On Thu, Jul 27, 2017 at 03:17:36PM +0200, yegorslists@xxxxxxxxxxxxxx wrote:
> From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
>
> Describe {rts,cts,dtr,dsr,rng,dcd}-gpios usage.
>
> Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Signed-off-by: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/serial/8250.txt | 26 +++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
> index 419ff6c..1c09db2 100644
> --- a/Documentation/devicetree/bindings/serial/8250.txt
> +++ b/Documentation/devicetree/bindings/serial/8250.txt
> @@ -48,6 +48,16 @@ Optional properties:
> - tx-threshold: Specify the TX FIFO low water indication for parts with
> programmable TX FIFO thresholds.
> - resets : phandle + reset specifier pairs
> +- rts-gpios:
> +- cts-gpios:
> +- dtr-gpios:
> +- dsr-gpios:
> +- rng-gpios:
> +- dcd-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD
> + line respectively. It will use specified GPIO instead of the peripheral
> + function pin for the UART feature. If unsure, don't specify this property.
These are already described in serial.txt.
> + If "wakeup-source" property is specified for the device this GPIO
> + initialization will be aborted.
Why? Many GPIOs can function as wake-up sources. You would need get the
IRQ for the GPIO. Also, some UARTs wake-up from the RX line. Not sure
about any 8250 flavors, but is probably implementation specific what is
the trigger for wake-up.
Rob
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