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authorKim, Milo <Milo.Kim@ti.com>2012-12-17 16:00:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-17 17:15:16 -0800
commit8cc9764c9c7d01a6e2c3ddac8f0ac7716be01868 (patch)
tree29a1e895f720dcd8ee969df19ba089401e870f8b /drivers/video
parent05a5d4d2640dfe934ec78ba577dd21baccb11aa6 (diff)
drivers/video/backlight/lp855x_bl.c: use generic PWM functions
The LP855x family devices support the PWM input for the backlight control. Period of the PWM is configurable in the platform side. Platform specific functions are unnecessary anymore because generic PWM functions are used inside the driver. (PWM input mode) To set the brightness, new lp855x_pwm_ctrl() is used. If a PWM device is not allocated, devm_pwm_get() is called. The PWM consumer name is from the chip name such as 'lp8550' and 'lp8556'. To get the brightness value, no additional handling is required. Just the value of 'props.brightness' is returned. If the PWM driver is not ready while initializing the LP855x driver, it's OK. The PWM device can be retrieved later, when the brightness value is changed. Documentation is updated with an example. [akpm@linux-foundation.org: coding-style simplification, per Thierry] Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com> Cc: Thierry Reding <thierry.reding@avionic-design.de> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Bryan Wu <bryan.wu@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/backlight/lp855x_bl.c37
1 files changed, 26 insertions, 11 deletions
diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index fd985e0681e9..b437541555ff 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -15,6 +15,7 @@
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/platform_data/lp855x.h>
+#include <linux/pwm.h>
/* Registers */
#define BRIGHTNESS_CTRL 0x00
@@ -36,6 +37,7 @@ struct lp855x {
struct device *dev;
struct mutex xfer_lock;
struct lp855x_platform_data *pdata;
+ struct pwm_device *pwm;
};
static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
@@ -121,6 +123,28 @@ static int lp855x_init_registers(struct lp855x *lp)
return ret;
}
+static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
+{
+ unsigned int period = lp->pdata->period_ns;
+ unsigned int duty = br * period / max_br;
+ struct pwm_device *pwm;
+
+ /* request pwm device with the consumer name */
+ if (!lp->pwm) {
+ pwm = devm_pwm_get(lp->dev, lp->chipname);
+ if (IS_ERR(pwm))
+ return;
+
+ lp->pwm = pwm;
+ }
+
+ pwm_config(lp->pwm, duty, period);
+ if (duty)
+ pwm_enable(lp->pwm);
+ else
+ pwm_disable(lp->pwm);
+}
+
static int lp855x_bl_update_status(struct backlight_device *bl)
{
struct lp855x *lp = bl_get_data(bl);
@@ -130,12 +154,10 @@ static int lp855x_bl_update_status(struct backlight_device *bl)
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);
+ lp855x_pwm_ctrl(lp, br, max_br);
} else if (mode == REGISTER_BASED) {
u8 val = bl->props.brightness;
@@ -150,14 +172,7 @@ 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) {
+ if (mode == REGISTER_BASED) {
u8 val = 0;
lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);

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