[U-Boot] [PATCH v2] sunxi: display: Use PWM to drive backlight where applicable

[Hans de Goede]

Hi,

On 26-08-16 16:15, Peter Korsgaard wrote:
>>>>>> "Hans" == Hans de Goede <hdegoede at redhat.com> writes:
>
>  > When the backlight's pwm input is connected to a pwm output of the SoC,
>  > actually use pwm to drive the backlight.
>
>  > The mean reason for doing this is to fix the backlight turning off
>  > for aprox. 1 second while the kernel is booting. This is caused by
>  > the kernel actually using pwm to drive the backlight, so that it
>  > can dim the backlight. First the pwm driver loads and switches the
>  > pinmux for the pin driving the backlight's pwm input to the pwm
>  > controller. Then about 1s later the actual backlight driver loads
>  > and tells the pwm driver to actually update the pwm settings, which
>  > have a power-on-reset value of "off".
>
>  > An additional advantage is that this allows us to initatiate the
>  > backlight at 80%, which is the kernel default, avoiding a brightness
>  > change while the kernel loads.
>
>  > +++ b/drivers/video/sunxi_display.c
>  > @@ -12,6 +12,7 @@
>  >  #include <asm/arch/clock.h>
>  >  #include <asm/arch/display.h>
>  >  #include <asm/arch/gpio.h>
>  > +#include <asm/arch/pwm.h>
>  >  #include <asm/global_data.h>
>  >  #include <asm/gpio.h>
>  >  #include <asm/io.h>
>  > @@ -34,7 +35,6 @@
>  >  #define PWM_ON 1
>  >  #define PWM_OFF 0
>  >  #endif
>  > -
>
> Unrelated white space change. Other than that:

Oops, fixed locally.

> Reviewed by: Peter Korsgaard <peter at korsgaard.com>

Thank you.

Regards,

Hans