From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH v2 02/10] pwm: Allow chips to support multiple PWMs. Date: Wed, 8 Feb 2012 09:17:20 +0000 Message-ID: <20120208091720.GI889@n2100.arm.linux.org.uk> References: <1328541585-24642-1-git-send-email-thierry.reding@avionic-design.de> <1328541585-24642-3-git-send-email-thierry.reding@avionic-design.de> <4F31AB63.3020301@gmail.com> <20120208081508.GA6673@avionic-0098.mockup.avionic-design.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120208081508.GA6673-RM9K5IK7kjIQXX3q8xo1gnVAuStQJXxyR5q1nwbD4aMs9pC9oP6+/A@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: Ryan Mallon , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mike Frysinger , Arnd Bergmann , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Mark Brown , Matthias Kaehlcke , Rob Herring , Grant Likely , Olof Johansson , Richard Purdie , Colin Cross , Mitch Bradley , Eric Miao , Sascha Hauer , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Kurt Van Dijck List-Id: linux-tegra@vger.kernel.org On Wed, Feb 08, 2012 at 09:15:08AM +0100, Thierry Reding wrote: > * Ryan Mallon wrote: > > On 07/02/12 02:19, Thierry Reding wrote: > > > The total maximum number of PWM devices is currently fixed to 64, but > > > can easily be made configurable via Kconfig. > > > > It would be better to make the code handle arbitrary numbers of PWMs. A > > Kconfig knob becomes annoying when you have more than one platform > > configured into the kernel. > > AFAICT handling an arbitrary number of PWMs will only be possible once we get > rid of the global namespace and therefore should be postponed for later. I > may be wrong, though, so if anybody can point me in the right direction I'm > perfectly happy to change that in this series. One solution would be to look at how genirq handles this. Eg, it uses a radix tree to store the irqdescs rather than an array, and a bitmap showing which global numbers are allocated. From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Wed, 8 Feb 2012 09:17:20 +0000 Subject: [PATCH v2 02/10] pwm: Allow chips to support multiple PWMs. In-Reply-To: <20120208081508.GA6673@avionic-0098.mockup.avionic-design.de> References: <1328541585-24642-1-git-send-email-thierry.reding@avionic-design.de> <1328541585-24642-3-git-send-email-thierry.reding@avionic-design.de> <4F31AB63.3020301@gmail.com> <20120208081508.GA6673@avionic-0098.mockup.avionic-design.de> Message-ID: <20120208091720.GI889@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Feb 08, 2012 at 09:15:08AM +0100, Thierry Reding wrote: > * Ryan Mallon wrote: > > On 07/02/12 02:19, Thierry Reding wrote: > > > The total maximum number of PWM devices is currently fixed to 64, but > > > can easily be made configurable via Kconfig. > > > > It would be better to make the code handle arbitrary numbers of PWMs. A > > Kconfig knob becomes annoying when you have more than one platform > > configured into the kernel. > > AFAICT handling an arbitrary number of PWMs will only be possible once we get > rid of the global namespace and therefore should be postponed for later. I > may be wrong, though, so if anybody can point me in the right direction I'm > perfectly happy to change that in this series. One solution would be to look at how genirq handles this. Eg, it uses a radix tree to store the irqdescs rather than an array, and a bitmap showing which global numbers are allocated.