root/drivers/iio/dac/ad5592r-base.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AD5592R Digital <-> Analog converters driver
 *
 * Copyright 2014-2016 Analog Devices Inc.
 * Author: Paul Cercueil <paul.cercueil@analog.com>
 */

#include <linux/bitops.h>
#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/property.h>

#include <dt-bindings/iio/adi,ad5592r.h>

#include "ad5592r-base.h"

static int ad5592r_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct ad5592r_state *st = gpiochip_get_data(chip);
        int ret = 0;
        u8 val = 0;

        scoped_guard(mutex, &st->gpio_lock) {
                if (st->gpio_out & BIT(offset))
                        val = st->gpio_val;
                else
                        ret = st->ops->gpio_read(st, &val);
        }

        if (ret < 0)
                return ret;

        return !!(val & BIT(offset));
}

static int ad5592r_gpio_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        struct ad5592r_state *st = gpiochip_get_data(chip);

        guard(mutex)(&st->gpio_lock);

        if (value)
                st->gpio_val |= BIT(offset);
        else
                st->gpio_val &= ~BIT(offset);

        return st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
}

static int ad5592r_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
        struct ad5592r_state *st = gpiochip_get_data(chip);
        int ret;

        guard(mutex)(&st->gpio_lock);

        st->gpio_out &= ~BIT(offset);
        st->gpio_in |= BIT(offset);

        ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
        if (ret < 0)
                return ret;

        return st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
}

static int ad5592r_gpio_direction_output(struct gpio_chip *chip,
                                         unsigned offset, int value)
{
        struct ad5592r_state *st = gpiochip_get_data(chip);
        int ret;

        guard(mutex)(&st->gpio_lock);

        if (value)
                st->gpio_val |= BIT(offset);
        else
                st->gpio_val &= ~BIT(offset);

        st->gpio_in &= ~BIT(offset);
        st->gpio_out |= BIT(offset);

        ret = st->ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
        if (ret < 0)
                return ret;

        ret = st->ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
        if (ret < 0)
                return ret;

        return st->ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
}

static int ad5592r_gpio_request(struct gpio_chip *chip, unsigned offset)
{
        struct ad5592r_state *st = gpiochip_get_data(chip);

        if (!(st->gpio_map & BIT(offset))) {
                dev_err(st->dev, "GPIO %d is reserved by alternate function\n",
                        offset);
                return -ENODEV;
        }

        return 0;
}

static const char * const ad5592r_gpio_names[] = {
        "GPIO0", "GPIO1", "GPIO2", "GPIO3", "GPIO4", "GPIO5", "GPIO6", "GPIO7",
};

static int ad5592r_gpio_init(struct ad5592r_state *st)
{
        if (!st->gpio_map)
                return 0;

        st->gpiochip.label = dev_name(st->dev);
        st->gpiochip.base = -1;
        st->gpiochip.ngpio = 8;
        st->gpiochip.parent = st->dev;
        st->gpiochip.can_sleep = true;
        st->gpiochip.direction_input = ad5592r_gpio_direction_input;
        st->gpiochip.direction_output = ad5592r_gpio_direction_output;
        st->gpiochip.get = ad5592r_gpio_get;
        st->gpiochip.set = ad5592r_gpio_set;
        st->gpiochip.request = ad5592r_gpio_request;
        st->gpiochip.owner = THIS_MODULE;
        st->gpiochip.names = ad5592r_gpio_names;

        mutex_init(&st->gpio_lock);

        return gpiochip_add_data(&st->gpiochip, st);
}

static void ad5592r_gpio_cleanup(struct ad5592r_state *st)
{
        if (st->gpio_map)
                gpiochip_remove(&st->gpiochip);

        mutex_destroy(&st->gpio_lock);
}

static int ad5592r_reset(struct ad5592r_state *st)
{
        struct gpio_desc *gpio;

        gpio = devm_gpiod_get_optional(st->dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(gpio))
                return PTR_ERR(gpio);

        if (gpio) {
                udelay(1);
                gpiod_set_value(gpio, 1);
        } else {
                scoped_guard(mutex, &st->lock)
                        /* Writing this magic value resets the device */
                        st->ops->reg_write(st, AD5592R_REG_RESET, 0xdac);
        }

        udelay(250);

        return 0;
}

static int ad5592r_get_vref(struct ad5592r_state *st)
{
        int ret;

        if (st->reg) {
                ret = regulator_get_voltage(st->reg);
                if (ret < 0)
                        return ret;

                return ret / 1000;
        } else {
                return 2500;
        }
}

static int ad5592r_set_channel_modes(struct ad5592r_state *st)
{
        const struct ad5592r_rw_ops *ops = st->ops;
        int ret;
        unsigned i;
        u8 pulldown = 0, tristate = 0, dac = 0, adc = 0;
        u16 read_back;

        for (i = 0; i < st->num_channels; i++) {
                switch (st->channel_modes[i]) {
                case CH_MODE_DAC:
                        dac |= BIT(i);
                        break;

                case CH_MODE_ADC:
                        adc |= BIT(i);
                        break;

                case CH_MODE_DAC_AND_ADC:
                        dac |= BIT(i);
                        adc |= BIT(i);
                        break;

                case CH_MODE_GPIO:
                        st->gpio_map |= BIT(i);
                        st->gpio_in |= BIT(i); /* Default to input */
                        break;

                case CH_MODE_UNUSED:
                default:
                        switch (st->channel_offstate[i]) {
                        case CH_OFFSTATE_OUT_TRISTATE:
                                tristate |= BIT(i);
                                break;

                        case CH_OFFSTATE_OUT_LOW:
                                st->gpio_out |= BIT(i);
                                break;

                        case CH_OFFSTATE_OUT_HIGH:
                                st->gpio_out |= BIT(i);
                                st->gpio_val |= BIT(i);
                                break;

                        case CH_OFFSTATE_PULLDOWN:
                        default:
                                pulldown |= BIT(i);
                                break;
                        }
                }
        }

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

        /* Pull down unused pins to GND */
        ret = ops->reg_write(st, AD5592R_REG_PULLDOWN, pulldown);
        if (ret)
                return ret;

        ret = ops->reg_write(st, AD5592R_REG_TRISTATE, tristate);
        if (ret)
                return ret;

        /* Configure pins that we use */
        ret = ops->reg_write(st, AD5592R_REG_DAC_EN, dac);
        if (ret)
                return ret;

        ret = ops->reg_write(st, AD5592R_REG_ADC_EN, adc);
        if (ret)
                return ret;

        ret = ops->reg_write(st, AD5592R_REG_GPIO_SET, st->gpio_val);
        if (ret)
                return ret;

        ret = ops->reg_write(st, AD5592R_REG_GPIO_OUT_EN, st->gpio_out);
        if (ret)
                return ret;

        ret = ops->reg_write(st, AD5592R_REG_GPIO_IN_EN, st->gpio_in);
        if (ret)
                return ret;

        /* Verify that we can read back at least one register */
        ret = ops->reg_read(st, AD5592R_REG_ADC_EN, &read_back);
        if (!ret && (read_back & 0xff) != adc)
                return -EIO;

        return 0;
}

static int ad5592r_reset_channel_modes(struct ad5592r_state *st)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(st->channel_modes); i++)
                st->channel_modes[i] = CH_MODE_UNUSED;

        return ad5592r_set_channel_modes(st);
}

static int ad5592r_write_raw(struct iio_dev *iio_dev,
        struct iio_chan_spec const *chan, int val, int val2, long mask)
{
        struct ad5592r_state *st = iio_priv(iio_dev);
        int ret = 0;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:

                if (val >= (1 << chan->scan_type.realbits) || val < 0)
                        return -EINVAL;

                if (!chan->output)
                        return -EINVAL;

                scoped_guard(mutex, &st->lock) {
                        ret = st->ops->write_dac(st, chan->channel, val);
                        if (!ret)
                                st->cached_dac[chan->channel] = val;
                }
                return ret;
        case IIO_CHAN_INFO_SCALE:
                if (chan->type == IIO_VOLTAGE) {
                        bool gain;

                        if (val == st->scale_avail[0][0] &&
                                val2 == st->scale_avail[0][1])
                                gain = false;
                        else if (val == st->scale_avail[1][0] &&
                                 val2 == st->scale_avail[1][1])
                                gain = true;
                        else
                                return -EINVAL;

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

                        ret = st->ops->reg_read(st, AD5592R_REG_CTRL,
                                                &st->cached_gp_ctrl);
                        if (ret < 0)
                                return ret;

                        if (chan->output) {
                                if (gain)
                                        st->cached_gp_ctrl |=
                                                AD5592R_REG_CTRL_DAC_RANGE;
                                else
                                        st->cached_gp_ctrl &=
                                                ~AD5592R_REG_CTRL_DAC_RANGE;
                        } else {
                                if (gain)
                                        st->cached_gp_ctrl |=
                                                AD5592R_REG_CTRL_ADC_RANGE;
                                else
                                        st->cached_gp_ctrl &=
                                                ~AD5592R_REG_CTRL_ADC_RANGE;
                        }

                        return st->ops->reg_write(st, AD5592R_REG_CTRL,
                                                  st->cached_gp_ctrl);
                }
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int ad5592r_read_raw(struct iio_dev *iio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long m)
{
        struct ad5592r_state *st = iio_priv(iio_dev);
        u16 read_val = 0;
        int ret = 0, mult = 0;

        switch (m) {
        case IIO_CHAN_INFO_RAW:
                if (!chan->output) {
                        scoped_guard(mutex, &st->lock)
                                ret = st->ops->read_adc(st, chan->channel,
                                                        &read_val);
                        if (ret)
                                return ret;

                        if ((read_val >> 12 & 0x7) != (chan->channel & 0x7)) {
                                dev_err(st->dev, "Error while reading channel %u\n",
                                                chan->channel);
                                return -EIO;
                        }

                        read_val &= GENMASK(11, 0);

                } else {
                        scoped_guard(mutex, &st->lock)
                                read_val = st->cached_dac[chan->channel];
                }

                dev_dbg(st->dev, "Channel %u read: 0x%04hX\n",
                                chan->channel, read_val);

                *val = (int) read_val;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = ad5592r_get_vref(st);

                if (chan->type == IIO_TEMP) {
                        s64 tmp = *val * (3767897513LL / 25LL);
                        *val = div_s64_rem(tmp, 1000000000LL, val2);

                        return IIO_VAL_INT_PLUS_NANO;
                }

                scoped_guard(mutex, &st->lock) {
                        if (chan->output)
                                mult = !!(st->cached_gp_ctrl &
                                        AD5592R_REG_CTRL_DAC_RANGE);
                        else
                                mult = !!(st->cached_gp_ctrl &
                                        AD5592R_REG_CTRL_ADC_RANGE);
                }

                *val *= ++mult;

                *val2 = chan->scan_type.realbits;

                return IIO_VAL_FRACTIONAL_LOG2;
        case IIO_CHAN_INFO_OFFSET: {
                ret = ad5592r_get_vref(st);

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

                if (st->cached_gp_ctrl & AD5592R_REG_CTRL_ADC_RANGE)
                        *val = (-34365 * 25) / ret;
                else
                        *val = (-75365 * 25) / ret;

                return IIO_VAL_INT;
        }
        default:
                return -EINVAL;
        }
}

static int ad5592r_write_raw_get_fmt(struct iio_dev *indio_dev,
                                 struct iio_chan_spec const *chan, long mask)
{
        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                return IIO_VAL_INT_PLUS_NANO;

        default:
                return IIO_VAL_INT_PLUS_MICRO;
        }

        return -EINVAL;
}

static const struct iio_info ad5592r_info = {
        .read_raw = ad5592r_read_raw,
        .write_raw = ad5592r_write_raw,
        .write_raw_get_fmt = ad5592r_write_raw_get_fmt,
};

static ssize_t ad5592r_show_scale_available(struct iio_dev *iio_dev,
                                           uintptr_t private,
                                           const struct iio_chan_spec *chan,
                                           char *buf)
{
        struct ad5592r_state *st = iio_priv(iio_dev);

        return sprintf(buf, "%d.%09u %d.%09u\n",
                st->scale_avail[0][0], st->scale_avail[0][1],
                st->scale_avail[1][0], st->scale_avail[1][1]);
}

static const struct iio_chan_spec_ext_info ad5592r_ext_info[] = {
        {
         .name = "scale_available",
         .read = ad5592r_show_scale_available,
         .shared = IIO_SHARED_BY_TYPE,
         },
        { }
};

static void ad5592r_setup_channel(struct iio_dev *iio_dev,
                struct iio_chan_spec *chan, bool output, unsigned id)
{
        chan->type = IIO_VOLTAGE;
        chan->indexed = 1;
        chan->output = output;
        chan->channel = id;
        chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
        chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
        chan->scan_type.sign = 'u';
        chan->scan_type.realbits = 12;
        chan->scan_type.storagebits = 16;
        chan->ext_info = ad5592r_ext_info;
}

static int ad5592r_alloc_channels(struct iio_dev *iio_dev)
{
        struct ad5592r_state *st = iio_priv(iio_dev);
        unsigned i, curr_channel = 0,
                 num_channels = st->num_channels;
        struct iio_chan_spec *channels;
        struct fwnode_handle *child;
        u32 reg, tmp;
        int ret;

        device_for_each_child_node(st->dev, child) {
                ret = fwnode_property_read_u32(child, "reg", &reg);
                if (ret || reg >= ARRAY_SIZE(st->channel_modes))
                        continue;

                ret = fwnode_property_read_u32(child, "adi,mode", &tmp);
                if (!ret)
                        st->channel_modes[reg] = tmp;

                ret = fwnode_property_read_u32(child, "adi,off-state", &tmp);
                if (!ret)
                        st->channel_offstate[reg] = tmp;
        }

        channels = devm_kcalloc(st->dev,
                        1 + 2 * num_channels, sizeof(*channels),
                        GFP_KERNEL);
        if (!channels)
                return -ENOMEM;

        for (i = 0; i < num_channels; i++) {
                switch (st->channel_modes[i]) {
                case CH_MODE_DAC:
                        ad5592r_setup_channel(iio_dev, &channels[curr_channel],
                                        true, i);
                        curr_channel++;
                        break;

                case CH_MODE_ADC:
                        ad5592r_setup_channel(iio_dev, &channels[curr_channel],
                                        false, i);
                        curr_channel++;
                        break;

                case CH_MODE_DAC_AND_ADC:
                        ad5592r_setup_channel(iio_dev, &channels[curr_channel],
                                        true, i);
                        curr_channel++;
                        ad5592r_setup_channel(iio_dev, &channels[curr_channel],
                                        false, i);
                        curr_channel++;
                        break;

                default:
                        continue;
                }
        }

        channels[curr_channel].type = IIO_TEMP;
        channels[curr_channel].channel = 8;
        channels[curr_channel].info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
                                   BIT(IIO_CHAN_INFO_SCALE) |
                                   BIT(IIO_CHAN_INFO_OFFSET);
        curr_channel++;

        iio_dev->num_channels = curr_channel;
        iio_dev->channels = channels;

        return 0;
}

static void ad5592r_init_scales(struct ad5592r_state *st, int vref_mV)
{
        s64 tmp = (s64)vref_mV * 1000000000LL >> 12;

        st->scale_avail[0][0] =
                div_s64_rem(tmp, 1000000000LL, &st->scale_avail[0][1]);
        st->scale_avail[1][0] =
                div_s64_rem(tmp * 2, 1000000000LL, &st->scale_avail[1][1]);
}

int ad5592r_probe(struct device *dev, const char *name,
                const struct ad5592r_rw_ops *ops)
{
        struct iio_dev *iio_dev;
        struct ad5592r_state *st;
        int ret;

        iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
        if (!iio_dev)
                return -ENOMEM;

        st = iio_priv(iio_dev);
        st->dev = dev;
        st->ops = ops;
        st->num_channels = 8;
        dev_set_drvdata(dev, iio_dev);

        ret = devm_mutex_init(dev, &st->lock);
        if (ret)
                return ret;

        st->reg = devm_regulator_get_optional(dev, "vref");
        if (IS_ERR(st->reg)) {
                if ((PTR_ERR(st->reg) != -ENODEV) && dev_fwnode(dev))
                        return PTR_ERR(st->reg);

                st->reg = NULL;
        } else {
                ret = regulator_enable(st->reg);
                if (ret)
                        return ret;
        }

        iio_dev->name = name;
        iio_dev->info = &ad5592r_info;
        iio_dev->modes = INDIO_DIRECT_MODE;

        ad5592r_init_scales(st, ad5592r_get_vref(st));

        ret = ad5592r_reset(st);
        if (ret)
                goto error_disable_reg;

        ret = ops->reg_write(st, AD5592R_REG_PD,
                     (st->reg == NULL) ? AD5592R_REG_PD_EN_REF : 0);
        if (ret)
                goto error_disable_reg;

        ret = ad5592r_alloc_channels(iio_dev);
        if (ret)
                goto error_disable_reg;

        ret = ad5592r_set_channel_modes(st);
        if (ret)
                goto error_reset_ch_modes;

        ret = iio_device_register(iio_dev);
        if (ret)
                goto error_reset_ch_modes;

        ret = ad5592r_gpio_init(st);
        if (ret)
                goto error_dev_unregister;

        return 0;

error_dev_unregister:
        iio_device_unregister(iio_dev);

error_reset_ch_modes:
        ad5592r_reset_channel_modes(st);

error_disable_reg:
        if (st->reg)
                regulator_disable(st->reg);

        return ret;
}
EXPORT_SYMBOL_NS_GPL(ad5592r_probe, "IIO_AD5592R");

void ad5592r_remove(struct device *dev)
{
        struct iio_dev *iio_dev = dev_get_drvdata(dev);
        struct ad5592r_state *st = iio_priv(iio_dev);

        iio_device_unregister(iio_dev);
        ad5592r_reset_channel_modes(st);
        ad5592r_gpio_cleanup(st);

        if (st->reg)
                regulator_disable(st->reg);
}
EXPORT_SYMBOL_NS_GPL(ad5592r_remove, "IIO_AD5592R");

MODULE_AUTHOR("Paul Cercueil <paul.cercueil@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
MODULE_LICENSE("GPL v2");