On Mon, Mar 04, 2013 at 08:43:50PM -0800, Andrew Chew wrote: > The backlight enable GPIO is specified in the device tree node for > backlight. > > Signed-off-by: Andrew Chew <ac...@nvidia.com> > --- > I decided to go ahead with disabling/enabling the backlight via GPIO as > needed. Note that I named the new functions pwm_backlight_enable() and > pwm_backlight_disable() (instead of something more gpio-specific) because > I thought it would be convenient to have a generic hook for when someone > wants to add yet more stuff to be done on enable/disable. > > I tested this by going into /sys/class/backlight/backlight.n and manually > adjusting the brightness, and checked the gpio state to see that it had > the appropriate value. > > .../bindings/video/backlight/pwm-backlight.txt | 2 + > drivers/video/backlight/pwm_bl.c | 50 > ++++++++++++++++++-- > include/linux/pwm_backlight.h | 2 + > 3 files changed, 50 insertions(+), 4 deletions(-) > > diff --git > a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt > b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt > index 1e4fc72..1ed4f0f 100644 > --- a/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt > +++ b/Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt > @@ -14,6 +14,8 @@ Required properties: > Optional properties: > - pwm-names: a list of names for the PWM devices specified in the > "pwms" property (see PWM binding[0]) > + - enable-gpio: a GPIO that needs to be used to enable the backlight
According to Documentation/devicetree/bindings/gpio/gpio.txt this should be called "enable-gpios". > + - enable-gpio-active-high: polarity of GPIO is active high (default is low) There is OF_GPIO_ACTIVE_LOW, which is automatically parsed from the second cell of a GPIO specifier. It will only work if you request the GPIO using of_get_named_gpio_flags(), though, so it will only work in the non-DT case. I think using a regulator would be more appropriate, since it gives you more flexibility than a plain GPIO. Does anybody see a problem with using a regulator instead? Thierry
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