From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: PWM... Date: Sun, 19 Jan 2014 21:26:40 +0100 Message-ID: <201401192126.41543.arnd@arndb.de> References: <20140119164956.GR15937@n2100.arm.linux.org.uk> <20140119193026.GS15937@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.8]:63134 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751909AbaASU0v (ORCPT ); Sun, 19 Jan 2014 15:26:51 -0500 In-Reply-To: <20140119193026.GS15937@n2100.arm.linux.org.uk> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Russell King - ARM Linux Cc: Olof Johansson , "linux-arm-kernel@lists.infradead.org" , Thierry Reding , linux-pwm@vger.kernel.org, "arm@kernel.org" , "devicetree@vger.kernel.org" On Sunday 19 January 2014, Russell King - ARM Linux wrote: > On Sun, Jan 19, 2014 at 11:11:41AM -0800, Olof Johansson wrote: > > On Sun, Jan 19, 2014 at 11:08 AM, Arnd Bergmann wrote: > > Ah, yes, if you add a cell that can be done. There'll still be the > > "dead" first cell that will always be 0, but that's alright. > > Does it not mean that PWM specifications of: > > <&pwm1 0 n> <&pwm2 0 n> > > would need to be converted to: > > <&pwm1 0 n 0> <&pwm2 0 n 0> > > in every DT file referring to these PWMs - because isn't this just > treated in DT as one single array of values? (If DT knew how many > were in each specification, we wouldn't need the #foo-cells...) Right: if you change an existing dts file from #pwm-cells=<2> to #pwm-cells=<3>, that requires changing all references to the pwm controller at the same time. If both the per-soc .dtsi files and the per-board .dts files contain references to the same pwm controller, that can end up in significant work. I have not checked if this is the case for i.MX though. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Sun, 19 Jan 2014 21:26:40 +0100 Subject: PWM... In-Reply-To: <20140119193026.GS15937@n2100.arm.linux.org.uk> References: <20140119164956.GR15937@n2100.arm.linux.org.uk> <20140119193026.GS15937@n2100.arm.linux.org.uk> Message-ID: <201401192126.41543.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sunday 19 January 2014, Russell King - ARM Linux wrote: > On Sun, Jan 19, 2014 at 11:11:41AM -0800, Olof Johansson wrote: > > On Sun, Jan 19, 2014 at 11:08 AM, Arnd Bergmann wrote: > > Ah, yes, if you add a cell that can be done. There'll still be the > > "dead" first cell that will always be 0, but that's alright. > > Does it not mean that PWM specifications of: > > <&pwm1 0 n> <&pwm2 0 n> > > would need to be converted to: > > <&pwm1 0 n 0> <&pwm2 0 n 0> > > in every DT file referring to these PWMs - because isn't this just > treated in DT as one single array of values? (If DT knew how many > were in each specification, we wouldn't need the #foo-cells...) Right: if you change an existing dts file from #pwm-cells=<2> to #pwm-cells=<3>, that requires changing all references to the pwm controller at the same time. If both the per-soc .dtsi files and the per-board .dts files contain references to the same pwm controller, that can end up in significant work. I have not checked if this is the case for i.MX though. Arnd