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>
17 #include <linux/platform_data/lp855x.h>
18 #include <linux/pwm.h>
20 /* LP8550/1/2/3/6 Registers */
21 #define LP855X_BRIGHTNESS_CTRL 0x00
22 #define LP855X_DEVICE_CTRL 0x01
23 #define LP855X_EEPROM_START 0xA0
24 #define LP855X_EEPROM_END 0xA7
25 #define LP8556_EPROM_START 0xA0
26 #define LP8556_EPROM_END 0xAF
28 /* LP8557 Registers */
29 #define LP8557_BL_CMD 0x00
30 #define LP8557_BL_MASK 0x01
31 #define LP8557_BL_ON 0x01
32 #define LP8557_BL_OFF 0x00
33 #define LP8557_BRIGHTNESS_CTRL 0x04
34 #define LP8557_CONFIG 0x10
35 #define LP8557_EPROM_START 0x10
36 #define LP8557_EPROM_END 0x1E
39 #define DEFAULT_BL_NAME "lcd-backlight"
40 #define MAX_BRIGHTNESS 255
45 * struct lp855x_device_config
46 * @pre_init_device: init device function call before updating the brightness
47 * @reg_brightness: register address for brigthenss control
48 * @reg_devicectrl: register address for device control
49 * @post_init_device: late init device function call
51 struct lp855x_device_config
{
52 int (*pre_init_device
)(struct lp855x
*);
55 int (*post_init_device
)(struct lp855x
*);
60 enum lp855x_chip_id chip_id
;
61 struct lp855x_device_config
*cfg
;
62 struct i2c_client
*client
;
63 struct backlight_device
*bl
;
65 struct lp855x_platform_data
*pdata
;
66 struct pwm_device
*pwm
;
69 static int lp855x_write_byte(struct lp855x
*lp
, u8 reg
, u8 data
)
71 return i2c_smbus_write_byte_data(lp
->client
, reg
, data
);
74 static int lp855x_update_bit(struct lp855x
*lp
, u8 reg
, u8 mask
, u8 data
)
79 ret
= i2c_smbus_read_byte_data(lp
->client
, reg
);
81 dev_err(lp
->dev
, "failed to read 0x%.2x\n", reg
);
89 return lp855x_write_byte(lp
, reg
, tmp
);
92 static bool lp855x_is_valid_rom_area(struct lp855x
*lp
, u8 addr
)
96 switch (lp
->chip_id
) {
101 start
= LP855X_EEPROM_START
;
102 end
= LP855X_EEPROM_END
;
105 start
= LP8556_EPROM_START
;
106 end
= LP8556_EPROM_END
;
109 start
= LP8557_EPROM_START
;
110 end
= LP8557_EPROM_END
;
116 return (addr
>= start
&& addr
<= end
);
119 static int lp8557_bl_off(struct lp855x
*lp
)
121 /* BL_ON = 0 before updating EPROM settings */
122 return lp855x_update_bit(lp
, LP8557_BL_CMD
, LP8557_BL_MASK
,
126 static int lp8557_bl_on(struct lp855x
*lp
)
128 /* BL_ON = 1 after updating EPROM settings */
129 return lp855x_update_bit(lp
, LP8557_BL_CMD
, LP8557_BL_MASK
,
133 static struct lp855x_device_config lp855x_dev_cfg
= {
134 .reg_brightness
= LP855X_BRIGHTNESS_CTRL
,
135 .reg_devicectrl
= LP855X_DEVICE_CTRL
,
138 static struct lp855x_device_config lp8557_dev_cfg
= {
139 .reg_brightness
= LP8557_BRIGHTNESS_CTRL
,
140 .reg_devicectrl
= LP8557_CONFIG
,
141 .pre_init_device
= lp8557_bl_off
,
142 .post_init_device
= lp8557_bl_on
,
146 * Device specific configuration flow
148 * a) pre_init_device(optional)
149 * b) update the brightness register
150 * c) update device control register
151 * d) update ROM area(optional)
152 * e) post_init_device(optional)
155 static int lp855x_configure(struct lp855x
*lp
)
159 struct lp855x_platform_data
*pd
= lp
->pdata
;
161 switch (lp
->chip_id
) {
162 case LP8550
... LP8556
:
163 lp
->cfg
= &lp855x_dev_cfg
;
166 lp
->cfg
= &lp8557_dev_cfg
;
172 if (lp
->cfg
->pre_init_device
) {
173 ret
= lp
->cfg
->pre_init_device(lp
);
175 dev_err(lp
->dev
, "pre init device err: %d\n", ret
);
180 val
= pd
->initial_brightness
;
181 ret
= lp855x_write_byte(lp
, lp
->cfg
->reg_brightness
, val
);
185 val
= pd
->device_control
;
186 ret
= lp855x_write_byte(lp
, lp
->cfg
->reg_devicectrl
, val
);
190 if (pd
->load_new_rom_data
&& pd
->size_program
) {
191 for (i
= 0; i
< pd
->size_program
; i
++) {
192 addr
= pd
->rom_data
[i
].addr
;
193 val
= pd
->rom_data
[i
].val
;
194 if (!lp855x_is_valid_rom_area(lp
, addr
))
197 ret
= lp855x_write_byte(lp
, addr
, val
);
203 if (lp
->cfg
->post_init_device
) {
204 ret
= lp
->cfg
->post_init_device(lp
);
206 dev_err(lp
->dev
, "post init device err: %d\n", ret
);
217 static void lp855x_pwm_ctrl(struct lp855x
*lp
, int br
, int max_br
)
219 unsigned int period
= lp
->pdata
->period_ns
;
220 unsigned int duty
= br
* period
/ max_br
;
221 struct pwm_device
*pwm
;
223 /* request pwm device with the consumer name */
225 pwm
= devm_pwm_get(lp
->dev
, lp
->chipname
);
232 pwm_config(lp
->pwm
, duty
, period
);
236 pwm_disable(lp
->pwm
);
239 static int lp855x_bl_update_status(struct backlight_device
*bl
)
241 struct lp855x
*lp
= bl_get_data(bl
);
242 enum lp855x_brightness_ctrl_mode mode
= lp
->pdata
->mode
;
244 if (bl
->props
.state
& BL_CORE_SUSPENDED
)
245 bl
->props
.brightness
= 0;
247 if (mode
== PWM_BASED
) {
248 int br
= bl
->props
.brightness
;
249 int max_br
= bl
->props
.max_brightness
;
251 lp855x_pwm_ctrl(lp
, br
, max_br
);
253 } else if (mode
== REGISTER_BASED
) {
254 u8 val
= bl
->props
.brightness
;
255 lp855x_write_byte(lp
, lp
->cfg
->reg_brightness
, val
);
261 static int lp855x_bl_get_brightness(struct backlight_device
*bl
)
263 return bl
->props
.brightness
;
266 static const struct backlight_ops lp855x_bl_ops
= {
267 .options
= BL_CORE_SUSPENDRESUME
,
268 .update_status
= lp855x_bl_update_status
,
269 .get_brightness
= lp855x_bl_get_brightness
,
272 static int lp855x_backlight_register(struct lp855x
*lp
)
274 struct backlight_device
*bl
;
275 struct backlight_properties props
;
276 struct lp855x_platform_data
*pdata
= lp
->pdata
;
277 char *name
= pdata
->name
? : DEFAULT_BL_NAME
;
279 props
.type
= BACKLIGHT_PLATFORM
;
280 props
.max_brightness
= MAX_BRIGHTNESS
;
282 if (pdata
->initial_brightness
> props
.max_brightness
)
283 pdata
->initial_brightness
= props
.max_brightness
;
285 props
.brightness
= pdata
->initial_brightness
;
287 bl
= backlight_device_register(name
, lp
->dev
, lp
,
288 &lp855x_bl_ops
, &props
);
297 static void lp855x_backlight_unregister(struct lp855x
*lp
)
300 backlight_device_unregister(lp
->bl
);
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
);
307 return scnprintf(buf
, BUF_SIZE
, "%s\n", lp
->chipname
);
310 static ssize_t
lp855x_get_bl_ctl_mode(struct device
*dev
,
311 struct device_attribute
*attr
, char *buf
)
313 struct lp855x
*lp
= dev_get_drvdata(dev
);
314 enum lp855x_brightness_ctrl_mode mode
= lp
->pdata
->mode
;
315 char *strmode
= NULL
;
317 if (mode
== PWM_BASED
)
318 strmode
= "pwm based";
319 else if (mode
== REGISTER_BASED
)
320 strmode
= "register based";
322 return scnprintf(buf
, BUF_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
,
338 static int lp855x_probe(struct i2c_client
*cl
, const struct i2c_device_id
*id
)
341 struct lp855x_platform_data
*pdata
= cl
->dev
.platform_data
;
342 enum lp855x_brightness_ctrl_mode mode
;
346 dev_err(&cl
->dev
, "no platform data supplied\n");
350 if (!i2c_check_functionality(cl
->adapter
, I2C_FUNC_SMBUS_I2C_BLOCK
))
353 lp
= devm_kzalloc(&cl
->dev
, sizeof(struct lp855x
), GFP_KERNEL
);
361 lp
->chipname
= id
->name
;
362 lp
->chip_id
= id
->driver_data
;
363 i2c_set_clientdata(cl
, lp
);
365 ret
= lp855x_configure(lp
);
367 dev_err(lp
->dev
, "device config err: %d", ret
);
371 ret
= lp855x_backlight_register(lp
);
374 "failed to register backlight. err: %d\n", ret
);
378 ret
= sysfs_create_group(&lp
->dev
->kobj
, &lp855x_attr_group
);
380 dev_err(lp
->dev
, "failed to register sysfs. err: %d\n", ret
);
384 backlight_update_status(lp
->bl
);
388 lp855x_backlight_unregister(lp
);
393 static int lp855x_remove(struct i2c_client
*cl
)
395 struct lp855x
*lp
= i2c_get_clientdata(cl
);
397 lp
->bl
->props
.brightness
= 0;
398 backlight_update_status(lp
->bl
);
399 sysfs_remove_group(&lp
->dev
->kobj
, &lp855x_attr_group
);
400 lp855x_backlight_unregister(lp
);
405 static const struct i2c_device_id lp855x_ids
[] = {
414 MODULE_DEVICE_TABLE(i2c
, lp855x_ids
);
416 static struct i2c_driver lp855x_driver
= {
420 .probe
= lp855x_probe
,
421 .remove
= lp855x_remove
,
422 .id_table
= lp855x_ids
,
425 module_i2c_driver(lp855x_driver
);
427 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
428 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
429 MODULE_LICENSE("GPL");