On Thu, Nov 22, 2018 at 3:49 AM Tom Burkart <tom@xxxxxxxxxx> wrote: > > This patch implements the device tree changes required for the pps > echo functionality for pps-gpio, that sysfs claims is available > already. > > This patch was originally written by Lukas Senger as part of a masters > thesis project and modified for inclusion into the linux kernel by Tom > Burkart. > > Signed-off-by: Lukas Senger <lukas@xxxxxxxxxxxx> > Signed-off-by: Tom Burkart <tom@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/pps/pps-gpio.txt | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pps/pps-gpio.txt b/Documentation/devicetree/bindings/pps/pps-gpio.txt > index 1155d49c2699..e09f6f2405c5 100644 > --- a/Documentation/devicetree/bindings/pps/pps-gpio.txt > +++ b/Documentation/devicetree/bindings/pps/pps-gpio.txt > @@ -7,10 +7,15 @@ Required properties: > - compatible: should be "pps-gpio" > - gpios: one PPS GPIO in the format described by ../gpio/gpio.txt > > +Additional required properties for the PPS ECHO functionality: > +- echo-gpios: one PPS ECHO GPIO in the format described by ../gpio/gpio.txt > +- echo-active-ms: duration in ms of the active portion of the echo pulse > + > Optional properties: > - assert-falling-edge: when present, assert is indicated by a falling edge > (instead of by a rising edge) > - capture-clear: when present, also capture the PPS clear event > +- invert-pps-echo: when present, invert the PPS ECHO pulse Why do you need this? Can't you just make the echo gpio GPIO_ACTIVE_LOW? BTW, using the flag probably should have been done for 'assert-falling-edge' as well. Rob
