From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH v3 1/3] mfd: mc13xxx: add device tree probe support Date: Wed, 21 Dec 2011 01:37:03 +0000 Message-ID: <20111221013702.GB15398@opensource.wolfsonmicro.com> References: <20111220005708.GM2860@opensource.wolfsonmicro.com> <20111220020101.GD5683@S2100-06.ap.freescale.net> <20111220015931.GX2860@opensource.wolfsonmicro.com> <20111220030347.GB2995@S2101-09.ap.freescale.net> <20111220112510.GL2866@opensource.wolfsonmicro.com> <20111220135251.GB5129@S2101-09.ap.freescale.net> <20111220143558.GT2866@opensource.wolfsonmicro.com> <20111220153101.GD5348@S2101-09.ap.freescale.net> <20111220232526.GA6551@opensource.wolfsonmicro.com> <20111221012519.GA5983@S2101-09.ap.freescale.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20111221012519.GA5983@S2101-09.ap.freescale.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Shawn Guo Cc: Samuel Ortiz , devicetree-discuss@lists.ozlabs.org, Liam Girdwood , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Shawn Guo , Sascha Hauer , linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Wed, Dec 21, 2011 at 09:25:21AM +0800, Shawn Guo wrote: > On Tue, Dec 20, 2011 at 11:25:27PM +0000, Mark Brown wrote: > > It's unique but I feel the disadvantages in terms of legibility of the > > resulting device trees are substantial - we want humans to be able to > > read and write device trees, preferrably without having to dig out the > > datasheet for the part. > Eh, device tree is all about describing hardware. I do not understand > what is wrong with looking at hardware manual when writing dts. For the same reason we define constants for register names and values when writing drivers - so humans can make sense of what's in front of them and to reduce the chance of errors when things are being written. > > So long as the names are reasonably sensible > > and can be understood in the case of any lack of clarity we should be > > OK. > The problem is even if we have the name defined that way, it has to be > matched to the name used in mc13892 driver somehow, if we want to use > name as the key to find the regulator defined in mc13892 driver as > array mc13892_regulators[]. This doesn't seem like a problem - the most obvious thing would just be to adjust the strings in the code to correspond to what the device tree binding says. > > This is the whole reason why I'm saying that you need to define the > > names used in the binding - if the names are a defined part of the > > binding then there's nothing driver specific about them. > Can you please help me understand how this can be achieved with an > example? Taking 'mc13892__sw1' as the example, if I read your comment > before correctly, 'sw1' is the name that you are suggesting. How this > name can be nothing driver specific? After all, we need to find > regulator MC13892_SW1 defined in mc13892_regulators[] by matching name > 'sw1' defined by binding and name 'MC13892_SW1' defined by driver > somehow, if we want to use name to bind the regulator. Your binding document would say something like "the regulators are bound using their names as listed below with their enable bits: sw1 - SW1 regulator (register X bit Y) " so in the binding document it would say what strings map onto which regulators. Then any driver implementing that binding would pick the same strings. From mboxrd@z Thu Jan 1 00:00:00 1970 From: broonie@opensource.wolfsonmicro.com (Mark Brown) Date: Wed, 21 Dec 2011 01:37:03 +0000 Subject: [PATCH v3 1/3] mfd: mc13xxx: add device tree probe support In-Reply-To: <20111221012519.GA5983@S2101-09.ap.freescale.net> References: <20111220005708.GM2860@opensource.wolfsonmicro.com> <20111220020101.GD5683@S2100-06.ap.freescale.net> <20111220015931.GX2860@opensource.wolfsonmicro.com> <20111220030347.GB2995@S2101-09.ap.freescale.net> <20111220112510.GL2866@opensource.wolfsonmicro.com> <20111220135251.GB5129@S2101-09.ap.freescale.net> <20111220143558.GT2866@opensource.wolfsonmicro.com> <20111220153101.GD5348@S2101-09.ap.freescale.net> <20111220232526.GA6551@opensource.wolfsonmicro.com> <20111221012519.GA5983@S2101-09.ap.freescale.net> Message-ID: <20111221013702.GB15398@opensource.wolfsonmicro.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 21, 2011 at 09:25:21AM +0800, Shawn Guo wrote: > On Tue, Dec 20, 2011 at 11:25:27PM +0000, Mark Brown wrote: > > It's unique but I feel the disadvantages in terms of legibility of the > > resulting device trees are substantial - we want humans to be able to > > read and write device trees, preferrably without having to dig out the > > datasheet for the part. > Eh, device tree is all about describing hardware. I do not understand > what is wrong with looking at hardware manual when writing dts. For the same reason we define constants for register names and values when writing drivers - so humans can make sense of what's in front of them and to reduce the chance of errors when things are being written. > > So long as the names are reasonably sensible > > and can be understood in the case of any lack of clarity we should be > > OK. > The problem is even if we have the name defined that way, it has to be > matched to the name used in mc13892 driver somehow, if we want to use > name as the key to find the regulator defined in mc13892 driver as > array mc13892_regulators[]. This doesn't seem like a problem - the most obvious thing would just be to adjust the strings in the code to correspond to what the device tree binding says. > > This is the whole reason why I'm saying that you need to define the > > names used in the binding - if the names are a defined part of the > > binding then there's nothing driver specific about them. > Can you please help me understand how this can be achieved with an > example? Taking 'mc13892__sw1' as the example, if I read your comment > before correctly, 'sw1' is the name that you are suggesting. How this > name can be nothing driver specific? After all, we need to find > regulator MC13892_SW1 defined in mc13892_regulators[] by matching name > 'sw1' defined by binding and name 'MC13892_SW1' defined by driver > somehow, if we want to use name to bind the regulator. Your binding document would say something like "the regulators are bound using their names as listed below with their enable bits: sw1 - SW1 regulator (register X bit Y) " so in the binding document it would say what strings map onto which regulators. Then any driver implementing that binding would pick the same strings.