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

Maxime Ripard
2018-09-27T17:17:47Z

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.
>=20
> 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
>=20
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
> .../dts/allwinner/sun50i-a64-bananapi-m64.dts | 42 +++++++++++++++++++
> 1 file changed, 42 insertions(+)
>=20
> 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"
> =20
> #include <dt-bindings/gpio/gpio.h>
> +#include <dt-bindings/pwm/pwm.h>
> =20
> / {
> model =3D "BananaPi-M64";
> @@ -56,6 +57,24 @@
> serial1 =3D &uart1;
> };
> =20
> + vdd_bl: regulator@0 {
> + compatible =3D "regulator-fixed";
> + regulator-name =3D "bl-3v3";
> + regulator-min-microvolt =3D <3300000>;
> + regulator-max-microvolt =3D <3300000>;
> + gpio =3D <&pio 3 7 GPIO_ACTIVE_HIGH>; /* PD7 */
> + enable-active-high;
> + };
> +
> + backlight_dsi: backlight-dsi {
> + compatible =3D "pwm-backlight";
> + pwms =3D <&r_pwm 0 50000 PWM_POLARITY_INVERTED>;
> + brightness-levels =3D <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

--=20
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering