[PATCH v2] ARM: dts: armadillo800eva: Split LCD mux and gpio

[PATCH v2] ARM: dts: armadillo800eva: Split LCD mux and gpio

[Geert Uytterhoeven]

Configuration of the lcd0 pinmux group and GPIO hog for the external
GPIO mux are done using a single device node, causing the "output-high"
property to be applied to both.  This will fail for the pinmux group,
but doesn't cause any harm, as the failure is ignored silently.

However, after "pinctrl: sh-pfc: propagate errors on group config", the
failure will become fatal, leading to a broken display:

    sh-pfc e6050000.pin-controller: pin_config_group_set op failed for group 102
    sh-pfc e6050000.pin-controller: Error applying setting, reverse things back
    sh-pfc e6050000.pin-controller: failed to select default state

Move the GPIO hog to its own node to fix this.

Fixes: ffd2f9a5afb730b9 ("ARM: shmobile: armadillo800eva dts: Add pinctrl and gpio-hog for lcdc0")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This is a hard dependency for "pinctrl: sh-pfc: propagate errors on
group config" (https://patchwork.kernel.org/patch/9186713/).

v2:
  - Keep the GPIO hog, but move it to its own node, instead of using
    another level of subnodes.  As the GPIO hog node is not referenced from
    a pinctrl-0 property, pinconf doesn't fail with "No pin or group
    provided in DT node".
---
 arch/arm/boot/dts/r8a7740-armadillo800eva.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/r8a7740-armadillo800eva.dts b/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
index 297b1f10f7346a9f..8c85d3ee5f5e7bfd 100644
--- a/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
+++ b/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
@@ -273,7 +273,9 @@
 	lcd0_pins: lcd0 {
 		groups = "lcd0_data24_0", "lcd0_lclk_1", "lcd0_sync";
 		function = "lcd0";
+	};
 
+	lcd0_mux {
 		/* DBGMD/LCDC0/FSIA MUX */
 		gpio-hog;
 		gpios = <176 0>;
-- 
2.7.4

Re: [PATCH v2] ARM: dts: armadillo800eva: Split LCD mux and gpio

[Laurent Pinchart]

Hi Geert,

Thank you for the patch.

On Thursday 01 Jun 2017 12:27:00 Geert Uytterhoeven wrote:
> Configuration of the lcd0 pinmux group and GPIO hog for the external
> GPIO mux are done using a single device node, causing the "output-high"
> property to be applied to both.  This will fail for the pinmux group,
> but doesn't cause any harm, as the failure is ignored silently.
> 
> However, after "pinctrl: sh-pfc: propagate errors on group config", the
> failure will become fatal, leading to a broken display:
> 
>     sh-pfc e6050000.pin-controller: pin_config_group_set op failed for group
> 102 sh-pfc e6050000.pin-controller: Error applying setting, reverse things
> back sh-pfc e6050000.pin-controller: failed to select default state
> 
> Move the GPIO hog to its own node to fix this.
> 
> Fixes: ffd2f9a5afb730b9 ("ARM: shmobile: armadillo800eva dts: Add pinctrl
> and gpio-hog for lcdc0") Signed-off-by: Geert Uytterhoeven
> <geert+renesas@glider.be>
> ---
> This is a hard dependency for "pinctrl: sh-pfc: propagate errors on
> group config" (https://patchwork.kernel.org/patch/9186713/).
> 
> v2:
>   - Keep the GPIO hog, but move it to its own node, instead of using
>     another level of subnodes.  As the GPIO hog node is not referenced from
>     a pinctrl-0 property, pinconf doesn't fail with "No pin or group
>     provided in DT node".

I like this approach better, it allows us to drive the output instead of 
pulling it up, without requiring a full implementation of output drive control 
in the pfc driver.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  arch/arm/boot/dts/r8a7740-armadillo800eva.dts | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
> b/arch/arm/boot/dts/r8a7740-armadillo800eva.dts index
> 297b1f10f7346a9f..8c85d3ee5f5e7bfd 100644
> --- a/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
> +++ b/arch/arm/boot/dts/r8a7740-armadillo800eva.dts
> @@ -273,7 +273,9 @@
>  	lcd0_pins: lcd0 {
>  		groups = "lcd0_data24_0", "lcd0_lclk_1", "lcd0_sync";
>  		function = "lcd0";
> +	};
> 
> +	lcd0_mux {
>  		/* DBGMD/LCDC0/FSIA MUX */
>  		gpio-hog;
>  		gpios = <176 0>;

-- 
Regards,

Laurent Pinchart

Re: [PATCH v2] ARM: dts: armadillo800eva: Split LCD mux and gpio

[Simon Horman]

On Fri, Jun 02, 2017 at 08:53:26AM +0300, Laurent Pinchart wrote:
> Hi Geert,
> 
> Thank you for the patch.
> 
> On Thursday 01 Jun 2017 12:27:00 Geert Uytterhoeven wrote:
> > Configuration of the lcd0 pinmux group and GPIO hog for the external
> > GPIO mux are done using a single device node, causing the "output-high"
> > property to be applied to both.  This will fail for the pinmux group,
> > but doesn't cause any harm, as the failure is ignored silently.
> > 
> > However, after "pinctrl: sh-pfc: propagate errors on group config", the
> > failure will become fatal, leading to a broken display:
> > 
> >     sh-pfc e6050000.pin-controller: pin_config_group_set op failed for group
> > 102 sh-pfc e6050000.pin-controller: Error applying setting, reverse things
> > back sh-pfc e6050000.pin-controller: failed to select default state
> > 
> > Move the GPIO hog to its own node to fix this.
> > 
> > Fixes: ffd2f9a5afb730b9 ("ARM: shmobile: armadillo800eva dts: Add pinctrl
> > and gpio-hog for lcdc0") Signed-off-by: Geert Uytterhoeven
> > <geert+renesas@glider.be>
> > ---
> > This is a hard dependency for "pinctrl: sh-pfc: propagate errors on
> > group config" (https://patchwork.kernel.org/patch/9186713/).
> > 
> > v2:
> >   - Keep the GPIO hog, but move it to its own node, instead of using
> >     another level of subnodes.  As the GPIO hog node is not referenced from
> >     a pinctrl-0 property, pinconf doesn't fail with "No pin or group
> >     provided in DT node".
> 
> I like this approach better, it allows us to drive the output instead of 
> pulling it up, without requiring a full implementation of output drive control 
> in the pfc driver.
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Thanks, I have queued this up as a fix for v4.12.