Subject: Re: [PATCH 5/5] ARM: dts: exynos: Add display support for exynos5250-manta

From: Lukas Timmermann <[email-masked]>
Date: Tue, 28 Apr 2026 11:44:05 +0200

On Sat, Apr 25, 2026 at 11:58:47AM +0200, Krzysztof Kozlowski wrote:
> On Thu, Apr 23, 2026 at 11:14:41PM +0200, Lukas Timmermann wrote:
> > Adds the necessary entries for panel and backlight as
> > well as the fimd controller.
> > 
> > Signed-off-by: Alexandre Marquet <[email-masked]>
> > Signed-off-by: Lukas Timmermann <[email-masked]>
> > ---
> >  arch/arm/boot/dts/samsung/exynos5250-manta.dts | 99 ++++++++++++++++++++++++++
> >  1 file changed, 99 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/samsung/exynos5250-manta.dts b/arch/arm/boot/dts/samsung/exynos5250-manta.dts
> > index 76d3657eb22f..eb97a28ff4e3 100644
> > --- a/arch/arm/boot/dts/samsung/exynos5250-manta.dts
> > +++ b/arch/arm/boot/dts/samsung/exynos5250-manta.dts
> > @@ -25,6 +25,29 @@ aliases {
> >  		mmc1 = &mmc_1; /* WiFi */
> >  	};
> >  
> > +	backlight: backlight {
> > +		compatible = "pwm-backlight";
> > +		pwms = <&pwm 0 1000000 0>;
> > +
> > +		brightness-levels = <2 255>; /* TODO */
> > +		num-interpolated-steps = <254>; /* TODO */
> > +		default-brightness-level = <102>; /* TODO */
> > +		post-pwm-on-delay-ms = <97>; /* TODO */
> > +
> > +		power-supply = <&backlight_reg>;
> > +		enable-gpios = <&gpg0 5 GPIO_ACTIVE_HIGH>;
> > +
> > +		pinctrl-0 = <&led_bl_reset &pwm0_out>;
> > +		pinctrl-names = "default";
> > +	};
> > +
> > +	backlight_reg: regulator-backlight {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "APS_EN_18V";
> > +		pinctrl-0 = <&aps_en_18v>;
> > +		pinctrl-names = "default";
> 
> No enable GPIO? No voltage?
> 
> > +	};
> > +
> >  	/* Voltage source unknown */
> >  	bmp180_vdda_reg: regulator-bmp180-vdda {
> >  		compatible = "regulator-fixed";
> > @@ -105,6 +128,28 @@ multi-led {
> >  		leds = <&status_red>, <&status_green>, <&status_blue>, <&status_white>;
> >  	};
> >  
> > +	panel {
> > +		compatible = "samsung,ltl101dl02-002";
> > +
> > +		backlight = <&backlight>;
> > +		power-supply = <&panel_reg>;
> > +		enable-gpios = <&gph1 7 GPIO_ACTIVE_HIGH>;
> > +		pinctrl-0 = <&lcd_en>;
> > +		pinctrl-names = "default";
> > +		no-hpd;
> > +
> > +		port {
> > +			panel: endpoint {
> > +				remote-endpoint = <&dp_out>;
> > +			};
> > +		};
> > +	};
> > +
> > +	panel_reg: regulator-panel {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "LCD_EN";
> 
> That's incomplete. You should have at least voltage.
> 
> > +	};
> > +
> >  	pwrseq: mmc1-pwrseq {
> >  		compatible = "mmc-pwrseq-simple";
> >  
> > @@ -146,10 +191,36 @@ &cpu1 {
> >  	cpu-supply = <&buck2_reg>;
> >  };
> >  
> > +&dp {
> > +	status = "okay";
> > +
> > +	samsung,color-space = <0>;
> > +	samsung,color-depth = <1>;
> > +	samsung,link-rate = <0x0a>;
> > +	samsung,lane-count = <4>;
> > +	samsung,dynamic-range = <0>;
> > +	samsung,ycbcr-coeff = <0>;
> > +
> > +	ports {
> > +		port {
> > +			dp_out: endpoint {
> > +				remote-endpoint = <&panel>;
> > +			};
> > +		};
> > +	};
> > +};
> > +
> >  &ehci {
> >  	status = "disabled";
> >  };
> >  
> > +&fimd {
> > +	status = "okay";
> > +
> > +	assigned-clocks = <&clock CLK_MOUT_FIMD1>, <&clock CLK_MOUT_VPLL>;
> > +	assigned-clock-parents = <&clock CLK_MOUT_VPLL>;
> > +};
> > +
> >  &i2c_1 {
> >  	status = "okay";
> >  
> > @@ -396,6 +467,12 @@ ldo25_reg: LDO25 {
> >  	};
> >  };
> >  
> > +&mali {
> > +	status = "okay";
> > +
> > +	mali-supply = <&buck4_reg>;
> > +};
> > +
> >  &mixer {
> >  	status = "okay";
> >  };
> > @@ -489,6 +566,14 @@ wlan_irq: wlan-irq-pins {
> >  };
> >  
> >  &pinctrl_1 {
> > +	aps_en_18v: aps-en-18v-pins {
> > +		samsung,pins = "gph1-6";
> > +		samsung,pin-function = <EXYNOS_PIN_FUNC_OUTPUT>; /* TODO */
> 
> TODO why? IOW, what are you missing here? Was this tested?
> 
> TODO note can stay, but I would prefer to see short comment explaining
> why.
> 
> 
> Best regards,
> Krzysztof
> 
> 
Yes, this patch was tested for function. I added reminders to triple check these
values before sending the patch but obviously forgot to remove them afterwards.
They won't be in v2 of this patch.

Also thanks for commenting on gpio and voltage, I try to search in 
the downstream kernel to find values or add comments when there
is no information.

Best regards
Lukas