From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XC3er-0004GZ-5O for linux-mtd@lists.infradead.org; Tue, 29 Jul 2014 09:25:23 +0000 Date: Tue, 29 Jul 2014 10:24:44 +0100 From: Mark Rutland To: Scott Wood Subject: Re: [PATCH] devicetree/bindings: Add binding for micron n25q512a memory Message-ID: <20140729092444.GI2576@leverpostej> References: <1404382376-3115-1-git-send-email-Priyanka.Jain@freescale.com> <1404425400.21434.89.camel@snotra.buserror.net> <1404768354.21434.191.camel@snotra.buserror.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1404768354.21434.191.camel@snotra.buserror.net> Cc: Jain Priyanka-B32167 , "linux-spi@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-mtd@lists.infradead.org" , "devicetree@vger.kernel.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Jul 07, 2014 at 10:25:54PM +0100, Scott Wood wrote: > On Thu, 2014-07-03 at 23:08 -0500, Jain Priyanka-B32167 wrote: > > > > > -----Original Message----- > > > From: Wood Scott-B07421 > > > Sent: Friday, July 04, 2014 3:40 AM > > > To: Jain Priyanka-B32167 > > > Cc: devicetree@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux- > > > spi@vger.kernel.org; linux-mtd@lists.infradead.org > > > Subject: Re: [PATCH] devicetree/bindings: Add binding for micron n25q512a > > > memory > > > > > > On Thu, 2014-07-03 at 15:42 +0530, Priyanka Jain wrote: > > > > -Micron n25q512a memory is supported by m25p80 driver. > > > > Add compatible field required to support n25q512a in m25p80.txt -Add > > > > micron to the vendor-prefixes.txt file > > > > > > > > Signed-off-by: Priyanka Jain > > > > --- > > > > Documentation/devicetree/bindings/mtd/m25p80.txt | 1 + > > > > .../devicetree/bindings/vendor-prefixes.txt | 1 + > > > > 2 files changed, 2 insertions(+), 0 deletions(-) > > > > > > Why did you send this to the ppc list but not the spi or mtd lists? > > > > > [Jain Priyanka-B32167] Sorry, I missed that > > > I'm having a hard time following the flow of how these SPI devices get > > > bound -- is the compatible involved at all? I don't see this string > > > (with vendor prefix included) in the driver. I do see a table that > > > contains what looks like device IDs. If the device can report its id, > > > shouldn't we rely on that rather than device tree compatible? > > > > > > -Scott > > [Jain Priyanka-B32167] > > Spi driver has a check to device name corresponding to device-id and compare to what is passed in dts string. > > Please go into more detail. I don't see where the string > "micron,n25q512a" appears in the current kernel. I do see "n25q512a", > but how does that compare successfully with the version of the string > that has a vendor compatible? The spi code has a hack to not require an of_device_id_table: of_register_spi_devices calls of_modalias_node, which for a given "foo,bar" compatible string will set spi->modalias to "bar", by cutting off everything up to and including the comma. Later, spi_match_id can match a device with an spi_device_id->name of "bar". Thus "micron,n25q512a" can match one of the entries already in drivers/mtd/spi-nor/spi-nor.c. This is a real pain when searching around. Thanks, Mark.