[linux-2.6-block.git] / drivers / video / backlight / lp855x_bl.c

/*
 * TI LP855x Backlight Driver
 *
 *			Copyright (C) 2011 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/of.h>
#include <linux/platform_data/lp855x.h>
#include <linux/pwm.h>
#include <linux/regulator/consumer.h>

/* LP8550/1/2/3/6 Registers */
#define LP855X_BRIGHTNESS_CTRL		0x00
#define LP855X_DEVICE_CTRL		0x01
#define LP855X_EEPROM_START		0xA0
#define LP855X_EEPROM_END		0xA7
#define LP8556_EPROM_START		0xA0
#define LP8556_EPROM_END		0xAF

/* LP8555/7 Registers */
#define LP8557_BL_CMD			0x00
#define LP8557_BL_MASK			0x01
#define LP8557_BL_ON			0x01
#define LP8557_BL_OFF			0x00
#define LP8557_BRIGHTNESS_CTRL		0x04
#define LP8557_CONFIG			0x10
#define LP8555_EPROM_START		0x10
#define LP8555_EPROM_END		0x7A
#define LP8557_EPROM_START		0x10
#define LP8557_EPROM_END		0x1E

#define DEFAULT_BL_NAME		"lcd-backlight"
#define MAX_BRIGHTNESS		255

enum lp855x_brightness_ctrl_mode {
	PWM_BASED = 1,
	REGISTER_BASED,
};

struct lp855x;

/*
 * struct lp855x_device_config
 * @pre_init_device: init device function call before updating the brightness
 * @reg_brightness: register address for brigthenss control
 * @reg_devicectrl: register address for device control
 * @post_init_device: late init device function call
 */
struct lp855x_device_config {
	int (*pre_init_device)(struct lp855x *);
	u8 reg_brightness;
	u8 reg_devicectrl;
	int (*post_init_device)(struct lp855x *);
};

struct lp855x {
	const char *chipname;
	enum lp855x_chip_id chip_id;
	enum lp855x_brightness_ctrl_mode mode;
	struct lp855x_device_config *cfg;
	struct i2c_client *client;
	struct backlight_device *bl;
	struct device *dev;
	struct lp855x_platform_data *pdata;
	struct pwm_device *pwm;
	struct regulator *supply;	/* regulator for VDD input */
};

static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
{
	return i2c_smbus_write_byte_data(lp->client, reg, data);
}

static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
{
	int ret;
	u8 tmp;

	ret = i2c_smbus_read_byte_data(lp->client, reg);
	if (ret < 0) {
		dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
		return ret;
	}

	tmp = (u8)ret;
	tmp &= ~mask;
	tmp |= data & mask;

	return lp855x_write_byte(lp, reg, tmp);
}

static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
{
	u8 start, end;

	switch (lp->chip_id) {
	case LP8550:
	case LP8551:
	case LP8552:
	case LP8553:
		start = LP855X_EEPROM_START;
		end = LP855X_EEPROM_END;
		break;
	case LP8556:
		start = LP8556_EPROM_START;
		end = LP8556_EPROM_END;
		break;
	case LP8555:
		start = LP8555_EPROM_START;
		end = LP8555_EPROM_END;
		break;
	case LP8557:
		start = LP8557_EPROM_START;
		end = LP8557_EPROM_END;
		break;
	default:
		return false;
	}

	return addr >= start && addr <= end;
}

static int lp8557_bl_off(struct lp855x *lp)
{
	/* BL_ON = 0 before updating EPROM settings */
	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
				LP8557_BL_OFF);
}

static int lp8557_bl_on(struct lp855x *lp)
{
	/* BL_ON = 1 after updating EPROM settings */
	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
				LP8557_BL_ON);
}

static struct lp855x_device_config lp855x_dev_cfg = {
	.reg_brightness = LP855X_BRIGHTNESS_CTRL,
	.reg_devicectrl = LP855X_DEVICE_CTRL,
};

static struct lp855x_device_config lp8557_dev_cfg = {
	.reg_brightness = LP8557_BRIGHTNESS_CTRL,
	.reg_devicectrl = LP8557_CONFIG,
	.pre_init_device = lp8557_bl_off,
	.post_init_device = lp8557_bl_on,
};

/*
 * Device specific configuration flow
 *
 *    a) pre_init_device(optional)
 *    b) update the brightness register
 *    c) update device control register
 *    d) update ROM area(optional)
 *    e) post_init_device(optional)
 *
 */
static int lp855x_configure(struct lp855x *lp)
{
	u8 val, addr;
	int i, ret;
	struct lp855x_platform_data *pd = lp->pdata;

	switch (lp->chip_id) {
	case LP8550:
	case LP8551:
	case LP8552:
	case LP8553:
	case LP8556:
		lp->cfg = &lp855x_dev_cfg;
		break;
	case LP8555:
	case LP8557:
		lp->cfg = &lp8557_dev_cfg;
		break;
	default:
		return -EINVAL;
	}

	if (lp->cfg->pre_init_device) {
		ret = lp->cfg->pre_init_device(lp);
		if (ret) {
			dev_err(lp->dev, "pre init device err: %d\n", ret);
			goto err;
		}
	}

	val = pd->initial_brightness;
	ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
	if (ret)
		goto err;

	val = pd->device_control;
	ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
	if (ret)
		goto err;

	if (pd->size_program > 0) {
		for (i = 0; i < pd->size_program; i++) {
			addr = pd->rom_data[i].addr;
			val = pd->rom_data[i].val;
			if (!lp855x_is_valid_rom_area(lp, addr))
				continue;

			ret = lp855x_write_byte(lp, addr, val);
			if (ret)
				goto err;
		}
	}

	if (lp->cfg->post_init_device) {
		ret = lp->cfg->post_init_device(lp);
		if (ret) {
			dev_err(lp->dev, "post init device err: %d\n", ret);
			goto err;
		}
	}

	return 0;

err:
	return ret;
}

static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
{
	unsigned int period = lp->pdata->period_ns;
	unsigned int duty = br * period / max_br;
	struct pwm_device *pwm;

	/* request pwm device with the consumer name */
	if (!lp->pwm) {
		pwm = devm_pwm_get(lp->dev, lp->chipname);
		if (IS_ERR(pwm))
			return;

		lp->pwm = pwm;

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

	pwm_config(lp->pwm, duty, period);
	if (duty)
		pwm_enable(lp->pwm);
	else
		pwm_disable(lp->pwm);
}

static int lp855x_bl_update_status(struct backlight_device *bl)
{
	struct lp855x *lp = bl_get_data(bl);
	int brightness = bl->props.brightness;

	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
		brightness = 0;

	if (lp->mode == PWM_BASED)
		lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
	else if (lp->mode == REGISTER_BASED)
		lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);

	return 0;
}

static const struct backlight_ops lp855x_bl_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = lp855x_bl_update_status,
};

static int lp855x_backlight_register(struct lp855x *lp)
{
	struct backlight_device *bl;
	struct backlight_properties props;
	struct lp855x_platform_data *pdata = lp->pdata;
	const char *name = pdata->name ? : DEFAULT_BL_NAME;

	memset(&props, 0, sizeof(props));
	props.type = BACKLIGHT_PLATFORM;
	props.max_brightness = MAX_BRIGHTNESS;

	if (pdata->initial_brightness > props.max_brightness)
		pdata->initial_brightness = props.max_brightness;

	props.brightness = pdata->initial_brightness;

	bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
				       &lp855x_bl_ops, &props);
	if (IS_ERR(bl))
		return PTR_ERR(bl);

	lp->bl = bl;

	return 0;
}

static ssize_t lp855x_get_chip_id(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct lp855x *lp = dev_get_drvdata(dev);

	return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
}

static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct lp855x *lp = dev_get_drvdata(dev);
	char *strmode = NULL;

	if (lp->mode == PWM_BASED)
		strmode = "pwm based";
	else if (lp->mode == REGISTER_BASED)
		strmode = "register based";

	return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
}

static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);

static struct attribute *lp855x_attributes[] = {
	&dev_attr_chip_id.attr,
	&dev_attr_bl_ctl_mode.attr,
	NULL,
};

static const struct attribute_group lp855x_attr_group = {
	.attrs = lp855x_attributes,
};

#ifdef CONFIG_OF
static int lp855x_parse_dt(struct lp855x *lp)
{
	struct device *dev = lp->dev;
	struct device_node *node = dev->of_node;
	struct lp855x_platform_data *pdata;
	int rom_length;

	if (!node) {
		dev_err(dev, "no platform data\n");
		return -EINVAL;
	}

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

	of_property_read_string(node, "bl-name", &pdata->name);
	of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
	of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
	of_property_read_u32(node, "pwm-period", &pdata->period_ns);

	/* Fill ROM platform data if defined */
	rom_length = of_get_child_count(node);
	if (rom_length > 0) {
		struct lp855x_rom_data *rom;
		struct device_node *child;
		int i = 0;

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

		for_each_child_of_node(node, child) {
			of_property_read_u8(child, "rom-addr", &rom[i].addr);
			of_property_read_u8(child, "rom-val", &rom[i].val);
			i++;
		}

		pdata->size_program = rom_length;
		pdata->rom_data = &rom[0];
	}

	lp->pdata = pdata;

	return 0;
}
#else
static int lp855x_parse_dt(struct lp855x *lp)
{
	return -EINVAL;
}
#endif

static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
	struct lp855x *lp;
	int ret;

	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
		return -EIO;

	lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
	if (!lp)
		return -ENOMEM;

	lp->client = cl;
	lp->dev = &cl->dev;
	lp->chipname = id->name;
	lp->chip_id = id->driver_data;
	lp->pdata = dev_get_platdata(&cl->dev);

	if (!lp->pdata) {
		ret = lp855x_parse_dt(lp);
		if (ret < 0)
			return ret;
	}

	if (lp->pdata->period_ns > 0)
		lp->mode = PWM_BASED;
	else
		lp->mode = REGISTER_BASED;

	lp->supply = devm_regulator_get(lp->dev, "power");
	if (IS_ERR(lp->supply)) {
		if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
			return -EPROBE_DEFER;
		lp->supply = NULL;
	}

	if (lp->supply) {
		ret = regulator_enable(lp->supply);
		if (ret < 0) {
			dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
			return ret;
		}
	}

	i2c_set_clientdata(cl, lp);

	ret = lp855x_configure(lp);
	if (ret) {
		dev_err(lp->dev, "device config err: %d", ret);
		return ret;
	}

	ret = lp855x_backlight_register(lp);
	if (ret) {
		dev_err(lp->dev,
			"failed to register backlight. err: %d\n", ret);
		return ret;
	}

	ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
	if (ret) {
		dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
		return ret;
	}

	backlight_update_status(lp->bl);
	return 0;
}

static int lp855x_remove(struct i2c_client *cl)
{
	struct lp855x *lp = i2c_get_clientdata(cl);

	lp->bl->props.brightness = 0;
	backlight_update_status(lp->bl);
	if (lp->supply)
		regulator_disable(lp->supply);
	sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);

	return 0;
}

static const struct of_device_id lp855x_dt_ids[] = {
	{ .compatible = "ti,lp8550", },
	{ .compatible = "ti,lp8551", },
	{ .compatible = "ti,lp8552", },
	{ .compatible = "ti,lp8553", },
	{ .compatible = "ti,lp8555", },
	{ .compatible = "ti,lp8556", },
	{ .compatible = "ti,lp8557", },
	{ }
};
MODULE_DEVICE_TABLE(of, lp855x_dt_ids);

static const struct i2c_device_id lp855x_ids[] = {
	{"lp8550", LP8550},
	{"lp8551", LP8551},
	{"lp8552", LP8552},
	{"lp8553", LP8553},
	{"lp8555", LP8555},
	{"lp8556", LP8556},
	{"lp8557", LP8557},
	{ }
};
MODULE_DEVICE_TABLE(i2c, lp855x_ids);

static struct i2c_driver lp855x_driver = {
	.driver = {
		   .name = "lp855x",
		   .of_match_table = of_match_ptr(lp855x_dt_ids),
		   },
	.probe = lp855x_probe,
	.remove = lp855x_remove,
	.id_table = lp855x_ids,
};

module_i2c_driver(lp855x_driver);

MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
7be865ab KM	1	/*
	2	* TI LP855x Backlight Driver
	3	*
	4	* Copyright (C) 2011 Texas Instruments
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/slab.h>
	14	#include <linux/i2c.h>
	15	#include <linux/backlight.h>
	16	#include <linux/err.h>
4add0664	17	#include <linux/of.h>
f7f95056	18	#include <linux/platform_data/lp855x.h>
8cc9764c	19	#include <linux/pwm.h>
829b030e	20	#include <linux/regulator/consumer.h>
7be865ab	21
26e8ccc2 KM	22	/* LP8550/1/2/3/6 Registers */
	23	#define LP855X_BRIGHTNESS_CTRL 0x00
	24	#define LP855X_DEVICE_CTRL 0x01
	25	#define LP855X_EEPROM_START 0xA0
	26	#define LP855X_EEPROM_END 0xA7
	27	#define LP8556_EPROM_START 0xA0
	28	#define LP8556_EPROM_END 0xAF
	29
5812c13a	30	/* LP8555/7 Registers */
26e8ccc2 KM	31	#define LP8557_BL_CMD 0x00
	32	#define LP8557_BL_MASK 0x01
	33	#define LP8557_BL_ON 0x01
	34	#define LP8557_BL_OFF 0x00
	35	#define LP8557_BRIGHTNESS_CTRL 0x04
	36	#define LP8557_CONFIG 0x10
5812c13a MK	37	#define LP8555_EPROM_START 0x10
5812c13a MK	38	#define LP8555_EPROM_END 0x7A
26e8ccc2 KM	39	#define LP8557_EPROM_START 0x10
26e8ccc2 KM	40	#define LP8557_EPROM_END 0x1E
7be865ab	41
7be865ab KM	42	#define DEFAULT_BL_NAME "lcd-backlight"
	43	#define MAX_BRIGHTNESS 255
	44
0b818573 KM	45	enum lp855x_brightness_ctrl_mode {
	46	PWM_BASED = 1,
	47	REGISTER_BASED,
	48	};
	49
68853bc2 KM	50	struct lp855x;
	51
	52	/*
	53	* struct lp855x_device_config
	54	* @pre_init_device: init device function call before updating the brightness
	55	* @reg_brightness: register address for brigthenss control
	56	* @reg_devicectrl: register address for device control
	57	* @post_init_device: late init device function call
	58	*/
	59	struct lp855x_device_config {
	60	int (pre_init_device)(struct lp855x );
	61	u8 reg_brightness;
	62	u8 reg_devicectrl;
	63	int (post_init_device)(struct lp855x );
	64	};
	65
7be865ab KM	66	struct lp855x {
	67	const char *chipname;
	68	enum lp855x_chip_id chip_id;
0b818573	69	enum lp855x_brightness_ctrl_mode mode;
68853bc2	70	struct lp855x_device_config *cfg;
7be865ab KM	71	struct i2c_client *client;
	72	struct backlight_device *bl;
	73	struct device *dev;
7be865ab	74	struct lp855x_platform_data *pdata;
8cc9764c	75	struct pwm_device *pwm;
fe009175	76	struct regulator supply; / regulator for VDD input */
7be865ab KM	77	};
7be865ab KM	78
7be865ab KM	79	static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
7be865ab KM	80	{
eaa4d02f	81	return i2c_smbus_write_byte_data(lp->client, reg, data);
7be865ab KM	82	}
7be865ab KM	83
26e8ccc2 KM	84	static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
	85	{
	86	int ret;
	87	u8 tmp;
	88
	89	ret = i2c_smbus_read_byte_data(lp->client, reg);
	90	if (ret < 0) {
	91	dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
	92	return ret;
	93	}
	94
	95	tmp = (u8)ret;
	96	tmp &= ~mask;
	97	tmp \|= data & mask;
	98
	99	return lp855x_write_byte(lp, reg, tmp);
	100	}
	101
7be865ab KM	102	static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
	103	{
	104	u8 start, end;
	105
	106	switch (lp->chip_id) {
	107	case LP8550:
	108	case LP8551:
	109	case LP8552:
	110	case LP8553:
26e8ccc2 KM	111	start = LP855X_EEPROM_START;
26e8ccc2 KM	112	end = LP855X_EEPROM_END;
7be865ab KM	113	break;
7be865ab KM	114	case LP8556:
26e8ccc2 KM	115	start = LP8556_EPROM_START;
	116	end = LP8556_EPROM_END;
	117	break;
5812c13a MK	118	case LP8555:
	119	start = LP8555_EPROM_START;
	120	end = LP8555_EPROM_END;
	121	break;
26e8ccc2 KM	122	case LP8557:
	123	start = LP8557_EPROM_START;
	124	end = LP8557_EPROM_END;
7be865ab KM	125	break;
	126	default:
	127	return false;
	128	}
	129
2ce23860	130	return addr >= start && addr <= end;
7be865ab KM	131	}
7be865ab KM	132
26e8ccc2 KM	133	static int lp8557_bl_off(struct lp855x *lp)
	134	{
	135	/* BL_ON = 0 before updating EPROM settings */
	136	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
	137	LP8557_BL_OFF);
	138	}
	139
	140	static int lp8557_bl_on(struct lp855x *lp)
	141	{
	142	/* BL_ON = 1 after updating EPROM settings */
	143	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
	144	LP8557_BL_ON);
	145	}
	146
68853bc2	147	static struct lp855x_device_config lp855x_dev_cfg = {
26e8ccc2 KM	148	.reg_brightness = LP855X_BRIGHTNESS_CTRL,
	149	.reg_devicectrl = LP855X_DEVICE_CTRL,
	150	};
	151
	152	static struct lp855x_device_config lp8557_dev_cfg = {
	153	.reg_brightness = LP8557_BRIGHTNESS_CTRL,
	154	.reg_devicectrl = LP8557_CONFIG,
	155	.pre_init_device = lp8557_bl_off,
	156	.post_init_device = lp8557_bl_on,
68853bc2 KM	157	};
	158
	159	/*
	160	* Device specific configuration flow
	161	*
	162	* a) pre_init_device(optional)
	163	* b) update the brightness register
	164	* c) update device control register
	165	* d) update ROM area(optional)
	166	* e) post_init_device(optional)
	167	*
	168	*/
	169	static int lp855x_configure(struct lp855x *lp)
7be865ab KM	170	{
	171	u8 val, addr;
	172	int i, ret;
	173	struct lp855x_platform_data *pd = lp->pdata;
	174
68853bc2	175	switch (lp->chip_id) {
5812c13a MK	176	case LP8550:
	177	case LP8551:
	178	case LP8552:
	179	case LP8553:
	180	case LP8556:
68853bc2 KM	181	lp->cfg = &lp855x_dev_cfg;
68853bc2 KM	182	break;
5812c13a	183	case LP8555:
26e8ccc2 KM	184	case LP8557:
	185	lp->cfg = &lp8557_dev_cfg;
	186	break;
68853bc2 KM	187	default:
	188	return -EINVAL;
	189	}
	190
	191	if (lp->cfg->pre_init_device) {
	192	ret = lp->cfg->pre_init_device(lp);
	193	if (ret) {
	194	dev_err(lp->dev, "pre init device err: %d\n", ret);
	195	goto err;
	196	}
	197	}
	198
7be865ab	199	val = pd->initial_brightness;
68853bc2	200	ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
7be865ab	201	if (ret)
68853bc2	202	goto err;
7be865ab KM	203
7be865ab KM	204	val = pd->device_control;
68853bc2	205	ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
7be865ab	206	if (ret)
68853bc2	207	goto err;
7be865ab	208
c365e59d	209	if (pd->size_program > 0) {
7be865ab KM	210	for (i = 0; i < pd->size_program; i++) {
	211	addr = pd->rom_data[i].addr;
	212	val = pd->rom_data[i].val;
	213	if (!lp855x_is_valid_rom_area(lp, addr))
	214	continue;
	215
	216	ret = lp855x_write_byte(lp, addr, val);
	217	if (ret)
68853bc2 KM	218	goto err;
	219	}
	220	}
	221
	222	if (lp->cfg->post_init_device) {
	223	ret = lp->cfg->post_init_device(lp);
	224	if (ret) {
	225	dev_err(lp->dev, "post init device err: %d\n", ret);
	226	goto err;
7be865ab KM	227	}
	228	}
	229
68853bc2 KM	230	return 0;
	231
	232	err:
7be865ab KM	233	return ret;
	234	}
	235
8cc9764c KM	236	static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
	237	{
	238	unsigned int period = lp->pdata->period_ns;
	239	unsigned int duty = br * period / max_br;
	240	struct pwm_device *pwm;
	241
	242	/* request pwm device with the consumer name */
	243	if (!lp->pwm) {
	244	pwm = devm_pwm_get(lp->dev, lp->chipname);
	245	if (IS_ERR(pwm))
	246	return;
	247
	248	lp->pwm = pwm;
6fbab835 BB	249
	250	/*
	251	* FIXME: pwm_apply_args() should be removed when switching to
	252	* the atomic PWM API.
	253	*/
	254	pwm_apply_args(pwm);
8cc9764c KM	255	}
	256
	257	pwm_config(lp->pwm, duty, period);
	258	if (duty)
	259	pwm_enable(lp->pwm);
	260	else
	261	pwm_disable(lp->pwm);
	262	}
	263
7be865ab KM	264	static int lp855x_bl_update_status(struct backlight_device *bl)
	265	{
	266	struct lp855x *lp = bl_get_data(bl);
61c1c614	267	int brightness = bl->props.brightness;
7be865ab	268
9f0a511f	269	if (bl->props.state & (BL_CORE_SUSPENDED \| BL_CORE_FBBLANK))
61c1c614	270	brightness = 0;
7be865ab	271
61c1c614 SP	272	if (lp->mode == PWM_BASED)
	273	lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
	274	else if (lp->mode == REGISTER_BASED)
	275	lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
7be865ab KM	276
	277	return 0;
	278	}
	279
7be865ab KM	280	static const struct backlight_ops lp855x_bl_ops = {
	281	.options = BL_CORE_SUSPENDRESUME,
	282	.update_status = lp855x_bl_update_status,
7be865ab KM	283	};
	284
	285	static int lp855x_backlight_register(struct lp855x *lp)
	286	{
	287	struct backlight_device *bl;
	288	struct backlight_properties props;
	289	struct lp855x_platform_data *pdata = lp->pdata;
600ffd33	290	const char *name = pdata->name ? : DEFAULT_BL_NAME;
7be865ab	291
9f7898f3	292	memset(&props, 0, sizeof(props));
7be865ab KM	293	props.type = BACKLIGHT_PLATFORM;
	294	props.max_brightness = MAX_BRIGHTNESS;
	295
	296	if (pdata->initial_brightness > props.max_brightness)
	297	pdata->initial_brightness = props.max_brightness;
	298
	299	props.brightness = pdata->initial_brightness;
	300
6255e8e9	301	bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
7be865ab KM	302	&lp855x_bl_ops, &props);
	303	if (IS_ERR(bl))
	304	return PTR_ERR(bl);
	305
	306	lp->bl = bl;
	307
	308	return 0;
	309	}
	310
7be865ab KM	311	static ssize_t lp855x_get_chip_id(struct device *dev,
	312	struct device_attribute attr, char buf)
	313	{
	314	struct lp855x *lp = dev_get_drvdata(dev);
a94cb126	315
6a7aeb1a	316	return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
7be865ab KM	317	}
	318
	319	static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
	320	struct device_attribute attr, char buf)
	321	{
	322	struct lp855x *lp = dev_get_drvdata(dev);
7be865ab KM	323	char *strmode = NULL;
7be865ab KM	324
0b818573	325	if (lp->mode == PWM_BASED)
7be865ab	326	strmode = "pwm based";
0b818573	327	else if (lp->mode == REGISTER_BASED)
7be865ab KM	328	strmode = "register based";
7be865ab KM	329
6a7aeb1a	330	return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
7be865ab KM	331	}
	332
	333	static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
	334	static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
	335
	336	static struct attribute *lp855x_attributes[] = {
	337	&dev_attr_chip_id.attr,
	338	&dev_attr_bl_ctl_mode.attr,
	339	NULL,
	340	};
	341
	342	static const struct attribute_group lp855x_attr_group = {
	343	.attrs = lp855x_attributes,
	344	};
	345
4add0664	346	#ifdef CONFIG_OF
47726656	347	static int lp855x_parse_dt(struct lp855x *lp)
4add0664	348	{
47726656 SP	349	struct device *dev = lp->dev;
47726656 SP	350	struct device_node *node = dev->of_node;
4add0664 KM	351	struct lp855x_platform_data *pdata;
	352	int rom_length;
	353
	354	if (!node) {
	355	dev_err(dev, "no platform data\n");
	356	return -EINVAL;
	357	}
	358
	359	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	360	if (!pdata)
	361	return -ENOMEM;
	362
	363	of_property_read_string(node, "bl-name", &pdata->name);
	364	of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
	365	of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
	366	of_property_read_u32(node, "pwm-period", &pdata->period_ns);
	367
	368	/* Fill ROM platform data if defined */
	369	rom_length = of_get_child_count(node);
	370	if (rom_length > 0) {
	371	struct lp855x_rom_data *rom;
	372	struct device_node *child;
	373	int i = 0;
	374
	375	rom = devm_kzalloc(dev, sizeof(rom) rom_length, GFP_KERNEL);
	376	if (!rom)
	377	return -ENOMEM;
	378
	379	for_each_child_of_node(node, child) {
	380	of_property_read_u8(child, "rom-addr", &rom[i].addr);
	381	of_property_read_u8(child, "rom-val", &rom[i].val);
	382	i++;
	383	}
	384
	385	pdata->size_program = rom_length;
	386	pdata->rom_data = &rom[0];
	387	}
	388
47726656	389	lp->pdata = pdata;
4add0664 KM	390
	391	return 0;
	392	}
	393	#else
47726656	394	static int lp855x_parse_dt(struct lp855x *lp)
4add0664 KM	395	{
	396	return -EINVAL;
	397	}
	398	#endif
	399
7be865ab KM	400	static int lp855x_probe(struct i2c_client cl, const struct i2c_device_id id)
	401	{
	402	struct lp855x *lp;
7be865ab KM	403	int ret;
7be865ab KM	404
7be865ab KM	405	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
	406	return -EIO;
	407
	408	lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
	409	if (!lp)
	410	return -ENOMEM;
	411
7be865ab KM	412	lp->client = cl;
7be865ab KM	413	lp->dev = &cl->dev;
7be865ab KM	414	lp->chipname = id->name;
7be865ab KM	415	lp->chip_id = id->driver_data;
47726656 SP	416	lp->pdata = dev_get_platdata(&cl->dev);
	417
	418	if (!lp->pdata) {
	419	ret = lp855x_parse_dt(lp);
	420	if (ret < 0)
	421	return ret;
	422	}
	423
	424	if (lp->pdata->period_ns > 0)
	425	lp->mode = PWM_BASED;
	426	else
	427	lp->mode = REGISTER_BASED;
	428
fe009175 MK	429	lp->supply = devm_regulator_get(lp->dev, "power");
	430	if (IS_ERR(lp->supply)) {
	431	if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
	432	return -EPROBE_DEFER;
	433	lp->supply = NULL;
	434	}
	435
	436	if (lp->supply) {
	437	ret = regulator_enable(lp->supply);
829b030e SP	438	if (ret < 0) {
	439	dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
	440	return ret;
	441	}
	442	}
	443
7be865ab KM	444	i2c_set_clientdata(cl, lp);
7be865ab KM	445
68853bc2	446	ret = lp855x_configure(lp);
7be865ab	447	if (ret) {
68853bc2	448	dev_err(lp->dev, "device config err: %d", ret);
6255e8e9	449	return ret;
7be865ab KM	450	}
	451
	452	ret = lp855x_backlight_register(lp);
	453	if (ret) {
	454	dev_err(lp->dev,
	455	"failed to register backlight. err: %d\n", ret);
6255e8e9	456	return ret;
7be865ab KM	457	}
	458
	459	ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
	460	if (ret) {
	461	dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
6255e8e9	462	return ret;
7be865ab KM	463	}
	464
	465	backlight_update_status(lp->bl);
	466	return 0;
7be865ab KM	467	}
7be865ab KM	468
7e4b9d0b	469	static int lp855x_remove(struct i2c_client *cl)
7be865ab KM	470	{
	471	struct lp855x *lp = i2c_get_clientdata(cl);
	472
	473	lp->bl->props.brightness = 0;
	474	backlight_update_status(lp->bl);
fe009175 MK	475	if (lp->supply)
fe009175 MK	476	regulator_disable(lp->supply);
7be865ab	477	sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
7be865ab KM	478
	479	return 0;
	480	}
	481
4add0664 KM	482	static const struct of_device_id lp855x_dt_ids[] = {
	483	{ .compatible = "ti,lp8550", },
	484	{ .compatible = "ti,lp8551", },
	485	{ .compatible = "ti,lp8552", },
	486	{ .compatible = "ti,lp8553", },
5812c13a	487	{ .compatible = "ti,lp8555", },
4add0664 KM	488	{ .compatible = "ti,lp8556", },
	489	{ .compatible = "ti,lp8557", },
	490	{ }
	491	};
	492	MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
	493
7be865ab KM	494	static const struct i2c_device_id lp855x_ids[] = {
	495	{"lp8550", LP8550},
	496	{"lp8551", LP8551},
	497	{"lp8552", LP8552},
	498	{"lp8553", LP8553},
5812c13a	499	{"lp8555", LP8555},
7be865ab	500	{"lp8556", LP8556},
26e8ccc2	501	{"lp8557", LP8557},
7be865ab KM	502	{ }
	503	};
	504	MODULE_DEVICE_TABLE(i2c, lp855x_ids);
	505
	506	static struct i2c_driver lp855x_driver = {
	507	.driver = {
	508	.name = "lp855x",
4add0664	509	.of_match_table = of_match_ptr(lp855x_dt_ids),
7be865ab KM	510	},
7be865ab KM	511	.probe = lp855x_probe,
d1723fa2	512	.remove = lp855x_remove,
7be865ab KM	513	.id_table = lp855x_ids,
	514	};
	515
	516	module_i2c_driver(lp855x_driver);
	517
	518	MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
	519	MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
	520	MODULE_LICENSE("GPL");