* [PATCH] ARM: dts: at91: nattis: initialize the BLON pin as output-low early
@ 2018-11-20 21:20 Peter Rosin
2018-11-21 11:25 ` Alexandre Belloni
0 siblings, 1 reply; 2+ messages in thread
From: Peter Rosin @ 2018-11-20 21:20 UTC (permalink / raw)
To: linux-kernel
Cc: Peter Rosin, Nicolas Ferre, Alexandre Belloni, Rob Herring,
Mark Rutland, linux-arm-kernel, devicetree
The pwm-backlight driver initializes BLON (the enable gpio) to
output-high if the gpio is input on probe. Initializing the gpio
to output-low before the driver probes prevents this action by
the pwm-backlight driver and gets rid of a nasty blink of full
backlight with an uninitialized panel.
Signed-off-by: Peter Rosin <peda@axentia.se>
---
arch/arm/boot/dts/at91-nattis-2-natte-2.dts | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/arm/boot/dts/at91-nattis-2-natte-2.dts b/arch/arm/boot/dts/at91-nattis-2-natte-2.dts
index 911d2c7c1500..0f6d335125e2 100644
--- a/arch/arm/boot/dts/at91-nattis-2-natte-2.dts
+++ b/arch/arm/boot/dts/at91-nattis-2-natte-2.dts
@@ -60,6 +60,8 @@
power-supply = <&bl_reg>;
enable-gpios = <&pioA 20 GPIO_ACTIVE_HIGH>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_blon>;
};
panel: panel {
@@ -164,6 +166,12 @@
(AT91_PINCTRL_OUTPUT |
AT91_PINCTRL_OUTPUT_VAL(0))>;
};
+
+ pinctrl_blon: blon {
+ atmel,pins = <AT91_PIOA 20 AT91_PERIPH_GPIO
+ (AT91_PINCTRL_OUTPUT |
+ AT91_PINCTRL_OUTPUT_VAL(0))>;
+ };
};
};
--
2.11.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ARM: dts: at91: nattis: initialize the BLON pin as output-low early
2018-11-20 21:20 [PATCH] ARM: dts: at91: nattis: initialize the BLON pin as output-low early Peter Rosin
@ 2018-11-21 11:25 ` Alexandre Belloni
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Belloni @ 2018-11-21 11:25 UTC (permalink / raw)
To: Peter Rosin
Cc: linux-kernel, Nicolas Ferre, Rob Herring, Mark Rutland,
linux-arm-kernel, devicetree
On 20/11/2018 21:20:43+0000, Peter Rosin wrote:
> The pwm-backlight driver initializes BLON (the enable gpio) to
> output-high if the gpio is input on probe. Initializing the gpio
> to output-low before the driver probes prevents this action by
> the pwm-backlight driver and gets rid of a nasty blink of full
> backlight with an uninitialized panel.
>
> Signed-off-by: Peter Rosin <peda@axentia.se>
> ---
> arch/arm/boot/dts/at91-nattis-2-natte-2.dts | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
Applied, thanks.
--
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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