Hi Hans,
On 26 August 2016 at 08:21, Hans de Goede hdegoede@redhat.com wrote:
Hi,
On 26-08-16 16:15, Peter Korsgaard wrote:
> > "Hans" == Hans de Goede hdegoede@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@korsgaard.com
Thank you.
Can this move to driver model for the PWM, and for the display for that matter?
Regards,
Hans
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Regards, Simon