Hi,

On Mon, Dec 05, 2011 at 02:18:41PM +0530, Thomas Abraham wrote:
> The power source to the lcd panel or the lcd interface such as lvds
> transmitters could be controlled by a regulator supply. Add support
> for enabling/disabling the regulator when switching power to lcd.
> 
> Two new elements 'min_uV' and 'max_uV' in the platform data are added
> to allow platform code to specifiy the desired output voltage from the
> regulator.
> 
> Cc: Ben Dooks <ben-li...@fluff.org>
> Signed-off-by: Thomas Abraham <thomas.abra...@linaro.org>
> ---
>  drivers/video/backlight/platform_lcd.c |   29 +++++++++++++++++++++++++++++
>  include/video/platform_lcd.h           |    7 +++++++
>  2 files changed, 36 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/video/backlight/platform_lcd.c 
> b/drivers/video/backlight/platform_lcd.c
> index 302330a..ffa8108 100644
> --- a/drivers/video/backlight/platform_lcd.c
> +++ b/drivers/video/backlight/platform_lcd.c
> @@ -17,6 +17,8 @@
>  #include <linux/backlight.h>
>  #include <linux/lcd.h>
>  #include <linux/slab.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/regulator/machine.h>
>  
>  #include <video/platform_lcd.h>
>  
> @@ -44,11 +46,38 @@ static int platform_lcd_get_power(struct lcd_device *lcd)
>  static int platform_lcd_set_power(struct lcd_device *lcd, int power)
>  {
>       struct platform_lcd *plcd = to_our_lcd(lcd);
> +     struct regulator *lcd_regulator;
>       int lcd_power = 1;
>  
>       if (power == FB_BLANK_POWERDOWN || plcd->suspended)
>               lcd_power = 0;
>  
> +     /*
> +      * If power to lcd and/or lcd interface is controlled using a regulator,
> +      * enable or disable the regulator based in the power setting.
> +      */
> +     lcd_regulator = regulator_get(plcd->us, "vcc_lcd");
> +     if (IS_ERR(lcd_regulator)) {
> +             dev_info(plcd->us, "could not get regulator\n");
> +             goto set_power;
> +     }
> +
> +     if (lcd_power) {
> +             if (plcd->pdata->min_uV || plcd->pdata->max_uV)
> +                     if (regulator_set_voltage(lcd_regulator,
> +                             plcd->pdata->min_uV, plcd->pdata->max_uV))
> +                             dev_info(plcd->us,
> +                                     "regulator voltage set failed\n");
> +
> +             if (regulator_enable(lcd_regulator))
> +                     dev_info(plcd->us, "failed to enable regulator\n");
> +     } else {
> +             regulator_disable(lcd_regulator);
> +     }
> +
> +     regulator_put(lcd_regulator);

I wonder why you ->get() and ->put() everytime here. Wouldn't it be
enough to ->get() on probe() and ->put() on remove() ??

-- 
balbi

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