drivers/leds/leds-lm3692x.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 // TI LM3692x LED chip family driver
 // Copyright (C) 2017-18 Texas Instruments Incorporated - https://www.ti.com/

 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/leds.h>
 #include <linux/log2.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>

 #define LM36922_MODEL	0
 #define LM36923_MODEL	1

 #define LM3692X_REV		0x0
 #define LM3692X_RESET		0x1
 #define LM3692X_EN		0x10
 #define LM3692X_BRT_CTRL	0x11
 #define LM3692X_PWM_CTRL	0x12
 #define LM3692X_BOOST_CTRL	0x13
 #define LM3692X_AUTO_FREQ_HI	0x15
 #define LM3692X_AUTO_FREQ_LO	0x16
 #define LM3692X_BL_ADJ_THRESH	0x17
 #define LM3692X_BRT_LSB		0x18
 #define LM3692X_BRT_MSB		0x19
 #define LM3692X_FAULT_CTRL	0x1e
 #define LM3692X_FAULT_FLAGS	0x1f

 #define LM3692X_SW_RESET	BIT(0)
 #define LM3692X_DEVICE_EN	BIT(0)
 #define LM3692X_LED1_EN		BIT(1)
 #define LM3692X_LED2_EN		BIT(2)
 #define LM36923_LED3_EN		BIT(3)
 #define LM3692X_ENABLE_MASK	(LM3692X_DEVICE_EN | LM3692X_LED1_EN | \
 				 LM3692X_LED2_EN | LM36923_LED3_EN)

 /* Brightness Control Bits */
 #define LM3692X_BL_ADJ_POL	BIT(0)
 #define LM3692X_RAMP_RATE_125us	0x00
 #define LM3692X_RAMP_RATE_250us	BIT(1)
 #define LM3692X_RAMP_RATE_500us BIT(2)
 #define LM3692X_RAMP_RATE_1ms	(BIT(1) | BIT(2))
 #define LM3692X_RAMP_RATE_2ms	BIT(3)
 #define LM3692X_RAMP_RATE_4ms	(BIT(3) | BIT(1))
 #define LM3692X_RAMP_RATE_8ms	(BIT(2) | BIT(3))
 #define LM3692X_RAMP_RATE_16ms	(BIT(1) | BIT(2) | BIT(3))
 #define LM3692X_RAMP_EN		BIT(4)
 #define LM3692X_BRHT_MODE_REG	0x00
 #define LM3692X_BRHT_MODE_PWM	BIT(5)
 #define LM3692X_BRHT_MODE_MULTI_RAMP BIT(6)
 #define LM3692X_BRHT_MODE_RAMP_MULTI (BIT(5) | BIT(6))
 #define LM3692X_MAP_MODE_EXP	BIT(7)

 /* PWM Register Bits */
 #define LM3692X_PWM_FILTER_100	BIT(0)
 #define LM3692X_PWM_FILTER_150	BIT(1)
 #define LM3692X_PWM_FILTER_200	(BIT(0) | BIT(1))
 #define LM3692X_PWM_HYSTER_1LSB BIT(2)
 #define LM3692X_PWM_HYSTER_2LSB	BIT(3)
 #define LM3692X_PWM_HYSTER_3LSB (BIT(3) | BIT(2))
 #define LM3692X_PWM_HYSTER_4LSB BIT(4)
 #define LM3692X_PWM_HYSTER_5LSB (BIT(4) | BIT(2))
 #define LM3692X_PWM_HYSTER_6LSB (BIT(4) | BIT(3))
 #define LM3692X_PWM_POLARITY	BIT(5)
 #define LM3692X_PWM_SAMP_4MHZ	BIT(6)
 #define LM3692X_PWM_SAMP_24MHZ	BIT(7)

 /* Boost Control Bits */
 #define LM3692X_OCP_PROT_1A	BIT(0)
 #define LM3692X_OCP_PROT_1_25A	BIT(1)
 #define LM3692X_OCP_PROT_1_5A	(BIT(0) | BIT(1))
 #define LM3692X_OVP_21V		BIT(2)
 #define LM3692X_OVP_25V		BIT(3)
 #define LM3692X_OVP_29V		(BIT(2) | BIT(3))
 #define LM3692X_MIN_IND_22UH	BIT(4)
 #define LM3692X_BOOST_SW_1MHZ	BIT(5)
 #define LM3692X_BOOST_SW_NO_SHIFT	BIT(6)

 /* Fault Control Bits */
 #define LM3692X_FAULT_CTRL_OVP BIT(0)
 #define LM3692X_FAULT_CTRL_OCP BIT(1)
 #define LM3692X_FAULT_CTRL_TSD BIT(2)
 #define LM3692X_FAULT_CTRL_OPEN BIT(3)

 /* Fault Flag Bits */
 #define LM3692X_FAULT_FLAG_OVP BIT(0)
 #define LM3692X_FAULT_FLAG_OCP BIT(1)
 #define LM3692X_FAULT_FLAG_TSD BIT(2)
 #define LM3692X_FAULT_FLAG_SHRT BIT(3)
 #define LM3692X_FAULT_FLAG_OPEN BIT(4)

 /**
  * struct lm3692x_led -
  * @lock - Lock for reading/writing the device
  * @client - Pointer to the I2C client
  * @led_dev - LED class device pointer
  * @regmap - Devices register map
  * @enable_gpio - VDDIO/EN gpio to enable communication interface
  * @regulator - LED supply regulator pointer
  * @led_enable - LED sync to be enabled
  * @model_id - Current device model ID enumerated
  */
 struct lm3692x_led {
 	struct mutex lock;
 	struct i2c_client *client;
 	struct led_classdev led_dev;
 	struct regmap *regmap;
 	struct gpio_desc *enable_gpio;
 	struct regulator *regulator;
 	int led_enable;
 	int model_id;

 	u8 boost_ctrl, brightness_ctrl;
 	bool enabled;
 };

 static const struct reg_default lm3692x_reg_defs[] = {
 	{LM3692X_EN, 0xf},
 	{LM3692X_BRT_CTRL, 0x61},
 	{LM3692X_PWM_CTRL, 0x73},
 	{LM3692X_BOOST_CTRL, 0x6f},
 	{LM3692X_AUTO_FREQ_HI, 0x0},
 	{LM3692X_AUTO_FREQ_LO, 0x0},
 	{LM3692X_BL_ADJ_THRESH, 0x0},
 	{LM3692X_BRT_LSB, 0x7},
 	{LM3692X_BRT_MSB, 0xff},
 	{LM3692X_FAULT_CTRL, 0x7},
 };

 static const struct regmap_config lm3692x_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,

 	.max_register = LM3692X_FAULT_FLAGS,
 	.reg_defaults = lm3692x_reg_defs,
 	.num_reg_defaults = ARRAY_SIZE(lm3692x_reg_defs),
 	.cache_type = REGCACHE_RBTREE,
 };

 static int lm3692x_fault_check(struct lm3692x_led *led)
 {
 	int ret;
 	unsigned int read_buf;

 	ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
 	if (ret)
 		return ret;

 	if (read_buf)
 		dev_err(&led->client->dev, "Detected a fault 0x%X\n", read_buf);

 	/* The first read may clear the fault.  Check again to see if the fault
 	 * still exits and return that value.
 	 */
 	regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
 	if (read_buf)
 		dev_err(&led->client->dev, "Second read of fault flags 0x%X\n",
 			read_buf);

 	return read_buf;
 }

 static int lm3692x_leds_enable(struct lm3692x_led *led)
 {
 	int enable_state;
 	int ret, reg_ret;

 	if (led->enabled)
 		return 0;

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

 	if (led->enable_gpio)
 		gpiod_direction_output(led->enable_gpio, 1);

 	ret = lm3692x_fault_check(led);
 	if (ret) {
 		dev_err(&led->client->dev, "Cannot read/clear faults: %d\n",
 			ret);
 		goto out;
 	}

 	ret = regmap_write(led->regmap, LM3692X_BRT_CTRL, 0x00);
 	if (ret)
 		goto out;

 	/*
 	 * For glitch free operation, the following data should
 	 * only be written while LEDx enable bits are 0 and the device enable
 	 * bit is set to 1.
 	 * per Section 7.5.14 of the data sheet
 	 */
 	ret = regmap_write(led->regmap, LM3692X_EN, LM3692X_DEVICE_EN);
 	if (ret)
 		goto out;

 	/* Set the brightness to 0 so when enabled the LEDs do not come
 	 * on with full brightness.
 	 */
 	ret = regmap_write(led->regmap, LM3692X_BRT_MSB, 0);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_BRT_LSB, 0);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_PWM_CTRL,
 		LM3692X_PWM_FILTER_100 | LM3692X_PWM_SAMP_24MHZ);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL, led->boost_ctrl);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
 	if (ret)
 		goto out;

 	ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
 			LM3692X_BL_ADJ_POL | LM3692X_RAMP_EN);
 	if (ret)
 		goto out;

 	switch (led->led_enable) {
 	case 0:
 	default:
 		if (led->model_id == LM36923_MODEL)
 			enable_state = LM3692X_LED1_EN | LM3692X_LED2_EN |
 			       LM36923_LED3_EN;
 		else
 			enable_state = LM3692X_LED1_EN | LM3692X_LED2_EN;

 		break;
 	case 1:
 		enable_state = LM3692X_LED1_EN;
 		break;
 	case 2:
 		enable_state = LM3692X_LED2_EN;
 		break;

 	case 3:
 		if (led->model_id == LM36923_MODEL) {
 			enable_state = LM36923_LED3_EN;
 			break;
 		}

 		ret = -EINVAL;
 		dev_err(&led->client->dev,
 			"LED3 sync not available on this device\n");
 		goto out;
 	}

 	ret = regmap_update_bits(led->regmap, LM3692X_EN, LM3692X_ENABLE_MASK,
 				 enable_state | LM3692X_DEVICE_EN);

 	led->enabled = true;
 	return ret;
 out:
 	dev_err(&led->client->dev, "Fail writing initialization values\n");

 	if (led->enable_gpio)
 		gpiod_direction_output(led->enable_gpio, 0);

 	if (led->regulator) {
 		reg_ret = regulator_disable(led->regulator);
 		if (reg_ret)
 			dev_err(&led->client->dev,
 				"Failed to disable regulator: %d\n", reg_ret);
 	}

 	return ret;
 }

 static int lm3692x_leds_disable(struct lm3692x_led *led)
 {
 	int ret;

 	if (!led->enabled)
 		return 0;

 	ret = regmap_update_bits(led->regmap, LM3692X_EN, LM3692X_DEVICE_EN, 0);
 	if (ret) {
 		dev_err(&led->client->dev, "Failed to disable regulator: %d\n",
 			ret);
 		return ret;
 	}

 	if (led->enable_gpio)
 		gpiod_direction_output(led->enable_gpio, 0);

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

 	led->enabled = false;
 	return ret;
 }

 static int lm3692x_brightness_set(struct led_classdev *led_cdev,
 				enum led_brightness brt_val)
 {
 	struct lm3692x_led *led =
 			container_of(led_cdev, struct lm3692x_led, led_dev);
 	int ret;
 	int led_brightness_lsb = (brt_val >> 5);

 	mutex_lock(&led->lock);

 	if (brt_val == 0) {
 		ret = lm3692x_leds_disable(led);
 		goto out;
 	} else {
 		lm3692x_leds_enable(led);
 	}

 	ret = lm3692x_fault_check(led);
 	if (ret) {
 		dev_err(&led->client->dev, "Cannot read/clear faults: %d\n",
 			ret);
 		goto out;
 	}

 	ret = regmap_write(led->regmap, LM3692X_BRT_MSB, brt_val);
 	if (ret) {
 		dev_err(&led->client->dev, "Cannot write MSB: %d\n", ret);
 		goto out;
 	}

 	ret = regmap_write(led->regmap, LM3692X_BRT_LSB, led_brightness_lsb);
 	if (ret) {
 		dev_err(&led->client->dev, "Cannot write LSB: %d\n", ret);
 		goto out;
 	}
 out:
 	mutex_unlock(&led->lock);
 	return ret;
 }

 static enum led_brightness lm3692x_max_brightness(struct lm3692x_led *led,
 						  u32 max_cur)
 {
 	u32 max_code;

 	/* see p.12 of LM36922 data sheet for brightness formula */
 	max_code = ((max_cur * 1000) - 37806) / 12195;
 	if (max_code > 0x7FF)
 		max_code = 0x7FF;

 	return max_code >> 3;
 }

 static int lm3692x_probe_dt(struct lm3692x_led *led)
 {
 	struct fwnode_handle *child = NULL;
 	struct led_init_data init_data = {};
 	u32 ovp, max_cur;
 	int ret;

 	led->enable_gpio = devm_gpiod_get_optional(&led->client->dev,
 						   "enable", GPIOD_OUT_LOW);
 	if (IS_ERR(led->enable_gpio)) {
 		ret = PTR_ERR(led->enable_gpio);
 		dev_err(&led->client->dev, "Failed to get enable gpio: %d\n",
 			ret);
 		return ret;
 	}

 	led->regulator = devm_regulator_get_optional(&led->client->dev, "vled");
 	if (IS_ERR(led->regulator)) {
 		ret = PTR_ERR(led->regulator);
 		if (ret != -ENODEV) {
 			if (ret != -EPROBE_DEFER)
 				dev_err(&led->client->dev,
 					"Failed to get vled regulator: %d\n",
 					ret);
 			return ret;
 		}
 		led->regulator = NULL;
 	}

 	led->boost_ctrl = LM3692X_BOOST_SW_1MHZ |
 		LM3692X_BOOST_SW_NO_SHIFT |
 		LM3692X_OCP_PROT_1_5A;
 	ret = device_property_read_u32(&led->client->dev,
 				       "ti,ovp-microvolt", &ovp);
 	if (ret) {
 		led->boost_ctrl |= LM3692X_OVP_29V;
 	} else {
 		switch (ovp) {
 		case 17000000:
 			break;
 		case 21000000:
 			led->boost_ctrl |= LM3692X_OVP_21V;
 			break;
 		case 25000000:
 			led->boost_ctrl |= LM3692X_OVP_25V;
 			break;
 		case 29000000:
 			led->boost_ctrl |= LM3692X_OVP_29V;
 			break;
 		default:
 			dev_err(&led->client->dev, "Invalid OVP %d\n", ovp);
 			return -EINVAL;
 		}
 	}

 	child = device_get_next_child_node(&led->client->dev, child);
 	if (!child) {
 		dev_err(&led->client->dev, "No LED Child node\n");
 		return -ENODEV;
 	}

 	fwnode_property_read_string(child, "linux,default-trigger",
 				    &led->led_dev.default_trigger);

 	ret = fwnode_property_read_u32(child, "reg", &led->led_enable);
 	if (ret) {
 		dev_err(&led->client->dev, "reg DT property missing\n");
 		return ret;
 	}

 	ret = fwnode_property_read_u32(child, "led-max-microamp", &max_cur);
 	led->led_dev.max_brightness = ret ? LED_FULL :
 		lm3692x_max_brightness(led, max_cur);

 	init_data.fwnode = child;
 	init_data.devicename = led->client->name;
 	init_data.default_label = ":";

 	ret = devm_led_classdev_register_ext(&led->client->dev, &led->led_dev,
 					     &init_data);
 	if (ret) {
 		dev_err(&led->client->dev, "led register err: %d\n", ret);
 		return ret;
 	}

 	return 0;
 }

 static int lm3692x_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
 	struct lm3692x_led *led;
 	int ret;

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

 	mutex_init(&led->lock);
 	led->client = client;
 	led->led_dev.brightness_set_blocking = lm3692x_brightness_set;
 	led->model_id = id->driver_data;
 	i2c_set_clientdata(client, led);

 	led->regmap = devm_regmap_init_i2c(client, &lm3692x_regmap_config);
 	if (IS_ERR(led->regmap)) {
 		ret = PTR_ERR(led->regmap);
 		dev_err(&client->dev, "Failed to allocate register map: %d\n",
 			ret);
 		return ret;
 	}

 	ret = lm3692x_probe_dt(led);
 	if (ret)
 		return ret;

 	ret = lm3692x_leds_enable(led);
 	if (ret)
 		return ret;

 	return 0;
 }

 static int lm3692x_remove(struct i2c_client *client)
 {
 	struct lm3692x_led *led = i2c_get_clientdata(client);
 	int ret;

 	ret = lm3692x_leds_disable(led);
 	if (ret)
 		return ret;
 	mutex_destroy(&led->lock);

 	return 0;
 }

 static const struct i2c_device_id lm3692x_id[] = {
 	{ "lm36922", LM36922_MODEL },
 	{ "lm36923", LM36923_MODEL },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, lm3692x_id);

 static const struct of_device_id of_lm3692x_leds_match[] = {
 	{ .compatible = "ti,lm36922", },
 	{ .compatible = "ti,lm36923", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);

 static struct i2c_driver lm3692x_driver = {
 	.driver = {
 		.name	= "lm3692x",
 		.of_match_table = of_lm3692x_leds_match,
 	},
 	.probe		= lm3692x_probe,
 	.remove		= lm3692x_remove,
 	.id_table	= lm3692x_id,
 };
 module_i2c_driver(lm3692x_driver);

 MODULE_DESCRIPTION("Texas Instruments LM3692X LED driver");
 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	// TI LM3692x LED chip family driver
	// Copyright (C) 2017-18 Texas Instruments Incorporated - https://www.ti.com/

	#include <linux/gpio/consumer.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/leds.h>
	#include <linux/log2.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/of_gpio.h>
	#include <linux/regmap.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.h>

	#define LM36922_MODEL 0
	#define LM36923_MODEL 1

	#define LM3692X_REV 0x0
	#define LM3692X_RESET 0x1
	#define LM3692X_EN 0x10
	#define LM3692X_BRT_CTRL 0x11
	#define LM3692X_PWM_CTRL 0x12
	#define LM3692X_BOOST_CTRL 0x13
	#define LM3692X_AUTO_FREQ_HI 0x15
	#define LM3692X_AUTO_FREQ_LO 0x16
	#define LM3692X_BL_ADJ_THRESH 0x17
	#define LM3692X_BRT_LSB 0x18
	#define LM3692X_BRT_MSB 0x19
	#define LM3692X_FAULT_CTRL 0x1e
	#define LM3692X_FAULT_FLAGS 0x1f

	#define LM3692X_SW_RESET BIT(0)
	#define LM3692X_DEVICE_EN BIT(0)
	#define LM3692X_LED1_EN BIT(1)
	#define LM3692X_LED2_EN BIT(2)
	#define LM36923_LED3_EN BIT(3)
	#define LM3692X_ENABLE_MASK (LM3692X_DEVICE_EN \| LM3692X_LED1_EN \| \
	LM3692X_LED2_EN \| LM36923_LED3_EN)

	/* Brightness Control Bits */
	#define LM3692X_BL_ADJ_POL BIT(0)
	#define LM3692X_RAMP_RATE_125us 0x00
	#define LM3692X_RAMP_RATE_250us BIT(1)
	#define LM3692X_RAMP_RATE_500us BIT(2)
	#define LM3692X_RAMP_RATE_1ms (BIT(1) \| BIT(2))
	#define LM3692X_RAMP_RATE_2ms BIT(3)
	#define LM3692X_RAMP_RATE_4ms (BIT(3) \| BIT(1))
	#define LM3692X_RAMP_RATE_8ms (BIT(2) \| BIT(3))
	#define LM3692X_RAMP_RATE_16ms (BIT(1) \| BIT(2) \| BIT(3))
	#define LM3692X_RAMP_EN BIT(4)
	#define LM3692X_BRHT_MODE_REG 0x00
	#define LM3692X_BRHT_MODE_PWM BIT(5)
	#define LM3692X_BRHT_MODE_MULTI_RAMP BIT(6)
	#define LM3692X_BRHT_MODE_RAMP_MULTI (BIT(5) \| BIT(6))
	#define LM3692X_MAP_MODE_EXP BIT(7)

	/* PWM Register Bits */
	#define LM3692X_PWM_FILTER_100 BIT(0)
	#define LM3692X_PWM_FILTER_150 BIT(1)
	#define LM3692X_PWM_FILTER_200 (BIT(0) \| BIT(1))
	#define LM3692X_PWM_HYSTER_1LSB BIT(2)
	#define LM3692X_PWM_HYSTER_2LSB BIT(3)
	#define LM3692X_PWM_HYSTER_3LSB (BIT(3) \| BIT(2))
	#define LM3692X_PWM_HYSTER_4LSB BIT(4)
	#define LM3692X_PWM_HYSTER_5LSB (BIT(4) \| BIT(2))
	#define LM3692X_PWM_HYSTER_6LSB (BIT(4) \| BIT(3))
	#define LM3692X_PWM_POLARITY BIT(5)
	#define LM3692X_PWM_SAMP_4MHZ BIT(6)
	#define LM3692X_PWM_SAMP_24MHZ BIT(7)

	/* Boost Control Bits */
	#define LM3692X_OCP_PROT_1A BIT(0)
	#define LM3692X_OCP_PROT_1_25A BIT(1)
	#define LM3692X_OCP_PROT_1_5A (BIT(0) \| BIT(1))
	#define LM3692X_OVP_21V BIT(2)
	#define LM3692X_OVP_25V BIT(3)
	#define LM3692X_OVP_29V (BIT(2) \| BIT(3))
	#define LM3692X_MIN_IND_22UH BIT(4)
	#define LM3692X_BOOST_SW_1MHZ BIT(5)
	#define LM3692X_BOOST_SW_NO_SHIFT BIT(6)

	/* Fault Control Bits */
	#define LM3692X_FAULT_CTRL_OVP BIT(0)
	#define LM3692X_FAULT_CTRL_OCP BIT(1)
	#define LM3692X_FAULT_CTRL_TSD BIT(2)
	#define LM3692X_FAULT_CTRL_OPEN BIT(3)

	/* Fault Flag Bits */
	#define LM3692X_FAULT_FLAG_OVP BIT(0)
	#define LM3692X_FAULT_FLAG_OCP BIT(1)
	#define LM3692X_FAULT_FLAG_TSD BIT(2)
	#define LM3692X_FAULT_FLAG_SHRT BIT(3)
	#define LM3692X_FAULT_FLAG_OPEN BIT(4)

	/**
	* struct lm3692x_led -
	* @lock - Lock for reading/writing the device
	* @client - Pointer to the I2C client
	* @led_dev - LED class device pointer
	* @regmap - Devices register map
	* @enable_gpio - VDDIO/EN gpio to enable communication interface
	* @regulator - LED supply regulator pointer
	* @led_enable - LED sync to be enabled
	* @model_id - Current device model ID enumerated
	*/
	struct lm3692x_led {
	struct mutex lock;
	struct i2c_client *client;
	struct led_classdev led_dev;
	struct regmap *regmap;
	struct gpio_desc *enable_gpio;
	struct regulator *regulator;
	int led_enable;
	int model_id;

	u8 boost_ctrl, brightness_ctrl;
	bool enabled;
	};

	static const struct reg_default lm3692x_reg_defs[] = {
	{LM3692X_EN, 0xf},
	{LM3692X_BRT_CTRL, 0x61},
	{LM3692X_PWM_CTRL, 0x73},
	{LM3692X_BOOST_CTRL, 0x6f},
	{LM3692X_AUTO_FREQ_HI, 0x0},
	{LM3692X_AUTO_FREQ_LO, 0x0},
	{LM3692X_BL_ADJ_THRESH, 0x0},
	{LM3692X_BRT_LSB, 0x7},
	{LM3692X_BRT_MSB, 0xff},
	{LM3692X_FAULT_CTRL, 0x7},
	};

	static const struct regmap_config lm3692x_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,

	.max_register = LM3692X_FAULT_FLAGS,
	.reg_defaults = lm3692x_reg_defs,
	.num_reg_defaults = ARRAY_SIZE(lm3692x_reg_defs),
	.cache_type = REGCACHE_RBTREE,
	};

	static int lm3692x_fault_check(struct lm3692x_led *led)
	{
	int ret;
	unsigned int read_buf;

	ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
	if (ret)
	return ret;

	if (read_buf)
	dev_err(&led->client->dev, "Detected a fault 0x%X\n", read_buf);

	/* The first read may clear the fault. Check again to see if the fault
	* still exits and return that value.
	*/
	regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
	if (read_buf)
	dev_err(&led->client->dev, "Second read of fault flags 0x%X\n",
	read_buf);

	return read_buf;
	}

	static int lm3692x_leds_enable(struct lm3692x_led *led)
	{
	int enable_state;
	int ret, reg_ret;

	if (led->enabled)
	return 0;

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

	if (led->enable_gpio)
	gpiod_direction_output(led->enable_gpio, 1);

	ret = lm3692x_fault_check(led);
	if (ret) {
	dev_err(&led->client->dev, "Cannot read/clear faults: %d\n",
	ret);
	goto out;
	}

	ret = regmap_write(led->regmap, LM3692X_BRT_CTRL, 0x00);
	if (ret)
	goto out;

	/*
	* For glitch free operation, the following data should
	* only be written while LEDx enable bits are 0 and the device enable
	* bit is set to 1.
	* per Section 7.5.14 of the data sheet
	*/
	ret = regmap_write(led->regmap, LM3692X_EN, LM3692X_DEVICE_EN);
	if (ret)
	goto out;

	/* Set the brightness to 0 so when enabled the LEDs do not come
	* on with full brightness.
	*/
	ret = regmap_write(led->regmap, LM3692X_BRT_MSB, 0);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_BRT_LSB, 0);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_PWM_CTRL,
	LM3692X_PWM_FILTER_100 \| LM3692X_PWM_SAMP_24MHZ);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL, led->boost_ctrl);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
	if (ret)
	goto out;

	ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
	LM3692X_BL_ADJ_POL \| LM3692X_RAMP_EN);
	if (ret)
	goto out;

	switch (led->led_enable) {
	case 0:
	default:
	if (led->model_id == LM36923_MODEL)
	enable_state = LM3692X_LED1_EN \| LM3692X_LED2_EN \|
	LM36923_LED3_EN;
	else
	enable_state = LM3692X_LED1_EN \| LM3692X_LED2_EN;

	break;
	case 1:
	enable_state = LM3692X_LED1_EN;
	break;
	case 2:
	enable_state = LM3692X_LED2_EN;
	break;

	case 3:
	if (led->model_id == LM36923_MODEL) {
	enable_state = LM36923_LED3_EN;
	break;
	}

	ret = -EINVAL;
	dev_err(&led->client->dev,
	"LED3 sync not available on this device\n");
	goto out;
	}

	ret = regmap_update_bits(led->regmap, LM3692X_EN, LM3692X_ENABLE_MASK,
	enable_state \| LM3692X_DEVICE_EN);

	led->enabled = true;
	return ret;
	out:
	dev_err(&led->client->dev, "Fail writing initialization values\n");

	if (led->enable_gpio)
	gpiod_direction_output(led->enable_gpio, 0);

	if (led->regulator) {
	reg_ret = regulator_disable(led->regulator);
	if (reg_ret)
	dev_err(&led->client->dev,
	"Failed to disable regulator: %d\n", reg_ret);
	}

	return ret;
	}

	static int lm3692x_leds_disable(struct lm3692x_led *led)
	{
	int ret;

	if (!led->enabled)
	return 0;

	ret = regmap_update_bits(led->regmap, LM3692X_EN, LM3692X_DEVICE_EN, 0);
	if (ret) {
	dev_err(&led->client->dev, "Failed to disable regulator: %d\n",
	ret);
	return ret;
	}

	if (led->enable_gpio)
	gpiod_direction_output(led->enable_gpio, 0);

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

	led->enabled = false;
	return ret;
	}

	static int lm3692x_brightness_set(struct led_classdev *led_cdev,
	enum led_brightness brt_val)
	{
	struct lm3692x_led *led =
	container_of(led_cdev, struct lm3692x_led, led_dev);
	int ret;
	int led_brightness_lsb = (brt_val >> 5);

	mutex_lock(&led->lock);

	if (brt_val == 0) {
	ret = lm3692x_leds_disable(led);
	goto out;
	} else {
	lm3692x_leds_enable(led);
	}

	ret = lm3692x_fault_check(led);
	if (ret) {
	dev_err(&led->client->dev, "Cannot read/clear faults: %d\n",
	ret);
	goto out;
	}

	ret = regmap_write(led->regmap, LM3692X_BRT_MSB, brt_val);
	if (ret) {
	dev_err(&led->client->dev, "Cannot write MSB: %d\n", ret);
	goto out;
	}

	ret = regmap_write(led->regmap, LM3692X_BRT_LSB, led_brightness_lsb);
	if (ret) {
	dev_err(&led->client->dev, "Cannot write LSB: %d\n", ret);
	goto out;
	}
	out:
	mutex_unlock(&led->lock);
	return ret;
	}

	static enum led_brightness lm3692x_max_brightness(struct lm3692x_led *led,
	u32 max_cur)
	{
	u32 max_code;

	/* see p.12 of LM36922 data sheet for brightness formula */
	max_code = ((max_cur * 1000) - 37806) / 12195;
	if (max_code > 0x7FF)
	max_code = 0x7FF;

	return max_code >> 3;
	}

	static int lm3692x_probe_dt(struct lm3692x_led *led)
	{
	struct fwnode_handle *child = NULL;
	struct led_init_data init_data = {};
	u32 ovp, max_cur;
	int ret;

	led->enable_gpio = devm_gpiod_get_optional(&led->client->dev,
	"enable", GPIOD_OUT_LOW);
	if (IS_ERR(led->enable_gpio)) {
	ret = PTR_ERR(led->enable_gpio);
	dev_err(&led->client->dev, "Failed to get enable gpio: %d\n",
	ret);
	return ret;
	}

	led->regulator = devm_regulator_get_optional(&led->client->dev, "vled");
	if (IS_ERR(led->regulator)) {
	ret = PTR_ERR(led->regulator);
	if (ret != -ENODEV) {
	if (ret != -EPROBE_DEFER)
	dev_err(&led->client->dev,
	"Failed to get vled regulator: %d\n",
	ret);
	return ret;
	}
	led->regulator = NULL;
	}

	led->boost_ctrl = LM3692X_BOOST_SW_1MHZ \|
	LM3692X_BOOST_SW_NO_SHIFT \|
	LM3692X_OCP_PROT_1_5A;
	ret = device_property_read_u32(&led->client->dev,
	"ti,ovp-microvolt", &ovp);
	if (ret) {
	led->boost_ctrl \|= LM3692X_OVP_29V;
	} else {
	switch (ovp) {
	case 17000000:
	break;
	case 21000000:
	led->boost_ctrl \|= LM3692X_OVP_21V;
	break;
	case 25000000:
	led->boost_ctrl \|= LM3692X_OVP_25V;
	break;
	case 29000000:
	led->boost_ctrl \|= LM3692X_OVP_29V;
	break;
	default:
	dev_err(&led->client->dev, "Invalid OVP %d\n", ovp);
	return -EINVAL;
	}
	}

	child = device_get_next_child_node(&led->client->dev, child);
	if (!child) {
	dev_err(&led->client->dev, "No LED Child node\n");
	return -ENODEV;
	}

	fwnode_property_read_string(child, "linux,default-trigger",
	&led->led_dev.default_trigger);

	ret = fwnode_property_read_u32(child, "reg", &led->led_enable);
	if (ret) {
	dev_err(&led->client->dev, "reg DT property missing\n");
	return ret;
	}

	ret = fwnode_property_read_u32(child, "led-max-microamp", &max_cur);
	led->led_dev.max_brightness = ret ? LED_FULL :
	lm3692x_max_brightness(led, max_cur);

	init_data.fwnode = child;
	init_data.devicename = led->client->name;
	init_data.default_label = ":";

	ret = devm_led_classdev_register_ext(&led->client->dev, &led->led_dev,
	&init_data);
	if (ret) {
	dev_err(&led->client->dev, "led register err: %d\n", ret);
	return ret;
	}

	return 0;
	}

	static int lm3692x_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct lm3692x_led *led;
	int ret;

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

	mutex_init(&led->lock);
	led->client = client;
	led->led_dev.brightness_set_blocking = lm3692x_brightness_set;
	led->model_id = id->driver_data;
	i2c_set_clientdata(client, led);

	led->regmap = devm_regmap_init_i2c(client, &lm3692x_regmap_config);
	if (IS_ERR(led->regmap)) {
	ret = PTR_ERR(led->regmap);
	dev_err(&client->dev, "Failed to allocate register map: %d\n",
	ret);
	return ret;
	}

	ret = lm3692x_probe_dt(led);
	if (ret)
	return ret;

	ret = lm3692x_leds_enable(led);
	if (ret)
	return ret;

	return 0;
	}

	static int lm3692x_remove(struct i2c_client *client)
	{
	struct lm3692x_led *led = i2c_get_clientdata(client);
	int ret;

	ret = lm3692x_leds_disable(led);
	if (ret)
	return ret;
	mutex_destroy(&led->lock);

	return 0;
	}

	static const struct i2c_device_id lm3692x_id[] = {
	{ "lm36922", LM36922_MODEL },
	{ "lm36923", LM36923_MODEL },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, lm3692x_id);

	static const struct of_device_id of_lm3692x_leds_match[] = {
	{ .compatible = "ti,lm36922", },
	{ .compatible = "ti,lm36923", },
	{},
	};
	MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);

	static struct i2c_driver lm3692x_driver = {
	.driver = {
	.name = "lm3692x",
	.of_match_table = of_lm3692x_leds_match,
	},
	.probe = lm3692x_probe,
	.remove = lm3692x_remove,
	.id_table = lm3692x_id,
	};
	module_i2c_driver(lm3692x_driver);

	MODULE_DESCRIPTION("Texas Instruments LM3692X LED driver");
	MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
	MODULE_LICENSE("GPL v2");