From mboxrd@z Thu Jan 1 00:00:00 1970 From: Javier Martinez Canillas Subject: Re: [RFC PATCH 1/4] spi: spidev: Add Google SPI flash compatible string Date: Wed, 20 May 2015 13:21:53 +0200 Message-ID: <555C6E51.5030601@collabora.co.uk> References: <1432042454-19234-1-git-send-email-javier.martinez@collabora.co.uk> <1432042454-19234-2-git-send-email-javier.martinez@collabora.co.uk> <20150520101318.GB21577@sirena.org.uk> <555C5F65.7010204@collabora.co.uk> <20150520103746.GD21577@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150520103746.GD21577@sirena.org.uk> Sender: linux-kernel-owner@vger.kernel.org To: Mark Brown Cc: Kukjin Kim , Krzysztof Kozlowski , Olof Johansson , Doug Anderson , David Hendricks , linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org Hello Mark, On 05/20/2015 12:37 PM, Mark Brown wrote: > On Wed, May 20, 2015 at 12:18:13PM +0200, Javier Martinez Canillas wrote: >> On 05/20/2015 12:13 PM, Mark Brown wrote: > >> > This is adding a binding with no documentation, documentation is >> > mandatory for all bindings. > >> Yes, I missed... sorry about that. Do you agree with the approach >> though so I can re-spin the patches adding the missing DT binding? > > It's probably OK but I didn't really drill through since the binding was > missing. If these parts are commodity as described it seems surprising > that they aren't compatible with any existing kernel driver. > The ChromeOS user-space just uses flashrom to send a raw stream of bytes via spidev to the SPI NOR flash chip. There is drivers/mtd/spi-nor/spi-nor.c but AFAIU there are some limitations when interfacing the flash through the MTD layer, for example there isn't a way to set the SPI flash write protection through MTD. But I'll do some investigation before re-spinning the patches. BTW, the other "rohm,dh2228fv" compatible string in spidev added by commit 8fad805bdc52 ("spi: spidev: Add Rohm DH2228FV DAC compatible string"), also does not have a documented DT binding so that should be fixed as well. Best regards, Javier