sunxi: display: Use PWM to drive backlight where applicable
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.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed by: Peter Korsgaard <peter@korsgaard.com>
diff --git a/arch/arm/include/asm/arch-sunxi/gpio.h b/arch/arm/include/asm/arch-sunxi/gpio.h
index bff7d14..85a4ec3 100644
--- a/arch/arm/include/asm/arch-sunxi/gpio.h
+++ b/arch/arm/include/asm/arch-sunxi/gpio.h
@@ -150,6 +150,7 @@
#define SUN6I_GPA_SDC3 4
#define SUN8I_H3_GPA_UART0 2
+#define SUN4I_GPB_PWM 2
#define SUN4I_GPB_TWI0 2
#define SUN4I_GPB_TWI1 2
#define SUN5I_GPB_TWI1 2
@@ -186,6 +187,8 @@
#define SUN6I_GPG_TWI3 2
#define SUN5I_GPG_UART1 4
+#define SUN6I_GPH_PWM 2
+#define SUN8I_GPH_PWM 2
#define SUN4I_GPH_SDC1 5
#define SUN6I_GPH_TWI0 2
#define SUN8I_GPH_TWI0 2