root/drivers/leds/flash/leds-ktd2692.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * LED driver : leds-ktd2692.c
 *
 * Copyright (C) 2015 Samsung Electronics
 * Ingi Kim <ingi2.kim@samsung.com>
 */

#include <linux/cleanup.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/leds-expresswire.h>
#include <linux/led-class-flash.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

/* Value related the movie mode */
#define KTD2692_MOVIE_MODE_CURRENT_LEVELS       16
#define KTD2692_MM_TO_FL_RATIO(x)               ((x) / 3)
#define KTD2692_MM_MIN_CURR_THRESHOLD_SCALE     8

/* Value related the flash mode */
#define KTD2692_FLASH_MODE_TIMEOUT_LEVELS       8
#define KTD2692_FLASH_MODE_TIMEOUT_DISABLE      0
#define KTD2692_FLASH_MODE_CURR_PERCENT(x)      (((x) * 16) / 100)

/* Macro for getting offset of flash timeout */
#define GET_TIMEOUT_OFFSET(timeout, step)       ((timeout) / (step))

/* Base register address */
#define KTD2692_REG_LVP_BASE                    0x00
#define KTD2692_REG_FLASH_TIMEOUT_BASE          0x20
#define KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE  0x40
#define KTD2692_REG_MOVIE_CURRENT_BASE          0x60
#define KTD2692_REG_FLASH_CURRENT_BASE          0x80
#define KTD2692_REG_MODE_BASE                   0xA0

/* KTD2692 default length of name */
#define KTD2692_NAME_LENGTH                     20

/* Movie / Flash Mode Control */
enum ktd2692_led_mode {
        KTD2692_MODE_DISABLE = 0,       /* default */
        KTD2692_MODE_MOVIE,
        KTD2692_MODE_FLASH,
};

struct ktd2692_led_config_data {
        /* maximum LED current in movie mode */
        u32 movie_max_microamp;
        /* maximum LED current in flash mode */
        u32 flash_max_microamp;
        /* maximum flash timeout */
        u32 flash_max_timeout;
        /* max LED brightness level */
        enum led_brightness max_brightness;
};

const struct expresswire_timing ktd2692_timing = {
        .poweroff_us = 700,
        .data_start_us = 10,
        .end_of_data_low_us = 10,
        .end_of_data_high_us = 350,
        .short_bitset_us = 4,
        .long_bitset_us = 12
};

struct ktd2692_context {
        /* Common ExpressWire properties (ctrl GPIO and timing) */
        struct expresswire_common_props props;

        /* Related LED Flash class device */
        struct led_classdev_flash fled_cdev;

        /* secures access to the device */
        struct mutex lock;
        struct regulator *regulator;

        struct gpio_desc *aux_gpio;

        enum ktd2692_led_mode mode;
        enum led_brightness torch_brightness;
};

static struct ktd2692_context *fled_cdev_to_led(
                                struct led_classdev_flash *fled_cdev)
{
        return container_of(fled_cdev, struct ktd2692_context, fled_cdev);
}

static int ktd2692_led_brightness_set(struct led_classdev *led_cdev,
                                       enum led_brightness brightness)
{
        struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);
        struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);

        mutex_lock(&led->lock);

        if (brightness == LED_OFF) {
                led->mode = KTD2692_MODE_DISABLE;
                gpiod_direction_output(led->aux_gpio, 0);
        } else {
                expresswire_write_u8(&led->props, brightness |
                                        KTD2692_REG_MOVIE_CURRENT_BASE);
                led->mode = KTD2692_MODE_MOVIE;
        }

        expresswire_write_u8(&led->props, led->mode | KTD2692_REG_MODE_BASE);
        mutex_unlock(&led->lock);

        return 0;
}

static int ktd2692_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
                                        bool state)
{
        struct ktd2692_context *led = fled_cdev_to_led(fled_cdev);
        struct led_flash_setting *timeout = &fled_cdev->timeout;
        u32 flash_tm_reg;

        mutex_lock(&led->lock);

        if (state) {
                flash_tm_reg = GET_TIMEOUT_OFFSET(timeout->val, timeout->step);
                expresswire_write_u8(&led->props, flash_tm_reg
                                | KTD2692_REG_FLASH_TIMEOUT_BASE);

                led->mode = KTD2692_MODE_FLASH;
                gpiod_direction_output(led->aux_gpio, 1);
        } else {
                led->mode = KTD2692_MODE_DISABLE;
                gpiod_direction_output(led->aux_gpio, 0);
        }

        expresswire_write_u8(&led->props, led->mode | KTD2692_REG_MODE_BASE);

        fled_cdev->led_cdev.brightness = LED_OFF;
        led->mode = KTD2692_MODE_DISABLE;

        mutex_unlock(&led->lock);

        return 0;
}

static int ktd2692_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
                                         u32 timeout)
{
        return 0;
}

static void ktd2692_init_movie_current_max(struct ktd2692_led_config_data *cfg)
{
        u32 offset, step;
        u32 movie_current_microamp;

        offset = KTD2692_MOVIE_MODE_CURRENT_LEVELS;
        step = KTD2692_MM_TO_FL_RATIO(cfg->flash_max_microamp)
                / KTD2692_MOVIE_MODE_CURRENT_LEVELS;

        do {
                movie_current_microamp = step * offset;
                offset--;
        } while ((movie_current_microamp > cfg->movie_max_microamp) &&
                (offset > 0));

        cfg->max_brightness = offset;
}

static void ktd2692_init_flash_timeout(struct led_classdev_flash *fled_cdev,
                                       struct ktd2692_led_config_data *cfg)
{
        struct led_flash_setting *setting;

        setting = &fled_cdev->timeout;
        setting->min = KTD2692_FLASH_MODE_TIMEOUT_DISABLE;
        setting->max = cfg->flash_max_timeout;
        setting->step = cfg->flash_max_timeout
                        / (KTD2692_FLASH_MODE_TIMEOUT_LEVELS - 1);
        setting->val = cfg->flash_max_timeout;
}

static void ktd2692_setup(struct ktd2692_context *led)
{
        led->mode = KTD2692_MODE_DISABLE;
        expresswire_power_off(&led->props);
        gpiod_direction_output(led->aux_gpio, 0);

        expresswire_write_u8(&led->props, (KTD2692_MM_MIN_CURR_THRESHOLD_SCALE - 1)
                                 | KTD2692_REG_MM_MIN_CURR_THRESHOLD_BASE);
        expresswire_write_u8(&led->props, KTD2692_FLASH_MODE_CURR_PERCENT(45)
                                 | KTD2692_REG_FLASH_CURRENT_BASE);
}

static void regulator_disable_action(void *_data)
{
        struct device *dev = _data;
        struct ktd2692_context *led = dev_get_drvdata(dev);
        int ret;

        ret = regulator_disable(led->regulator);
        if (ret)
                dev_err(dev, "Failed to disable supply: %d\n", ret);
}

static int ktd2692_parse_dt(struct ktd2692_context *led, struct device *dev,
                            struct ktd2692_led_config_data *cfg)
{
        struct device_node *np = dev_of_node(dev);
        int ret;

        if (!np)
                return -ENXIO;

        led->props.ctrl_gpio = devm_gpiod_get(dev, "ctrl", GPIOD_ASIS);
        ret = PTR_ERR_OR_ZERO(led->props.ctrl_gpio);
        if (ret)
                return dev_err_probe(dev, ret, "cannot get ctrl-gpios\n");

        led->aux_gpio = devm_gpiod_get_optional(dev, "aux", GPIOD_ASIS);
        if (IS_ERR(led->aux_gpio))
                return dev_err_probe(dev, PTR_ERR(led->aux_gpio), "cannot get aux-gpios\n");

        led->regulator = devm_regulator_get(dev, "vin");
        if (IS_ERR(led->regulator))
                led->regulator = NULL;

        if (led->regulator) {
                ret = regulator_enable(led->regulator);
                if (ret) {
                        dev_err(dev, "Failed to enable supply: %d\n", ret);
                } else {
                        ret = devm_add_action_or_reset(dev,
                                                regulator_disable_action, dev);
                        if (ret)
                                return ret;
                }
        }

        struct device_node *child_node __free(device_node) =
                of_get_next_available_child(np, NULL);
        if (!child_node) {
                dev_err(dev, "No DT child node found for connected LED.\n");
                return -EINVAL;
        }

        led->fled_cdev.led_cdev.name =
                of_get_property(child_node, "label", NULL) ? : child_node->name;

        ret = of_property_read_u32(child_node, "led-max-microamp",
                                   &cfg->movie_max_microamp);
        if (ret) {
                dev_err(dev, "failed to parse led-max-microamp\n");
                return ret;
        }

        ret = of_property_read_u32(child_node, "flash-max-microamp",
                                   &cfg->flash_max_microamp);
        if (ret) {
                dev_err(dev, "failed to parse flash-max-microamp\n");
                return ret;
        }

        ret = of_property_read_u32(child_node, "flash-max-timeout-us",
                                   &cfg->flash_max_timeout);
        if (ret) {
                dev_err(dev, "failed to parse flash-max-timeout-us\n");
                return ret;
        }

        return 0;
}

static const struct led_flash_ops flash_ops = {
        .strobe_set = ktd2692_led_flash_strobe_set,
        .timeout_set = ktd2692_led_flash_timeout_set,
};

static int ktd2692_probe(struct platform_device *pdev)
{
        struct ktd2692_context *led;
        struct led_classdev *led_cdev;
        struct led_classdev_flash *fled_cdev;
        struct ktd2692_led_config_data led_cfg;
        int ret;

        led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
        if (!led)
                return -ENOMEM;

        fled_cdev = &led->fled_cdev;
        led_cdev = &fled_cdev->led_cdev;
        led->props.timing = ktd2692_timing;

        ret = ktd2692_parse_dt(led, &pdev->dev, &led_cfg);
        if (ret)
                return ret;

        ktd2692_init_flash_timeout(fled_cdev, &led_cfg);
        ktd2692_init_movie_current_max(&led_cfg);

        fled_cdev->ops = &flash_ops;

        led_cdev->max_brightness = led_cfg.max_brightness;
        led_cdev->brightness_set_blocking = ktd2692_led_brightness_set;
        led_cdev->flags |= LED_CORE_SUSPENDRESUME | LED_DEV_CAP_FLASH;

        mutex_init(&led->lock);

        platform_set_drvdata(pdev, led);

        ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
        if (ret) {
                dev_err(&pdev->dev, "can't register LED %s\n", led_cdev->name);
                mutex_destroy(&led->lock);
                return ret;
        }

        ktd2692_setup(led);

        return 0;
}

static void ktd2692_remove(struct platform_device *pdev)
{
        struct ktd2692_context *led = platform_get_drvdata(pdev);

        led_classdev_flash_unregister(&led->fled_cdev);

        mutex_destroy(&led->lock);
}

static const struct of_device_id ktd2692_match[] = {
        { .compatible = "kinetic,ktd2692", },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, ktd2692_match);

static struct platform_driver ktd2692_driver = {
        .driver = {
                .name  = "ktd2692",
                .of_match_table = ktd2692_match,
        },
        .probe  = ktd2692_probe,
        .remove = ktd2692_remove,
};

module_platform_driver(ktd2692_driver);

MODULE_IMPORT_NS("EXPRESSWIRE");
MODULE_AUTHOR("Ingi Kim <ingi2.kim@samsung.com>");
MODULE_DESCRIPTION("Kinetic KTD2692 LED driver");
MODULE_LICENSE("GPL v2");