/*
 *      LED Flash class driver for the AAT1290
 *      1.5A Step-Up Current Regulator for Flash LEDs
 *
 *      Copyright (C) 2015, Samsung Electronics Co., Ltd.
 *      Author: Jacek Anaszewski <j.anaszewski@samsung.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/led-class-flash.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <media/v4l2-flash-led-class.h>

#define AAT1290_MOVIE_MODE_CURRENT_ADDR 17
#define AAT1290_MAX_MM_CURR_PERCENT_0   16
#define AAT1290_MAX_MM_CURR_PERCENT_100 1

#define AAT1290_FLASH_SAFETY_TIMER_ADDR 18

#define AAT1290_MOVIE_MODE_CONFIG_ADDR  19
#define AAT1290_MOVIE_MODE_OFF          1
#define AAT1290_MOVIE_MODE_ON           3

#define AAT1290_MM_CURRENT_RATIO_ADDR   20
#define AAT1290_MM_TO_FL_1_92           1

#define AAT1290_MM_TO_FL_RATIO          1000 / 1920
#define AAT1290_MAX_MM_CURRENT(fl_max)  (fl_max * AAT1290_MM_TO_FL_RATIO)

#define AAT1290_LATCH_TIME_MIN_US       500
#define AAT1290_LATCH_TIME_MAX_US       1000
#define AAT1290_EN_SET_TICK_TIME_US     1
#define AAT1290_FLEN_OFF_DELAY_TIME_US  10
#define AAT1290_FLASH_TM_NUM_LEVELS     16
#define AAT1290_MM_CURRENT_SCALE_SIZE   15


struct aat1290_led_config_data {
        /* maximum LED current in movie mode */
        u32 max_mm_current;
        /* maximum LED current in flash mode */
        u32 max_flash_current;
        /* maximum flash timeout */
        u32 max_flash_tm;
        /* external strobe capability */
        bool has_external_strobe;
        /* max LED brightness level */
        enum led_brightness max_brightness;
};

struct aat1290_led {
        /* platform device data */
        struct platform_device *pdev;
        /* secures access to the device */
        struct mutex lock;

        /* corresponding LED Flash class device */
        struct led_classdev_flash fled_cdev;
        /* V4L2 Flash device */
        struct v4l2_flash *v4l2_flash;

        /* FLEN pin */
        struct gpio_desc *gpio_fl_en;
        /* EN|SET pin  */
        struct gpio_desc *gpio_en_set;
        /* movie mode current scale */
        int *mm_current_scale;
        /* device mode */
        bool movie_mode;

        /* brightness cache */
        unsigned int torch_brightness;
};

static struct aat1290_led *fled_cdev_to_led(
                                struct led_classdev_flash *fled_cdev)
{
        return container_of(fled_cdev, struct aat1290_led, fled_cdev);
}

static struct led_classdev_flash *led_cdev_to_fled_cdev(
                                struct led_classdev *led_cdev)
{
        return container_of(led_cdev, struct led_classdev_flash, led_cdev);
}

static void aat1290_as2cwire_write(struct aat1290_led *led, int addr, int value)
{
        int i;

        gpiod_direction_output(led->gpio_fl_en, 0);
        gpiod_direction_output(led->gpio_en_set, 0);

        udelay(AAT1290_FLEN_OFF_DELAY_TIME_US);

        /* write address */
        for (i = 0; i < addr; ++i) {
                udelay(AAT1290_EN_SET_TICK_TIME_US);
                gpiod_direction_output(led->gpio_en_set, 0);
                udelay(AAT1290_EN_SET_TICK_TIME_US);
                gpiod_direction_output(led->gpio_en_set, 1);
        }

        usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);

        /* write data */
        for (i = 0; i < value; ++i) {
                udelay(AAT1290_EN_SET_TICK_TIME_US);
                gpiod_direction_output(led->gpio_en_set, 0);
                udelay(AAT1290_EN_SET_TICK_TIME_US);
                gpiod_direction_output(led->gpio_en_set, 1);
        }

        usleep_range(AAT1290_LATCH_TIME_MIN_US, AAT1290_LATCH_TIME_MAX_US);
}

static void aat1290_set_flash_safety_timer(struct aat1290_led *led,
                                        unsigned int micro_sec)
{
        struct led_classdev_flash *fled_cdev = &led->fled_cdev;
        struct led_flash_setting *flash_tm = &fled_cdev->timeout;
        int flash_tm_reg = AAT1290_FLASH_TM_NUM_LEVELS -
                                (micro_sec / flash_tm->step) + 1;

        aat1290_as2cwire_write(led, AAT1290_FLASH_SAFETY_TIMER_ADDR,
                                                        flash_tm_reg);
}

/* LED subsystem callbacks */

static int aat1290_led_brightness_set(struct led_classdev *led_cdev,
                                        enum led_brightness brightness)
{
        struct led_classdev_flash *fled_cdev = led_cdev_to_fled_cdev(led_cdev);
        struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

        mutex_lock(&led->lock);

        if (brightness == 0) {
                gpiod_direction_output(led->gpio_fl_en, 0);
                gpiod_direction_output(led->gpio_en_set, 0);
                led->movie_mode = false;
        } else {
                if (!led->movie_mode) {
                        aat1290_as2cwire_write(led,
                                AAT1290_MM_CURRENT_RATIO_ADDR,
                                AAT1290_MM_TO_FL_1_92);
                        led->movie_mode = true;
                }

                aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CURRENT_ADDR,
                                AAT1290_MAX_MM_CURR_PERCENT_0 - brightness);
                aat1290_as2cwire_write(led, AAT1290_MOVIE_MODE_CONFIG_ADDR,
                                AAT1290_MOVIE_MODE_ON);
        }

        mutex_unlock(&led->lock);

        return 0;
}

static int aat1290_led_flash_strobe_set(struct led_classdev_flash *fled_cdev,
                                         bool state)

{
        struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
        struct led_classdev *led_cdev = &fled_cdev->led_cdev;
        struct led_flash_setting *timeout = &fled_cdev->timeout;

        mutex_lock(&led->lock);

        if (state) {
                aat1290_set_flash_safety_timer(led, timeout->val);
                gpiod_direction_output(led->gpio_fl_en, 1);
        } else {
                gpiod_direction_output(led->gpio_fl_en, 0);
                gpiod_direction_output(led->gpio_en_set, 0);
        }

        /*
         * To reenter movie mode after a flash event the part must be cycled
         * off and back on to reset the movie mode and reprogrammed via the
         * AS2Cwire. Therefore the brightness and movie_mode properties needs
         * to be updated here to reflect the actual state.
         */
        led_cdev->brightness = 0;
        led->movie_mode = false;

        mutex_unlock(&led->lock);

        return 0;
}

static int aat1290_led_flash_timeout_set(struct led_classdev_flash *fled_cdev,
                                                u32 timeout)
{
        /*
         * Don't do anything - flash timeout is cached in the led-class-flash
         * core and will be applied in the strobe_set op, as writing the
         * safety timer register spuriously turns the torch mode on.
         */

        return 0;
}

static int aat1290_led_parse_dt(struct aat1290_led *led,
                        struct aat1290_led_config_data *cfg,
                        struct device_node **sub_node)
{
        struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
        struct device *dev = &led->pdev->dev;
        struct device_node *child_node;
#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
        struct pinctrl *pinctrl;
#endif
        int ret = 0;

        led->gpio_fl_en = devm_gpiod_get(dev, "flen", GPIOD_ASIS);
        if (IS_ERR(led->gpio_fl_en)) {
                ret = PTR_ERR(led->gpio_fl_en);
                dev_err(dev, "Unable to claim gpio \"flen\".\n");
                return ret;
        }

        led->gpio_en_set = devm_gpiod_get(dev, "enset", GPIOD_ASIS);
        if (IS_ERR(led->gpio_en_set)) {
                ret = PTR_ERR(led->gpio_en_set);
                dev_err(dev, "Unable to claim gpio \"enset\".\n");
                return ret;
        }

#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
        pinctrl = devm_pinctrl_get_select_default(&led->pdev->dev);
        if (IS_ERR(pinctrl)) {
                cfg->has_external_strobe = false;
                dev_info(dev,
                         "No support for external strobe detected.\n");
        } else {
                cfg->has_external_strobe = true;
        }
#endif

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

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

        ret = of_property_read_u32(child_node, "led-max-microamp",
                                &cfg->max_mm_current);
        /*
         * led-max-microamp will default to 1/20 of flash-max-microamp
         * in case it is missing.
         */
        if (ret < 0)
                dev_warn(dev,
                        "led-max-microamp DT property missing\n");

        ret = of_property_read_u32(child_node, "flash-max-microamp",
                                &cfg->max_flash_current);
        if (ret < 0) {
                dev_err(dev,
                        "flash-max-microamp DT property missing\n");
                goto err_parse_dt;
        }

        ret = of_property_read_u32(child_node, "flash-max-timeout-us",
                                &cfg->max_flash_tm);
        if (ret < 0) {
                dev_err(dev,
                        "flash-max-timeout-us DT property missing\n");
                goto err_parse_dt;
        }

        *sub_node = child_node;

err_parse_dt:
        of_node_put(child_node);

        return ret;
}

static void aat1290_led_validate_mm_current(struct aat1290_led *led,
                                        struct aat1290_led_config_data *cfg)
{
        int i, b = 0, e = AAT1290_MM_CURRENT_SCALE_SIZE;

        while (e - b > 1) {
                i = b + (e - b) / 2;
                if (cfg->max_mm_current < led->mm_current_scale[i])
                        e = i;
                else
                        b = i;
        }

        cfg->max_mm_current = led->mm_current_scale[b];
        cfg->max_brightness = b + 1;
}

static int init_mm_current_scale(struct aat1290_led *led,
                        struct aat1290_led_config_data *cfg)
{
        int max_mm_current_percent[] = { 20, 22, 25, 28, 32, 36, 40, 45, 50, 56,
                                                63, 71, 79, 89, 100 };
        int i, max_mm_current =
                        AAT1290_MAX_MM_CURRENT(cfg->max_flash_current);

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

        for (i = 0; i < AAT1290_MM_CURRENT_SCALE_SIZE; ++i)
                led->mm_current_scale[i] = max_mm_current *
                                          max_mm_current_percent[i] / 100;

        return 0;
}

static int aat1290_led_get_configuration(struct aat1290_led *led,
                                        struct aat1290_led_config_data *cfg,
                                        struct device_node **sub_node)
{
        int ret;

        ret = aat1290_led_parse_dt(led, cfg, sub_node);
        if (ret < 0)
                return ret;
        /*
         * Init non-linear movie mode current scale basing
         * on the max flash current from led configuration.
         */
        ret = init_mm_current_scale(led, cfg);
        if (ret < 0)
                return ret;

        aat1290_led_validate_mm_current(led, cfg);

#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
#else
        devm_kfree(&led->pdev->dev, led->mm_current_scale);
#endif

        return 0;
}

static void aat1290_init_flash_timeout(struct aat1290_led *led,
                                struct aat1290_led_config_data *cfg)
{
        struct led_classdev_flash *fled_cdev = &led->fled_cdev;
        struct led_flash_setting *setting;

        /* Init flash timeout setting */
        setting = &fled_cdev->timeout;
        setting->min = cfg->max_flash_tm / AAT1290_FLASH_TM_NUM_LEVELS;
        setting->max = cfg->max_flash_tm;
        setting->step = setting->min;
        setting->val = setting->max;
}

#if IS_ENABLED(CONFIG_V4L2_FLASH_LED_CLASS)
static enum led_brightness aat1290_intensity_to_brightness(
                                        struct v4l2_flash *v4l2_flash,
                                        s32 intensity)
{
        struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
        struct aat1290_led *led = fled_cdev_to_led(fled_cdev);
        int i;

        for (i = AAT1290_MM_CURRENT_SCALE_SIZE - 1; i >= 0; --i)
                if (intensity >= led->mm_current_scale[i])
                        return i + 1;

        return 1;
}

static s32 aat1290_brightness_to_intensity(struct v4l2_flash *v4l2_flash,
                                        enum led_brightness brightness)
{
        struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
        struct aat1290_led *led = fled_cdev_to_led(fled_cdev);

        return led->mm_current_scale[brightness - 1];
}

static int aat1290_led_external_strobe_set(struct v4l2_flash *v4l2_flash,
                                                bool enable)
{
        struct aat1290_led *led = fled_cdev_to_led(v4l2_flash->fled_cdev);
        struct led_classdev_flash *fled_cdev = v4l2_flash->fled_cdev;
        struct led_classdev *led_cdev = &fled_cdev->led_cdev;
        struct pinctrl *pinctrl;

        gpiod_direction_output(led->gpio_fl_en, 0);
        gpiod_direction_output(led->gpio_en_set, 0);

        led->movie_mode = false;
        led_cdev->brightness = 0;

        pinctrl = devm_pinctrl_get_select(&led->pdev->dev,
                                                enable ? "isp" : "host");
        if (IS_ERR(pinctrl)) {
                dev_warn(&led->pdev->dev, "Unable to switch strobe source.\n");
                return PTR_ERR(pinctrl);
        }

        return 0;
}

static void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
                                        struct aat1290_led_config_data *led_cfg,
                                        struct v4l2_flash_config *v4l2_sd_cfg)
{
        struct led_classdev *led_cdev = &led->fled_cdev.led_cdev;
        struct led_flash_setting *s;

        strlcpy(v4l2_sd_cfg->dev_name, led_cdev->name,
                sizeof(v4l2_sd_cfg->dev_name));

        s = &v4l2_sd_cfg->torch_intensity;
        s->min = led->mm_current_scale[0];
        s->max = led_cfg->max_mm_current;
        s->step = 1;
        s->val = s->max;

        v4l2_sd_cfg->has_external_strobe = led_cfg->has_external_strobe;
}

static const struct v4l2_flash_ops v4l2_flash_ops = {
        .external_strobe_set = aat1290_led_external_strobe_set,
        .intensity_to_led_brightness = aat1290_intensity_to_brightness,
        .led_brightness_to_intensity = aat1290_brightness_to_intensity,
};
#else
static inline void aat1290_init_v4l2_flash_config(struct aat1290_led *led,
                                struct aat1290_led_config_data *led_cfg,
                                struct v4l2_flash_config *v4l2_sd_cfg)
{
}
static const struct v4l2_flash_ops v4l2_flash_ops;
#endif

static const struct led_flash_ops flash_ops = {
        .strobe_set = aat1290_led_flash_strobe_set,
        .timeout_set = aat1290_led_flash_timeout_set,
};

static int aat1290_led_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *sub_node = NULL;
        struct aat1290_led *led;
        struct led_classdev *led_cdev;
        struct led_classdev_flash *fled_cdev;
        struct aat1290_led_config_data led_cfg = {};
        struct v4l2_flash_config v4l2_sd_cfg = {};
        int ret;

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

        led->pdev = pdev;
        platform_set_drvdata(pdev, led);

        fled_cdev = &led->fled_cdev;
        fled_cdev->ops = &flash_ops;
        led_cdev = &fled_cdev->led_cdev;

        ret = aat1290_led_get_configuration(led, &led_cfg, &sub_node);
        if (ret < 0)
                return ret;

        mutex_init(&led->lock);

        /* Initialize LED Flash class device */
        led_cdev->brightness_set_blocking = aat1290_led_brightness_set;
        led_cdev->max_brightness = led_cfg.max_brightness;
        led_cdev->flags |= LED_DEV_CAP_FLASH;

        aat1290_init_flash_timeout(led, &led_cfg);

        /* Register LED Flash class device */
        ret = led_classdev_flash_register(&pdev->dev, fled_cdev);
        if (ret < 0)
                goto err_flash_register;

        aat1290_init_v4l2_flash_config(led, &led_cfg, &v4l2_sd_cfg);

        /* Create V4L2 Flash subdev. */
        led->v4l2_flash = v4l2_flash_init(dev, sub_node, fled_cdev, NULL,
                                          &v4l2_flash_ops, &v4l2_sd_cfg);
        if (IS_ERR(led->v4l2_flash)) {
                ret = PTR_ERR(led->v4l2_flash);
                goto error_v4l2_flash_init;
        }

        return 0;

error_v4l2_flash_init:
        led_classdev_flash_unregister(fled_cdev);
err_flash_register:
        mutex_destroy(&led->lock);

        return ret;
}

static int aat1290_led_remove(struct platform_device *pdev)
{
        struct aat1290_led *led = platform_get_drvdata(pdev);

        v4l2_flash_release(led->v4l2_flash);
        led_classdev_flash_unregister(&led->fled_cdev);

        mutex_destroy(&led->lock);

        return 0;
}

static const struct of_device_id aat1290_led_dt_match[] = {
        { .compatible = "skyworks,aat1290" },
        {},
};
MODULE_DEVICE_TABLE(of, aat1290_led_dt_match);

static struct platform_driver aat1290_led_driver = {
        .probe          = aat1290_led_probe,
        .remove         = aat1290_led_remove,
        .driver         = {
                .name   = "aat1290",
                .of_match_table = aat1290_led_dt_match,
        },
};

module_platform_driver(aat1290_led_driver);

MODULE_AUTHOR("Jacek Anaszewski <j.anaszewski@samsung.com>");
MODULE_DESCRIPTION("Skyworks Current Regulator for Flash LEDs");
MODULE_LICENSE("GPL v2");