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Commit 49c34b8e authored by Jacek Anaszewski's avatar Jacek Anaszewski Committed by Bryan Wu
Browse files

leds: Add driver for AAT1290 flash LED controller 



This patch adds a driver for the 1.5A Step-Up Current Regulator
for Flash LEDs. The device is programmed through a Skyworks proprietary
AS2Cwire serial digital interface.

Signed-off-by: default avatarJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
parent 2269fe09

drivers/leds/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -42,6 +42,14 @@ config LEDS_88PM860X 
	  This option enables support for on-chip LED drivers found on Marvell

	  Semiconductor 88PM8606 PMIC.



config LEDS_AAT1290

	tristate "LED support for the AAT1290"

	depends on LEDS_CLASS_FLASH

	depends on GPIOLIB

	depends on OF

	help

	 This option enables support for the LEDs on the AAT1290.



config LEDS_LM3530

	tristate "LCD Backlight driver for LM3530"

	depends on LEDS_CLASS

drivers/leds/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ obj-$(CONFIG_LEDS_TRIGGERS) += led-triggers.o 


# LED Platform Drivers

obj-$(CONFIG_LEDS_88PM860X)		+= leds-88pm860x.o

obj-$(CONFIG_LEDS_AAT1290)		+= leds-aat1290.o

obj-$(CONFIG_LEDS_BD2802)		+= leds-bd2802.o

obj-$(CONFIG_LEDS_LOCOMO)		+= leds-locomo.o

obj-$(CONFIG_LEDS_LM3530)		+= leds-lm3530.o

drivers/leds/leds-aat1290.c

0 → 100644
+451 −0
Original line number Diff line number Diff line 
/*

 *	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/platform_device.h>

#include <linux/slab.h>

#include <linux/workqueue.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;

	/* 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;



	/* 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;

	/* assures led-triggers compatibility */

	struct work_struct work_brightness_set;

};



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 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);

}



static void aat1290_brightness_set(struct aat1290_led *led,

					enum led_brightness brightness)

{

	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);

}



/* LED subsystem callbacks */



static void aat1290_brightness_set_work(struct work_struct *work)

{

	struct aat1290_led *led =

		container_of(work, struct aat1290_led, work_brightness_set);



	aat1290_brightness_set(led, led->torch_brightness);

}



static void aat1290_led_brightness_set(struct led_classdev *led_cdev,

					enum led_brightness brightness)

{

	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);



	led->torch_brightness = brightness;

	schedule_work(&led->work_brightness_set);

}



static int aat1290_led_brightness_set_sync(struct led_classdev *led_cdev,

					enum led_brightness brightness)

{

	struct led_classdev_flash *fled_cdev = lcdev_to_flcdev(led_cdev);

	struct aat1290_led *led = fled_cdev_to_led(fled_cdev);



	aat1290_brightness_set(led, brightness);



	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 led_classdev *led_cdev = &led->fled_cdev.led_cdev;

	struct device *dev = &led->pdev->dev;

	struct device_node *child_node;

	int ret = 0;



	led->gpio_fl_en = devm_gpiod_get(dev, "flen");

	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");

	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;

	}



	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");

		return ret;

	}



	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");

		return ret;

	}



	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;

}



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 = kzalloc(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)

{

	int ret;



	ret = aat1290_led_parse_dt(led, cfg);

	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);



	kfree(led->mm_current_scale);



	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;

}



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 aat1290_led *led;

	struct led_classdev *led_cdev;

	struct led_classdev_flash *fled_cdev;

	struct aat1290_led_config_data led_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);

	if (ret < 0)

		return ret;



	mutex_init(&led->lock);



	/* Initialize LED Flash class device */

	led_cdev->brightness_set = aat1290_led_brightness_set;

	led_cdev->brightness_set_sync = aat1290_led_brightness_set_sync;

	led_cdev->max_brightness = led_cfg.max_brightness;

	led_cdev->flags |= LED_DEV_CAP_FLASH;

	INIT_WORK(&led->work_brightness_set, aat1290_brightness_set_work);



	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;



	return 0;



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);



	led_classdev_flash_unregister(&led->fled_cdev);

	cancel_work_sync(&led->work_brightness_set);



	mutex_destroy(&led->lock);



	return 0;

}



static const struct of_device_id aat1290_led_dt_match[] = {

	{ .compatible = "skyworks,aat1290" },

	{},

};



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");