[PATCH 8/9] arm: dts: imx8mm_evk: add pwm1/backlight support

[Michael Walle]

Am 2022-03-16 12:51, schrieb Tommaso Merciai:
> On Wed, Mar 16, 2022 at 12:45:22PM +0100, Michael Walle wrote:
>> Am 2022-03-16 12:42, schrieb Tommaso Merciai:
>> > On Wed, Mar 16, 2022 at 11:30:19AM +0100, Michael Walle wrote:
>> > > > Add pwm1/backlight support nodes for imx8mm_evk board
>> > > >
>> > > > Signed-off-by: Tommaso Merciai <tommaso.merciai at amarulasolutions.com>
>> > > > ---
>> > > >  arch/arm/dts/imx8mm-evk.dtsi | 21 +++++++++++++++++++++
>> > > >  1 file changed, 21 insertions(+)
>> > > >
>> > > > diff --git a/arch/arm/dts/imx8mm-evk.dtsi b/arch/arm/dts/imx8mm-evk.dtsi
>> > > > index 60179e006d..e7a2bd8a64 100644
>> > > > --- a/arch/arm/dts/imx8mm-evk.dtsi
>> > > > +++ b/arch/arm/dts/imx8mm-evk.dtsi
>> > > > @@ -41,6 +41,15 @@
>> > > >  		enable-active-high;
>> > > >  	};
>> > > >
>> > > > +	backlight: backlight {
>> > > > +		status = "disabled";
>> > > > +		compatible = "pwm-backlight";
>> > > > +		pwms = <&pwm1 0 5000000>;
>> > > > +		brightness-levels = <0 255>;
>> > > > +		num-interpolated-steps = <255>;
>> > > > +		default-brightness-level = <250>;
>> > > > +	};
>> > > > +
>> > > >  	ir-receiver {
>> > > >  		compatible = "gpio-ir-receiver";
>> > > >  		gpios = <&gpio1 13 GPIO_ACTIVE_LOW>;
>> > > > @@ -350,6 +359,12 @@
>> > > >  	status = "okay";
>> > > >  };
>> > > >
>> > > > +&pwm1 {
>> > > > +	pinctrl-names = "default";
>> > > > +	pinctrl-0 = <&pinctrl_backlight>;
>> > > > +	status = "disabled";
>> > > > +};
>> > > > +
>> > > >  &iomuxc {
>> > > >  	pinctrl_fec1: fec1grp {
>> > > >  		fsl,pins = <
>> > > > @@ -491,4 +506,10 @@
>> > > >  			MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B	0x166
>> > > >  		>;
>> > > >  	};
>> > > > +
>> > > > +	pinctrl_backlight: backlightgrp {
>> > > > +		fsl,pins = <
>> > > > +			MX8MM_IOMUXC_GPIO1_IO01_PWM1_OUT	0x06
>> > > > +		>;
>> > > > +	};
>> > >
>> > > Will this also be submitted to upstream linux? Otherwise, the device
>> > > trees will diverge.
>> > >
>> > > -michael
>> >
>> > Hi,
>> > At the moment on upstream linux, backlight on pwm1 is not handle. This
>> > will also be submitted on upstream Linux once will merged on U-Boot.
>> 
>> Actually, it should be the other way around, because the device trees
>> should be synced with linux once in a while. So while I don't oppose
>> to do it this way, your changes might eventually be overwritten if
>> this won't be merged with linux.
>> 
>> -michael
> 
> Hi Michael,
> Then you suggest to submit to the Kernel also?

The goal should be to have the kernel device trees in sync with
the kernel. So yes, it should also be submitted to the kernel
device tree.

-michael