Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752565AbaJFMX3 (ORCPT ); Mon, 6 Oct 2014 08:23:29 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:51502 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbaJFMX0 (ORCPT ); Mon, 6 Oct 2014 08:23:26 -0400 Date: Mon, 6 Oct 2014 14:23:23 +0200 From: Thierry Reding To: Mark Rutland Cc: Boris Brezillon , David Airlie , "dri-devel@lists.freedesktop.org" , Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , Andrew Victor , Samuel Ortiz , Lee Jones , "linux-pwm@vger.kernel.org" , Rob Clark , "linux-arm-kernel@lists.infradead.org" , Rob Herring , Pawel Moll , Ian Campbell , Kumar Gala , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Mark Yao Subject: Re: [PATCH v7 04/11] pwm: add DT bindings documentation for atmel-hlcdc-pwm driver Message-ID: <20141006122322.GA26833@ulmo> References: <1412175188-28278-1-git-send-email-boris.brezillon@free-electrons.com> <1412175188-28278-5-git-send-email-boris.brezillon@free-electrons.com> <20141006101350.GD25202@ulmo> <20141006113326.GG24686@leverpostej> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="huq684BweRXVnRxX" Content-Disposition: inline In-Reply-To: <20141006113326.GG24686@leverpostej> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --huq684BweRXVnRxX Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Oct 06, 2014 at 12:33:26PM +0100, Mark Rutland wrote: > On Mon, Oct 06, 2014 at 11:13:51AM +0100, Thierry Reding wrote: > > On Wed, Oct 01, 2014 at 04:53:01PM +0200, Boris Brezillon wrote: > > > From: Boris BREZILLON > > >=20 > > > The HLCDC IP available in some Atmel SoCs (i.e. sam9x5i.e. at91sam9n1= 2, > > > at91sam9x5 family or sama5d3 family) provide a PWM device. > > >=20 > > > The DT bindings used for this PWM device is following the default 3 c= ells > > > bindings described in Documentation/devicetree/bindings/pwm/pwm.txt. > > >=20 > > > Signed-off-by: Boris Brezillon > > > --- > > > .../devicetree/bindings/pwm/atmel-hlcdc-pwm.txt | 55 ++++++++++++= ++++++++++ > > > 1 file changed, 55 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/pwm/atmel-hlcdc= -pwm.txt > > >=20 > > > diff --git a/Documentation/devicetree/bindings/pwm/atmel-hlcdc-pwm.tx= t b/Documentation/devicetree/bindings/pwm/atmel-hlcdc-pwm.txt > > > new file mode 100644 > > > index 0000000..86ad3e2 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/pwm/atmel-hlcdc-pwm.txt > > > @@ -0,0 +1,55 @@ > > > +Device-Tree bindings for Atmel's HLCDC (High LCD Controller) PWM dri= ver > > > + > > > +The Atmel HLCDC PWM is subdevice of the HLCDC MFD device. > > > +See ../mfd/atmel-hlcdc.txt for more details. > > > + > > > +Required properties: > > > + - compatible: value should be one of the following: > > > + "atmel,hlcdc-pwm" > > > + - pinctr-names: the pin control state names. Should contain "defaul= t". > > > + - pinctrl-0: should contain the pinctrl states described by pinctrl > > > + default. > > > + - #pwm-cells: should be set to 3. This PWM chip use the default 3 c= ells > > > + bindings defined in Documentation/devicetree/bindings/pwm/pwm.txt. > > > + The first cell encodes the PWM id (0 is the only acceptable value= here, > > > + because the chip only provide one PWM). > > > + The second cell encodes the PWM period in nanoseconds. > > > + The third cell encodes the PWM flags (the only supported flag is > > > + PWM_POLARITY_INVERTED) > >=20 > > Given that this already refers to the default 3 cells binding it doesn't > > need to repeat part of the contents of pwm.txt. >=20 > Given that pwm.txt states: >=20 > pwm-specifier : array of #pwm-cells specifying the given PWM=20 > (controller specific) It also goes on to say that: " pwm-specifier typically encodes the chip-relative PWM number and the PWM period in nanoseconds. Optionally, the pwm-specifier can encode a number of flags (defined in ) in a third cell: - PWM_POLARITY_INVERTED: invert the PWM signal polarity " > I'd leave it here. Just because pwm.txt gives an example of a controller > specific meaning for the pwm cells, I don't think we should rely on it > everywhere. If we do have a default meaning for a specifier and the majority (in case of PWM every single one) of the device-specific bindings use it, then I don't think it makes sense to duplicate information everywhere else. We've been doing the same thing across the kernel for a long time now, why should PWM be special? Thierry --huq684BweRXVnRxX Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJUMom6AAoJEN0jrNd/PrOh8FIQAIEVLFN32GN4Icf9hhoLRttx 2wqD4fsUCQcgzdwBFsFnOu4sYXvVHrLISEiew/F7loerSOhtme6AH6Qi8BnVkLnv oEEwQ2fby9vlMD+z8eKjiy4T4VHJj5i3dmwpjwMq3Cvt4kBtkJ7hihphGb+ueW1B SG17Ne3y+R/ONeIkcL++0Kkd3f9a4nChWUjG47RViTWHxR8hRX6VS2vOtT7aTD19 WCcdwHQt5jzp9gmQqoPqhYKkWNV8XNX2vLTnL5diZJRsZQjrGKVB4jclXWqK9sqb gl5xSMLWJYO8mO3wruDSktWeA3JT/+sNiWh6eFcZSrCMmtsC48VrYS+p1g9RtQFO hA8CPwxOK1YW36JqFfig2pmGV/ubFox0knKewACYRQleg3jwRr+z/Cuo4nzmR0am pI+H31lk0geIQ5v57DQSe0MmGkaB8zElCO5xXFxUNBHV/gYS7TSVpK2UoYPO6ZoB crM8clf/YMwwNe8RTEJx2OrsYFtbuBocz41wvF5vfiiVMTVZ8wTWcyJqosNsDDb2 yKMrP3fsH1iuDwZFKMa6VvzpgqClaT9r4dRk4gQottmYFsTU9+p8QccrpJv7git2 WWn3nWtnZfoWe7NwtCnzuTAbLLYW/8Y5K63wFFjkp1NUoDeWxA0sY1qNU8nP1VeT uH//Nr4gW1NCnAbnpbSI =mZO3 -----END PGP SIGNATURE----- --huq684BweRXVnRxX-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/