On Tue, Dec 11, 2018 at 10:18:24AM +0800, Mark Zhang wrote:
> On 12/10/2018 6:29 PM, Thierry Reding wrote:
> > On Mon, Dec 10, 2018 at 05:43:56PM +0800, Mark Zhang wrote:
> >> Add gpio-keys nodes for the power button.
> >>
> >> Signed-off-by: Mark Zhang <markz@xxxxxxxxxx>
> >> ---
> >> arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi | 15 +++++++++++++++
> >> 1 file changed, 15 insertions(+)
> >>
> >> diff --git a/arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi b/arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi
> >> index ac52286ab9ab..1053f18cc4ae 100644
> >> --- a/arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi
> >> +++ b/arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi
> >> @@ -1,5 +1,6 @@
> >> // SPDX-License-Identifier: GPL-2.0
> >>
> >> +#include <dt-bindings/input/input.h>
> >> #include "tegra210.dtsi"
> >>
> >> / {
> >> @@ -52,6 +53,20 @@
> >> };
> >> };
> >>
> >> + gpio-keys {
> >> + compatible = "gpio-keys";
> >> + gpio-keys,name = "gpio-keys";
> >
> > This property is not only undocumented, it's also unsupported. Let's
> > just drop it. Bonus points for sending in a patch that removes the only
> > other occurrence of this from:
>
> I saw this property is documented here:
> Documentation/devicetree/bindings/input/gpio-keys.txt
You must be looking at a different version than I. Where is the version
of that file that you're looking at?
> Also in drivers/input/keyboard/gpio_keys.c, there is driver which is
> compatible with this property though I didn't read it in detail.
There's no code in that driver to parse this property. There is a
property which seems to do what you want, but it is called "label".
It's also not necessary since the gpio-keys driver will use the device
name if no label was defined and the device name in this case should
match what you're passing in as name ("gpio-keys"), so you're not
gaining anything by adding that property.
> Anyway could you explain more why this property is not supported?
>
> >
> > arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
> >
> > Also, the Shield TV has an LED that's on when the device is powered on,
> > does that happen automatically in hardware, or would that be done as a
> > GPIO (or LED) as well?
>
> Yeah that "green" LED is actually a PWM LED and the brightness is
> adjustable. So what this patch tries to introduce is the power button of
> the Shield which is a GPIO key.
Okay, good. Sounds like it should be easy to add the LED later on.
Thierry
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