Commit 7be865ab authored by Kim, Milo's avatar Kim, Milo Committed by Linus Torvalds

backlight: new backlight driver for LP855x devices

THis driver supports TI LP8550/LP8551/LP8552/LP8553/LP8556 backlight
devices.

The brightness can be controlled by the I2C or PWM input.  The lp855x
driver provides both modes.  For the PWM control, pwm-specific functions
can be defined in the platform data.  And some information can be read
via the sysfs(lp855x device attributes).

For details, please refer to Documentation/backlight/lp855x-driver.txt.

[axel.lin@gmail.com: add missing mutex_unlock in lp855x_read_byte() error path]
[axel.lin@gmail.com: check platform data in lp855x_probe()]
[axel.lin@gmail.com: small cleanups]
[dan.carpenter@oracle.com: silence a compiler warning]
[axel.lin@gmail.com: use id->driver_data to differentiate lp855x chips]
[akpm@linux-foundation.org: simplify boolean return expression]
Signed-off-by: default avatarMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: default avatarAxel Lin <axel.lin@gmail.com>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 050ea48b
Kernel driver lp855x
====================
Backlight driver for LP855x ICs
Supported chips:
Texas Instruments LP8550, LP8551, LP8552, LP8553 and LP8556
Author: Milo(Woogyom) Kim <milo.kim@ti.com>
Description
-----------
* Brightness control
Brightness can be controlled by the pwm input or the i2c command.
The lp855x driver supports both cases.
* Device attributes
1) bl_ctl_mode
Backlight control mode.
Value : pwm based or register based
2) chip_id
The lp855x chip id.
Value : lp8550/lp8551/lp8552/lp8553/lp8556
Platform data for lp855x
------------------------
For supporting platform specific data, the lp855x platform data can be used.
* name : Backlight driver name. If it is not defined, default name is set.
* mode : Brightness control mode. PWM or register based.
* device_control : Value of DEVICE CONTROL register.
* initial_brightness : Initial value of backlight brightness.
* pwm_data : Platform specific pwm generation functions.
Only valid when brightness is pwm input mode.
Functions should be implemented by PWM driver.
- pwm_set_intensity() : set duty of PWM
- pwm_get_intensity() : get current duty of PWM
* load_new_rom_data :
0 : use default configuration data
1 : update values of eeprom or eprom registers on loading driver
* size_program : Total size of lp855x_rom_data.
* rom_data : List of new eeprom/eprom registers.
example 1) lp8552 platform data : i2c register mode with new eeprom data
#define EEPROM_A5_ADDR 0xA5
#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */
static struct lp855x_rom_data lp8552_eeprom_arr[] = {
{EEPROM_A5_ADDR, EEPROM_A5_VAL},
};
static struct lp855x_platform_data lp8552_pdata = {
.name = "lcd-bl",
.mode = REGISTER_BASED,
.device_control = I2C_CONFIG(LP8552),
.initial_brightness = INITIAL_BRT,
.load_new_rom_data = 1,
.size_program = ARRAY_SIZE(lp8552_eeprom_arr),
.rom_data = lp8552_eeprom_arr,
};
example 2) lp8556 platform data : pwm input mode with default rom data
static struct lp855x_platform_data lp8556_pdata = {
.mode = PWM_BASED,
.device_control = PWM_CONFIG(LP8556),
.initial_brightness = INITIAL_BRT,
.pwm_data = {
.pwm_set_intensity = platform_pwm_set_intensity,
.pwm_get_intensity = platform_pwm_get_intensity,
},
};
......@@ -334,6 +334,13 @@ config BACKLIGHT_AAT2870
If you have a AnalogicTech AAT2870 say Y to enable the
backlight driver.
config BACKLIGHT_LP855X
tristate "Backlight driver for TI LP855X"
depends on BACKLIGHT_CLASS_DEVICE && I2C
help
This supports TI LP8550, LP8551, LP8552, LP8553 and LP8556
backlight driver.
endif # BACKLIGHT_CLASS_DEVICE
endif # BACKLIGHT_LCD_SUPPORT
......@@ -22,6 +22,7 @@ obj-$(CONFIG_BACKLIGHT_GENERIC) += generic_bl.o
obj-$(CONFIG_BACKLIGHT_HP700) += jornada720_bl.o
obj-$(CONFIG_BACKLIGHT_HP680) += hp680_bl.o
obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomolcd.o
obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o
obj-$(CONFIG_BACKLIGHT_OMAP1) += omap1_bl.o
obj-$(CONFIG_BACKLIGHT_PROGEAR) += progear_bl.o
obj-$(CONFIG_BACKLIGHT_CARILLO_RANCH) += cr_bllcd.o
......
/*
* 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/lp855x.h>
/* Registers */
#define BRIGHTNESS_CTRL (0x00)
#define DEVICE_CTRL (0x01)
#define BUF_SIZE 20
#define DEFAULT_BL_NAME "lcd-backlight"
#define MAX_BRIGHTNESS 255
struct lp855x {
const char *chipname;
enum lp855x_chip_id chip_id;
struct i2c_client *client;
struct backlight_device *bl;
struct device *dev;
struct mutex xfer_lock;
struct lp855x_platform_data *pdata;
};
static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
{
int ret;
mutex_lock(&lp->xfer_lock);
ret = i2c_smbus_read_byte_data(lp->client, reg);
if (ret < 0) {
mutex_unlock(&lp->xfer_lock);
dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
return ret;
}
mutex_unlock(&lp->xfer_lock);
*data = (u8)ret;
return 0;
}
static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
{
int ret;
mutex_lock(&lp->xfer_lock);
ret = i2c_smbus_write_byte_data(lp->client, reg, data);
mutex_unlock(&lp->xfer_lock);
return ret;
}
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 = EEPROM_START;
end = EEPROM_END;
break;
case LP8556:
start = EPROM_START;
end = EPROM_END;
break;
default:
return false;
}
return (addr >= start && addr <= end);
}
static int lp855x_init_registers(struct lp855x *lp)
{
u8 val, addr;
int i, ret;
struct lp855x_platform_data *pd = lp->pdata;
val = pd->initial_brightness;
ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
if (ret)
return ret;
val = pd->device_control;
ret = lp855x_write_byte(lp, DEVICE_CTRL, val);
if (ret)
return ret;
if (pd->load_new_rom_data && pd->size_program) {
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)
return ret;
}
}
return ret;
}
static int lp855x_bl_update_status(struct backlight_device *bl)
{
struct lp855x *lp = bl_get_data(bl);
enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
if (bl->props.state & BL_CORE_SUSPENDED)
bl->props.brightness = 0;
if (mode == PWM_BASED) {
struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
int br = bl->props.brightness;
int max_br = bl->props.max_brightness;
if (pd->pwm_set_intensity)
pd->pwm_set_intensity(br, max_br);
} else if (mode == REGISTER_BASED) {
u8 val = bl->props.brightness;
lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
}
return 0;
}
static int lp855x_bl_get_brightness(struct backlight_device *bl)
{
struct lp855x *lp = bl_get_data(bl);
enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
if (mode == PWM_BASED) {
struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
int max_br = bl->props.max_brightness;
if (pd->pwm_get_intensity)
bl->props.brightness = pd->pwm_get_intensity(max_br);
} else if (mode == REGISTER_BASED) {
u8 val = 0;
lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
bl->props.brightness = val;
}
return bl->props.brightness;
}
static const struct backlight_ops lp855x_bl_ops = {
.options = BL_CORE_SUSPENDRESUME,
.update_status = lp855x_bl_update_status,
.get_brightness = lp855x_bl_get_brightness,
};
static int lp855x_backlight_register(struct lp855x *lp)
{
struct backlight_device *bl;
struct backlight_properties props;
struct lp855x_platform_data *pdata = lp->pdata;
char *name = pdata->name ? : DEFAULT_BL_NAME;
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 = backlight_device_register(name, lp->dev, lp,
&lp855x_bl_ops, &props);
if (IS_ERR(bl))
return PTR_ERR(bl);
lp->bl = bl;
return 0;
}
static void lp855x_backlight_unregister(struct lp855x *lp)
{
if (lp->bl)
backlight_device_unregister(lp->bl);
}
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, BUF_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);
enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
char *strmode = NULL;
if (mode == PWM_BASED)
strmode = "pwm based";
else if (mode == REGISTER_BASED)
strmode = "register based";
return scnprintf(buf, BUF_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,
};
static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
struct lp855x *lp;
struct lp855x_platform_data *pdata = cl->dev.platform_data;
enum lp855x_brightness_ctrl_mode mode;
int ret;
if (!pdata) {
dev_err(&cl->dev, "no platform data supplied\n");
return -EINVAL;
}
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;
mode = pdata->mode;
lp->client = cl;
lp->dev = &cl->dev;
lp->pdata = pdata;
lp->chipname = id->name;
lp->chip_id = id->driver_data;
i2c_set_clientdata(cl, lp);
mutex_init(&lp->xfer_lock);
ret = lp855x_init_registers(lp);
if (ret) {
dev_err(lp->dev, "i2c communication err: %d", ret);
if (mode == REGISTER_BASED)
goto err_dev;
}
ret = lp855x_backlight_register(lp);
if (ret) {
dev_err(lp->dev,
"failed to register backlight. err: %d\n", ret);
goto err_dev;
}
ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
if (ret) {
dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
goto err_sysfs;
}
backlight_update_status(lp->bl);
return 0;
err_sysfs:
lp855x_backlight_unregister(lp);
err_dev:
return ret;
}
static int __devexit lp855x_remove(struct i2c_client *cl)
{
struct lp855x *lp = i2c_get_clientdata(cl);
lp->bl->props.brightness = 0;
backlight_update_status(lp->bl);
sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
lp855x_backlight_unregister(lp);
return 0;
}
static const struct i2c_device_id lp855x_ids[] = {
{"lp8550", LP8550},
{"lp8551", LP8551},
{"lp8552", LP8552},
{"lp8553", LP8553},
{"lp8556", LP8556},
{ }
};
MODULE_DEVICE_TABLE(i2c, lp855x_ids);
static struct i2c_driver lp855x_driver = {
.driver = {
.name = "lp855x",
},
.probe = lp855x_probe,
.remove = __devexit_p(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");
/*
* 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.
*
*/
#ifndef _LP855X_H
#define _LP855X_H
#define BL_CTL_SHFT (0)
#define BRT_MODE_SHFT (1)
#define BRT_MODE_MASK (0x06)
/* Enable backlight. Only valid when BRT_MODE=10(I2C only) */
#define ENABLE_BL (1)
#define DISABLE_BL (0)
#define I2C_CONFIG(id) id ## _I2C_CONFIG
#define PWM_CONFIG(id) id ## _PWM_CONFIG
/* DEVICE CONTROL register - LP8550 */
#define LP8550_PWM_CONFIG (LP8550_PWM_ONLY << BRT_MODE_SHFT)
#define LP8550_I2C_CONFIG ((ENABLE_BL << BL_CTL_SHFT) | \
(LP8550_I2C_ONLY << BRT_MODE_SHFT))
/* DEVICE CONTROL register - LP8551 */
#define LP8551_PWM_CONFIG LP8550_PWM_CONFIG
#define LP8551_I2C_CONFIG LP8550_I2C_CONFIG
/* DEVICE CONTROL register - LP8552 */
#define LP8552_PWM_CONFIG LP8550_PWM_CONFIG
#define LP8552_I2C_CONFIG LP8550_I2C_CONFIG
/* DEVICE CONTROL register - LP8553 */
#define LP8553_PWM_CONFIG LP8550_PWM_CONFIG
#define LP8553_I2C_CONFIG LP8550_I2C_CONFIG
/* DEVICE CONTROL register - LP8556 */
#define LP8556_PWM_CONFIG (LP8556_PWM_ONLY << BRT_MODE_SHFT)
#define LP8556_COMB1_CONFIG (LP8556_COMBINED1 << BRT_MODE_SHFT)
#define LP8556_I2C_CONFIG ((ENABLE_BL << BL_CTL_SHFT) | \
(LP8556_I2C_ONLY << BRT_MODE_SHFT))
#define LP8556_COMB2_CONFIG (LP8556_COMBINED2 << BRT_MODE_SHFT)
/* ROM area boundary */
#define EEPROM_START (0xA0)
#define EEPROM_END (0xA7)
#define EPROM_START (0xA0)
#define EPROM_END (0xAF)
enum lp855x_chip_id {
LP8550,
LP8551,
LP8552,
LP8553,
LP8556,
};
enum lp855x_brightness_ctrl_mode {
PWM_BASED = 1,
REGISTER_BASED,
};
enum lp8550_brighntess_source {
LP8550_PWM_ONLY,
LP8550_I2C_ONLY = 2,
};
enum lp8551_brighntess_source {
LP8551_PWM_ONLY = LP8550_PWM_ONLY,
LP8551_I2C_ONLY = LP8550_I2C_ONLY,
};
enum lp8552_brighntess_source {
LP8552_PWM_ONLY = LP8550_PWM_ONLY,
LP8552_I2C_ONLY = LP8550_I2C_ONLY,
};
enum lp8553_brighntess_source {
LP8553_PWM_ONLY = LP8550_PWM_ONLY,
LP8553_I2C_ONLY = LP8550_I2C_ONLY,
};
enum lp8556_brightness_source {
LP8556_PWM_ONLY,
LP8556_COMBINED1, /* pwm + i2c before the shaper block */
LP8556_I2C_ONLY,
LP8556_COMBINED2, /* pwm + i2c after the shaper block */
};
struct lp855x_pwm_data {
void (*pwm_set_intensity) (int brightness, int max_brightness);
int (*pwm_get_intensity) (int max_brightness);
};
struct lp855x_rom_data {
u8 addr;
u8 val;
};
/**
* struct lp855x_platform_data
* @name : Backlight driver name. If it is not defined, default name is set.
* @mode : brightness control by pwm or lp855x register
* @device_control : value of DEVICE CONTROL register
* @initial_brightness : initial value of backlight brightness
* @pwm_data : platform specific pwm generation functions.
Only valid when mode is PWM_BASED.
* @load_new_rom_data :
0 : use default configuration data
1 : update values of eeprom or eprom registers on loading driver
* @size_program : total size of lp855x_rom_data
* @rom_data : list of new eeprom/eprom registers
*/
struct lp855x_platform_data {
char *name;
enum lp855x_brightness_ctrl_mode mode;
u8 device_control;
int initial_brightness;
struct lp855x_pwm_data pwm_data;
u8 load_new_rom_data;
int size_program;
struct lp855x_rom_data *rom_data;
};
#endif
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