[PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[Tommaso Merciai]

Add pwm1/backlight support nodes for imx8mm_evk board. Align with u-boot
dts

References:
 - https://patchwork.ozlabs.org/project/uboot/patch/20220326111911.13720-9-tommaso.merciai@amarulasolutions.com/

Signed-off-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
---
 arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
index 6d67df7692f1..55566708f667 100644
--- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
@@ -59,6 +59,15 @@ reg_usdhc2_vmmc: regulator-usdhc2 {
 		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>;
@@ -395,6 +404,12 @@ &wdog1 {
 	status = "okay";
 };
 
+&pwm1 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_backlight>;
+	status = "disabled";
+};
+
 &iomuxc {
 	pinctrl_fec1: fec1grp {
 		fsl,pins = <
@@ -549,4 +564,10 @@ pinctrl_wdog: wdoggrp {
 			MX8MM_IOMUXC_GPIO1_IO02_WDOG1_WDOG_B	0x166
 		>;
 	};
+
+	pinctrl_backlight: backlightgrp {
+		fsl,pins = <
+			MX8MM_IOMUXC_GPIO1_IO01_PWM1_OUT	0x06
+		>;
+	};
 };
-- 
2.25.1

Re: [PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[Krzysztof Kozlowski]

On 13/04/2022 12:20, Tommaso Merciai wrote:
> Add pwm1/backlight support nodes for imx8mm_evk board. Align with u-boot
> dts
> 
> References:
>  - https://patchwork.ozlabs.org/project/uboot/patch/20220326111911.13720-9-tommaso.merciai@amarulasolutions.com/
> 
> Signed-off-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
> ---
>  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 21 +++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> index 6d67df7692f1..55566708f667 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> @@ -59,6 +59,15 @@ reg_usdhc2_vmmc: regulator-usdhc2 {
>  		enable-active-high;
>  	};
>  
> +	backlight: backlight {
> +		status = "disabled";

Why 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>;
> @@ -395,6 +404,12 @@ &wdog1 {
>  	status = "okay";
>  };
>  
> +&pwm1 {
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&pinctrl_backlight>;
> +	status = "disabled";

Same here.


Best regards,
Krzysztof

Re: [PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[Tommaso Merciai]

On Wed, Apr 13, 2022 at 12:28:00PM +0200, Krzysztof Kozlowski wrote:
> On 13/04/2022 12:20, Tommaso Merciai wrote:
> > Add pwm1/backlight support nodes for imx8mm_evk board. Align with u-boot
> > dts
> > 
> > References:
> >  - https://patchwork.ozlabs.org/project/uboot/patch/20220326111911.13720-9-tommaso.merciai@amarulasolutions.com/
> > 
> > Signed-off-by: Tommaso Merciai <tommaso.merciai@amarulasolutions.com>
> > ---
> >  arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi | 21 +++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > index 6d67df7692f1..55566708f667 100644
> > --- a/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi
> > @@ -59,6 +59,15 @@ reg_usdhc2_vmmc: regulator-usdhc2 {
> >  		enable-active-high;
> >  	};
> >  
> > +	backlight: backlight {
> > +		status = "disabled";
> 
> Why 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>;
> > @@ -395,6 +404,12 @@ &wdog1 {
> >  	status = "okay";
> >  };
> >  
> > +&pwm1 {
> > +	pinctrl-names = "default";
> > +	pinctrl-0 = <&pinctrl_backlight>;
> > +	status = "disabled";
> 
> Same here.
> 
> 
> Best regards,
> Krzysztof

Hi Krzysztof,
I think is better to keep disable into .dtsi and enable it at .dts
level.
What do you think about?

Regards,
Tommaso
-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
__________________________________

Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
info@amarulasolutions.com
www.amarulasolutions.com

Re: [PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[Krzysztof Kozlowski]

On 13/04/2022 13:58, Tommaso Merciai wrote:
>>> +	backlight: backlight {
>>> +		status = "disabled";
>>
>> Why 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>;
>>> @@ -395,6 +404,12 @@ &wdog1 {
>>>  	status = "okay";
>>>  };
>>>  
>>> +&pwm1 {
>>> +	pinctrl-names = "default";
>>> +	pinctrl-0 = <&pinctrl_backlight>;
>>> +	status = "disabled";
>>
>> Same here.
>>
>>
>> Best regards,
>> Krzysztof
> 
> Hi Krzysztof,
> I think is better to keep disable into .dtsi and enable it at .dts
> level.
> What do you think about?

Why better? This is already board DTSI, not a SoC DTSI. All boards using
it are supposed to have it available, aren't they?

Usually nodes should be disabled in a DTSI if they need some resources
not available in that DTSI. For example if they need some supply. It's
not the case here, right?


Best regards,
Krzysztof

Re: [PATCH] arm64: dts: imx8mm-evk: add pwm1/backlight support

[Tommaso Merciai]

On Wed, Apr 13, 2022 at 02:27:00PM +0200, Krzysztof Kozlowski wrote:
> On 13/04/2022 13:58, Tommaso Merciai wrote:
> >>> +	backlight: backlight {
> >>> +		status = "disabled";
> >>
> >> Why 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>;
> >>> @@ -395,6 +404,12 @@ &wdog1 {
> >>>  	status = "okay";
> >>>  };
> >>>  
> >>> +&pwm1 {
> >>> +	pinctrl-names = "default";
> >>> +	pinctrl-0 = <&pinctrl_backlight>;
> >>> +	status = "disabled";
> >>
> >> Same here.
> >>
> >>
> >> Best regards,
> >> Krzysztof
> > 
> > Hi Krzysztof,
> > I think is better to keep disable into .dtsi and enable it at .dts
> > level.
> > What do you think about?
> 
> Why better? This is already board DTSI, not a SoC DTSI. All boards using
> it are supposed to have it available, aren't they?
> 
> Usually nodes should be disabled in a DTSI if they need some resources
> not available in that DTSI. For example if they need some supply. It's
> not the case here, right?

Hi Krzysztof,
Yes, right I check both schematics (DSI_BL_PWM). We can set PWM enable.
I'll update status in v2.

> 
> 
> Best regards,
> Krzysztof

Regards,
Tommaso

-- 
Tommaso Merciai
Embedded Linux Engineer
tommaso.merciai@amarulasolutions.com
__________________________________

Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
info@amarulasolutions.com
www.amarulasolutions.com