From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756596AbbAHPOe (ORCPT ); Thu, 8 Jan 2015 10:14:34 -0500 Received: from mailapp01.imgtec.com ([195.59.15.196]:36329 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063AbbAHPOc (ORCPT ); Thu, 8 Jan 2015 10:14:32 -0500 Message-ID: <54AE9E54.2010506@imgtec.com> Date: Thu, 8 Jan 2015 12:12:20 -0300 From: Ezequiel Garcia User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: =?gbk?Q?=22Peter_Pan_=C5=CB=B6=B0_=28peterpandong=29=22?= , "robh+dt@kernel.org" , "pawel.moll@arm.com" , "mark.rutland@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "dwmw2@infradead.org" , "Brian Norris" CC: "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , =?gbk?Q?=22Qi_Wang_=CD=F5=C6=F0_=28qiwang=29=22?= , =?gbk?Q?=22Frank_Liu_=C1=F5=C8=BA_=28frankliu=29=22?= , =?gbk?Q?=22Melanie_Zhang_=D5=C5=D1=E0_=28me?= =?gbk?Q?laniezhang=29=22?= Subject: Re: [PATCH 3/3] mtd: spi-nand: add devicetree binding References: <87F60714EC601C4C83DFF1D2E3D390A04AB425@NTXXIAMBX02.xacn.micron.com> <54ADF66F.7090400@imgtec.com> <87F60714EC601C4C83DFF1D2E3D390A04AB4EA@NTXXIAMBX02.xacn.micron.com> In-Reply-To: <87F60714EC601C4C83DFF1D2E3D390A04AB4EA@NTXXIAMBX02.xacn.micron.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.100.200.148] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/08/2015 02:04 AM, Peter Pan ΕΛΆ° (peterpandong) wrote: >>> This commit adds the devicetree binding document that specifies the >>> spi nand devices support. >>> >>> Signed-off-by: Peter Pan >>> --- >>> Documentation/devicetree/bindings/mtd/spi-nand.txt | 22 >> ++++++++++++++++++++++ >>> 1 file changed, 22 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/mtd/spi- >> nand.txt >>> >>> diff --git a/Documentation/devicetree/bindings/mtd/spi-nand.txt >> b/Documentation/devicetree/bindings/mtd/spi-nand.txt >>> new file mode 100644 >>> index 0000000..9dd3efd >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/mtd/spi-nand.txt >>> @@ -0,0 +1,22 @@ >>> +* NAND driver for MT29F, GD5F and similar SPI NAND flash chips >>> + >>> +Required properties: >>> +- #address-cells, #size-cells : Must be present if the device has >> sub-nodes >>> + representing partitions. >>> +- compatible : Should be the manufacturer and the name of the chip. >> Bear in mind >>> >> >> Unless I'm mistaken, we don't need the chip ID here, as SPI NAND allows >> to autodetect the device. Any reason why we can't just use a generic >> compatible "spi-nand" here? >> -- >> Ezequiel > > In fact, I don't know how to autodetect the SPI NAND device. Micron device and > Gigadevice device have different read ID functions. The Chip ID here is used to > determine which function to use. > Isn't the difference between the Read ID very minor? One of the vendor needs a 2-byte ID read, and the other one needs a 3-byte ID read. So you can just try with 2-byte, and if that fails (no vendor ID is found on the first byte), you can try with the 3-byte command. It's not the most elegant solution, but it's not super awful either. -- Ezequiel