backlight: add new lp8788 backlight driver

TI LP8788 PMU supports regulators, battery charger, RTC, ADC, backlight
dri= ver and current sinks.  This patch enables LP8788 backlight module.

(Brightness mode)
The brightness is controlled by PWM input or I2C register.
All modes are supported in the driver.

(Platform data)
Configurable data can be defined in the platform side.
 name                  : backlight driver name. (default: "lcd-backlight")
 initial_brightness    : initial value of backlight brightness
 bl_mode               : brightness control by PWM or lp8788 register
 dim_mode              : dimming mode selection
 full_scale            : full scale current setting
 rise_time             : brightness ramp up step time
 fall_time             : brightness ramp down step time
 pwm_pol               : PWM polarity setting when bl_mode is PWM based
 period_ns             : platform specific PWM period value. unit is nano.

The default values are set in case no platform data is defined.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: "devendra.aaru" <devendra.aaru@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 19 deletions

diff --git a/include/linux/mfd/lp8788.h b/include/linux/mfd/lp8788.h
index 2a32b16f79cb..786bf6679a28 100644
--- a/include/linux/mfd/lp8788.h
+++ b/include/linux/mfd/lp8788.h
@@ -16,6 +16,7 @@
 
 #include <linux/gpio.h>
 #include <linux/irqdomain.h>
+#include <linux/pwm.h>
 #include <linux/regmap.h>
 
 #define LP8788_DEV_BUCK         "lp8788-buck"
@@ -124,11 +125,6 @@ enum lp8788_bl_ramp_step {
         LP8788_RAMP_65538us,
 };
 
-enum lp8788_bl_pwm_polarity {
-        LP8788_PWM_ACTIVE_HIGH,
-        LP8788_PWM_ACTIVE_LOW,
-};
-
 enum lp8788_isink_scale {
         LP8788_ISINK_SCALE_100mA,
         LP8788_ISINK_SCALE_120mA,
@@ -229,16 +225,6 @@ struct lp8788_charger_platform_data {
 };
 
 /*
- * struct lp8788_bl_pwm_data
- * @pwm_set_intensity     : set duty of pwm
- * @pwm_get_intensity     : get current duty of pwm
- */
-struct lp8788_bl_pwm_data {
-        void (*pwm_set_intensity) (int brightness, int max_brightness);
-        int (*pwm_get_intensity) (int max_brightness);
-};
-
-/*
  * struct lp8788_backlight_platform_data
  * @name                  : backlight driver name. (default: "lcd-backlight")
  * @initial_brightness    : initial value of backlight brightness
@@ -248,8 +234,8 @@ struct lp8788_bl_pwm_data {
  * @rise_time             : brightness ramp up step time
  * @fall_time             : brightness ramp down step time
  * @pwm_pol               : pwm polarity setting when bl_mode is pwm based
- * @pwm_data              : platform specific pwm generation functions
- *                          only valid when bl_mode is pwm based
+ * @period_ns             : platform specific pwm period value. unit is nano.
+                            Only valid when bl_mode is LP8788_BL_COMB_PWM_BASED
  */
 struct lp8788_backlight_platform_data {
         char *name;
@@ -259,8 +245,8 @@ struct lp8788_backlight_platform_data {
         enum lp8788_bl_full_scale_current full_scale;
         enum lp8788_bl_ramp_step rise_time;
         enum lp8788_bl_ramp_step fall_time;
-        enum lp8788_bl_pwm_polarity pwm_pol;
-        struct lp8788_bl_pwm_data pwm_data;
+        enum pwm_polarity pwm_pol;
+        unsigned int period_ns;
 };
 
 /*