// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/leds-pwm.c
 *
 * simple PWM based LED control
 *
 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
 *
 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
 */

#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

struct led_pwm {
        const char      *name;
        u8              active_low;
        u8              default_state;
        unsigned int    max_brightness;
};

struct led_pwm_data {
        struct gpio_desc        *enable_gpio;
        struct led_classdev     cdev;
        struct pwm_device       *pwm;
        struct pwm_state        pwmstate;
        unsigned int            active_low;
};

struct led_pwm_priv {
        int num_leds;
        struct led_pwm_data leds[];
};

static int led_pwm_set(struct led_classdev *led_cdev,
                       enum led_brightness brightness)
{
        struct led_pwm_data *led_dat =
                container_of(led_cdev, struct led_pwm_data, cdev);
        unsigned int max = led_dat->cdev.max_brightness;
        unsigned long long duty = led_dat->pwmstate.period;

        duty *= brightness;
        do_div(duty, max);

        if (led_dat->active_low)
                duty = led_dat->pwmstate.period - duty;

        gpiod_set_value_cansleep(led_dat->enable_gpio, !!brightness);

        led_dat->pwmstate.duty_cycle = duty;
        /*
         * Disabling a PWM doesn't guarantee that it emits the inactive level.
         * So keep it on. Only for suspending the PWM should be disabled because
         * otherwise it refuses to suspend. The possible downside is that the
         * LED might stay (or even go) on.
         */
        led_dat->pwmstate.enabled = !(led_cdev->flags & LED_SUSPENDED);
        return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate);
}

static int led_pwm_default_brightness_get(struct fwnode_handle *fwnode,
                                          int max_brightness)
{
        unsigned int default_brightness;
        int ret;

        ret = fwnode_property_read_u32(fwnode, "default-brightness",
                                       &default_brightness);
        if (ret < 0 || default_brightness > max_brightness)
                default_brightness = max_brightness;

        return default_brightness;
}

__attribute__((nonnull))
static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
                       struct led_pwm *led, struct fwnode_handle *fwnode)
{
        struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
        struct led_init_data init_data = { .fwnode = fwnode };
        int ret;

        led_data->active_low = led->active_low;
        led_data->cdev.name = led->name;
        led_data->cdev.brightness = LED_OFF;
        led_data->cdev.max_brightness = led->max_brightness;
        led_data->cdev.flags = LED_CORE_SUSPENDRESUME;

        led_data->pwm = devm_fwnode_pwm_get(dev, fwnode, NULL);
        if (IS_ERR(led_data->pwm))
                return dev_err_probe(dev, PTR_ERR(led_data->pwm),
                                     "unable to request PWM for %s\n",
                                     led->name);

        led_data->cdev.brightness_set_blocking = led_pwm_set;

        /* init PWM state */
        switch (led->default_state) {
        case LEDS_DEFSTATE_KEEP:
                pwm_get_state(led_data->pwm, &led_data->pwmstate);
                if (led_data->pwmstate.period)
                        break;
                led->default_state = LEDS_DEFSTATE_OFF;
                dev_warn(dev,
                        "failed to read period for %s, default to off",
                        led->name);
                fallthrough;
        default:
                pwm_init_state(led_data->pwm, &led_data->pwmstate);
                break;
        }

        /* set brightness */
        switch (led->default_state) {
        case LEDS_DEFSTATE_ON:
                led_data->cdev.brightness =
                        led_pwm_default_brightness_get(fwnode, led->max_brightness);
                break;
        case LEDS_DEFSTATE_KEEP:
                {
                uint64_t brightness;

                brightness = led->max_brightness;
                brightness *= led_data->pwmstate.duty_cycle;
                do_div(brightness, led_data->pwmstate.period);
                led_data->cdev.brightness = brightness;
                }
                break;
        }

        /*
         * Claim the GPIO as GPIOD_ASIS and set the value
         * later on to honor the different default states
         */
        led_data->enable_gpio = devm_fwnode_gpiod_get(dev, fwnode, "enable", GPIOD_ASIS, NULL);
        if (IS_ERR(led_data->enable_gpio)) {
                if (PTR_ERR(led_data->enable_gpio) == -ENOENT)
                        /* Enable GPIO is optional */
                        led_data->enable_gpio = NULL;
                else
                        return PTR_ERR(led_data->enable_gpio);
        }

        gpiod_direction_output(led_data->enable_gpio, !!led_data->cdev.brightness);

        ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);
        if (ret) {
                dev_err(dev, "failed to register PWM led for %s: %d\n",
                        led->name, ret);
                return ret;
        }

        if (led->default_state != LEDS_DEFSTATE_KEEP) {
                ret = led_pwm_set(&led_data->cdev, led_data->cdev.brightness);
                if (ret) {
                        dev_err(dev, "failed to set led PWM value for %s: %d",
                                led->name, ret);
                        return ret;
                }
        }

        priv->num_leds++;
        return 0;
}

static int led_pwm_create_fwnode(struct device *dev, struct led_pwm_priv *priv)
{
        struct led_pwm led;
        int ret;

        device_for_each_child_node_scoped(dev, fwnode) {
                memset(&led, 0, sizeof(led));

                ret = fwnode_property_read_string(fwnode, "label", &led.name);
                if (ret && is_of_node(fwnode))
                        led.name = to_of_node(fwnode)->name;

                if (!led.name)
                        return -EINVAL;

                led.active_low = fwnode_property_read_bool(fwnode,
                                                           "active-low");
                fwnode_property_read_u32(fwnode, "max-brightness",
                                         &led.max_brightness);

                led.default_state = led_init_default_state_get(fwnode);

                ret = led_pwm_add(dev, priv, &led, fwnode);
                if (ret)
                        return ret;
        }

        return 0;
}

static int led_pwm_probe(struct platform_device *pdev)
{
        struct led_pwm_priv *priv;
        int ret = 0;
        int count;

        count = device_get_child_node_count(&pdev->dev);

        if (!count)
                return -EINVAL;

        priv = devm_kzalloc(&pdev->dev, struct_size(priv, leds, count),
                            GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        ret = led_pwm_create_fwnode(&pdev->dev, priv);

        if (ret)
                return ret;

        platform_set_drvdata(pdev, priv);

        return 0;
}

static const struct of_device_id of_pwm_leds_match[] = {
        { .compatible = "pwm-leds", },
        {},
};
MODULE_DEVICE_TABLE(of, of_pwm_leds_match);

static struct platform_driver led_pwm_driver = {
        .probe          = led_pwm_probe,
        .driver         = {
                .name   = "leds_pwm",
                .of_match_table = of_pwm_leds_match,
        },
};

module_platform_driver(led_pwm_driver);

MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
MODULE_DESCRIPTION("generic PWM LED driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:leds-pwm");