From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 00/23] RFC: exynos multiplatform support Date: Thu, 7 Mar 2013 03:02:46 +0000 Message-ID: <201303070302.46593.arnd@arndb.de> References: <1362505353-8873-1-git-send-email-arnd@arndb.de> <201303061050.42451.arnd@arndb.de> <20130306123426.GB17079@avionic-0098.mockup.avionic-design.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.8]:54067 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751639Ab3CGDC7 (ORCPT ); Wed, 6 Mar 2013 22:02:59 -0500 In-Reply-To: <20130306123426.GB17079@avionic-0098.mockup.avionic-design.de> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Thierry Reding Cc: Tomasz Figa , Tomasz Figa , Thomas Abraham , Kukjin Kim , Tushar Behera , Deepak Saxena , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Olof Johansson On Wednesday 06 March 2013, Thierry Reding wrote: > > Option 2 would probably come down to having a trivial MFD driver exposing > > a regmap. You can probably reuse drivers/mfd/syscon.c for this and make > > the node compatible with "syscon" to designate the clock registers as > > a system-wide resource, making the other device nodes register-less. > > I think option 2 is the standard method if one hardware block provides > several logical devices. I find it to be a pretty nice solution to this > problem. We also have precedent in the PWM subsystem. The TWL chips for > instance use it to create a platform device which is later driven by a > PWM driver. One difference though is that the TWL chip is a heterogenous MFD that has a lot of different sub-devices, where in case of Exynos the timer device has a set of identical units, each of which can be used either as a PWM or as a clocksource or other timer. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Thu, 7 Mar 2013 03:02:46 +0000 Subject: [PATCH 00/23] RFC: exynos multiplatform support In-Reply-To: <20130306123426.GB17079@avionic-0098.mockup.avionic-design.de> References: <1362505353-8873-1-git-send-email-arnd@arndb.de> <201303061050.42451.arnd@arndb.de> <20130306123426.GB17079@avionic-0098.mockup.avionic-design.de> Message-ID: <201303070302.46593.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 06 March 2013, Thierry Reding wrote: > > Option 2 would probably come down to having a trivial MFD driver exposing > > a regmap. You can probably reuse drivers/mfd/syscon.c for this and make > > the node compatible with "syscon" to designate the clock registers as > > a system-wide resource, making the other device nodes register-less. > > I think option 2 is the standard method if one hardware block provides > several logical devices. I find it to be a pretty nice solution to this > problem. We also have precedent in the PWM subsystem. The TWL chips for > instance use it to create a platform device which is later driven by a > PWM driver. One difference though is that the TWL chip is a heterogenous MFD that has a lot of different sub-devices, where in case of Exynos the timer device has a set of identical units, each of which can be used either as a PWM or as a clocksource or other timer. Arnd