[PATCH 0/2] Add PM8937 PWM and display backlight for Redmi 5A

[PATCH 0/2] Add PM8937 PWM and display backlight for Redmi 5A

[Barnabás Czémán]

This patch series add pwm node for pm8937 and enables
pwm backlight for Redmi 5A.

Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
---
Barnabás Czémán (1):
      arm64: dts: qcom: msm8917-xiaomi-riva: Add display backlight

Daniil Titov (1):
      arm64: dts: qcom: pm8937: Add LPG PWM driver

 arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts | 25 ++++++++++++++++++++++++
 arch/arm64/boot/dts/qcom/pm8937.dtsi             |  8 ++++++++
 2 files changed, 33 insertions(+)
---
base-commit: c674aa7c289e51659e40dda0f954886ef7f80042
change-id: 20250212-pm8937-pwm-0f3bae4cd207

Best regards,
-- 
Barnabás Czémán <barnabas.czeman@mainlining.org>

[PATCH 1/2] arm64: dts: qcom: pm8937: Add LPG PWM driver

[Barnabás Czémán]

From: Daniil Titov <daniilt971@gmail.com>

Add PWM/LPG node to the PM8937 dtsi so devices
which use this block can enable them.

Signed-off-by: Daniil Titov <daniilt971@gmail.com>
Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
---
 arch/arm64/boot/dts/qcom/pm8937.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/pm8937.dtsi b/arch/arm64/boot/dts/qcom/pm8937.dtsi
index 42b3575b36ff4d37df11ccb5ed68e965e3716300..d13f39d81386b9493e33411e7fa0fb69e94644f4 100644
--- a/arch/arm64/boot/dts/qcom/pm8937.dtsi
+++ b/arch/arm64/boot/dts/qcom/pm8937.dtsi
@@ -143,6 +143,14 @@ pmic@1 {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
+		pm8937_pwm: pwm {
+			compatible = "qcom,pm8916-pwm";
+
+			#pwm-cells = <2>;
+
+			status = "disabled";
+		};
+
 		pm8937_spmi_regulators: regulators {
 			compatible = "qcom,pm8937-regulators";
 		};

-- 
2.48.1

[PATCH 2/2] arm64: dts: qcom: msm8917-xiaomi-riva: Add display backlight

[Barnabás Czémán]

Redmi 5A display uses pwm backlight, add support for it.

Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
---
 arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts | 25 ++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
index f1d22535fedd94467ba3f0a88b2110ce5360e7e1..8808306c989f54116052667887f9bf36b63c4c64 100644
--- a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
+++ b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
@@ -20,6 +20,14 @@ / {
 	qcom,msm-id = <QCOM_ID_MSM8917 0>;
 	qcom,board-id = <0x1000b 2>, <0x2000b 2>;
 
+	pwm_backlight: backlight {
+		compatible = "pwm-backlight";
+		pwms = <&pm8937_pwm 0 100000>;
+		brightness-levels = <0 255>;
+		num-interpolated-steps = <255>;
+		default-brightness-level = <128>;
+	};
+
 	battery: battery {
 		compatible = "simple-battery";
 		charge-full-design-microamp-hours = <3000000>;
@@ -131,6 +139,23 @@ bq25601@6b{
 	};
 };
 
+&pm8937_gpios {
+	pwm_enable_default: pwm-enable-default-state {
+		pins = "gpio8";
+		function = "dtest2";
+		output-low;
+		bias-disable;
+		qcom,drive-strength = <2>;
+	};
+};
+
+&pm8937_pwm {
+	pinctrl-0 = <&pwm_enable_default>;
+	pinctrl-names = "default";
+
+	status = "okay";
+};
+
 &pm8937_resin {
 	linux,code = <KEY_VOLUMEDOWN>;
 

-- 
2.48.1

Re: [PATCH 1/2] arm64: dts: qcom: pm8937: Add LPG PWM driver

[Konrad Dybcio]

On 12.02.2025 11:21 PM, Barnabás Czémán wrote:
> From: Daniil Titov <daniilt971@gmail.com>
> 
> Add PWM/LPG node to the PM8937 dtsi so devices
> which use this block can enable them.
> 
> Signed-off-by: Daniil Titov <daniilt971@gmail.com>
> Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
> ---
>  arch/arm64/boot/dts/qcom/pm8937.dtsi | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/pm8937.dtsi b/arch/arm64/boot/dts/qcom/pm8937.dtsi
> index 42b3575b36ff4d37df11ccb5ed68e965e3716300..d13f39d81386b9493e33411e7fa0fb69e94644f4 100644
> --- a/arch/arm64/boot/dts/qcom/pm8937.dtsi
> +++ b/arch/arm64/boot/dts/qcom/pm8937.dtsi
> @@ -143,6 +143,14 @@ pmic@1 {
>  		#address-cells = <1>;
>  		#size-cells = <0>;
>  
> +		pm8937_pwm: pwm {
> +			compatible = "qcom,pm8916-pwm";

Please add a new compatible with this one as fallback, i.e.

compatible = "qcom,pm8937-pwm", "qcom,pm8916-pwm";

and add it in dt-bindings

Konrad

Re: [PATCH 2/2] arm64: dts: qcom: msm8917-xiaomi-riva: Add display backlight

[Konrad Dybcio]

On 12.02.2025 11:21 PM, Barnabás Czémán wrote:
> Redmi 5A display uses pwm backlight, add support for it.
> 
> Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
> ---
>  arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts | 25 ++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
> index f1d22535fedd94467ba3f0a88b2110ce5360e7e1..8808306c989f54116052667887f9bf36b63c4c64 100644
> --- a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
> +++ b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
> @@ -20,6 +20,14 @@ / {
>  	qcom,msm-id = <QCOM_ID_MSM8917 0>;
>  	qcom,board-id = <0x1000b 2>, <0x2000b 2>;
>  
> +	pwm_backlight: backlight {
> +		compatible = "pwm-backlight";
> +		pwms = <&pm8937_pwm 0 100000>;
> +		brightness-levels = <0 255>;
> +		num-interpolated-steps = <255>;
> +		default-brightness-level = <128>;
> +	};
> +
>  	battery: battery {
>  		compatible = "simple-battery";
>  		charge-full-design-microamp-hours = <3000000>;
> @@ -131,6 +139,23 @@ bq25601@6b{
>  	};
>  };
>  
> +&pm8937_gpios {
> +	pwm_enable_default: pwm-enable-default-state {
> +		pins = "gpio8";
> +		function = "dtest2";

Are you sure?
> +		output-low;
> +		bias-disable;
> +		qcom,drive-strength = <2>;
> +	};
> +};
> +
> +&pm8937_pwm {
> +	pinctrl-0 = <&pwm_enable_default>;
> +	pinctrl-names = "default";

We normally put this under the backlight node, but I'm not sure which
one is more correct.. it may be that this one is, given we're
controlling the pin that the PWM signal is sent through

Konrad

Re: [PATCH 2/2] arm64: dts: qcom: msm8917-xiaomi-riva: Add display backlight

[barnabas.czeman]

On 2025-02-12 23:31, Konrad Dybcio wrote:
> On 12.02.2025 11:21 PM, Barnabás Czémán wrote:
>> Redmi 5A display uses pwm backlight, add support for it.
>> 
>> Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
>> ---
>>  arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts | 25 
>> ++++++++++++++++++++++++
>>  1 file changed, 25 insertions(+)
>> 
>> diff --git a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts 
>> b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
>> index 
>> f1d22535fedd94467ba3f0a88b2110ce5360e7e1..8808306c989f54116052667887f9bf36b63c4c64 
>> 100644
>> --- a/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
>> +++ b/arch/arm64/boot/dts/qcom/msm8917-xiaomi-riva.dts
>> @@ -20,6 +20,14 @@ / {
>>  	qcom,msm-id = <QCOM_ID_MSM8917 0>;
>>  	qcom,board-id = <0x1000b 2>, <0x2000b 2>;
>> 
>> +	pwm_backlight: backlight {
>> +		compatible = "pwm-backlight";
>> +		pwms = <&pm8937_pwm 0 100000>;
>> +		brightness-levels = <0 255>;
>> +		num-interpolated-steps = <255>;
>> +		default-brightness-level = <128>;
>> +	};
>> +
>>  	battery: battery {
>>  		compatible = "simple-battery";
>>  		charge-full-design-microamp-hours = <3000000>;
>> @@ -131,6 +139,23 @@ bq25601@6b{
>>  	};
>>  };
>> 
>> +&pm8937_gpios {
>> +	pwm_enable_default: pwm-enable-default-state {
>> +		pins = "gpio8";
>> +		function = "dtest2";
> 
> Are you sure?
Yes, 
https://github.com/Mi-Thorium/kernel_devicetree_xiaomi-msm8937/blob/dts/mi8937/4.9/master/wingtech/msm8917/common/pm8937.dtsi#L24-L31
>> +		output-low;
>> +		bias-disable;
>> +		qcom,drive-strength = <2>;
>> +	};
>> +};
>> +
>> +&pm8937_pwm {
>> +	pinctrl-0 = <&pwm_enable_default>;
>> +	pinctrl-names = "default";
> 
> We normally put this under the backlight node, but I'm not sure which
> one is more correct.. it may be that this one is, given we're
> controlling the pin that the PWM signal is sent through

It is for enabling pwm and not backlight,
it should be placed here otherwise backlight will not work correctly.
> 
> Konrad