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backlight: lp855x_bl: support new LP8557 device
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LP8557 is one of LP855x family device, but it has different register map
and initialization process.  To support this device, device specific
configuration is done through the lp855x_device_config structure.

Few register definitions are fixed for better readability.
  BRIGHTNESS_CTRL -> LP855X_BRIGHTNESS_CTRL
  DEVICE_CTRL     -> LP855X_DEVICE_CTRL
  EEPROM_START    -> LP855X_EEPROM_START
  EEPROM_END      -> LP855X_EEPROM_END
  EPROM_START     -> LP8556_EPROM_START
  EPROM_END       -> LP8556_EPROM_END

And LP8557 register definitions are added.  New register function,
lp855x_update_bit() is added.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Kim, Milo authored and Linus Torvalds committed Feb 22, 2013
1 parent 68853bc commit 26e8ccc
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Showing 4 changed files with 94 additions and 18 deletions.
4 changes: 2 additions & 2 deletions Documentation/backlight/lp855x-driver.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ Kernel driver lp855x
Backlight driver for LP855x ICs

Supported chips:
Texas Instruments LP8550, LP8551, LP8552, LP8553 and LP8556
Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8556 and LP8557

Author: Milo(Woogyom) Kim <milo.kim@ti.com>

Expand All @@ -24,7 +24,7 @@ Value : pwm based or register based

2) chip_id
The lp855x chip id.
Value : lp8550/lp8551/lp8552/lp8553/lp8556
Value : lp8550/lp8551/lp8552/lp8553/lp8556/lp8557

Platform data for lp855x
------------------------
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2 changes: 1 addition & 1 deletion drivers/video/backlight/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -381,7 +381,7 @@ 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
This supports TI LP8550, LP8551, LP8552, LP8553, LP8556 and LP8557
backlight driver.

config BACKLIGHT_OT200
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87 changes: 72 additions & 15 deletions drivers/video/backlight/lp855x_bl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,13 +17,23 @@
#include <linux/platform_data/lp855x.h>
#include <linux/pwm.h>

/* Registers */
#define BRIGHTNESS_CTRL 0x00
#define DEVICE_CTRL 0x01
#define EEPROM_START 0xA0
#define EEPROM_END 0xA7
#define EPROM_START 0xA0
#define EPROM_END 0xAF
/* LP8550/1/2/3/6 Registers */
#define LP855X_BRIGHTNESS_CTRL 0x00
#define LP855X_DEVICE_CTRL 0x01
#define LP855X_EEPROM_START 0xA0
#define LP855X_EEPROM_END 0xA7
#define LP8556_EPROM_START 0xA0
#define LP8556_EPROM_END 0xAF

/* LP8557 Registers */
#define LP8557_BL_CMD 0x00
#define LP8557_BL_MASK 0x01
#define LP8557_BL_ON 0x01
#define LP8557_BL_OFF 0x00
#define LP8557_BRIGHTNESS_CTRL 0x04
#define LP8557_CONFIG 0x10
#define LP8557_EPROM_START 0x10
#define LP8557_EPROM_END 0x1E

#define BUF_SIZE 20
#define DEFAULT_BL_NAME "lcd-backlight"
Expand Down Expand Up @@ -75,6 +85,24 @@ static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
return i2c_smbus_write_byte_data(lp->client, reg, data);
}

static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
{
int ret;
u8 tmp;

ret = i2c_smbus_read_byte_data(lp->client, reg);
if (ret < 0) {
dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
return ret;
}

tmp = (u8)ret;
tmp &= ~mask;
tmp |= data & mask;

return lp855x_write_byte(lp, reg, tmp);
}

static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
{
u8 start, end;
Expand All @@ -84,12 +112,16 @@ static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
case LP8551:
case LP8552:
case LP8553:
start = EEPROM_START;
end = EEPROM_END;
start = LP855X_EEPROM_START;
end = LP855X_EEPROM_END;
break;
case LP8556:
start = EPROM_START;
end = EPROM_END;
start = LP8556_EPROM_START;
end = LP8556_EPROM_END;
break;
case LP8557:
start = LP8557_EPROM_START;
end = LP8557_EPROM_END;
break;
default:
return false;
Expand All @@ -98,9 +130,30 @@ static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
return (addr >= start && addr <= end);
}

static int lp8557_bl_off(struct lp855x *lp)
{
/* BL_ON = 0 before updating EPROM settings */
return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
LP8557_BL_OFF);
}

static int lp8557_bl_on(struct lp855x *lp)
{
/* BL_ON = 1 after updating EPROM settings */
return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
LP8557_BL_ON);
}

static struct lp855x_device_config lp855x_dev_cfg = {
.reg_brightness = BRIGHTNESS_CTRL,
.reg_devicectrl = DEVICE_CTRL,
.reg_brightness = LP855X_BRIGHTNESS_CTRL,
.reg_devicectrl = LP855X_DEVICE_CTRL,
};

static struct lp855x_device_config lp8557_dev_cfg = {
.reg_brightness = LP8557_BRIGHTNESS_CTRL,
.reg_devicectrl = LP8557_CONFIG,
.pre_init_device = lp8557_bl_off,
.post_init_device = lp8557_bl_on,
};

/*
Expand All @@ -123,6 +176,9 @@ static int lp855x_configure(struct lp855x *lp)
case LP8550 ... LP8556:
lp->cfg = &lp855x_dev_cfg;
break;
case LP8557:
lp->cfg = &lp8557_dev_cfg;
break;
default:
return -EINVAL;
}
Expand Down Expand Up @@ -210,7 +266,7 @@ static int lp855x_bl_update_status(struct backlight_device *bl)

} else if (mode == REGISTER_BASED) {
u8 val = bl->props.brightness;
lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
}

return 0;
Expand All @@ -224,7 +280,7 @@ static int lp855x_bl_get_brightness(struct backlight_device *bl)
if (mode == REGISTER_BASED) {
u8 val = 0;

lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
lp855x_read_byte(lp, lp->cfg->reg_brightness, &val);
bl->props.brightness = val;
}

Expand Down Expand Up @@ -376,6 +432,7 @@ static const struct i2c_device_id lp855x_ids[] = {
{"lp8552", LP8552},
{"lp8553", LP8553},
{"lp8556", LP8556},
{"lp8557", LP8557},
{ }
};
MODULE_DEVICE_TABLE(i2c, lp855x_ids);
Expand Down
19 changes: 19 additions & 0 deletions include/linux/platform_data/lp855x.h
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Original file line number Diff line number Diff line change
Expand Up @@ -49,12 +49,24 @@
#define LP8556_FAST_CONFIG BIT(7) /* use it if EPROMs should be maintained
when exiting the low power mode */

/* CONFIG register - LP8557 */
#define LP8557_PWM_STANDBY BIT(7)
#define LP8557_PWM_FILTER BIT(6)
#define LP8557_RELOAD_EPROM BIT(3) /* use it if EPROMs should be reset
when the backlight turns on */
#define LP8557_OFF_OPENLEDS BIT(2)
#define LP8557_PWM_CONFIG LP8557_PWM_ONLY
#define LP8557_I2C_CONFIG LP8557_I2C_ONLY
#define LP8557_COMB1_CONFIG LP8557_COMBINED1
#define LP8557_COMB2_CONFIG LP8557_COMBINED2

enum lp855x_chip_id {
LP8550,
LP8551,
LP8552,
LP8553,
LP8556,
LP8557,
};

enum lp855x_brightness_ctrl_mode {
Expand Down Expand Up @@ -89,6 +101,13 @@ enum lp8556_brightness_source {
LP8556_COMBINED2, /* pwm + i2c after the shaper block */
};

enum lp8557_brightness_source {
LP8557_PWM_ONLY,
LP8557_I2C_ONLY,
LP8557_COMBINED1, /* pwm + i2c after the shaper block */
LP8557_COMBINED2, /* pwm + i2c before the shaper block */
};

struct lp855x_rom_data {
u8 addr;
u8 val;
Expand Down

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