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>
21 /* LP8550/1/2/3/6 Registers */
22 #define LP855X_BRIGHTNESS_CTRL 0x00
23 #define LP855X_DEVICE_CTRL 0x01
24 #define LP855X_EEPROM_START 0xA0
25 #define LP855X_EEPROM_END 0xA7
26 #define LP8556_EPROM_START 0xA0
27 #define LP8556_EPROM_END 0xAF
29 /* LP8555/7 Registers */
30 #define LP8557_BL_CMD 0x00
31 #define LP8557_BL_MASK 0x01
32 #define LP8557_BL_ON 0x01
33 #define LP8557_BL_OFF 0x00
34 #define LP8557_BRIGHTNESS_CTRL 0x04
35 #define LP8557_CONFIG 0x10
36 #define LP8555_EPROM_START 0x10
37 #define LP8555_EPROM_END 0x7A
38 #define LP8557_EPROM_START 0x10
39 #define LP8557_EPROM_END 0x1E
41 #define DEFAULT_BL_NAME "lcd-backlight"
42 #define MAX_BRIGHTNESS 255
44 enum lp855x_brightness_ctrl_mode
{
52 * struct lp855x_device_config
53 * @pre_init_device: init device function call before updating the brightness
54 * @reg_brightness: register address for brigthenss control
55 * @reg_devicectrl: register address for device control
56 * @post_init_device: late init device function call
58 struct lp855x_device_config
{
59 int (*pre_init_device
)(struct lp855x
*);
62 int (*post_init_device
)(struct lp855x
*);
67 enum lp855x_chip_id chip_id
;
68 enum lp855x_brightness_ctrl_mode mode
;
69 struct lp855x_device_config
*cfg
;
70 struct i2c_client
*client
;
71 struct backlight_device
*bl
;
73 struct lp855x_platform_data
*pdata
;
74 struct pwm_device
*pwm
;
77 static int lp855x_write_byte(struct lp855x
*lp
, u8 reg
, u8 data
)
79 return i2c_smbus_write_byte_data(lp
->client
, reg
, data
);
82 static int lp855x_update_bit(struct lp855x
*lp
, u8 reg
, u8 mask
, u8 data
)
87 ret
= i2c_smbus_read_byte_data(lp
->client
, reg
);
89 dev_err(lp
->dev
, "failed to read 0x%.2x\n", reg
);
97 return lp855x_write_byte(lp
, reg
, tmp
);
100 static bool lp855x_is_valid_rom_area(struct lp855x
*lp
, u8 addr
)
104 switch (lp
->chip_id
) {
109 start
= LP855X_EEPROM_START
;
110 end
= LP855X_EEPROM_END
;
113 start
= LP8556_EPROM_START
;
114 end
= LP8556_EPROM_END
;
117 start
= LP8555_EPROM_START
;
118 end
= LP8555_EPROM_END
;
121 start
= LP8557_EPROM_START
;
122 end
= LP8557_EPROM_END
;
128 return (addr
>= start
&& addr
<= end
);
131 static int lp8557_bl_off(struct lp855x
*lp
)
133 /* BL_ON = 0 before updating EPROM settings */
134 return lp855x_update_bit(lp
, LP8557_BL_CMD
, LP8557_BL_MASK
,
138 static int lp8557_bl_on(struct lp855x
*lp
)
140 /* BL_ON = 1 after updating EPROM settings */
141 return lp855x_update_bit(lp
, LP8557_BL_CMD
, LP8557_BL_MASK
,
145 static struct lp855x_device_config lp855x_dev_cfg
= {
146 .reg_brightness
= LP855X_BRIGHTNESS_CTRL
,
147 .reg_devicectrl
= LP855X_DEVICE_CTRL
,
150 static struct lp855x_device_config lp8557_dev_cfg
= {
151 .reg_brightness
= LP8557_BRIGHTNESS_CTRL
,
152 .reg_devicectrl
= LP8557_CONFIG
,
153 .pre_init_device
= lp8557_bl_off
,
154 .post_init_device
= lp8557_bl_on
,
158 * Device specific configuration flow
160 * a) pre_init_device(optional)
161 * b) update the brightness register
162 * c) update device control register
163 * d) update ROM area(optional)
164 * e) post_init_device(optional)
167 static int lp855x_configure(struct lp855x
*lp
)
171 struct lp855x_platform_data
*pd
= lp
->pdata
;
173 switch (lp
->chip_id
) {
179 lp
->cfg
= &lp855x_dev_cfg
;
183 lp
->cfg
= &lp8557_dev_cfg
;
189 if (lp
->cfg
->pre_init_device
) {
190 ret
= lp
->cfg
->pre_init_device(lp
);
192 dev_err(lp
->dev
, "pre init device err: %d\n", ret
);
197 val
= pd
->initial_brightness
;
198 ret
= lp855x_write_byte(lp
, lp
->cfg
->reg_brightness
, val
);
202 val
= pd
->device_control
;
203 ret
= lp855x_write_byte(lp
, lp
->cfg
->reg_devicectrl
, val
);
207 if (pd
->size_program
> 0) {
208 for (i
= 0; i
< pd
->size_program
; i
++) {
209 addr
= pd
->rom_data
[i
].addr
;
210 val
= pd
->rom_data
[i
].val
;
211 if (!lp855x_is_valid_rom_area(lp
, addr
))
214 ret
= lp855x_write_byte(lp
, addr
, val
);
220 if (lp
->cfg
->post_init_device
) {
221 ret
= lp
->cfg
->post_init_device(lp
);
223 dev_err(lp
->dev
, "post init device err: %d\n", ret
);
234 static void lp855x_pwm_ctrl(struct lp855x
*lp
, int br
, int max_br
)
236 unsigned int period
= lp
->pdata
->period_ns
;
237 unsigned int duty
= br
* period
/ max_br
;
238 struct pwm_device
*pwm
;
240 /* request pwm device with the consumer name */
242 pwm
= devm_pwm_get(lp
->dev
, lp
->chipname
);
249 pwm_config(lp
->pwm
, duty
, period
);
253 pwm_disable(lp
->pwm
);
256 static int lp855x_bl_update_status(struct backlight_device
*bl
)
258 struct lp855x
*lp
= bl_get_data(bl
);
260 if (bl
->props
.state
& (BL_CORE_SUSPENDED
| BL_CORE_FBBLANK
))
261 bl
->props
.brightness
= 0;
263 if (lp
->mode
== PWM_BASED
) {
264 int br
= bl
->props
.brightness
;
265 int max_br
= bl
->props
.max_brightness
;
267 lp855x_pwm_ctrl(lp
, br
, max_br
);
269 } else if (lp
->mode
== REGISTER_BASED
) {
270 u8 val
= bl
->props
.brightness
;
271 lp855x_write_byte(lp
, lp
->cfg
->reg_brightness
, val
);
277 static int lp855x_bl_get_brightness(struct backlight_device
*bl
)
279 return bl
->props
.brightness
;
282 static const struct backlight_ops lp855x_bl_ops
= {
283 .options
= BL_CORE_SUSPENDRESUME
,
284 .update_status
= lp855x_bl_update_status
,
285 .get_brightness
= lp855x_bl_get_brightness
,
288 static int lp855x_backlight_register(struct lp855x
*lp
)
290 struct backlight_device
*bl
;
291 struct backlight_properties props
;
292 struct lp855x_platform_data
*pdata
= lp
->pdata
;
293 const char *name
= pdata
->name
? : DEFAULT_BL_NAME
;
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
);
317 return scnprintf(buf
, PAGE_SIZE
, "%s\n", lp
->chipname
);
320 static ssize_t
lp855x_get_bl_ctl_mode(struct device
*dev
,
321 struct device_attribute
*attr
, char *buf
)
323 struct lp855x
*lp
= dev_get_drvdata(dev
);
324 char *strmode
= NULL
;
326 if (lp
->mode
== PWM_BASED
)
327 strmode
= "pwm based";
328 else if (lp
->mode
== REGISTER_BASED
)
329 strmode
= "register based";
331 return scnprintf(buf
, PAGE_SIZE
, "%s\n", strmode
);
334 static DEVICE_ATTR(chip_id
, S_IRUGO
, lp855x_get_chip_id
, NULL
);
335 static DEVICE_ATTR(bl_ctl_mode
, S_IRUGO
, lp855x_get_bl_ctl_mode
, NULL
);
337 static struct attribute
*lp855x_attributes
[] = {
338 &dev_attr_chip_id
.attr
,
339 &dev_attr_bl_ctl_mode
.attr
,
343 static const struct attribute_group lp855x_attr_group
= {
344 .attrs
= lp855x_attributes
,
348 static int lp855x_parse_dt(struct device
*dev
, struct device_node
*node
)
350 struct lp855x_platform_data
*pdata
;
354 dev_err(dev
, "no platform data\n");
358 pdata
= devm_kzalloc(dev
, sizeof(*pdata
), GFP_KERNEL
);
362 of_property_read_string(node
, "bl-name", &pdata
->name
);
363 of_property_read_u8(node
, "dev-ctrl", &pdata
->device_control
);
364 of_property_read_u8(node
, "init-brt", &pdata
->initial_brightness
);
365 of_property_read_u32(node
, "pwm-period", &pdata
->period_ns
);
367 /* Fill ROM platform data if defined */
368 rom_length
= of_get_child_count(node
);
369 if (rom_length
> 0) {
370 struct lp855x_rom_data
*rom
;
371 struct device_node
*child
;
374 rom
= devm_kzalloc(dev
, sizeof(*rom
) * rom_length
, GFP_KERNEL
);
378 for_each_child_of_node(node
, child
) {
379 of_property_read_u8(child
, "rom-addr", &rom
[i
].addr
);
380 of_property_read_u8(child
, "rom-val", &rom
[i
].val
);
384 pdata
->size_program
= rom_length
;
385 pdata
->rom_data
= &rom
[0];
388 dev
->platform_data
= pdata
;
393 static int lp855x_parse_dt(struct device
*dev
, struct device_node
*node
)
399 static int lp855x_probe(struct i2c_client
*cl
, const struct i2c_device_id
*id
)
402 struct lp855x_platform_data
*pdata
= dev_get_platdata(&cl
->dev
);
403 struct device_node
*node
= cl
->dev
.of_node
;
407 ret
= lp855x_parse_dt(&cl
->dev
, node
);
411 pdata
= dev_get_platdata(&cl
->dev
);
414 if (!i2c_check_functionality(cl
->adapter
, I2C_FUNC_SMBUS_I2C_BLOCK
))
417 lp
= devm_kzalloc(&cl
->dev
, sizeof(struct lp855x
), GFP_KERNEL
);
421 if (pdata
->period_ns
> 0)
422 lp
->mode
= PWM_BASED
;
424 lp
->mode
= REGISTER_BASED
;
429 lp
->chipname
= id
->name
;
430 lp
->chip_id
= id
->driver_data
;
431 i2c_set_clientdata(cl
, lp
);
433 ret
= lp855x_configure(lp
);
435 dev_err(lp
->dev
, "device config err: %d", ret
);
439 ret
= lp855x_backlight_register(lp
);
442 "failed to register backlight. err: %d\n", ret
);
446 ret
= sysfs_create_group(&lp
->dev
->kobj
, &lp855x_attr_group
);
448 dev_err(lp
->dev
, "failed to register sysfs. err: %d\n", ret
);
452 backlight_update_status(lp
->bl
);
456 static int lp855x_remove(struct i2c_client
*cl
)
458 struct lp855x
*lp
= i2c_get_clientdata(cl
);
460 lp
->bl
->props
.brightness
= 0;
461 backlight_update_status(lp
->bl
);
462 sysfs_remove_group(&lp
->dev
->kobj
, &lp855x_attr_group
);
467 static const struct of_device_id lp855x_dt_ids
[] = {
468 { .compatible
= "ti,lp8550", },
469 { .compatible
= "ti,lp8551", },
470 { .compatible
= "ti,lp8552", },
471 { .compatible
= "ti,lp8553", },
472 { .compatible
= "ti,lp8555", },
473 { .compatible
= "ti,lp8556", },
474 { .compatible
= "ti,lp8557", },
477 MODULE_DEVICE_TABLE(of
, lp855x_dt_ids
);
479 static const struct i2c_device_id lp855x_ids
[] = {
489 MODULE_DEVICE_TABLE(i2c
, lp855x_ids
);
491 static struct i2c_driver lp855x_driver
= {
494 .of_match_table
= of_match_ptr(lp855x_dt_ids
),
496 .probe
= lp855x_probe
,
497 .remove
= lp855x_remove
,
498 .id_table
= lp855x_ids
,
501 module_i2c_driver(lp855x_driver
);
503 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
504 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
505 MODULE_LICENSE("GPL");