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: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 131 insertions, 0 deletions

diff --git a/include/linux/lp855x.h b/include/linux/lp855x.h
new file mode 100644
index 00000000000..781a490a451
--- /dev/null
+++ b/include/linux/lp855x.h
@@ -0,0 +1,131 @@
+/*
+ * 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