Re: [PATCH 1/5] power: reset: Add UART-based MCU poweroff DT bindings

Rob Herring
2019-08-12T23:50:36Z

On Mon, Jul 22, 2019 at 09:53:01PM +0200, Evgeny Kolesnikov wrote:
> This adds device tree bindings of the poweroff driver
> for power managing micro controller units that are connected
> to a board via the UART interface.
>
> Signed-off-by: Evgeny Kolesnikov <evgenyz@gmail.com>
> ---
> .../bindings/power/reset/uart-poweroff.txt | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/power/reset/uart-poweroff.txt
>
> diff --git a/Documentation/devicetree/bindings/power/reset/uart-poweroff.txt b/Documentation/devicetree/bindings/power/reset/uart-poweroff.txt
> new file mode 100644
> index 000000000000..86d036271b51
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/reset/uart-poweroff.txt
> @@ -0,0 +1,38 @@
> +* UART-based PM MCU power off driver
> +
> +Some devices have a microcontroller controlling the main power
> +supply. This microcontroller is connected to UART of the SoC.
> +Sending a sequence of characters tells the MCU to turn
> +the power off.

IMO, you should have a node representing the specific microcontroller.
Generic binding attempts like this generally don't work well because you
need a never ending addition of properties to deal with h/w (and f/w in
this case) differences. The properties you already have are evidence of
this.

Now, if you want a common driver, then that is a separate issue. You can
have multiple, specific bindings map to a common driver (or not, it's up
to the OS).

Rob