[PATCH 1/1] riscv: add DT binding for BOOT button on Maix board

[Heinrich Schuchardt]

On 11.09.20 09:14, Bin Meng wrote:
> On Thu, Sep 3, 2020 at 4:12 AM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>>
>> Add a device tree binding for the BOOT button on the Maix board.
>>
>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>> ---
>> Together with
>> [PATCH 1/1] cmd/button: return button status
>> https://lists.denx.de/pipermail/u-boot/2020-September/425221.html
>> we can use the button status to decide which program to boot.
>> ---
>>  arch/riscv/dts/k210-maix-bit.dts | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/arch/riscv/dts/k210-maix-bit.dts b/arch/riscv/dts/k210-maix-bit.dts
>> index e840e04ada..c2beec602c 100644
>> --- a/arch/riscv/dts/k210-maix-bit.dts
>> +++ b/arch/riscv/dts/k210-maix-bit.dts
>> @@ -8,6 +8,7 @@
>>  #include "k210.dtsi"
>>
>>  #include <dt-bindings/gpio/gpio.h>
>> +#include <dt-bindings/input/input.h>
>>
>>  / {
>>         model = "Sipeed Maix Bit 2.0";
>> @@ -33,6 +34,16 @@
>>                 };
>>         };
>>
>> +       gpio-keys {
>> +               compatible = "gpio-keys";
>> +
>> +               boot {
>> +                       label = "BOOT";
>> +                       linux,code = <BTN_0>;
>
> I cannot find how U-Boot is handling "linux,code". Any pointers?

U-Boot does not use the information. It is used by Linux to determine
which key code should be emitted. See

Documentation/devicetree/bindings/input/gpio-keys.txt

Hence this entry is only relevant if we pass our internal device tree to
Linux. In arch/arm/dts/ I saw that the property is typically set.

Best regards

Heinrich

>
>> +                       gpios = <&gpio0 0 GPIO_ACTIVE_LOW>;
>> +               };
>> +       };
>> +
>>         sound {
>>                 compatible = "simple-audio-card";
>>                 simple-audio-card,format = "i2s";
>> --
>
> Regards,
> Bin
>