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/err.h>
18 #include <linux/platform_data/lp855x.h>
19 #include <linux/pwm.h>
20 #include <linux/regulator/consumer.h>
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
30 /* LP8555/7 Registers */
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
37 #define LP8555_EPROM_START 0x10
38 #define LP8555_EPROM_END 0x7A
39 #define LP8557_EPROM_START 0x10
40 #define LP8557_EPROM_END 0x1E
42 #define DEFAULT_BL_NAME "lcd-backlight"
43 #define MAX_BRIGHTNESS 255
45 enum lp855x_brightness_ctrl_mode {
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
59 struct lp855x_device_config {
60 int (*pre_init_device)(struct lp855x *);
63 int (*post_init_device)(struct lp855x *);
68 enum lp855x_chip_id chip_id;
69 enum lp855x_brightness_ctrl_mode mode;
70 struct lp855x_device_config *cfg;
71 struct i2c_client *client;
72 struct backlight_device *bl;
74 struct lp855x_platform_data *pdata;
75 struct pwm_device *pwm;
78 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
80 return i2c_smbus_write_byte_data(lp->client, reg, data);
83 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
88 ret = i2c_smbus_read_byte_data(lp->client, reg);
90 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
98 return lp855x_write_byte(lp, reg, tmp);
101 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
105 switch (lp->chip_id) {
110 start = LP855X_EEPROM_START;
111 end = LP855X_EEPROM_END;
114 start = LP8556_EPROM_START;
115 end = LP8556_EPROM_END;
118 start = LP8555_EPROM_START;
119 end = LP8555_EPROM_END;
122 start = LP8557_EPROM_START;
123 end = LP8557_EPROM_END;
129 return addr >= start && addr <= end;
132 static int lp8557_bl_off(struct lp855x *lp)
134 /* BL_ON = 0 before updating EPROM settings */
135 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
139 static int lp8557_bl_on(struct lp855x *lp)
141 /* BL_ON = 1 after updating EPROM settings */
142 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
146 static struct lp855x_device_config lp855x_dev_cfg = {
147 .reg_brightness = LP855X_BRIGHTNESS_CTRL,
148 .reg_devicectrl = LP855X_DEVICE_CTRL,
151 static struct lp855x_device_config lp8557_dev_cfg = {
152 .reg_brightness = LP8557_BRIGHTNESS_CTRL,
153 .reg_devicectrl = LP8557_CONFIG,
154 .pre_init_device = lp8557_bl_off,
155 .post_init_device = lp8557_bl_on,
159 * Device specific configuration flow
161 * a) pre_init_device(optional)
162 * b) update the brightness register
163 * c) update device control register
164 * d) update ROM area(optional)
165 * e) post_init_device(optional)
168 static int lp855x_configure(struct lp855x *lp)
172 struct lp855x_platform_data *pd = lp->pdata;
174 switch (lp->chip_id) {
180 lp->cfg = &lp855x_dev_cfg;
184 lp->cfg = &lp8557_dev_cfg;
190 if (lp->cfg->pre_init_device) {
191 ret = lp->cfg->pre_init_device(lp);
193 dev_err(lp->dev, "pre init device err: %d\n", ret);
198 val = pd->initial_brightness;
199 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
203 val = pd->device_control;
204 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
208 if (pd->size_program > 0) {
209 for (i = 0; i < pd->size_program; i++) {
210 addr = pd->rom_data[i].addr;
211 val = pd->rom_data[i].val;
212 if (!lp855x_is_valid_rom_area(lp, addr))
215 ret = lp855x_write_byte(lp, addr, val);
221 if (lp->cfg->post_init_device) {
222 ret = lp->cfg->post_init_device(lp);
224 dev_err(lp->dev, "post init device err: %d\n", ret);
235 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
237 unsigned int period = lp->pdata->period_ns;
238 unsigned int duty = br * period / max_br;
239 struct pwm_device *pwm;
241 /* request pwm device with the consumer name */
243 pwm = devm_pwm_get(lp->dev, lp->chipname);
250 pwm_config(lp->pwm, duty, period);
254 pwm_disable(lp->pwm);
257 static int lp855x_bl_update_status(struct backlight_device *bl)
259 struct lp855x *lp = bl_get_data(bl);
260 int brightness = bl->props.brightness;
262 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
265 if (lp->mode == PWM_BASED)
266 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
267 else if (lp->mode == REGISTER_BASED)
268 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
273 static const struct backlight_ops lp855x_bl_ops = {
274 .options = BL_CORE_SUSPENDRESUME,
275 .update_status = lp855x_bl_update_status,
278 static int lp855x_backlight_register(struct lp855x *lp)
280 struct backlight_device *bl;
281 struct backlight_properties props;
282 struct lp855x_platform_data *pdata = lp->pdata;
283 const char *name = pdata->name ? : DEFAULT_BL_NAME;
285 props.type = BACKLIGHT_PLATFORM;
286 props.max_brightness = MAX_BRIGHTNESS;
288 if (pdata->initial_brightness > props.max_brightness)
289 pdata->initial_brightness = props.max_brightness;
291 props.brightness = pdata->initial_brightness;
293 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
294 &lp855x_bl_ops, &props);
303 static ssize_t lp855x_get_chip_id(struct device *dev,
304 struct device_attribute *attr, char *buf)
306 struct lp855x *lp = dev_get_drvdata(dev);
308 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
311 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
312 struct device_attribute *attr, char *buf)
314 struct lp855x *lp = dev_get_drvdata(dev);
315 char *strmode = NULL;
317 if (lp->mode == PWM_BASED)
318 strmode = "pwm based";
319 else if (lp->mode == REGISTER_BASED)
320 strmode = "register based";
322 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
325 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
326 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
328 static struct attribute *lp855x_attributes[] = {
329 &dev_attr_chip_id.attr,
330 &dev_attr_bl_ctl_mode.attr,
334 static const struct attribute_group lp855x_attr_group = {
335 .attrs = lp855x_attributes,
339 static int lp855x_parse_dt(struct lp855x *lp)
341 struct device *dev = lp->dev;
342 struct device_node *node = dev->of_node;
343 struct lp855x_platform_data *pdata;
347 dev_err(dev, "no platform data\n");
351 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
355 of_property_read_string(node, "bl-name", &pdata->name);
356 of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
357 of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
358 of_property_read_u32(node, "pwm-period", &pdata->period_ns);
360 /* Fill ROM platform data if defined */
361 rom_length = of_get_child_count(node);
362 if (rom_length > 0) {
363 struct lp855x_rom_data *rom;
364 struct device_node *child;
367 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
371 for_each_child_of_node(node, child) {
372 of_property_read_u8(child, "rom-addr", &rom[i].addr);
373 of_property_read_u8(child, "rom-val", &rom[i].val);
377 pdata->size_program = rom_length;
378 pdata->rom_data = &rom[0];
381 pdata->supply = devm_regulator_get(dev, "power");
382 if (IS_ERR(pdata->supply)) {
383 if (PTR_ERR(pdata->supply) == -EPROBE_DEFER)
384 return -EPROBE_DEFER;
385 pdata->supply = NULL;
393 static int lp855x_parse_dt(struct lp855x *lp)
399 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
404 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
407 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
413 lp->chipname = id->name;
414 lp->chip_id = id->driver_data;
415 lp->pdata = dev_get_platdata(&cl->dev);
418 ret = lp855x_parse_dt(lp);
423 if (lp->pdata->period_ns > 0)
424 lp->mode = PWM_BASED;
426 lp->mode = REGISTER_BASED;
428 if (lp->pdata->supply) {
429 ret = regulator_enable(lp->pdata->supply);
431 dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
436 i2c_set_clientdata(cl, lp);
438 ret = lp855x_configure(lp);
440 dev_err(lp->dev, "device config err: %d", ret);
444 ret = lp855x_backlight_register(lp);
447 "failed to register backlight. err: %d\n", ret);
451 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
453 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
457 backlight_update_status(lp->bl);
461 static int lp855x_remove(struct i2c_client *cl)
463 struct lp855x *lp = i2c_get_clientdata(cl);
465 lp->bl->props.brightness = 0;
466 backlight_update_status(lp->bl);
467 if (lp->pdata->supply)
468 regulator_disable(lp->pdata->supply);
469 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
474 static const struct of_device_id lp855x_dt_ids[] = {
475 { .compatible = "ti,lp8550", },
476 { .compatible = "ti,lp8551", },
477 { .compatible = "ti,lp8552", },
478 { .compatible = "ti,lp8553", },
479 { .compatible = "ti,lp8555", },
480 { .compatible = "ti,lp8556", },
481 { .compatible = "ti,lp8557", },
484 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
486 static const struct i2c_device_id lp855x_ids[] = {
496 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
498 static struct i2c_driver lp855x_driver = {
501 .of_match_table = of_match_ptr(lp855x_dt_ids),
503 .probe = lp855x_probe,
504 .remove = lp855x_remove,
505 .id_table = lp855x_ids,
508 module_i2c_driver(lp855x_driver);
510 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
511 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
512 MODULE_LICENSE("GPL");