linux-imx

// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>

​

#include <linux/kernel.h>

#include <linux/platform_device.h>

#include <linux/leds.h>

#include <linux/delay.h>

#include <linux/gpio.h>

#include <linux/gpio/consumer.h>

#include <linux/slab.h>

#include <linux/module.h>

#include <linux/of.h>

#include <uapi/linux/uleds.h>

​

struct lt3593_led_data {

    char name[LED_MAX_NAME_SIZE];

    struct led_classdev cdev;

    struct gpio_desc *gpiod;

};

​

static int lt3593_led_set(struct led_classdev *led_cdev,

               enum led_brightness value)

{

    struct lt3593_led_data *led_dat =

        container_of(led_cdev, struct lt3593_led_data, cdev);

    int pulses;

​

    /*

     * The LT3593 resets its internal current level register to the maximum

     * level on the first falling edge on the control pin. Each following

     * falling edge decreases the current level by 625uA. Up to 32 pulses

     * can be sent, so the maximum power reduction is 20mA.

     * After a timeout of 128us, the value is taken from the register and

     * applied is to the output driver.

     */

​

    if (value == 0) {

        gpiod_set_value_cansleep(led_dat->gpiod, 0);

        return 0;

    }

​

    pulses = 32 - (value * 32) / 255;

​

    if (pulses == 0) {

        gpiod_set_value_cansleep(led_dat->gpiod, 0);

        mdelay(1);

        gpiod_set_value_cansleep(led_dat->gpiod, 1);

        return 0;

    }

​

    gpiod_set_value_cansleep(led_dat->gpiod, 1);

​

    while (pulses--) {

        gpiod_set_value_cansleep(led_dat->gpiod, 0);

        udelay(1);

        gpiod_set_value_cansleep(led_dat->gpiod, 1);

        udelay(1);

    }

​

    return 0;

}

​

static struct lt3593_led_data *lt3593_led_probe_pdata(struct device *dev)

{

    struct gpio_led_platform_data *pdata = dev_get_platdata(dev);

    const struct gpio_led *template = &pdata->leds[0];

    struct lt3593_led_data *led_data;

    int ret, state;

​

    if (pdata->num_leds != 1)

        return ERR_PTR(-EINVAL);

​

    led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);

    if (!led_data)

        return ERR_PTR(-ENOMEM);

​

    led_data->cdev.name = template->name;

    led_data->cdev.default_trigger = template->default_trigger;

    led_data->cdev.brightness_set_blocking = lt3593_led_set;

​

    state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);

    led_data->cdev.brightness = state ? LED_FULL : LED_OFF;

​

    if (!template->retain_state_suspended)

        led_data->cdev.flags |= LED_CORE_SUSPENDRESUME;

​

    ret = devm_gpio_request_one(dev, template->gpio, state ?

                    GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,

                    template->name);

    if (ret < 0)

        return ERR_PTR(ret);

​