drivers/video/backlight/lm3630a_bl.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
 * Simple driver for Texas Instruments LM3630A Backlight driver chip
 * Copyright (C) 2012 Texas Instruments
 */
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/backlight.h>
 #include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/uaccess.h>
 #include <linux/interrupt.h>
 #include <linux/regmap.h>
 #include <linux/gpio/consumer.h>
 #include <linux/pwm.h>
 #include <linux/platform_data/lm3630a_bl.h>

 #define REG_CTRL	0x00
 #define REG_BOOST	0x02
 #define REG_CONFIG	0x01
 #define REG_BRT_A	0x03
 #define REG_BRT_B	0x04
 #define REG_I_A		0x05
 #define REG_I_B		0x06
 #define REG_INT_STATUS	0x09
 #define REG_INT_EN	0x0A
 #define REG_FAULT	0x0B
 #define REG_PWM_OUTLOW	0x12
 #define REG_PWM_OUTHIGH	0x13
 #define REG_FILTER_STRENGTH	0x50
 #define REG_MAX		0x50

 #define INT_DEBOUNCE_MSEC	10

 #define LM3630A_BANK_0		0
 #define LM3630A_BANK_1		1

 #define LM3630A_NUM_SINKS	2
 #define LM3630A_SINK_0		0
 #define LM3630A_SINK_1		1

 struct lm3630a_chip {
 	struct device *dev;
 	struct delayed_work work;

 	int irq;
 	struct workqueue_struct *irqthread;
 	struct lm3630a_platform_data *pdata;
 	struct backlight_device *bleda;
 	struct backlight_device *bledb;
 	struct gpio_desc *enable_gpio;
 	struct regmap *regmap;
 	struct pwm_device *pwmd;
 };

 /* i2c access */
 static int lm3630a_read(struct lm3630a_chip *pchip, unsigned int reg)
 {
 	int rval;
 	unsigned int reg_val;

 	rval = regmap_read(pchip->regmap, reg, &reg_val);
 	if (rval < 0)
 		return rval;
 	return reg_val & 0xFF;
 }

 static int lm3630a_write(struct lm3630a_chip *pchip,
 			 unsigned int reg, unsigned int data)
 {
 	return regmap_write(pchip->regmap, reg, data);
 }

 static int lm3630a_update(struct lm3630a_chip *pchip,
 			  unsigned int reg, unsigned int mask,
 			  unsigned int data)
 {
 	return regmap_update_bits(pchip->regmap, reg, mask, data);
 }

 /* initialize chip */
 static int lm3630a_chip_init(struct lm3630a_chip *pchip)
 {
 	int rval;
 	struct lm3630a_platform_data *pdata = pchip->pdata;

 	usleep_range(1000, 2000);
 	/* set Filter Strength Register */
 	rval = lm3630a_write(pchip, REG_FILTER_STRENGTH, 0x03);
 	/* set Cofig. register */
 	rval |= lm3630a_update(pchip, REG_CONFIG, 0x07, pdata->pwm_ctrl);
 	/* set boost control */
 	rval |= lm3630a_write(pchip, REG_BOOST, 0x38);
 	/* set current A */
 	rval |= lm3630a_update(pchip, REG_I_A, 0x1F, 0x1F);
 	/* set current B */
 	rval |= lm3630a_write(pchip, REG_I_B, 0x1F);
 	/* set control */
 	rval |= lm3630a_update(pchip, REG_CTRL, 0x14, pdata->leda_ctrl);
 	rval |= lm3630a_update(pchip, REG_CTRL, 0x0B, pdata->ledb_ctrl);
 	usleep_range(1000, 2000);
 	/* set brightness A and B */
 	rval |= lm3630a_write(pchip, REG_BRT_A, pdata->leda_init_brt);
 	rval |= lm3630a_write(pchip, REG_BRT_B, pdata->ledb_init_brt);

 	if (rval < 0)
 		dev_err(pchip->dev, "i2c failed to access register\n");
 	return rval;
 }

 /* interrupt handling */
 static void lm3630a_delayed_func(struct work_struct *work)
 {
 	int rval;
 	struct lm3630a_chip *pchip;

 	pchip = container_of(work, struct lm3630a_chip, work.work);

 	rval = lm3630a_read(pchip, REG_INT_STATUS);
 	if (rval < 0) {
 		dev_err(pchip->dev,
 			"i2c failed to access REG_INT_STATUS Register\n");
 		return;
 	}

 	dev_info(pchip->dev, "REG_INT_STATUS Register is 0x%x\n", rval);
 }

 static irqreturn_t lm3630a_isr_func(int irq, void *chip)
 {
 	int rval;
 	struct lm3630a_chip *pchip = chip;
 	unsigned long delay = msecs_to_jiffies(INT_DEBOUNCE_MSEC);

 	queue_delayed_work(pchip->irqthread, &pchip->work, delay);

 	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
 	if (rval < 0) {
 		dev_err(pchip->dev, "i2c failed to access register\n");
 		return IRQ_NONE;
 	}
 	return IRQ_HANDLED;
 }

 static int lm3630a_intr_config(struct lm3630a_chip *pchip)
 {
 	int rval;

 	rval = lm3630a_write(pchip, REG_INT_EN, 0x87);
 	if (rval < 0)
 		return rval;

 	INIT_DELAYED_WORK(&pchip->work, lm3630a_delayed_func);
 	pchip->irqthread = create_singlethread_workqueue("lm3630a-irqthd");
 	if (!pchip->irqthread) {
 		dev_err(pchip->dev, "create irq thread fail\n");
 		return -ENOMEM;
 	}
 	if (request_threaded_irq
 	    (pchip->irq, NULL, lm3630a_isr_func,
 	     IRQF_TRIGGER_FALLING | IRQF_ONESHOT, "lm3630a_irq", pchip)) {
 		dev_err(pchip->dev, "request threaded irq fail\n");
 		destroy_workqueue(pchip->irqthread);
 		return -ENOMEM;
 	}
 	return rval;
 }

 static void lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
 {
 	unsigned int period = pchip->pdata->pwm_period;
 	unsigned int duty = br * period / br_max;

 	pwm_config(pchip->pwmd, duty, period);
 	if (duty)
 		pwm_enable(pchip->pwmd);
 	else
 		pwm_disable(pchip->pwmd);
 }

 /* update and get brightness */
 static int lm3630a_bank_a_update_status(struct backlight_device *bl)
 {
 	int ret;
 	struct lm3630a_chip *pchip = bl_get_data(bl);
 	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

 	/* pwm control */
 	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) {
 		lm3630a_pwm_ctrl(pchip, bl->props.brightness,
 				 bl->props.max_brightness);
 		return 0;
 	}

 	/* disable sleep */
 	ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
 	if (ret < 0)
 		goto out_i2c_err;
 	usleep_range(1000, 2000);
 	/* minimum brightness is 0x04 */
 	ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness);
 	if (bl->props.brightness < 0x4)
 		ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDA_ENABLE, 0);
 	else
 		ret |= lm3630a_update(pchip, REG_CTRL,
 				      LM3630A_LEDA_ENABLE, LM3630A_LEDA_ENABLE);
 	if (ret < 0)
 		goto out_i2c_err;
 	return 0;

 out_i2c_err:
 	dev_err(pchip->dev, "i2c failed to access (%pe)\n", ERR_PTR(ret));
 	return ret;
 }

 static int lm3630a_bank_a_get_brightness(struct backlight_device *bl)
 {
 	int brightness, rval;
 	struct lm3630a_chip *pchip = bl_get_data(bl);
 	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

 	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) {
 		rval = lm3630a_read(pchip, REG_PWM_OUTHIGH);
 		if (rval < 0)
 			goto out_i2c_err;
 		brightness = (rval & 0x01) << 8;
 		rval = lm3630a_read(pchip, REG_PWM_OUTLOW);
 		if (rval < 0)
 			goto out_i2c_err;
 		brightness |= rval;
 		goto out;
 	}

 	/* disable sleep */
 	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
 	if (rval < 0)
 		goto out_i2c_err;
 	usleep_range(1000, 2000);
 	rval = lm3630a_read(pchip, REG_BRT_A);
 	if (rval < 0)
 		goto out_i2c_err;
 	brightness = rval;

 out:
 	bl->props.brightness = brightness;
 	return bl->props.brightness;
 out_i2c_err:
 	dev_err(pchip->dev, "i2c failed to access register\n");
 	return 0;
 }

 static const struct backlight_ops lm3630a_bank_a_ops = {
 	.options = BL_CORE_SUSPENDRESUME,
 	.update_status = lm3630a_bank_a_update_status,
 	.get_brightness = lm3630a_bank_a_get_brightness,
 };

 /* update and get brightness */
 static int lm3630a_bank_b_update_status(struct backlight_device *bl)
 {
 	int ret;
 	struct lm3630a_chip *pchip = bl_get_data(bl);
 	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

 	/* pwm control */
 	if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) {
 		lm3630a_pwm_ctrl(pchip, bl->props.brightness,
 				 bl->props.max_brightness);
 		return 0;
 	}

 	/* disable sleep */
 	ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
 	if (ret < 0)
 		goto out_i2c_err;
 	usleep_range(1000, 2000);
 	/* minimum brightness is 0x04 */
 	ret = lm3630a_write(pchip, REG_BRT_B, bl->props.brightness);
 	if (bl->props.brightness < 0x4)
 		ret |= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDB_ENABLE, 0);
 	else
 		ret |= lm3630a_update(pchip, REG_CTRL,
 				      LM3630A_LEDB_ENABLE, LM3630A_LEDB_ENABLE);
 	if (ret < 0)
 		goto out_i2c_err;
 	return 0;

 out_i2c_err:
 	dev_err(pchip->dev, "i2c failed to access (%pe)\n", ERR_PTR(ret));
 	return ret;
 }

 static int lm3630a_bank_b_get_brightness(struct backlight_device *bl)
 {
 	int brightness, rval;
 	struct lm3630a_chip *pchip = bl_get_data(bl);
 	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

 	if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) {
 		rval = lm3630a_read(pchip, REG_PWM_OUTHIGH);
 		if (rval < 0)
 			goto out_i2c_err;
 		brightness = (rval & 0x01) << 8;
 		rval = lm3630a_read(pchip, REG_PWM_OUTLOW);
 		if (rval < 0)
 			goto out_i2c_err;
 		brightness |= rval;
 		goto out;
 	}

 	/* disable sleep */
 	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
 	if (rval < 0)
 		goto out_i2c_err;
 	usleep_range(1000, 2000);
 	rval = lm3630a_read(pchip, REG_BRT_B);
 	if (rval < 0)
 		goto out_i2c_err;
 	brightness = rval;

 out:
 	bl->props.brightness = brightness;
 	return bl->props.brightness;
 out_i2c_err:
 	dev_err(pchip->dev, "i2c failed to access register\n");
 	return 0;
 }

 static const struct backlight_ops lm3630a_bank_b_ops = {
 	.options = BL_CORE_SUSPENDRESUME,
 	.update_status = lm3630a_bank_b_update_status,
 	.get_brightness = lm3630a_bank_b_get_brightness,
 };

 static int lm3630a_backlight_register(struct lm3630a_chip *pchip)
 {
 	struct lm3630a_platform_data *pdata = pchip->pdata;
 	struct backlight_properties props;
 	const char *label;

 	props.type = BACKLIGHT_RAW;
 	if (pdata->leda_ctrl != LM3630A_LEDA_DISABLE) {
 		props.brightness = pdata->leda_init_brt;
 		props.max_brightness = pdata->leda_max_brt;
 		label = pdata->leda_label ? pdata->leda_label : "lm3630a_leda";
 		pchip->bleda =
 		    devm_backlight_device_register(pchip->dev, label,
 						   pchip->dev, pchip,
 						   &lm3630a_bank_a_ops, &props);
 		if (IS_ERR(pchip->bleda))
 			return PTR_ERR(pchip->bleda);
 	}

 	if ((pdata->ledb_ctrl != LM3630A_LEDB_DISABLE) &&
 	    (pdata->ledb_ctrl != LM3630A_LEDB_ON_A)) {
 		props.brightness = pdata->ledb_init_brt;
 		props.max_brightness = pdata->ledb_max_brt;
 		label = pdata->ledb_label ? pdata->ledb_label : "lm3630a_ledb";
 		pchip->bledb =
 		    devm_backlight_device_register(pchip->dev, label,
 						   pchip->dev, pchip,
 						   &lm3630a_bank_b_ops, &props);
 		if (IS_ERR(pchip->bledb))
 			return PTR_ERR(pchip->bledb);
 	}
 	return 0;
 }

 static const struct regmap_config lm3630a_regmap = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.max_register = REG_MAX,
 };

 static int lm3630a_parse_led_sources(struct fwnode_handle *node,
 				     int default_led_sources)
 {
 	u32 sources[LM3630A_NUM_SINKS];
 	int ret, num_sources, i;

 	num_sources = fwnode_property_count_u32(node, "led-sources");
 	if (num_sources < 0)
 		return default_led_sources;
 	else if (num_sources > ARRAY_SIZE(sources))
 		return -EINVAL;

 	ret = fwnode_property_read_u32_array(node, "led-sources", sources,
 					     num_sources);
 	if (ret)
 		return ret;

 	for (i = 0; i < num_sources; i++) {
 		if (sources[i] != LM3630A_SINK_0 && sources[i] != LM3630A_SINK_1)
 			return -EINVAL;

 		ret |= BIT(sources[i]);
 	}

 	return ret;
 }

 static int lm3630a_parse_bank(struct lm3630a_platform_data *pdata,
 			      struct fwnode_handle *node, int *seen_led_sources)
 {
 	int led_sources, ret;
 	const char *label;
 	u32 bank, val;
 	bool linear;

 	ret = fwnode_property_read_u32(node, "reg", &bank);
 	if (ret)
 		return ret;

 	if (bank != LM3630A_BANK_0 && bank != LM3630A_BANK_1)
 		return -EINVAL;

 	led_sources = lm3630a_parse_led_sources(node, BIT(bank));
 	if (led_sources < 0)
 		return led_sources;

 	if (*seen_led_sources & led_sources)
 		return -EINVAL;

 	*seen_led_sources |= led_sources;

 	linear = fwnode_property_read_bool(node,
 					   "ti,linear-mapping-mode");
 	if (bank) {
 		if (led_sources & BIT(LM3630A_SINK_0) ||
 		    !(led_sources & BIT(LM3630A_SINK_1)))
 			return -EINVAL;

 		pdata->ledb_ctrl = linear ?
 			LM3630A_LEDB_ENABLE_LINEAR :
 			LM3630A_LEDB_ENABLE;
 	} else {
 		if (!(led_sources & BIT(LM3630A_SINK_0)))
 			return -EINVAL;

 		pdata->leda_ctrl = linear ?
 			LM3630A_LEDA_ENABLE_LINEAR :
 			LM3630A_LEDA_ENABLE;

 		if (led_sources & BIT(LM3630A_SINK_1))
 			pdata->ledb_ctrl = LM3630A_LEDB_ON_A;
 	}

 	ret = fwnode_property_read_string(node, "label", &label);
 	if (!ret) {
 		if (bank)
 			pdata->ledb_label = label;
 		else
 			pdata->leda_label = label;
 	}

 	ret = fwnode_property_read_u32(node, "default-brightness",
 				       &val);
 	if (!ret) {
 		if (bank)
 			pdata->ledb_init_brt = val;
 		else
 			pdata->leda_init_brt = val;
 	}

 	ret = fwnode_property_read_u32(node, "max-brightness", &val);
 	if (!ret) {
 		if (bank)
 			pdata->ledb_max_brt = val;
 		else
 			pdata->leda_max_brt = val;
 	}

 	return 0;
 }

 static int lm3630a_parse_node(struct lm3630a_chip *pchip,
 			      struct lm3630a_platform_data *pdata)
 {
 	int ret = -ENODEV, seen_led_sources = 0;
 	struct fwnode_handle *node;

 	device_for_each_child_node(pchip->dev, node) {
 		ret = lm3630a_parse_bank(pdata, node, &seen_led_sources);
 		if (ret) {
 			fwnode_handle_put(node);
 			return ret;
 		}
 	}

 	return ret;
 }

 static int lm3630a_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct lm3630a_platform_data *pdata = dev_get_platdata(&client->dev);
 	struct lm3630a_chip *pchip;
 	int rval;

 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		dev_err(&client->dev, "fail : i2c functionality check\n");
 		return -EOPNOTSUPP;
 	}

 	pchip = devm_kzalloc(&client->dev, sizeof(struct lm3630a_chip),
 			     GFP_KERNEL);
 	if (!pchip)
 		return -ENOMEM;
 	pchip->dev = &client->dev;

 	pchip->regmap = devm_regmap_init_i2c(client, &lm3630a_regmap);
 	if (IS_ERR(pchip->regmap)) {
 		rval = PTR_ERR(pchip->regmap);
 		dev_err(&client->dev, "fail : allocate reg. map: %d\n", rval);
 		return rval;
 	}

 	i2c_set_clientdata(client, pchip);
 	if (pdata == NULL) {
 		pdata = devm_kzalloc(pchip->dev,
 				     sizeof(struct lm3630a_platform_data),
 				     GFP_KERNEL);
 		if (pdata == NULL)
 			return -ENOMEM;

 		/* default values */
 		pdata->leda_max_brt = LM3630A_MAX_BRIGHTNESS;
 		pdata->ledb_max_brt = LM3630A_MAX_BRIGHTNESS;
 		pdata->leda_init_brt = LM3630A_MAX_BRIGHTNESS;
 		pdata->ledb_init_brt = LM3630A_MAX_BRIGHTNESS;

 		rval = lm3630a_parse_node(pchip, pdata);
 		if (rval) {
 			dev_err(&client->dev, "fail : parse node\n");
 			return rval;
 		}
 	}
 	pchip->pdata = pdata;

 	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
 						GPIOD_OUT_HIGH);
 	if (IS_ERR(pchip->enable_gpio)) {
 		rval = PTR_ERR(pchip->enable_gpio);
 		return rval;
 	}

 	/* chip initialize */
 	rval = lm3630a_chip_init(pchip);
 	if (rval < 0) {
 		dev_err(&client->dev, "fail : init chip\n");
 		return rval;
 	}
 	/* backlight register */
 	rval = lm3630a_backlight_register(pchip);
 	if (rval < 0) {
 		dev_err(&client->dev, "fail : backlight register.\n");
 		return rval;
 	}
 	/* pwm */
 	if (pdata->pwm_ctrl != LM3630A_PWM_DISABLE) {
 		pchip->pwmd = devm_pwm_get(pchip->dev, "lm3630a-pwm");
 		if (IS_ERR(pchip->pwmd)) {
 			dev_err(&client->dev, "fail : get pwm device\n");
 			return PTR_ERR(pchip->pwmd);
 		}

 		/*
 		 * FIXME: pwm_apply_args() should be removed when switching to
 		 * the atomic PWM API.
 		 */
 		pwm_apply_args(pchip->pwmd);
 	}

 	/* interrupt enable  : irq 0 is not allowed */
 	pchip->irq = client->irq;
 	if (pchip->irq) {
 		rval = lm3630a_intr_config(pchip);
 		if (rval < 0)
 			return rval;
 	}
 	dev_info(&client->dev, "LM3630A backlight register OK.\n");
 	return 0;
 }

 static int lm3630a_remove(struct i2c_client *client)
 {
 	int rval;
 	struct lm3630a_chip *pchip = i2c_get_clientdata(client);

 	rval = lm3630a_write(pchip, REG_BRT_A, 0);
 	if (rval < 0)
 		dev_err(pchip->dev, "i2c failed to access register\n");

 	rval = lm3630a_write(pchip, REG_BRT_B, 0);
 	if (rval < 0)
 		dev_err(pchip->dev, "i2c failed to access register\n");

 	if (pchip->irq) {
 		free_irq(pchip->irq, pchip);
 		flush_workqueue(pchip->irqthread);
 		destroy_workqueue(pchip->irqthread);
 	}
 	return 0;
 }

 static const struct i2c_device_id lm3630a_id[] = {
 	{LM3630A_NAME, 0},
 	{}
 };

 MODULE_DEVICE_TABLE(i2c, lm3630a_id);

 static const struct of_device_id lm3630a_match_table[] = {
 	{ .compatible = "ti,lm3630a", },
 	{ },
 };

 MODULE_DEVICE_TABLE(of, lm3630a_match_table);

 static struct i2c_driver lm3630a_i2c_driver = {
 	.driver = {
 		   .name = LM3630A_NAME,
 		   .of_match_table = lm3630a_match_table,
 		   },
 	.probe = lm3630a_probe,
 	.remove = lm3630a_remove,
 	.id_table = lm3630a_id,
 };

 module_i2c_driver(lm3630a_i2c_driver);

 MODULE_DESCRIPTION("Texas Instruments Backlight driver for LM3630A");
 MODULE_AUTHOR("Daniel Jeong <gshark.jeong@gmail.com>");
 MODULE_AUTHOR("LDD MLP <ldd-mlp@list.ti.com>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Simple driver for Texas Instruments LM3630A Backlight driver chip
	* Copyright (C) 2012 Texas Instruments
	*/
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/i2c.h>
	#include <linux/backlight.h>
	#include <linux/err.h>
	#include <linux/delay.h>
	#include <linux/uaccess.h>
	#include <linux/interrupt.h>
	#include <linux/regmap.h>
	#include <linux/gpio/consumer.h>
	#include <linux/pwm.h>
	#include <linux/platform_data/lm3630a_bl.h>

	#define REG_CTRL 0x00
	#define REG_BOOST 0x02
	#define REG_CONFIG 0x01
	#define REG_BRT_A 0x03
	#define REG_BRT_B 0x04
	#define REG_I_A 0x05
	#define REG_I_B 0x06
	#define REG_INT_STATUS 0x09
	#define REG_INT_EN 0x0A
	#define REG_FAULT 0x0B
	#define REG_PWM_OUTLOW 0x12
	#define REG_PWM_OUTHIGH 0x13
	#define REG_FILTER_STRENGTH 0x50
	#define REG_MAX 0x50

	#define INT_DEBOUNCE_MSEC 10

	#define LM3630A_BANK_0 0
	#define LM3630A_BANK_1 1

	#define LM3630A_NUM_SINKS 2
	#define LM3630A_SINK_0 0
	#define LM3630A_SINK_1 1

	struct lm3630a_chip {
	struct device *dev;
	struct delayed_work work;

	int irq;
	struct workqueue_struct *irqthread;
	struct lm3630a_platform_data *pdata;
	struct backlight_device *bleda;
	struct backlight_device *bledb;
	struct gpio_desc *enable_gpio;
	struct regmap *regmap;
	struct pwm_device *pwmd;
	};

	/* i2c access */
	static int lm3630a_read(struct lm3630a_chip *pchip, unsigned int reg)
	{
	int rval;
	unsigned int reg_val;

	rval = regmap_read(pchip->regmap, reg, &reg_val);
	if (rval < 0)
	return rval;
	return reg_val & 0xFF;
	}

	static int lm3630a_write(struct lm3630a_chip *pchip,
	unsigned int reg, unsigned int data)
	{
	return regmap_write(pchip->regmap, reg, data);
	}

	static int lm3630a_update(struct lm3630a_chip *pchip,
	unsigned int reg, unsigned int mask,
	unsigned int data)
	{
	return regmap_update_bits(pchip->regmap, reg, mask, data);
	}

	/* initialize chip */
	static int lm3630a_chip_init(struct lm3630a_chip *pchip)
	{
	int rval;
	struct lm3630a_platform_data *pdata = pchip->pdata;

	usleep_range(1000, 2000);
	/* set Filter Strength Register */
	rval = lm3630a_write(pchip, REG_FILTER_STRENGTH, 0x03);
	/* set Cofig. register */
	rval \|= lm3630a_update(pchip, REG_CONFIG, 0x07, pdata->pwm_ctrl);
	/* set boost control */
	rval \|= lm3630a_write(pchip, REG_BOOST, 0x38);
	/* set current A */
	rval \|= lm3630a_update(pchip, REG_I_A, 0x1F, 0x1F);
	/* set current B */
	rval \|= lm3630a_write(pchip, REG_I_B, 0x1F);
	/* set control */
	rval \|= lm3630a_update(pchip, REG_CTRL, 0x14, pdata->leda_ctrl);
	rval \|= lm3630a_update(pchip, REG_CTRL, 0x0B, pdata->ledb_ctrl);
	usleep_range(1000, 2000);
	/* set brightness A and B */
	rval \|= lm3630a_write(pchip, REG_BRT_A, pdata->leda_init_brt);
	rval \|= lm3630a_write(pchip, REG_BRT_B, pdata->ledb_init_brt);

	if (rval < 0)
	dev_err(pchip->dev, "i2c failed to access register\n");
	return rval;
	}

	/* interrupt handling */
	static void lm3630a_delayed_func(struct work_struct *work)
	{
	int rval;
	struct lm3630a_chip *pchip;

	pchip = container_of(work, struct lm3630a_chip, work.work);

	rval = lm3630a_read(pchip, REG_INT_STATUS);
	if (rval < 0) {
	dev_err(pchip->dev,
	"i2c failed to access REG_INT_STATUS Register\n");
	return;
	}

	dev_info(pchip->dev, "REG_INT_STATUS Register is 0x%x\n", rval);
	}

	static irqreturn_t lm3630a_isr_func(int irq, void *chip)
	{
	int rval;
	struct lm3630a_chip *pchip = chip;
	unsigned long delay = msecs_to_jiffies(INT_DEBOUNCE_MSEC);

	queue_delayed_work(pchip->irqthread, &pchip->work, delay);

	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
	if (rval < 0) {
	dev_err(pchip->dev, "i2c failed to access register\n");
	return IRQ_NONE;
	}
	return IRQ_HANDLED;
	}

	static int lm3630a_intr_config(struct lm3630a_chip *pchip)
	{
	int rval;

	rval = lm3630a_write(pchip, REG_INT_EN, 0x87);
	if (rval < 0)
	return rval;

	INIT_DELAYED_WORK(&pchip->work, lm3630a_delayed_func);
	pchip->irqthread = create_singlethread_workqueue("lm3630a-irqthd");
	if (!pchip->irqthread) {
	dev_err(pchip->dev, "create irq thread fail\n");
	return -ENOMEM;
	}
	if (request_threaded_irq
	(pchip->irq, NULL, lm3630a_isr_func,
	IRQF_TRIGGER_FALLING \| IRQF_ONESHOT, "lm3630a_irq", pchip)) {
	dev_err(pchip->dev, "request threaded irq fail\n");
	destroy_workqueue(pchip->irqthread);
	return -ENOMEM;
	}
	return rval;
	}

	static void lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
	{
	unsigned int period = pchip->pdata->pwm_period;
	unsigned int duty = br * period / br_max;

	pwm_config(pchip->pwmd, duty, period);
	if (duty)
	pwm_enable(pchip->pwmd);
	else
	pwm_disable(pchip->pwmd);
	}

	/* update and get brightness */
	static int lm3630a_bank_a_update_status(struct backlight_device *bl)
	{
	int ret;
	struct lm3630a_chip *pchip = bl_get_data(bl);
	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

	/* pwm control */
	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) {
	lm3630a_pwm_ctrl(pchip, bl->props.brightness,
	bl->props.max_brightness);
	return 0;
	}

	/* disable sleep */
	ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
	if (ret < 0)
	goto out_i2c_err;
	usleep_range(1000, 2000);
	/* minimum brightness is 0x04 */
	ret = lm3630a_write(pchip, REG_BRT_A, bl->props.brightness);
	if (bl->props.brightness < 0x4)
	ret \|= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDA_ENABLE, 0);
	else
	ret \|= lm3630a_update(pchip, REG_CTRL,
	LM3630A_LEDA_ENABLE, LM3630A_LEDA_ENABLE);
	if (ret < 0)
	goto out_i2c_err;
	return 0;

	out_i2c_err:
	dev_err(pchip->dev, "i2c failed to access (%pe)\n", ERR_PTR(ret));
	return ret;
	}

	static int lm3630a_bank_a_get_brightness(struct backlight_device *bl)
	{
	int brightness, rval;
	struct lm3630a_chip *pchip = bl_get_data(bl);
	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

	if ((pwm_ctrl & LM3630A_PWM_BANK_A) != 0) {
	rval = lm3630a_read(pchip, REG_PWM_OUTHIGH);
	if (rval < 0)
	goto out_i2c_err;
	brightness = (rval & 0x01) << 8;
	rval = lm3630a_read(pchip, REG_PWM_OUTLOW);
	if (rval < 0)
	goto out_i2c_err;
	brightness \|= rval;
	goto out;
	}

	/* disable sleep */
	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
	if (rval < 0)
	goto out_i2c_err;
	usleep_range(1000, 2000);
	rval = lm3630a_read(pchip, REG_BRT_A);
	if (rval < 0)
	goto out_i2c_err;
	brightness = rval;

	out:
	bl->props.brightness = brightness;
	return bl->props.brightness;
	out_i2c_err:
	dev_err(pchip->dev, "i2c failed to access register\n");
	return 0;
	}

	static const struct backlight_ops lm3630a_bank_a_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = lm3630a_bank_a_update_status,
	.get_brightness = lm3630a_bank_a_get_brightness,
	};

	/* update and get brightness */
	static int lm3630a_bank_b_update_status(struct backlight_device *bl)
	{
	int ret;
	struct lm3630a_chip *pchip = bl_get_data(bl);
	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

	/* pwm control */
	if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) {
	lm3630a_pwm_ctrl(pchip, bl->props.brightness,
	bl->props.max_brightness);
	return 0;
	}

	/* disable sleep */
	ret = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
	if (ret < 0)
	goto out_i2c_err;
	usleep_range(1000, 2000);
	/* minimum brightness is 0x04 */
	ret = lm3630a_write(pchip, REG_BRT_B, bl->props.brightness);
	if (bl->props.brightness < 0x4)
	ret \|= lm3630a_update(pchip, REG_CTRL, LM3630A_LEDB_ENABLE, 0);
	else
	ret \|= lm3630a_update(pchip, REG_CTRL,
	LM3630A_LEDB_ENABLE, LM3630A_LEDB_ENABLE);
	if (ret < 0)
	goto out_i2c_err;
	return 0;

	out_i2c_err:
	dev_err(pchip->dev, "i2c failed to access (%pe)\n", ERR_PTR(ret));
	return ret;
	}

	static int lm3630a_bank_b_get_brightness(struct backlight_device *bl)
	{
	int brightness, rval;
	struct lm3630a_chip *pchip = bl_get_data(bl);
	enum lm3630a_pwm_ctrl pwm_ctrl = pchip->pdata->pwm_ctrl;

	if ((pwm_ctrl & LM3630A_PWM_BANK_B) != 0) {
	rval = lm3630a_read(pchip, REG_PWM_OUTHIGH);
	if (rval < 0)
	goto out_i2c_err;
	brightness = (rval & 0x01) << 8;
	rval = lm3630a_read(pchip, REG_PWM_OUTLOW);
	if (rval < 0)
	goto out_i2c_err;
	brightness \|= rval;
	goto out;
	}

	/* disable sleep */
	rval = lm3630a_update(pchip, REG_CTRL, 0x80, 0x00);
	if (rval < 0)
	goto out_i2c_err;
	usleep_range(1000, 2000);
	rval = lm3630a_read(pchip, REG_BRT_B);
	if (rval < 0)
	goto out_i2c_err;
	brightness = rval;

	out:
	bl->props.brightness = brightness;
	return bl->props.brightness;
	out_i2c_err:
	dev_err(pchip->dev, "i2c failed to access register\n");
	return 0;
	}

	static const struct backlight_ops lm3630a_bank_b_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = lm3630a_bank_b_update_status,
	.get_brightness = lm3630a_bank_b_get_brightness,
	};

	static int lm3630a_backlight_register(struct lm3630a_chip *pchip)
	{
	struct lm3630a_platform_data *pdata = pchip->pdata;
	struct backlight_properties props;
	const char *label;

	props.type = BACKLIGHT_RAW;
	if (pdata->leda_ctrl != LM3630A_LEDA_DISABLE) {
	props.brightness = pdata->leda_init_brt;
	props.max_brightness = pdata->leda_max_brt;
	label = pdata->leda_label ? pdata->leda_label : "lm3630a_leda";
	pchip->bleda =
	devm_backlight_device_register(pchip->dev, label,
	pchip->dev, pchip,
	&lm3630a_bank_a_ops, &props);
	if (IS_ERR(pchip->bleda))
	return PTR_ERR(pchip->bleda);
	}

	if ((pdata->ledb_ctrl != LM3630A_LEDB_DISABLE) &&
	(pdata->ledb_ctrl != LM3630A_LEDB_ON_A)) {
	props.brightness = pdata->ledb_init_brt;
	props.max_brightness = pdata->ledb_max_brt;
	label = pdata->ledb_label ? pdata->ledb_label : "lm3630a_ledb";
	pchip->bledb =
	devm_backlight_device_register(pchip->dev, label,
	pchip->dev, pchip,
	&lm3630a_bank_b_ops, &props);
	if (IS_ERR(pchip->bledb))
	return PTR_ERR(pchip->bledb);
	}
	return 0;
	}

	static const struct regmap_config lm3630a_regmap = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = REG_MAX,
	};

	static int lm3630a_parse_led_sources(struct fwnode_handle *node,
	int default_led_sources)
	{
	u32 sources[LM3630A_NUM_SINKS];
	int ret, num_sources, i;

	num_sources = fwnode_property_count_u32(node, "led-sources");
	if (num_sources < 0)
	return default_led_sources;
	else if (num_sources > ARRAY_SIZE(sources))
	return -EINVAL;

	ret = fwnode_property_read_u32_array(node, "led-sources", sources,
	num_sources);
	if (ret)
	return ret;

	for (i = 0; i < num_sources; i++) {
	if (sources[i] != LM3630A_SINK_0 && sources[i] != LM3630A_SINK_1)
	return -EINVAL;

	ret \|= BIT(sources[i]);
	}

	return ret;
	}

	static int lm3630a_parse_bank(struct lm3630a_platform_data *pdata,
	struct fwnode_handle node, int seen_led_sources)
	{
	int led_sources, ret;
	const char *label;
	u32 bank, val;
	bool linear;

	ret = fwnode_property_read_u32(node, "reg", &bank);
	if (ret)
	return ret;

	if (bank != LM3630A_BANK_0 && bank != LM3630A_BANK_1)
	return -EINVAL;

	led_sources = lm3630a_parse_led_sources(node, BIT(bank));
	if (led_sources < 0)
	return led_sources;

	if (*seen_led_sources & led_sources)
	return -EINVAL;

	*seen_led_sources \|= led_sources;

	linear = fwnode_property_read_bool(node,
	"ti,linear-mapping-mode");
	if (bank) {
	if (led_sources & BIT(LM3630A_SINK_0) \|\|
	!(led_sources & BIT(LM3630A_SINK_1)))
	return -EINVAL;

	pdata->ledb_ctrl = linear ?
	LM3630A_LEDB_ENABLE_LINEAR :
	LM3630A_LEDB_ENABLE;
	} else {
	if (!(led_sources & BIT(LM3630A_SINK_0)))
	return -EINVAL;

	pdata->leda_ctrl = linear ?
	LM3630A_LEDA_ENABLE_LINEAR :
	LM3630A_LEDA_ENABLE;

	if (led_sources & BIT(LM3630A_SINK_1))
	pdata->ledb_ctrl = LM3630A_LEDB_ON_A;
	}

	ret = fwnode_property_read_string(node, "label", &label);
	if (!ret) {
	if (bank)
	pdata->ledb_label = label;
	else
	pdata->leda_label = label;
	}

	ret = fwnode_property_read_u32(node, "default-brightness",
	&val);
	if (!ret) {
	if (bank)
	pdata->ledb_init_brt = val;
	else
	pdata->leda_init_brt = val;
	}

	ret = fwnode_property_read_u32(node, "max-brightness", &val);
	if (!ret) {
	if (bank)
	pdata->ledb_max_brt = val;
	else
	pdata->leda_max_brt = val;
	}

	return 0;
	}

	static int lm3630a_parse_node(struct lm3630a_chip *pchip,
	struct lm3630a_platform_data *pdata)
	{
	int ret = -ENODEV, seen_led_sources = 0;
	struct fwnode_handle *node;

	device_for_each_child_node(pchip->dev, node) {
	ret = lm3630a_parse_bank(pdata, node, &seen_led_sources);
	if (ret) {
	fwnode_handle_put(node);
	return ret;
	}
	}

	return ret;
	}

	static int lm3630a_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct lm3630a_platform_data *pdata = dev_get_platdata(&client->dev);
	struct lm3630a_chip *pchip;
	int rval;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	dev_err(&client->dev, "fail : i2c functionality check\n");
	return -EOPNOTSUPP;
	}

	pchip = devm_kzalloc(&client->dev, sizeof(struct lm3630a_chip),
	GFP_KERNEL);
	if (!pchip)
	return -ENOMEM;
	pchip->dev = &client->dev;

	pchip->regmap = devm_regmap_init_i2c(client, &lm3630a_regmap);
	if (IS_ERR(pchip->regmap)) {
	rval = PTR_ERR(pchip->regmap);
	dev_err(&client->dev, "fail : allocate reg. map: %d\n", rval);
	return rval;
	}

	i2c_set_clientdata(client, pchip);
	if (pdata == NULL) {
	pdata = devm_kzalloc(pchip->dev,
	sizeof(struct lm3630a_platform_data),
	GFP_KERNEL);
	if (pdata == NULL)
	return -ENOMEM;

	/* default values */
	pdata->leda_max_brt = LM3630A_MAX_BRIGHTNESS;
	pdata->ledb_max_brt = LM3630A_MAX_BRIGHTNESS;
	pdata->leda_init_brt = LM3630A_MAX_BRIGHTNESS;
	pdata->ledb_init_brt = LM3630A_MAX_BRIGHTNESS;

	rval = lm3630a_parse_node(pchip, pdata);
	if (rval) {
	dev_err(&client->dev, "fail : parse node\n");
	return rval;
	}
	}
	pchip->pdata = pdata;

	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
	GPIOD_OUT_HIGH);
	if (IS_ERR(pchip->enable_gpio)) {
	rval = PTR_ERR(pchip->enable_gpio);
	return rval;
	}

	/* chip initialize */
	rval = lm3630a_chip_init(pchip);
	if (rval < 0) {
	dev_err(&client->dev, "fail : init chip\n");
	return rval;
	}
	/* backlight register */
	rval = lm3630a_backlight_register(pchip);
	if (rval < 0) {
	dev_err(&client->dev, "fail : backlight register.\n");
	return rval;
	}
	/* pwm */
	if (pdata->pwm_ctrl != LM3630A_PWM_DISABLE) {
	pchip->pwmd = devm_pwm_get(pchip->dev, "lm3630a-pwm");
	if (IS_ERR(pchip->pwmd)) {
	dev_err(&client->dev, "fail : get pwm device\n");
	return PTR_ERR(pchip->pwmd);
	}

	/*
	* FIXME: pwm_apply_args() should be removed when switching to
	* the atomic PWM API.
	*/
	pwm_apply_args(pchip->pwmd);
	}

	/* interrupt enable : irq 0 is not allowed */
	pchip->irq = client->irq;
	if (pchip->irq) {
	rval = lm3630a_intr_config(pchip);
	if (rval < 0)
	return rval;
	}
	dev_info(&client->dev, "LM3630A backlight register OK.\n");
	return 0;
	}

	static int lm3630a_remove(struct i2c_client *client)
	{
	int rval;
	struct lm3630a_chip *pchip = i2c_get_clientdata(client);

	rval = lm3630a_write(pchip, REG_BRT_A, 0);
	if (rval < 0)
	dev_err(pchip->dev, "i2c failed to access register\n");

	rval = lm3630a_write(pchip, REG_BRT_B, 0);
	if (rval < 0)
	dev_err(pchip->dev, "i2c failed to access register\n");

	if (pchip->irq) {
	free_irq(pchip->irq, pchip);
	flush_workqueue(pchip->irqthread);
	destroy_workqueue(pchip->irqthread);
	}
	return 0;
	}

	static const struct i2c_device_id lm3630a_id[] = {
	{LM3630A_NAME, 0},
	{}
	};

	MODULE_DEVICE_TABLE(i2c, lm3630a_id);

	static const struct of_device_id lm3630a_match_table[] = {
	{ .compatible = "ti,lm3630a", },
	{ },
	};

	MODULE_DEVICE_TABLE(of, lm3630a_match_table);

	static struct i2c_driver lm3630a_i2c_driver = {
	.driver = {
	.name = LM3630A_NAME,
	.of_match_table = lm3630a_match_table,
	},
	.probe = lm3630a_probe,
	.remove = lm3630a_remove,
	.id_table = lm3630a_id,
	};

	module_i2c_driver(lm3630a_i2c_driver);

	MODULE_DESCRIPTION("Texas Instruments Backlight driver for LM3630A");
	MODULE_AUTHOR("Daniel Jeong <gshark.jeong@gmail.com>");
	MODULE_AUTHOR("LDD MLP <ldd-mlp@list.ti.com>");
	MODULE_LICENSE("GPL v2");