply ignored .polarity\n");

        if (last->polarity == state->polarity &&
            last->period > s2.period &&
            last->period <= state->period)
                dev_warn(pwmchip_parent(chip),
                         ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
                         state->period, s2.period, last->period);

        /*
         * Rounding period up is fine only if duty_cycle is 0 then, because a
         * flat line doesn't have a characteristic period.
         */
        if (state->period < s2.period && s2.duty_cycle)
                dev_warn(pwmchip_parent(chip),
                         ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
                         state->period, s2.period);

        if (last->polarity == state->polarity &&
            last->period == s2.period &&
            last->duty_cycle > s2.duty_cycle &&
            last->duty_cycle <= state->duty_cycle)
                dev_warn(pwmchip_parent(chip),
                         ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
                         state->duty_cycle, state->period,
                         s2.duty_cycle, s2.period,
                         last->duty_cycle, last->period);

        if (state->duty_cycle < s2.duty_cycle)
                dev_warn(pwmchip_parent(chip),
                         ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
                         state->duty_cycle, state->period,
                         s2.duty_cycle, s2.period);

        /* reapply the state that the driver reported being configured. */
        err = chip->ops->apply(chip, pwm, &s1);
        trace_pwm_apply(pwm, &s1, err);
        if (err) {
                *last = s1;
                dev_err(pwmchip_parent(chip), "failed to reapply current setting\n");
                return;
        }

        *last = (struct pwm_state){ 0 };
        err = chip->ops->get_state(chip, pwm, last);
        trace_pwm_get(pwm, last, err);
        if (err)
                return;

        /* reapplication of the current state should give an exact match */
        if (s1.enabled != last->enabled ||
            s1.polarity != last->polarity ||
            (s1.enabled && s1.period != last->period) ||
            (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
                dev_err(pwmchip_parent(chip),
                        ".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
                        s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
                        last->enabled, last->polarity, last->duty_cycle,
                        last->period);
        }
}

static bool pwm_state_valid(const struct pwm_state *state)
{
        /*
         * For a disabled state all other state description is irrelevant and
         * and supposed to be ignored. So also ignore any strange values and
         * consider the state ok.
         */
        if (!state->enabled)
                return true;

        if (!state->period)
                return false;

        if (state->duty_cycle > state->period)
                return false;

        return true;
}

static int __pwm_apply(struct pwm_device *pwm, const struct pwm_state *state)
{
        struct pwm_chip *chip;
        const struct pwm_ops *ops;
        int err;

        if (!pwm || !state)
                return -EINVAL;

        if (!pwm_state_valid(state)) {
                /*
                 * Allow to transition from one invalid state to another.
                 * This ensures that you can e.g. change the polarity while
                 * the period is zero. (This happens on stm32 when the hardware
                 * is in its poweron default state.) This greatly simplifies
                 * working with the sysfs API where you can only change one
                 * parameter at a time.
                 */
                if (!pwm_state_valid(&pwm->state)) {
                        pwm->state = *state;
                        return 0;
                }

                return -EINVAL;
        }

        chip = pwm->chip;
        ops = chip->ops;

        if (state->period == pwm->state.period &&
            state->duty_cycle == pwm->state.duty_cycle &&
            state->polarity == pwm->state.polarity &&
            state->enabled == pwm->state.enabled &&
            state->usage_power == pwm->state.usage_power)
                return 0;

        if (pwmchip_supports_waveform(chip)) {
                struct pwm_waveform wf;
                char wfhw[PWM_WFHWSIZE];

                BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw);

                pwm_state2wf(state, &wf);

                /*
                 * The rounding is wrong here for states with inverted polarity.
                 * While .apply() rounds down duty_cycle (which represents the
                 * time from the start of the period to the inner edge),
                 * .round_waveform_tohw() rounds down the time the PWM is high.
                 * Can be fixed if the need arises, until reported otherwise
                 * let's assume that consumers don't care.
                 */

                err = __pwm_round_waveform_tohw(chip, pwm, &wf, &wfhw);
                if (err) {
                        if (err > 0)
                                /*
                                 * This signals an invalid request, typically
                                 * the requested period (or duty_offset) is
                                 * smaller than possible with the hardware.
                                 */
                                return -EINVAL;

                        return err;
                }

                if (IS_ENABLED(CONFIG_PWM_DEBUG)) {
                        struct pwm_waveform wf_rounded;

                        err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
                        if (err)
                                return err;

                        if (!pwm_check_rounding(&wf, &wf_rounded))
                                dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
                                        wf.duty_length_ns, wf.period_length_ns, wf.duty_offset_ns,
                                        wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
                }

                err = __pwm_write_waveform(chip, pwm, &wfhw);
                if (err)
                        return err;

                pwm->state = *state;

        } else {
                err = ops->apply(chip, pwm, state);
                trace_pwm_apply(pwm, state, err);
                if (err)
                        return err;

                pwm->state = *state;

                /*
                 * only do this after pwm->state was applied as some
                 * implementations of .get_state() depend on this
                 */
                pwm_apply_debug(pwm, state);
        }

        return 0;
}

/**
 * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
 * Cannot be used in atomic context.
 * @pwm: PWM device
 * @state: new state to apply
 *
 * Returns: 0 on success, or a negative errno
 * Context: May sleep.
 */
int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
{
        int err;
        struct pwm_chip *chip = pwm->chip;

        /*
         * Some lowlevel driver's implementations of .apply() make use of
         * mutexes, also with some drivers only returning when the new
         * configuration is active calling pwm_apply_might_sleep() from atomic context
         * is a bad idea. So make it explicit that calling this function might
         * sleep.
         */
        might_sleep();

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        if (IS_ENABLED(CONFIG_PWM_DEBUG) && chip->atomic) {
                /*
                 * Catch any drivers that have been marked as atomic but
                 * that will sleep anyway.
                 */
                non_block_start();
                err = __pwm_apply(pwm, state);
                non_block_end();
        } else {
                err = __pwm_apply(pwm, state);
        }

        return err;
}
EXPORT_SYMBOL_GPL(pwm_apply_might_sleep);

/**
 * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
 * Not all PWM devices support this function, check with pwm_might_sleep().
 * @pwm: PWM device
 * @state: new state to apply
 *
 * Returns: 0 on success, or a negative errno
 * Context: Any
 */
int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
{
        struct pwm_chip *chip = pwm->chip;

        WARN_ONCE(!chip->atomic,
                  "sleeping PWM driver used in atomic context\n");

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        return __pwm_apply(pwm, state);
}
EXPORT_SYMBOL_GPL(pwm_apply_atomic);

/**
 * pwm_get_state_hw() - get the current PWM state from hardware
 * @pwm: PWM device
 * @state: state to fill with the current PWM state
 *
 * Similar to pwm_get_state() but reads the current PWM state from hardware
 * instead of the requested state.
 *
 * Returns: 0 on success or a negative error code on failure.
 * Context: May sleep.
 */
int pwm_get_state_hw(struct pwm_device *pwm, struct pwm_state *state)
{
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;
        int ret = -EOPNOTSUPP;

        might_sleep();

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        if (pwmchip_supports_waveform(chip) && ops->read_waveform) {
                char wfhw[PWM_WFHWSIZE];
                struct pwm_waveform wf;

                BUG_ON(PWM_WFHWSIZE < ops->sizeof_wfhw);

                ret = __pwm_read_waveform(chip, pwm, &wfhw);
                if (ret)
                        return ret;

                ret = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf);
                if (ret)
                        return ret;

                pwm_wf2state(&wf, state);

        } else if (ops->get_state) {
                ret = ops->get_state(chip, pwm, state);
                trace_pwm_get(pwm, state, ret);
        }

        return ret;
}
EXPORT_SYMBOL_GPL(pwm_get_state_hw);

/**
 * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
 * @pwm: PWM device
 *
 * This function will adjust the PWM config to the PWM arguments provided
 * by the DT or PWM lookup table. This is particularly useful to adapt
 * the bootloader config to the Linux one.
 *
 * Returns: 0 on success or a negative error code on failure.
 * Context: May sleep.
 */
int pwm_adjust_config(struct pwm_device *pwm)
{
        struct pwm_state state;
        struct pwm_args pargs;

        pwm_get_args(pwm, &pargs);
        pwm_get_state(pwm, &state);

        /*
         * If the current period is zero it means that either the PWM driver
         * does not support initial state retrieval or the PWM has not yet
         * been configured.
         *
         * In either case, we setup the new period and polarity, and assign a
         * duty cycle of 0.
         */
        if (!state.period) {
                state.duty_cycle = 0;
                state.period = pargs.period;
                state.polarity = pargs.polarity;

                return pwm_apply_might_sleep(pwm, &state);
        }

        /*
         * Adjust the PWM duty cycle/period based on the period value provided
         * in PWM args.
         */
        if (pargs.period != state.period) {
                u64 dutycycle = (u64)state.duty_cycle * pargs.period;

                do_div(dutycycle, state.period);
                state.duty_cycle = dutycycle;
                state.period = pargs.period;
        }

        /*
         * If the polarity changed, we should also change the duty cycle.
         */
        if (pargs.polarity != state.polarity) {
                state.polarity = pargs.polarity;
                state.duty_cycle = state.period - state.duty_cycle;
        }

        return pwm_apply_might_sleep(pwm, &state);
}
EXPORT_SYMBOL_GPL(pwm_adjust_config);

/**
 * pwm_capture() - capture and report a PWM signal
 * @pwm: PWM device
 * @result: structure to fill with capture result
 * @timeout: time to wait, in milliseconds, before giving up on capture
 *
 * Returns: 0 on success or a negative error code on failure.
 */
static int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
                       unsigned long timeout)
{
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;

        if (!ops->capture)
                return -ENOSYS;

        /*
         * Holding the pwm_lock is probably not needed. If you use pwm_capture()
         * and you're interested to speed it up, please convince yourself it's
         * really not needed, test and then suggest a patch on the mailing list.
         */
        guard(mutex)(&pwm_lock);

        guard(pwmchip)(chip);

        if (!chip->operational)
                return -ENODEV;

        return ops->capture(chip, pwm, result, timeout);
}

static struct pwm_chip *pwmchip_find_by_name(const char *name)
{
        struct pwm_chip *chip;
        unsigned long id, tmp;

        if (!name)
                return NULL;

        guard(mutex)(&pwm_lock);

        idr_for_each_entry_ul(&pwm_chips, chip, tmp, id) {
                if (device_match_name(pwmchip_parent(chip), name))
                        return chip;
        }

        return NULL;
}

static int pwm_device_request(struct pwm_device *pwm, const char *label)
{
        int err;
        struct pwm_chip *chip = pwm->chip;
        const struct pwm_ops *ops = chip->ops;

        if (test_bit(PWMF_REQUESTED, &pwm->flags))
                return -EBUSY;

        /*
         * This function is called while holding pwm_lock. As .operational only
         * changes while holding this lock, checking it here without holding the
         * chip lock is fine.
         */
        if (!chip->operational)
                return -ENODEV;

        if (!try_module_get(chip->owner))
                return -ENODEV;

        if (!get_device(&chip->dev)) {
                err = -ENODEV;
                goto err_get_device;
        }

        if (ops->request) {
                err = ops->request(chip, pwm);
                if (err) {
                        put_device(&chip->dev);
err_get_device:
                        module_put(chip->owner);
                        return err;
                }
        }

        if (ops->read_waveform || ops->get_state) {
                /*
                 * Zero-initialize state because most drivers are unaware of
                 * .usage_power. The other members of state are supposed to be
                 * set by lowlevel drivers. We still initialize the whole
                 * structure for simplicity even though this might paper over
                 * faulty implementations of .get_state().
                 */
                struct pwm_state state = { 0, };

                err = pwm_get_state_hw(pwm, &state);
                if (!err)
                        pwm->state = state;

                if (IS_ENABLED(CONFIG_PWM_DEBUG))
                        pwm->last = pwm->state;
        }

        set_bit(PWMF_REQUESTED, &pwm->flags);
        pwm->label = label;

        return 0;
}

/**
 * pwm_request_from_chip() - request a PWM device relative to a PWM chip
 * @chip: PWM chip
 * @index: per-chip index of the PWM to request
 * @label: a literal description string of this PWM
 *
 * Returns: A pointer to the PWM device at the given index of the given PWM
 * chip. A negative error code is returned if the index is not valid for the
 * specified PWM chip or if the PWM device cannot be requested.
 */
static struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
                                                unsigned int index,
                                                const char *label)
{
        struct pwm_device *pwm;
        int err;

        if (!chip || index >= chip->npwm)
                return ERR_PTR(-EINVAL);

        guard(mutex)(&pwm_lock);

        pwm = &chip->pwms[index];

        err = pwm_device_request(pwm, label);
        if (err < 0)
                return ERR_PTR(err);

        return pwm;
}

struct pwm_device *
of_pwm_xlate_with_flags(struct pwm_chip *chip, const struct of_phandle_args *args)
{
        struct pwm_device *pwm;

        /* period in the second cell and flags in the third cell are optional */
        if (args->args_count < 1)
                return ERR_PTR(-EINVAL);

        pwm = pwm_request_from_chip(chip, args->args[0], NULL);
        if (IS_ERR(pwm))
                return pwm;

        if (args->args_count > 1)
                pwm->args.period = args->args[1];

        pwm->args.polarity = PWM_POLARITY_NORMAL;
        if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
                pwm->args.polarity = PWM_POLARITY_INVERSED;

        return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags);

/*
 * This callback is used for PXA PWM chips that only have a single PWM line.
 * For such chips you could argue that passing the line number (i.e. the first
 * parameter in the common case) is useless as it's always zero. So compared to
 * the default xlate function of_pwm_xlate_with_flags() the first parameter is
 * the default period and the second are flags.
 *
 * Note that if #pwm-cells = <3>, the semantic is the same as for
 * of_pwm_xlate_with_flags() to allow converting the affected driver to
 * #pwm-cells = <3> without breaking the legacy binding.
 *
 * Don't use for new drivers.
 */
struct pwm_device *
of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
{
        struct pwm_device *pwm;

        if (args->args_count >= 3)
                return of_pwm_xlate_with_flags(chip, args);

        pwm = pwm_request_from_chip(chip, 0, NULL);
        if (IS_ERR(pwm))
                return pwm;

        if (args->args_count > 0)
                pwm->args.period = args->args[0];

        pwm->args.polarity = PWM_POLARITY_NORMAL;
        if (args->args_count > 1 && args->args[1] & PWM_POLARITY_INVERTED)
                pwm->args.polarity = PWM_POLARITY_INVERSED;

        return pwm;
}
EXPORT_SYMBOL_GPL(of_pwm_single_xlate);

struct pwm_export {
        struct device pwm_dev;
        struct pwm_device *pwm;
        struct mutex lock;
        struct pwm_state suspend;
};

static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev)
{
        return container_of(pwmchip_dev, struct pwm_chip, dev);
}

static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev)
{
        return container_of(pwm_dev, struct pwm_export, pwm_dev);
}

static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);

        return export->pwm;
}

static ssize_t period_show(struct device *pwm_dev,
                           struct device_attribute *attr,
                           char *buf)
{
        const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
        struct pwm_state state;

        pwm_get_state(pwm, &state);

        return sysfs_emit(buf, "%llu\n", state.period);
}

static ssize_t period_store(struct device *pwm_dev,
                            struct device_attribute *attr,
                            const char *buf, size_t size)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);
        struct pwm_device *pwm = export->pwm;
        struct pwm_state state;
        u64 val;
        int ret;

        ret = kstrtou64(buf, 0, &val);
        if (ret)
                return ret;

        guard(mutex)(&export->lock);

        pwm_get_state(pwm, &state);
        state.period = val;
        ret = pwm_apply_might_sleep(pwm, &state);

        return ret ? : size;
}

static ssize_t duty_cycle_show(struct device *pwm_dev,
                               struct device_attribute *attr,
                               char *buf)
{
        const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
        struct pwm_state state;

        pwm_get_state(pwm, &state);

        return sysfs_emit(buf, "%llu\n", state.duty_cycle);
}

static ssize_t duty_cycle_store(struct device *pwm_dev,
                                struct device_attribute *attr,
                                const char *buf, size_t size)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);
        struct pwm_device *pwm = export->pwm;
        struct pwm_state state;
        u64 val;
        int ret;

        ret = kstrtou64(buf, 0, &val);
        if (ret)
                return ret;

        guard(mutex)(&export->lock);

        pwm_get_state(pwm, &state);
        state.duty_cycle = val;
        ret = pwm_apply_might_sleep(pwm, &state);

        return ret ? : size;
}

static ssize_t enable_show(struct device *pwm_dev,
                           struct device_attribute *attr,
                           char *buf)
{
        const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
        struct pwm_state state;

        pwm_get_state(pwm, &state);

        return sysfs_emit(buf, "%d\n", state.enabled);
}

static ssize_t enable_store(struct device *pwm_dev,
                            struct device_attribute *attr,
                            const char *buf, size_t size)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);
        struct pwm_device *pwm = export->pwm;
        struct pwm_state state;
        int val, ret;

        ret = kstrtoint(buf, 0, &val);
        if (ret)
                return ret;

        guard(mutex)(&export->lock);

        pwm_get_state(pwm, &state);

        switch (val) {
        case 0:
                state.enabled = false;
                break;
        case 1:
                state.enabled = true;
                break;
        default:
                return -EINVAL;
        }

        ret = pwm_apply_might_sleep(pwm, &state);

        return ret ? : size;
}

static ssize_t polarity_show(struct device *pwm_dev,
                             struct device_attribute *attr,
                             char *buf)
{
        const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
        const char *polarity = "unknown";
        struct pwm_state state;

        pwm_get_state(pwm, &state);

        switch (state.polarity) {
        case PWM_POLARITY_NORMAL:
                polarity = "normal";
                break;

        case PWM_POLARITY_INVERSED:
                polarity = "inversed";
                break;
        }

        return sysfs_emit(buf, "%s\n", polarity);
}

static ssize_t polarity_store(struct device *pwm_dev,
                              struct device_attribute *attr,
                              const char *buf, size_t size)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);
        struct pwm_device *pwm = export->pwm;
        enum pwm_polarity polarity;
        struct pwm_state state;
        int ret;

        if (sysfs_streq(buf, "normal"))
                polarity = PWM_POLARITY_NORMAL;
        else if (sysfs_streq(buf, "inversed"))
                polarity = PWM_POLARITY_INVERSED;
        else
                return -EINVAL;

        guard(mutex)(&export->lock);

        pwm_get_state(pwm, &state);
        state.polarity = polarity;
        ret = pwm_apply_might_sleep(pwm, &state);

        return ret ? : size;
}

static ssize_t capture_show(struct device *pwm_dev,
                            struct device_attribute *attr,
                            char *buf)
{
        struct pwm_device *pwm = pwm_from_dev(pwm_dev);
        struct pwm_capture result;
        int ret;

        ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
        if (ret)
                return ret;

        return sysfs_emit(buf, "%u %u\n", result.period, result.duty_cycle);
}

static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);
static DEVICE_ATTR_RO(capture);

static struct attribute *pwm_attrs[] = {
        &dev_attr_period.attr,
        &dev_attr_duty_cycle.attr,
        &dev_attr_enable.attr,
        &dev_attr_polarity.attr,
        &dev_attr_capture.attr,
        NULL
};
ATTRIBUTE_GROUPS(pwm);

static void pwm_export_release(struct device *pwm_dev)
{
        struct pwm_export *export = pwmexport_from_dev(pwm_dev);

        kfree(export);
}

static int pwm_export_child(struct device *pwmchip_dev, struct pwm_device *pwm)
{
        struct pwm_export *export;
        char *pwm_prop[2];
        int ret;

        if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
                return -EBUSY;

        export = kzalloc_obj(*export);
        if (!export) {
                clear_bit(PWMF_EXPORTED, &pwm->flags);
                return -ENOMEM;
        }

        export->pwm = pwm;
        mutex_init(&export->lock);

        export->pwm_dev.release = pwm_export_release;
        export->pwm_dev.parent = pwmchip_dev;
        export->pwm_dev.devt = MKDEV(0, 0);
        export->pwm_dev.groups = pwm_groups;
        dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm);

        ret = device_register(&export->pwm_dev);
        if (ret) {
                clear_bit(PWMF_EXPORTED, &pwm->flags);
                put_device(&export->pwm_dev);
                export = NULL;
                return ret;
        }
        pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
        pwm_prop[1] = NULL;
        kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
        kfree(pwm_prop[0]);

        return 0;
}

static int pwm_unexport_match(struct device *pwm_dev, const void *data)
{
        return pwm_from_dev(pwm_dev) == data;
}

static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm)
{
        struct device *pwm_dev;
        char *pwm_prop[2];

        if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
                return -ENODEV;

        pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
        if (!pwm_dev)
                return -ENODEV;

        pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
        pwm_prop[1] = NULL;
        kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
        kfree(pwm_prop[0]);

        /* for device_find_child() */
        put_device(pwm_dev);
        device_unregister(pwm_dev);
        pwm_put(pwm);

        return 0;
}

static ssize_t export_store(struct device *pwmchip_dev,
                            struct device_attribute *attr,
                            const char *buf, size_t len)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
        struct pwm_device *pwm;
        unsigned int hwpwm;
        int ret;

        ret = kstrtouint(buf, 0, &hwpwm);
        if (ret < 0)
                return ret;

        if (hwpwm >= chip->npwm)
                return -ENODEV;

        pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
        if (IS_ERR(pwm))
                return PTR_ERR(pwm);

        ret = pwm_export_child(pwmchip_dev, pwm);
        if (ret < 0)
                pwm_put(pwm);

        return ret ? : len;
}
static DEVICE_ATTR_WO(export);

static ssize_t unexport_store(struct device *pwmchip_dev,
                              struct device_attribute *attr,
                              const char *buf, size_t len)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
        unsigned int hwpwm;
        int ret;

        ret = kstrtouint(buf, 0, &hwpwm);
        if (ret < 0)
                return ret;

        if (hwpwm >= chip->npwm)
                return -ENODEV;

        ret = pwm_unexport_child(pwmchip_dev, &chip->pwms[hwpwm]);

        return ret ? : len;
}
static DEVICE_ATTR_WO(unexport);

static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr,
                         char *buf)
{
        const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);

        return sysfs_emit(buf, "%u\n", chip->npwm);
}
static DEVICE_ATTR_RO(npwm);

static struct attribute *pwm_chip_attrs[] = {
        &dev_attr_export.attr,
        &dev_attr_unexport.attr,
        &dev_attr_npwm.attr,
        NULL,
};
ATTRIBUTE_GROUPS(pwm_chip);

/* takes export->lock on success */
static struct pwm_export *pwm_class_get_state(struct device *pwmchip_dev,
                                              struct pwm_device *pwm,
                                              struct pwm_state *state)
{
        struct device *pwm_dev;
        struct pwm_export *export;

        if (!test_bit(PWMF_EXPORTED, &pwm->flags))
                return NULL;

        pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
        if (!pwm_dev)
                return NULL;

        export = pwmexport_from_dev(pwm_dev);
        put_device(pwm_dev);    /* for device_find_child() */

        mutex_lock(&export->lock);
        pwm_get_state(pwm, state);

        return export;
}

static int pwm_class_apply_state(struct pwm_export *export,
                                 struct pwm_device *pwm,
                                 struct pwm_state *state)
{
        int ret = pwm_apply_might_sleep(pwm, state);

        /* release lock taken in pwm_class_get_state */
        mutex_unlock(&export->lock);

        return ret;
}

static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
        unsigned int i;
        int ret = 0;

        for (i = 0; i < npwm; i++) {
                struct pwm_device *pwm = &chip->pwms[i];
                struct pwm_state state;
                struct pwm_export *export;

                export = pwm_class_get_state(pwmchip_dev, pwm, &state);
                if (!export)
                        continue;

                /* If pwmchip was not enabled before suspend, do nothing. */
                if (!export->suspend.enabled) {
                        /* release lock taken in pwm_class_get_state */
                        mutex_unlock(&export->lock);
                        continue;
                }

                state.enabled = export->suspend.enabled;
                ret = pwm_class_apply_state(export, pwm, &state);
                if (ret < 0)
                        break;
        }

        return ret;
}

static int pwm_class_suspend(struct device *pwmchip_dev)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
        unsigned int i;
        int ret = 0;

        for (i = 0; i < chip->npwm; i++) {
                struct pwm_device *pwm = &chip->pwms[i];
                struct pwm_state state;
                struct pwm_export *export;

                export = pwm_class_get_state(pwmchip_dev, pwm, &state);
                if (!export)
                        continue;

                /*
                 * If pwmchip was not enabled before suspend, save
                 * state for resume time and do nothing else.
                 */
                export->suspend = state;
                if (!state.enabled) {
                        /* release lock taken in pwm_class_get_state */
                        mutex_unlock(&export->lock);
                        continue;
                }

                state.enabled = false;
                ret = pwm_class_apply_state(export, pwm, &state);
                if (ret < 0) {
                        /*
                         * roll back the PWM devices that were disabled by
                         * this suspend function.
                         */
                        pwm_class_resume_npwm(pwmchip_dev, i);
                        break;
                }
        }

        return ret;
}

static int pwm_class_resume(struct device *pwmchip_dev)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);

        return pwm_class_resume_npwm(pwmchip_dev, chip->npwm);
}

static DEFINE_SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);

static struct class pwm_class = {
        .name = "pwm",
        .dev_groups = pwm_chip_groups,
        .pm = pm_sleep_ptr(&pwm_class_pm_ops),
};

static void pwmchip_sysfs_unexport(struct pwm_chip *chip)
{
        unsigned int i;

        for (i = 0; i < chip->npwm; i++) {
                struct pwm_device *pwm = &chip->pwms[i];

                if (test_bit(PWMF_EXPORTED, &pwm->flags))
                        pwm_unexport_child(&chip->dev, pwm);
        }
}

#define PWMCHIP_ALIGN ARCH_DMA_MINALIGN

static void *pwmchip_priv(struct pwm_chip *chip)
{
        return (void *)chip + ALIGN(struct_size(chip, pwms, chip->npwm), PWMCHIP_ALIGN);
}

/* This is the counterpart to pwmchip_alloc() */
void pwmchip_put(struct pwm_chip *chip)
{
        put_device(&chip->dev);
}
EXPORT_SYMBOL_GPL(pwmchip_put);

void pwmchip_release(struct device *pwmchip_dev)
{
        struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);

        kfree(chip);
}
EXPORT_SYMBOL_GPL(pwmchip_release);

struct pwm_chip *pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
        struct pwm_chip *chip;
        struct device *pwmchip_dev;
        size_t alloc_size;
        unsigned int i;

        alloc_size = size_add(ALIGN(struct_size(chip, pwms, npwm), PWMCHIP_ALIGN),
                              sizeof_priv);

        chip = kzalloc(alloc_size, GFP_KERNEL);
        if (!chip)
                return ERR_PTR(-ENOMEM);

        chip->npwm = npwm;
        chip->uses_pwmchip_alloc = true;
        chip->operational = false;

        pwmchip_dev = &chip->dev;
        device_initialize(pwmchip_dev);
        pwmchip_dev->class = &pwm_class;
        pwmchip_dev->parent = parent;
        pwmchip_dev->release = pwmchip_release;

        pwmchip_set_drvdata(chip, pwmchip_priv(chip));

        for (i = 0; i < chip->npwm; i++) {
                struct pwm_device *pwm = &chip->pwms[i];
                pwm->chip = chip;
                pwm->hwpwm = i;
        }

        return chip;
}
EXPORT_SYMBOL_GPL(pwmchip_alloc);

static void devm_pwmchip_put(void *data)
{
        struct pwm_chip *chip = data;

        pwmchip_put(chip);
}

struct pwm_chip *devm_pwmchip_alloc(struct device *parent, unsigned int npwm, size_t sizeof_priv)
{
        struct pwm_chip *chip;
        int ret;

        chip = pwmchip_alloc(parent, npwm, sizeof_priv);
        if (IS_ERR(chip))
                return chip;

        ret = devm_add_action_or_reset(parent, devm_pwmchip_put, chip);
        if (ret)
                return ERR_PTR(ret);

        return chip;
}
EXPORT_SYMBOL_GPL(devm_pwmchip_alloc);

static void of_pwmchip_add(struct pwm_chip *chip)
{
        if (!pwmchip_parent(chip) || !pwmchip_parent(chip)->of_node)
                return;

        if (!chip->of_xlate)
                chip->of_xlate = of_pwm_xlate_with_flags;

        of_node_get(pwmchip_parent(chip)->of_node);
}

static void of_pwmchip_remove(struct pwm_chip *chip)
{
        if (pwmchip_parent(chip))
                of_node_put(pwmchip_parent(chip)->of_node);
}

static bool pwm_ops_check(const struct pwm_chip *chip)
{
        const struct pwm_ops *ops = chip->ops;

        if (ops->write_waveform) {
                if (!ops->round_waveform_tohw ||
                    !ops->round_waveform_fromhw)
                        return false;

                if (PWM_WFHWSIZE < ops->sizeof_wfhw) {
                        dev_warn(pwmchip_parent(chip), "PWM_WFHWSIZE < %zu\n", ops->sizeof_wfhw);
                        return false;
                }
        } else {
                if (!ops->apply)
                        return false;

                if (IS_ENABLED(CONFIG_PWM_DEBUG) && !ops->get_state)
                        dev_warn(pwmchip_parent(chip),
                                 "Please implement the .get_state() callback\n");
        }

        return true;
}

static struct device_link *pwm_device_link_add(struct device *dev,
                                               struct pwm_device *pwm)
{
        struct device_link *dl;

        if (!dev) {
                /*
                 * No device for the PWM consumer has been provided. It may
                 * impact the PM sequence ordering: the PWM supplier may get
                 * suspended before the consumer.
                 */
                dev_warn(pwmchip_parent(pwm->chip),
                         "No consumer device specified to create a link to\n");
                return NULL;
        }

        dl = device_link_add(dev, pwmchip_parent(pwm->chip), DL_FLAG_AUTOREMOVE_CONSUMER);
        if (!dl) {
                dev_err(dev, "failed to create device link to %s\n",
                        dev_name(pwmchip_parent(pwm->chip)));
                return ERR_PTR(-EINVAL);
        }

        return dl;
}

static struct pwm_chip *fwnode_to_pwmchip(struct fwnode_handle *fwnode)
{
        struct pwm_chip *chip;
        unsigned long id, tmp;

        guard(mutex)(&pwm_lock);

        idr_for_each_entry_ul(&pwm_chips, chip, tmp, id)
                if (pwmchip_parent(chip) && device_match_fwnode(pwmchip_parent(chip), fwnode))
                        return chip;

        return ERR_PTR(-EPROBE_DEFER);
}

/**
 * of_pwm_get() - request a PWM via the PWM framework
 * @dev: device for PWM consumer
 * @np: device node to get the PWM from
 * @con_id: consumer name
 *
 * Returns the PWM device parsed from the phandle and index specified in the
 * "pwms" property of a device tree node or a negative error-code on failure.
 * Values parsed from the device tree are stored in the returned PWM device
 * object.
 *
 * If con_id is NULL, the first PWM device listed in the "pwms" property will
 * be requested. Otherwise the "pwm-names" property is used to do a reverse
 * lookup of the PWM index. This also means that the "pwm-names" property
 * becomes mandatory for devices that look up the PWM device via the con_id
 * parameter.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
static struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
                                     const char *con_id)
{
        struct pwm_device *pwm = NULL;
        struct of_phandle_args args;
        struct device_link *dl;
        struct pwm_chip *chip;
        int index = 0;
        int err;

        if (con_id) {
                index = of_property_match_string(np, "pwm-names", con_id);
                if (index < 0)
                        return ERR_PTR(index);
        }

        err = of_parse_phandle_with_args_map(np, "pwms", "pwm", index, &args);
        if (err) {
                pr_err("%s(): can't parse \"pwms\" property\n", __func__);
                return ERR_PTR(err);
        }

        chip = fwnode_to_pwmchip(of_fwnode_handle(args.np));
        if (IS_ERR(chip)) {
                if (PTR_ERR(chip) != -EPROBE_DEFER)
                        pr_err("%s(): PWM chip not found\n", __func__);

                pwm = ERR_CAST(chip);
                goto put;
        }

        pwm = chip->of_xlate(chip, &args);
        if (IS_ERR(pwm))
                goto put;

        dl = pwm_device_link_add(dev, pwm);
        if (IS_ERR(dl)) {
                /* of_xlate ended up calling pwm_request_from_chip() */
                pwm_put(pwm);
                pwm = ERR_CAST(dl);
                goto put;
        }

        /*
         * If a consumer name was not given, try to look it up from the
         * "pwm-names" property if it exists. Otherwise use the name of
         * the user device node.
         */
        if (!con_id) {
                err = of_property_read_string_index(np, "pwm-names", index,
                                                    &con_id);
                if (err < 0)
                        con_id = np->name;
        }

        pwm->label = con_id;

put:
        of_node_put(args.np);

        return pwm;
}

/**
 * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI
 * @fwnode: firmware node to get the "pwms" property from
 *
 * Returns the PWM device parsed from the fwnode and index specified in the
 * "pwms" property or a negative error-code on failure.
 * Values parsed from the device tree are stored in the returned PWM device
 * object.
 *
 * This is analogous to of_pwm_get() except con_id is not yet supported.
 * ACPI entries must look like
 * Package () {"pwms", Package ()
 *     { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
static struct pwm_device *acpi_pwm_get(const struct fwnode_handle *fwnode)
{
        struct pwm_device *pwm;
        struct fwnode_reference_args args;
        struct pwm_chip *chip;
        int ret;

        memset(&args, 0, sizeof(args));

        ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
        if (ret < 0)
                return ERR_PTR(ret);

        if (args.nargs < 2)
                return ERR_PTR(-EPROTO);

        chip = fwnode_to_pwmchip(args.fwnode);
        if (IS_ERR(chip))
                return ERR_CAST(chip);

        pwm = pwm_request_from_chip(chip, args.args[0], NULL);
        if (IS_ERR(pwm))
                return pwm;

        pwm->args.period = args.args[1];
        pwm->args.polarity = PWM_POLARITY_NORMAL;

        if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED)
                pwm->args.polarity = PWM_POLARITY_INVERSED;

        return pwm;
}

static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);

/**
 * pwm_get() - look up and request a PWM device
 * @dev: device for PWM consumer
 * @con_id: consumer name
 *
 * Lookup is first attempted using DT. If the device was not instantiated from
 * a device tree, a PWM chip and a relative index is looked up via a table
 * supplied by board setup code (see pwm_add_table()).
 *
 * Once a PWM chip has been found the specified PWM device will be requested
 * and is ready to be used.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *pwm_get(struct device *dev, const char *con_id)
{
        const struct fwnode_handle *fwnode = dev ? dev_fwnode(dev) : NULL;
        const char *dev_id = dev ? dev_name(dev) : NULL;
        struct pwm_device *pwm;
        struct pwm_chip *chip;
        struct device_link *dl;
        unsigned int best = 0;
        struct pwm_lookup *p, *chosen = NULL;
        unsigned int match;
        int err;

        /* look up via DT first */
        if (is_of_node(fwnode))
                return of_pwm_get(dev, to_of_node(fwnode), con_id);

        /* then lookup via ACPI */
        if (is_acpi_node(fwnode)) {
                pwm = acpi_pwm_get(fwnode);
                if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
                        return pwm;
        }

        /*
         * We look up the provider in the static table typically provided by
         * board setup code. We first try to lookup the consumer device by
         * name. If the consumer device was passed in as NULL or if no match
         * was found, we try to find the consumer by directly looking it up
         * by name.
         *
         * If a match is found, the provider PWM chip is looked up by name
         * and a PWM device is requested using the PWM device per-chip index.
         *
         * The lookup algorithm was shamelessly taken from the clock
         * framework:
         *
         * We do slightly fuzzy matching here:
         *  An entry with a NULL ID is assumed to be a wildcard.
         *  If an entry has a device ID, it must match
         *  If an entry has a connection ID, it must match
         * Then we take the most specific entry - with the following order
         * of precedence: dev+con > dev only > con only.
         */
        scoped_guard(mutex, &pwm_lookup_lock)
                list_for_each_entry(p, &pwm_lookup_list, list) {
                        match = 0;

                        if (p->dev_id) {
                                if (!dev_id || strcmp(p->dev_id, dev_id))
                                        continue;

                                match += 2;
                        }

                        if (p->con_id) {
                                if (!con_id || strcmp(p->con_id, con_id))
                                        continue;

                                match += 1;
                        }

                        if (match > best) {
                                chosen = p;

                                if (match != 3)
                                        best = match;
                                else
                                        break;
                        }
                }

        if (!chosen)
                return ERR_PTR(-ENODEV);

        chip = pwmchip_find_by_name(chosen->provider);

        /*
         * If the lookup entry specifies a module, load the module and retry
         * the PWM chip lookup. This can be used to work around driver load
         * ordering issues if driver's can't be made to properly support the
         * deferred probe mechanism.
         */
        if (!chip && chosen->module) {
                err = request_module(chosen->module);
                if (err == 0)
                        chip = pwmchip_find_by_name(chosen->provider);
        }

        if (!chip)
                return ERR_PTR(-EPROBE_DEFER);

        pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
        if (IS_ERR(pwm))
                return pwm;

        dl = pwm_device_link_add(dev, pwm);
        if (IS_ERR(dl)) {
                pwm_put(pwm);
                return ERR_CAST(dl);
        }

        pwm->args.period = chosen->period;
        pwm->args.polarity = chosen->polarity;

        return pwm;
}
EXPORT_SYMBOL_GPL(pwm_get);

static void __pwm_put(struct pwm_device *pwm)
{
        struct pwm_chip *chip = pwm->chip;

        /*
         * Trigger a warning if a consumer called pwm_put() twice.
         * If the chip isn't operational, PWMF_REQUESTED was already cleared in
         * pwmchip_remove(). So don't warn in this case.
         */
        if (chip->operational && !test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
                pr_warn("PWM device already freed\n");
                return;
        }

        if (chip->operational && chip->ops->free)
                pwm->chip->ops->free(pwm->chip, pwm);

        pwm->label = NULL;

        put_device(&chip->dev);

        module_put(chip->owner);
}

/**
 * pwm_put() - release a PWM device
 * @pwm: PWM device
 */
void pwm_put(struct pwm_device *pwm)
{
        if (!pwm)
                return;

        guard(mutex)(&pwm_lock);

        __pwm_put(pwm);
}
EXPORT_SYMBOL_GPL(pwm_put);

static void devm_pwm_release(void *pwm)
{
        pwm_put(pwm);
}

/**
 * devm_pwm_get() - resource managed pwm_get()
 * @dev: device for PWM consumer
 * @con_id: consumer name
 *
 * This function performs like pwm_get() but the acquired PWM device will
 * automatically be released on driver detach.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
{
        struct pwm_device *pwm;
        int ret;

        pwm = pwm_get(dev, con_id);
        if (IS_ERR(pwm))
                return pwm;

        ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
        if (ret)
                return ERR_PTR(ret);

        return pwm;
}
EXPORT_SYMBOL_GPL(devm_pwm_get);

/**
 * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node
 * @dev: device for PWM consumer
 * @fwnode: firmware node to get the PWM from
 * @con_id: consumer name
 *
 * Returns the PWM device parsed from the firmware node. See of_pwm_get() and
 * acpi_pwm_get() for a detailed description.
 *
 * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
 * error code on failure.
 */
struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
                                       struct fwnode_handle *fwnode,
                                       const char *con_id)
{
        struct pwm_device *pwm = ERR_PTR(-ENODEV);
        int ret;

        if (is_of_node(fwnode))
                pwm = of_pwm_get(dev, to_of_node(fwnode), con_id);
        else if (is_acpi_node(fwnode))
                pwm = acpi_pwm_get(fwnode);
        if (IS_ERR(pwm))
                return pwm;

        ret = devm_add_action_or_reset(dev, devm_pwm_release, pwm);
        if (ret)
                return ERR_PTR(ret);

        return pwm;
}
EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);

struct pwm_cdev_data {
        struct pwm_chip *chip;
        struct pwm_device *pwm[];
};

static int pwm_cdev_open(struct inode *inode, struct file *file)
{
        struct pwm_chip *chip = container_of(inode->i_cdev, struct pwm_chip, cdev);
        struct pwm_cdev_data *cdata;

        guard(mutex)(&pwm_lock);

        if (!chip->operational)
                return -ENXIO;

        cdata = kzalloc_flex(*cdata, pwm, chip->npwm);
        if (!cdata)
                return -ENOMEM;

        cdata->chip = chip;

        file->private_data = cdata;

        return nonseekable_open(inode, file);
}

static int pwm_cdev_release(struct inode *inode, struct file *file)
{
        struct pwm_cdev_data *cdata = file->private_data;
        unsigned int i;

        for (i = 0; i < cdata->chip->npwm; ++i) {
                struct pwm_device *pwm = cdata->pwm[i];

                if (pwm) {
                        const char *label = pwm->label;

                        pwm_put(cdata->pwm[i]);
                        kfree(label);
                }
        }
        kfree(cdata);

        return 0;
}

static int pwm_cdev_request(struct pwm_cdev_data *cdata, unsigned int hwpwm)
{
        struct pwm_chip *chip = cdata->chip;

        if (hwpwm >= chip->npwm)
                return -EINVAL;

        if (!cdata->pwm[hwpwm]) {
                struct pwm_device *pwm = &chip->pwms[hwpwm];
                const char *label;
                int ret;

                label = kasprintf(GFP_KERNEL, "pwm-cdev (pid=%d)", current->pid);
                if (!label)
                        return -ENOMEM;

                ret = pwm_device_request(pwm, label);
                if (ret < 0) {
                        kfree(label);
                        return ret;
                }

                cdata->pwm[hwpwm] = pwm;
        }

        return 0;
}

static int pwm_cdev_free(struct pwm_cdev_data *cdata, unsigned int hwpwm)
{
        struct pwm_chip *chip = cdata->chip;

        if (hwpwm >= chip->npwm)
                return -EINVAL;

        if (cdata->pwm[hwpwm]) {
                struct pwm_device *pwm = cdata->pwm[hwpwm];
                const char *label = pwm->label;

                __pwm_put(pwm);

                kfree(label);

                cdata->pwm[hwpwm] = NULL;
        }

        return 0;
}

static struct pwm_device *pwm_cdev_get_requested_pwm(struct pwm_cdev_data *cdata,
                                                     u32 hwpwm)
{
        struct pwm_chip *chip = cdata->chip;

        if (hwpwm >= chip->npwm)
                return ERR_PTR(-EINVAL);

        if (cdata->pwm[hwpwm])
                return cdata->pwm[hwpwm];

        return ERR_PTR(-EINVAL);
}

static long pwm_cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        int ret = 0;
        struct pwm_cdev_data *cdata = file->private_data;
        struct pwm_chip *chip = cdata->chip;

        guard(mutex)(&pwm_lock);

        if (!chip->operational)
                return -ENODEV;

        switch (cmd) {
        case PWM_IOCTL_REQUEST:
                {
                        unsigned int hwpwm = arg;

                        return pwm_cdev_request(cdata, hwpwm);
                }

        case PWM_IOCTL_FREE:
                {
                        unsigned int hwpwm = arg;

                        return pwm_cdev_free(cdata, hwpwm);
                }

        case PWM_IOCTL_ROUNDWF:
                {
                        struct pwmchip_waveform cwf;
                        struct pwm_waveform wf;
                        struct pwm_device *pwm;

                        ret = copy_from_user(&cwf,
                                             (struct pwmchip_waveform __user *)arg,
                                             sizeof(cwf));
                        if (ret)
                                return -EFAULT;

                        if (cwf.__pad != 0)
                                return -EINVAL;

                        pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm);
                        if (IS_ERR(pwm))
                                return PTR_ERR(pwm);

                        wf = (struct pwm_waveform) {
                                .period_length_ns = cwf.period_length_ns,
                                .duty_length_ns = cwf.duty_length_ns,
                                .duty_offset_ns = cwf.duty_offset_ns,
                        };

                        ret = pwm_round_waveform_might_sleep(pwm, &wf);
                        if (ret < 0)
                                return ret;

                        cwf = (struct pwmchip_waveform) {
                                .hwpwm = cwf.hwpwm,
                                .period_length_ns = wf.period_length_ns,
                                .duty_length_ns = wf.duty_length_ns,
                                .duty_offset_ns = wf.duty_offset_ns,
                        };

                        ret = copy_to_user((struct pwmchip_waveform __user *)arg,
                                           &cwf, sizeof(cwf));
                        return ret ? -EFAULT : 0;
                }

        case PWM_IOCTL_GETWF:
                {
                        struct pwmchip_waveform cwf;
                        struct pwm_waveform wf;
                        struct pwm_device *pwm;

                        ret = copy_from_user(&cwf,
                                             (struct pwmchip_waveform __user *)arg,
                                             sizeof(cwf));
                        if (ret)
                                return -EFAULT;

                        if (cwf.__pad != 0)
                                return -EINVAL;

                        pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm);
                        if (IS_ERR(pwm))
                                return PTR_ERR(pwm);

                        ret = pwm_get_waveform_might_sleep(pwm, &wf);
                        if (ret)
                                return ret;

                        cwf = (struct pwmchip_waveform) {
                                .hwpwm = cwf.hwpwm,
                                .period_length_ns = wf.period_length_ns,
                                .duty_length_ns = wf.duty_length_ns,
                                .duty_offset_ns = wf.duty_offset_ns,
                        };

                        ret = copy_to_user((struct pwmchip_waveform __user *)arg,
                                           &cwf, sizeof(cwf));
                        return ret ? -EFAULT : 0;
                }

        case PWM_IOCTL_SETROUNDEDWF:
        case PWM_IOCTL_SETEXACTWF:
                {
                        struct pwmchip_waveform cwf;
                        struct pwm_waveform wf;
                        struct pwm_device *pwm;

                        ret = copy_from_user(&cwf,
                                             (struct pwmchip_waveform __user *)arg,
                                             sizeof(cwf));
                        if (ret)
                                return -EFAULT;

                        if (cwf.__pad != 0)
                                return -EINVAL;

                        wf = (struct pwm_waveform){
                                .period_length_ns = cwf.period_length_ns,
                                .duty_length_ns = cwf.duty_length_ns,
                                .duty_offset_ns = cwf.duty_offset_ns,
                        };

                        if (!pwm_wf_valid(&wf))
                                return -EINVAL;

                        pwm = pwm_cdev_get_requested_pwm(cdata, cwf.hwpwm);
                        if (IS_ERR(pwm))
                                return PTR_ERR(pwm);

                        ret = pwm_set_waveform_might_sleep(pwm, &wf,
                                                           cmd == PWM_IOCTL_SETEXACTWF);

                        /*
                         * If userspace cares about rounding deviations it has
                         * to check the values anyhow, so simplify handling for
                         * them and don't signal uprounding. This matches the
                         * behaviour of PWM_IOCTL_ROUNDWF which also returns 0
                         * in that case.
                         */
                        if (ret == 1)
                                ret = 0;

                        return ret;
                }

        default:
                return -ENOTTY;
        }
}

static const struct file_operations pwm_cdev_fileops = {
        .open = pwm_cdev_open,
        .release = pwm_cdev_release,
        .owner = THIS_MODULE,
        .unlocked_ioctl = pwm_cdev_ioctl,
};

static dev_t pwm_devt;

static int pwm_gpio_request(struct gpio_chip *gc, unsigned int offset)
{
        struct pwm_chip *chip = gpiochip_get_data(gc);
        struct pwm_device *pwm;

        pwm = pwm_request_from_chip(chip, offset, "pwm-gpio");
        if (IS_ERR(pwm))
                return PTR_ERR(pwm);

        return 0;
}

static void pwm_gpio_free(struct gpio_chip *gc, unsigned int offset)
{
        struct pwm_chip *chip = gpiochip_get_data(gc);

        pwm_put(&chip->pwms[offset]);
}

static int pwm_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
{
        return GPIO_LINE_DIRECTION_OUT;
}

static int pwm_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
{
        struct pwm_chip *chip = gpiochip_get_data(gc);
        struct pwm_device *pwm = &chip->pwms[offset];
        int ret;
        struct pwm_waveform wf = {
                .period_length_ns = 1,
        };

        ret = pwm_round_waveform_might_sleep(pwm, &wf);
        if (ret < 0)
                return ret;

        if (value)
                wf.duty_length_ns = wf.period_length_ns;
        else
                wf.duty_length_ns = 0;

        return pwm_set_waveform_might_sleep(pwm, &wf, true);
}

/**
 * __pwmchip_add() - register a new PWM chip
 * @chip: the PWM chip to add
 * @owner: reference to the module providing the chip.
 *
 * Register a new PWM chip. @owner is supposed to be THIS_MODULE, use the
 * pwmchip_add wrapper to do this right.
 *
 * Returns: 0 on success or a negative error code on failure.
 */
int __pwmchip_add(struct pwm_chip *chip, struct module *owner)
{
        int ret;

        if (!chip || !pwmchip_parent(chip) || !chip->ops || !chip->npwm)
                return -EINVAL;

        /*
         * a struct pwm_chip must be allocated using (devm_)pwmchip_alloc,
         * otherwise the embedded struct device might disappear too early
         * resulting in memory corruption.
         * Catch drivers that were not converted appropriately.
         */
        if (!chip->uses_pwmchip_alloc)
                return -EINVAL;

        if (!pwm_ops_check(chip))
                return -EINVAL;

        chip->owner = owner;

        if (chip->atomic)
                spin_lock_init(&chip->atomic_lock);
        else
                mutex_init(&chip->nonatomic_lock);

        guard(mutex)(&pwm_lock);

        ret = idr_alloc(&pwm_chips, chip, 0, 0, GFP_KERNEL);
        if (ret < 0)
                return ret;

        chip->id = ret;

        dev_set_name(&chip->dev, "pwmchip%u", chip->id);

        if (IS_ENABLED(CONFIG_OF))
                of_pwmchip_add(chip);

        scoped_guard(pwmchip, chip)
                chip->operational = true;

        if (chip->ops->write_waveform) {
                if (chip->id < PWM_MINOR_COUNT)
                        chip->dev.devt = MKDEV(MAJOR(pwm_devt), chip->id);
                else
                        dev_warn(&chip->dev, "chip id too high to create a chardev\n");
        }

        cdev_init(&chip->cdev, &pwm_cdev_fileops);
        chip->cdev.owner = owner;

        ret = cdev_device_add(&chip->cdev, &chip->dev);
        if (ret)
                goto err_device_add;

        if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform) {
                struct device *parent = pwmchip_parent(chip);

                chip->gpio = (typeof(chip->gpio)){
                        .label = dev_name(parent),
                        .parent = parent,
                        .request = pwm_gpio_request,
                        .free = pwm_gpio_free,
                        .get_direction = pwm_gpio_get_direction,
                        .set = pwm_gpio_set,
                        .base = -1,
                        .ngpio = chip->npwm,
                        .can_sleep = true,
                };

                ret = gpiochip_add_data(&chip->gpio, chip);
                if (ret)
                        goto err_gpiochip_add;
        }

        return 0;

err_gpiochip_add:

        cdev_device_del(&chip->cdev, &chip->dev);
err_device_add:

        scoped_guard(pwmchip, chip)
                chip->operational = false;

        if (IS_ENABLED(CONFIG_OF))
                of_pwmchip_remove(chip);

        idr_remove(&pwm_chips, chip->id);

        return ret;
}
EXPORT_SYMBOL_GPL(__pwmchip_add);

/**
 * pwmchip_remove() - remove a PWM chip
 * @chip: the PWM chip to remove
 *
 * Removes a PWM chip.
 */
void pwmchip_remove(struct pwm_chip *chip)
{
        if (IS_ENABLED(CONFIG_PWM_PROVIDE_GPIO) && chip->ops->write_waveform)
                gpiochip_remove(&chip->gpio);

        pwmchip_sysfs_unexport(chip);

        scoped_guard(mutex, &pwm_lock) {
                unsigned int i;

                scoped_guard(pwmchip, chip)
                        chip->operational = false;

                for (i = 0; i < chip->npwm; ++i) {
                        struct pwm_device *pwm = &chip->pwms[i];

                        if (test_and_clear_bit(PWMF_REQUESTED, &pwm->flags)) {
                                dev_warn(&chip->dev, "Freeing requested PWM #%u\n", i);
                                if (pwm->chip->ops->free)
                                        pwm->chip->ops->free(pwm->chip, pwm);
                        }
                }

                if (IS_ENABLED(CONFIG_OF))
                        of_pwmchip_remove(chip);

                idr_remove(&pwm_chips, chip->id);
        }

        cdev_device_del(&chip->cdev, &chip->dev);
}
EXPORT_SYMBOL_GPL(pwmchip_remove);

static void devm_pwmchip_remove(void *data)
{
        struct pwm_chip *chip = data;

        pwmchip_remove(chip);
}

int __devm_pwmchip_add(struct device *dev, struct pwm_chip *chip, struct module *owner)
{
        int ret;

        ret = __pwmchip_add(chip, owner);
        if (ret)
                return ret;

        return devm_add_action_or_reset(dev, devm_pwmchip_remove, chip);
}
EXPORT_SYMBOL_GPL(__devm_pwmchip_add);

/**
 * pwm_add_table() - register PWM device consumers
 * @table: array of consumers to register
 * @num: number of consumers in table
 */
void pwm_add_table(struct pwm_lookup *table, size_t num)
{
        guard(mutex)(&pwm_lookup_lock);

        while (num--) {
                list_add_tail(&table->list, &pwm_lookup_list);
                table++;
        }
}

/**
 * pwm_remove_table() - unregister PWM device consumers
 * @table: array of consumers to unregister
 * @num: number of consumers in table
 */
void pwm_remove_table(struct pwm_lookup *table, size_t num)
{
        guard(mutex)(&pwm_lookup_lock);

        while (num--) {
                list_del(&table->list);
                table++;
        }
}

static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
{
        unsigned int i;

        for (i = 0; i < chip->npwm; i++) {
                struct pwm_device *pwm = &chip->pwms[i];
                struct pwm_state state;
                int err;

                pwm_get_state(pwm, &state);

                seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);

                if (test_bit(PWMF_REQUESTED, &pwm->flags))
                        seq_puts(s, " requested");

                seq_puts(s, "\n");

                seq_printf(s, "  requested configuration: %3sabled, %llu/%llu ns, %s polarity",
                           state.enabled ? "en" : "dis", state.duty_cycle, state.period,
                           state.polarity ? "inverse" : "normal");
                if (state.usage_power)
                        seq_puts(s, ", usage_power");
                seq_puts(s, "\n");

                if (pwmchip_supports_waveform(chip)) {
                        struct pwm_waveform wf;

                        err = pwm_get_waveform_might_sleep(pwm, &wf);
                        if (!err)
                                seq_printf(s, "  actual configuration: %lld/%lld [+%lld]",
                                           wf.duty_length_ns, wf.period_length_ns, wf.duty_offset_ns);
                        else
                                seq_printf(s, "  actual configuration: read out error: %pe\n", ERR_PTR(err));
                } else {
                        struct pwm_state hwstate;

                        err = pwm_get_state_hw(pwm, &hwstate);
                        if (!err)
                                seq_printf(s, "  actual configuration:    %3sabled, %llu/%llu ns, %s polarity",
                                           hwstate.enabled ? "en" : "dis", hwstate.duty_cycle, hwstate.period,
                                           hwstate.polarity ? "inverse" : "normal");
                        else
                                seq_printf(s, "  actual configuration: read out error: %pe", ERR_PTR(err));
                }

                seq_puts(s, "\n");
        }
}

static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
{
        unsigned long id = *pos;
        void *ret;

        mutex_lock(&pwm_lock);
        s->private = "";

        ret = idr_get_next_ul(&pwm_chips, &id);
        *pos = id;
        return ret;
}

static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
        unsigned long id = *pos + 1;
        void *ret;

        s->private = "\n";

        ret = idr_get_next_ul(&pwm_chips, &id);
        *pos = id;
        return ret;
}

static void pwm_seq_stop(struct seq_file *s, void *v)
{
        mutex_unlock(&pwm_lock);
}

static int pwm_seq_show(struct seq_file *s, void *v)
{
        struct pwm_chip *chip = v;

        seq_printf(s, "%s%u: %s/%s, npwm: %u\n",
                   (char *)s->private, chip->id,
                   pwmchip_parent(chip)->bus ? pwmchip_parent(chip)->bus->name : "no-bus",
                   dev_name(pwmchip_parent(chip)), chip->npwm);

        pwm_dbg_show(chip, s);

        return 0;
}

static const struct seq_operations pwm_debugfs_sops = {
        .start = pwm_seq_start,
        .next = pwm_seq_next,
        .stop = pwm_seq_stop,
        .show = pwm_seq_show,
};

DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);

static int __init pwm_init(void)
{
        int ret;

        ret = alloc_chrdev_region(&pwm_devt, 0, PWM_MINOR_COUNT, "pwm");
        if (ret) {
                pr_err("Failed to initialize chrdev region for PWM usage\n");
                return ret;
        }

        ret = class_register(&pwm_class);
        if (ret) {
                pr_err("Failed to initialize PWM class (%pe)\n", ERR_PTR(ret));
                unregister_chrdev_region(pwm_devt, 256);
                return ret;
        }

        if (IS_ENABLED(CONFIG_DEBUG_FS))
                debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);

        return 0;
}
subsys_initcall(pwm_init);