Hi, On Sun, Jan 14, 2018 at 02:43:39PM +0800, Hao Zhang wrote: > 2018-01-11 20:47 GMT+08:00 Maxime Ripard <[email protected]>: > > On Thu, Jan 11, 2018 at 07:34:12PM +0800, hao_zhang wrote: > >> This patch add pwm node for r40. > >> > >> Signed-off-by: hao_zhang <[email protected]> > >> --- > >> arch/arm/boot/dts/sun8i-r40.dtsi | 13 +++++++++++++ > >> 1 file changed, 13 insertions(+) > >> > >> diff --git a/arch/arm/boot/dts/sun8i-r40.dtsi > >> b/arch/arm/boot/dts/sun8i-r40.dtsi > >> index 173dcc1..84c963c 100644 > >> --- a/arch/arm/boot/dts/sun8i-r40.dtsi > >> +++ b/arch/arm/boot/dts/sun8i-r40.dtsi > >> @@ -295,6 +295,11 @@ > >> bias-pull-up; > >> }; > >> > >> + pwm_pins: pwm-pins { > >> + pins = "PB2", "PB3"; > >> + function = "pwm"; > >> + }; > >> + > > > > Is it the only combination of pins that is usable? > > > > If so, you can add the pinctrl-0 property directly in the pwm nodes. > > > > There are 8 channel pwm of R40/V40/T3, the pins that can be configed > to pwm are: PB2, PB3, PI20, PI21, PB20, PB21, PB9, PB10
And a single controller, or several of them?
> PB2, PB3 can be configed on bananapi-m2-ultra and on my T3 board,
> but the other pins is not exist on the board or some pin is confilct
> with other functions, so i just add PB2, PB3. but i think split it
> is better, just like this :
>
> pwm0_pin: pwm0-pin {
> pins = "PB2";
> function = "pwm";
> };
>
> pwm1_pin: pwm1-pin {
> pins = "PB3";
> function = "pwm";
> };
Yep, that would be better. If it's just a matter of channels, maybe we
can even name them pwm-ch0-pin and pwm-ch1-pin? That would be more
explicit.
> the node of pwm2~7 should also be added here?
If there's no users, no.
> On sun8i-r40-bananapi-m2-ultra.dts:
> because of the special customize board, i think just add pinctrl-0 =
> <&pwm0_pin>
> (PB3 I just use to test pwm channel 1)for bananapi-m2-ultra board is enough.
>
> &pwm {
> pinctrl-names = "default";
> pinctrl-0 = <&pwm0_pin>;
> status = "okay";
> };
It depends if that PWM is used as a PWM all the time (for example to
drive a backlight for a panel tied to the board), or if it's exported
through one of the generic pin headers, please leave it populated but
disabled (with a comment that it is exported on one of the pin of the
headers)
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
signature.asc
Description: PGP signature
