v4.19.13 snapshot.
diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
new file mode 100644
index 0000000..2030a6b
--- /dev/null
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -0,0 +1,489 @@
+/*
+* Simple driver for Texas Instruments LM3630A Backlight driver chip
+* Copyright (C) 2012 Texas Instruments
+*
+* 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/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/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
+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 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 bl->props.brightness;
+	}
+
+	/* 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 bl->props.brightness;
+
+out_i2c_err:
+	dev_err(pchip->dev, "i2c failed to access\n");
+	return bl->props.brightness;
+}
+
+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 bl->props.brightness;
+	}
+
+	/* 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 bl->props.brightness;
+
+out_i2c_err:
+	dev_err(pchip->dev, "i2c failed to access REG_CTRL\n");
+	return bl->props.brightness;
+}
+
+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 backlight_properties props;
+	struct lm3630a_platform_data *pdata = pchip->pdata;
+
+	props.type = BACKLIGHT_RAW;
+	if (pdata->leda_ctrl != LM3630A_LEDA_DISABLE) {
+		props.brightness = pdata->leda_init_brt;
+		props.max_brightness = pdata->leda_max_brt;
+		pchip->bleda =
+		    devm_backlight_device_register(pchip->dev, "lm3630a_leda",
+						   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;
+		pchip->bledb =
+		    devm_backlight_device_register(pchip->dev, "lm3630a_ledb",
+						   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_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_ctrl = LM3630A_LEDA_ENABLE;
+		pdata->ledb_ctrl = LM3630A_LEDB_ENABLE;
+		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;
+	}
+	pchip->pdata = pdata;
+
+	/* 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 struct i2c_driver lm3630a_i2c_driver = {
+	.driver = {
+		   .name = LM3630A_NAME,
+		   },
+	.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");