From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Guo Subject: Re: [PATCH 1/2] ARM: dts: vf-colibri: split PWM pinctrl Date: Mon, 21 Dec 2015 21:46:40 +0800 Message-ID: <20151221134541.GD18410@tiger> References: <1449094307-6011-1-git-send-email-stefan@agner.ch> <20151214021801.GA25756@tiger> <86e283b5c7ed5f54ef25c9ff7e747834@agner.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <86e283b5c7ed5f54ef25c9ff7e747834-XLVq0VzYD2Y@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stefan Agner Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Sun, Dec 13, 2015 at 06:53:35PM -0800, Stefan Agner wrote: > On 2015-12-13 18:18, Shawn Guo wrote: > > On Wed, Dec 02, 2015 at 02:11:46PM -0800, Stefan Agner wrote: > >> Split PWM pins into separate pinctrl nodes to allow overrides which > >> select pins individually. This is useful for carrier boards which use > >> only one pin for PWM and would like to use the other pin for a > >> different purpose. > >> > >> Signed-off-by: Stefan Agner > >> --- > >> arch/arm/boot/dts/vf-colibri.dtsi | 18 ++++++++++++++---- > >> 1 file changed, 14 insertions(+), 4 deletions(-) > >> > >> diff --git a/arch/arm/boot/dts/vf-colibri.dtsi b/arch/arm/boot/dts/vf-colibri.dtsi > >> index e5949b9..924b660 100644 > >> --- a/arch/arm/boot/dts/vf-colibri.dtsi > >> +++ b/arch/arm/boot/dts/vf-colibri.dtsi > >> @@ -74,12 +74,12 @@ > >> > >> &pwm0 { > >> pinctrl-names = "default"; > >> - pinctrl-0 = <&pinctrl_pwm0>; > >> + pinctrl-0 = <&pinctrl_pwm0_a &pinctrl_pwm0_c>; > >> }; > >> > >> &pwm1 { > >> pinctrl-names = "default"; > >> - pinctrl-0 = <&pinctrl_pwm1>; > >> + pinctrl-0 = <&pinctrl_pwm1_b &pinctrl_pwm1_d>; > >> }; > > > > It may make more sense to define these pwm nodes in the final board > > level dts with only defining the pins that are actually used on the > > board. > > Well, if we follow that policy, we would have to remove almost anything > from the -colibri.dtsi device trees... > > The Colibri standard defines standard functionality, which is kept > compatible across modules with different SoC's. However, on almost all > pins different functionality is available, and we have some customer > which make use that.... > > So far we followed the policy that we define the pin/device > configuration of the standard functionality in the -colibri.dtsi files > (since this is the most used functionality). This allows us to also > "bug-fix" standard functionality without having to touch customers > (often out-of-tree) device trees. > > This change is not different from that approach, it merely splits the > pin configuration in two individual pinctrl nodes. This makes sense for > PWM signals since they can be used individually (compared to, lets say, > I2C, where it is more like "all or nothing")... It turned out that > several customers used PWM for the display back light, while using > PWM in a different function, therefor that change. Okay, sounds reasonable. But please be consistent on the naming. I would expect the pin groups named in scheme pinctrl_<0,1,2...>_. That said, in this case of pwm, they should be something like below. - pinctrl_pwm0_a - pinctrl_pwm0_b - pinctrl_pwm1_a - pinctrl_pwm1_b Shawn -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html