Re: [PATCH 12/12] arm64: dts: allwinner: bananapi-m64: Bananapi S070WV20-CT16 DSI panel

[Maxime Ripard]

On Thu, Sep 27, 2018 at 05:18:50PM +0530, Jagan Teki wrote:
> This patch add support for Bananapi S070WV20-CT16 DSI panel to
> BPI-M64 board.
> 
> DSI panel connected via board DSI port with,
> - DC1SW as AVDD supply
> - DCDC1 as DVDD supply
> - PD6 gpio for reset pin
> - PD5 gpio for backlight enable pin
> - PD7 gpio for backlight vdd supply
> 
> Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> ---
>  .../dts/allwinner/sun50i-a64-bananapi-m64.dts | 42 +++++++++++++++++++
>  1 file changed, 42 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts
> index ef1c90401bb2..c0be949be68d 100644
> --- a/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts
> +++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-bananapi-m64.dts
> @@ -45,6 +45,7 @@
>  #include "sun50i-a64.dtsi"
>  
>  #include <dt-bindings/gpio/gpio.h>
> +#include <dt-bindings/pwm/pwm.h>
>  
>  / {
>  	model = "BananaPi-M64";
> @@ -56,6 +57,24 @@
>  		serial1 = &uart1;
>  	};
>  
> +	vdd_bl: regulator@0 {
> +		compatible = "regulator-fixed";
> +		regulator-name = "bl-3v3";
> +		regulator-min-microvolt = <3300000>;
> +		regulator-max-microvolt = <3300000>;
> +		gpio = <&pio 3 7 GPIO_ACTIVE_HIGH>; /* PD7 */
> +		enable-active-high;
> +	};
> +
> +	backlight_dsi: backlight-dsi {
> +		compatible = "pwm-backlight";
> +		pwms = <&r_pwm 0 50000 PWM_POLARITY_INVERTED>;
> +		brightness-levels = <0 10 20 30 40 50 60 70 80 90 100>;

The brightness levels should be increasing linearly from a user point
of view. Usually, with a PWM backlight, a quadratic rule works much
better.

MMaxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com