2 * TI LP855x Backlight Driver
4 * Copyright (C) 2011 Texas Instruments
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.
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/i2c.h>
15 #include <linux/backlight.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
19 #include <linux/platform_data/lp855x.h>
20 #include <linux/pwm.h>
21 #include <linux/regulator/consumer.h>
23 /* LP8550/1/2/3/6 Registers */
24 #define LP855X_BRIGHTNESS_CTRL 0x00
25 #define LP855X_DEVICE_CTRL 0x01
26 #define LP855X_EEPROM_START 0xA0
27 #define LP855X_EEPROM_END 0xA7
28 #define LP8556_EPROM_START 0xA0
29 #define LP8556_EPROM_END 0xAF
31 /* LP8555/7 Registers */
32 #define LP8557_BL_CMD 0x00
33 #define LP8557_BL_MASK 0x01
34 #define LP8557_BL_ON 0x01
35 #define LP8557_BL_OFF 0x00
36 #define LP8557_BRIGHTNESS_CTRL 0x04
37 #define LP8557_CONFIG 0x10
38 #define LP8555_EPROM_START 0x10
39 #define LP8555_EPROM_END 0x7A
40 #define LP8557_EPROM_START 0x10
41 #define LP8557_EPROM_END 0x1E
43 #define DEFAULT_BL_NAME "lcd-backlight"
44 #define MAX_BRIGHTNESS 255
46 enum lp855x_brightness_ctrl_mode {
54 * struct lp855x_device_config
55 * @pre_init_device: init device function call before updating the brightness
56 * @reg_brightness: register address for brigthenss control
57 * @reg_devicectrl: register address for device control
58 * @post_init_device: late init device function call
60 struct lp855x_device_config {
61 int (*pre_init_device)(struct lp855x *);
64 int (*post_init_device)(struct lp855x *);
69 enum lp855x_chip_id chip_id;
70 enum lp855x_brightness_ctrl_mode mode;
71 struct lp855x_device_config *cfg;
72 struct i2c_client *client;
73 struct backlight_device *bl;
75 struct lp855x_platform_data *pdata;
76 struct pwm_device *pwm;
77 struct regulator *supply; /* regulator for VDD input */
78 struct regulator *enable; /* regulator for EN/VDDIO input */
81 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
83 return i2c_smbus_write_byte_data(lp->client, reg, data);
86 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
91 ret = i2c_smbus_read_byte_data(lp->client, reg);
93 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
101 return lp855x_write_byte(lp, reg, tmp);
104 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
108 switch (lp->chip_id) {
113 start = LP855X_EEPROM_START;
114 end = LP855X_EEPROM_END;
117 start = LP8556_EPROM_START;
118 end = LP8556_EPROM_END;
121 start = LP8555_EPROM_START;
122 end = LP8555_EPROM_END;
125 start = LP8557_EPROM_START;
126 end = LP8557_EPROM_END;
132 return addr >= start && addr <= end;
135 static int lp8557_bl_off(struct lp855x *lp)
137 /* BL_ON = 0 before updating EPROM settings */
138 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
142 static int lp8557_bl_on(struct lp855x *lp)
144 /* BL_ON = 1 after updating EPROM settings */
145 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
149 static struct lp855x_device_config lp855x_dev_cfg = {
150 .reg_brightness = LP855X_BRIGHTNESS_CTRL,
151 .reg_devicectrl = LP855X_DEVICE_CTRL,
154 static struct lp855x_device_config lp8557_dev_cfg = {
155 .reg_brightness = LP8557_BRIGHTNESS_CTRL,
156 .reg_devicectrl = LP8557_CONFIG,
157 .pre_init_device = lp8557_bl_off,
158 .post_init_device = lp8557_bl_on,
162 * Device specific configuration flow
164 * a) pre_init_device(optional)
165 * b) update the brightness register
166 * c) update device control register
167 * d) update ROM area(optional)
168 * e) post_init_device(optional)
171 static int lp855x_configure(struct lp855x *lp)
175 struct lp855x_platform_data *pd = lp->pdata;
177 switch (lp->chip_id) {
183 lp->cfg = &lp855x_dev_cfg;
187 lp->cfg = &lp8557_dev_cfg;
193 if (lp->cfg->pre_init_device) {
194 ret = lp->cfg->pre_init_device(lp);
196 dev_err(lp->dev, "pre init device err: %d\n", ret);
201 val = pd->initial_brightness;
202 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
206 val = pd->device_control;
207 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
211 if (pd->size_program > 0) {
212 for (i = 0; i < pd->size_program; i++) {
213 addr = pd->rom_data[i].addr;
214 val = pd->rom_data[i].val;
215 if (!lp855x_is_valid_rom_area(lp, addr))
218 ret = lp855x_write_byte(lp, addr, val);
224 if (lp->cfg->post_init_device) {
225 ret = lp->cfg->post_init_device(lp);
227 dev_err(lp->dev, "post init device err: %d\n", ret);
238 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
240 unsigned int period = lp->pdata->period_ns;
241 unsigned int duty = br * period / max_br;
242 struct pwm_device *pwm;
244 /* request pwm device with the consumer name */
246 pwm = devm_pwm_get(lp->dev, lp->chipname);
253 * FIXME: pwm_apply_args() should be removed when switching to
254 * the atomic PWM API.
259 pwm_config(lp->pwm, duty, period);
263 pwm_disable(lp->pwm);
266 static int lp855x_bl_update_status(struct backlight_device *bl)
268 struct lp855x *lp = bl_get_data(bl);
269 int brightness = bl->props.brightness;
271 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
274 if (lp->mode == PWM_BASED)
275 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
276 else if (lp->mode == REGISTER_BASED)
277 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
282 static const struct backlight_ops lp855x_bl_ops = {
283 .options = BL_CORE_SUSPENDRESUME,
284 .update_status = lp855x_bl_update_status,
287 static int lp855x_backlight_register(struct lp855x *lp)
289 struct backlight_device *bl;
290 struct backlight_properties props;
291 struct lp855x_platform_data *pdata = lp->pdata;
292 const char *name = pdata->name ? : DEFAULT_BL_NAME;
294 memset(&props, 0, sizeof(props));
295 props.type = BACKLIGHT_PLATFORM;
296 props.max_brightness = MAX_BRIGHTNESS;
298 if (pdata->initial_brightness > props.max_brightness)
299 pdata->initial_brightness = props.max_brightness;
301 props.brightness = pdata->initial_brightness;
303 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
304 &lp855x_bl_ops, &props);
313 static ssize_t lp855x_get_chip_id(struct device *dev,
314 struct device_attribute *attr, char *buf)
316 struct lp855x *lp = dev_get_drvdata(dev);
318 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
321 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
322 struct device_attribute *attr, char *buf)
324 struct lp855x *lp = dev_get_drvdata(dev);
325 char *strmode = NULL;
327 if (lp->mode == PWM_BASED)
328 strmode = "pwm based";
329 else if (lp->mode == REGISTER_BASED)
330 strmode = "register based";
332 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
335 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
336 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
338 static struct attribute *lp855x_attributes[] = {
339 &dev_attr_chip_id.attr,
340 &dev_attr_bl_ctl_mode.attr,
344 static const struct attribute_group lp855x_attr_group = {
345 .attrs = lp855x_attributes,
349 static int lp855x_parse_dt(struct lp855x *lp)
351 struct device *dev = lp->dev;
352 struct device_node *node = dev->of_node;
353 struct lp855x_platform_data *pdata;
357 dev_err(dev, "no platform data\n");
361 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
365 of_property_read_string(node, "bl-name", &pdata->name);
366 of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
367 of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
368 of_property_read_u32(node, "pwm-period", &pdata->period_ns);
370 /* Fill ROM platform data if defined */
371 rom_length = of_get_child_count(node);
372 if (rom_length > 0) {
373 struct lp855x_rom_data *rom;
374 struct device_node *child;
377 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
381 for_each_child_of_node(node, child) {
382 of_property_read_u8(child, "rom-addr", &rom[i].addr);
383 of_property_read_u8(child, "rom-val", &rom[i].val);
387 pdata->size_program = rom_length;
388 pdata->rom_data = &rom[0];
396 static int lp855x_parse_dt(struct lp855x *lp)
402 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
407 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
410 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
416 lp->chipname = id->name;
417 lp->chip_id = id->driver_data;
418 lp->pdata = dev_get_platdata(&cl->dev);
421 ret = lp855x_parse_dt(lp);
426 if (lp->pdata->period_ns > 0)
427 lp->mode = PWM_BASED;
429 lp->mode = REGISTER_BASED;
431 lp->supply = devm_regulator_get(lp->dev, "power");
432 if (IS_ERR(lp->supply)) {
433 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
434 return -EPROBE_DEFER;
438 lp->enable = devm_regulator_get_optional(lp->dev, "enable");
439 if (IS_ERR(lp->enable)) {
440 ret = PTR_ERR(lp->enable);
441 if (ret == -ENODEV) {
444 if (ret != -EPROBE_DEFER)
445 dev_err(lp->dev, "error getting enable regulator: %d\n",
452 ret = regulator_enable(lp->supply);
454 dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
460 ret = regulator_enable(lp->enable);
462 dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
467 * LP8555 datasheet says t_RESPONSE (time between VDDIO and
470 usleep_range(1000, 2000);
473 i2c_set_clientdata(cl, lp);
475 ret = lp855x_configure(lp);
477 dev_err(lp->dev, "device config err: %d", ret);
481 ret = lp855x_backlight_register(lp);
484 "failed to register backlight. err: %d\n", ret);
488 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
490 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
494 backlight_update_status(lp->bl);
500 regulator_disable(lp->enable);
503 regulator_disable(lp->supply);
508 static int lp855x_remove(struct i2c_client *cl)
510 struct lp855x *lp = i2c_get_clientdata(cl);
512 lp->bl->props.brightness = 0;
513 backlight_update_status(lp->bl);
515 regulator_disable(lp->enable);
517 regulator_disable(lp->supply);
518 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
523 static const struct of_device_id lp855x_dt_ids[] = {
524 { .compatible = "ti,lp8550", },
525 { .compatible = "ti,lp8551", },
526 { .compatible = "ti,lp8552", },
527 { .compatible = "ti,lp8553", },
528 { .compatible = "ti,lp8555", },
529 { .compatible = "ti,lp8556", },
530 { .compatible = "ti,lp8557", },
533 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
535 static const struct i2c_device_id lp855x_ids[] = {
545 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
547 static struct i2c_driver lp855x_driver = {
550 .of_match_table = of_match_ptr(lp855x_dt_ids),
552 .probe = lp855x_probe,
553 .remove = lp855x_remove,
554 .id_table = lp855x_ids,
557 module_i2c_driver(lp855x_driver);
559 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
560 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
561 MODULE_LICENSE("GPL");