From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH] mfd: syscon: Decouple syscon interface from syscon devices Date: Mon, 1 Sep 2014 12:25:49 +0100 Message-ID: <20140901112549.GM7374@lee--X1> References: <1408694991-21615-1-git-send-email-pankaj.dubey@samsung.com> <20140901074918.GB6226@lee--X1> <4121644.3haxjiIdIo@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <4121644.3haxjiIdIo@wuerfel> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Pankaj Dubey , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, kgene.kim@samsung.com, linux@arm.linux.org.uk, vikas.sajjan@samsung.com, joshi@samsung.com, naushad@samsung.com, thomas.ab@samsung.com, chow.kim@samsung.com, Tomasz Figa , broonie@kernel.org List-Id: linux-samsung-soc@vger.kernel.org On Mon, 01 Sep 2014, Arnd Bergmann wrote: > On Monday 01 September 2014 08:49:18 Lee Jones wrote: > > On Fri, 22 Aug 2014, Pankaj Dubey wrote: > >=20 > > > From: Tomasz Figa > > >=20 > > > Currently a syscon entity can be only registered directly through= a > > > platform device that binds to a dedicated driver. However in cert= ain use > > > cases it is desirable to make a device used with another driver a= syscon > > > interface provider. For example, certain SoCs (e.g. Exynos) conta= in > > > system controller blocks which perform various functions such as = power > > > domain control, CPU power management, low power mode control, but= in > > > addition contain certain IP integration glue, such as various sig= nal > > > masks, coprocessor power control, etc. In such case, there is a n= eed to > > > have a dedicated driver for such system controller but also share > > > registers with other drivers. The latter is where the syscon inte= rface > > > is helpful. > > >=20 > > > This patch decouples syscon object from syscon driver, so that it= can be > > > registered from any driver in addition to the original "syscon" p= latform > > > driver. > > >=20 > > > Signed-off-by: Tomasz Figa > > > Signed-off-by: Pankaj Dubey > > > --- > > >=20 > > > RFC patch [1] was posted by Tomasz Figa. This patch addresses som= e of > > > comments given by Arnd to RFC patch, and further decouples syscon= from > > > device model. It also gives flexibility of registering with sysco= n at > > > early stage using device_node object. > >=20 > > It would be helpful if Arnd gave this revision his blessing (Ack). >=20 > I never saw a reason why we don't take this all the way as discussed > a few times: Completely remove the dependency of syscon on having > a platform driver for it, and make it possible to just call > syscon_regmap_lookup_by_phandle() without having to register > it first. I think this sounds like a good end-state. Migrating over by supporting both methods in this way does sound like the correct thing to do though. Doing so is likely to dramatically reduce the effect on current users. --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog From mboxrd@z Thu Jan 1 00:00:00 1970 From: lee.jones@linaro.org (Lee Jones) Date: Mon, 1 Sep 2014 12:25:49 +0100 Subject: [PATCH] mfd: syscon: Decouple syscon interface from syscon devices In-Reply-To: <4121644.3haxjiIdIo@wuerfel> References: <1408694991-21615-1-git-send-email-pankaj.dubey@samsung.com> <20140901074918.GB6226@lee--X1> <4121644.3haxjiIdIo@wuerfel> Message-ID: <20140901112549.GM7374@lee--X1> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 01 Sep 2014, Arnd Bergmann wrote: > On Monday 01 September 2014 08:49:18 Lee Jones wrote: > > On Fri, 22 Aug 2014, Pankaj Dubey wrote: > > > > > From: Tomasz Figa > > > > > > Currently a syscon entity can be only registered directly through a > > > platform device that binds to a dedicated driver. However in certain use > > > cases it is desirable to make a device used with another driver a syscon > > > interface provider. For example, certain SoCs (e.g. Exynos) contain > > > system controller blocks which perform various functions such as power > > > domain control, CPU power management, low power mode control, but in > > > addition contain certain IP integration glue, such as various signal > > > masks, coprocessor power control, etc. In such case, there is a need to > > > have a dedicated driver for such system controller but also share > > > registers with other drivers. The latter is where the syscon interface > > > is helpful. > > > > > > This patch decouples syscon object from syscon driver, so that it can be > > > registered from any driver in addition to the original "syscon" platform > > > driver. > > > > > > Signed-off-by: Tomasz Figa > > > Signed-off-by: Pankaj Dubey > > > --- > > > > > > RFC patch [1] was posted by Tomasz Figa. This patch addresses some of > > > comments given by Arnd to RFC patch, and further decouples syscon from > > > device model. It also gives flexibility of registering with syscon at > > > early stage using device_node object. > > > > It would be helpful if Arnd gave this revision his blessing (Ack). > > I never saw a reason why we don't take this all the way as discussed > a few times: Completely remove the dependency of syscon on having > a platform driver for it, and make it possible to just call > syscon_regmap_lookup_by_phandle() without having to register > it first. I think this sounds like a good end-state. Migrating over by supporting both methods in this way does sound like the correct thing to do though. Doing so is likely to dramatically reduce the effect on current users. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog