From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v2 0/2] eeprom: at25: SPI transfer improvements Date: Wed, 30 Jan 2019 15:55:43 +0100 Message-ID: <20190130155543.5ab749b5@bbrezillon> References: <20190118140525.29189-1-geert+renesas@glider.be> <20190118230740.44239fcf@bbrezillon> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Geert Uytterhoeven , Arnd Bergmann , Greg Kroah-Hartman , MTD Maling List , Nguyen An Hoan , Linux Kernel Mailing List , linux-spi To: Geert Uytterhoeven Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-spi.vger.kernel.org On Tue, 29 Jan 2019 20:02:37 +0100 Geert Uytterhoeven wrote: > Hi Boris, > > On Fri, Jan 18, 2019 at 11:07 PM Boris Brezillon wrote: > > Did you consider converting this driver to spimem? Looks like the > > protocol used to communicate with the memory resembles the one used on > > SPI NANDs/NORs and fits pretty well in the spi_mem_op representation. > > > > By doing this conversion you'd allow people to connect an AT25 EEPROM > > to an advanced SPI controller that does not support regular SPI > > transfers and you wouldn't have to forge SPI messages manually. > > > > Here is a patch (only compile tested) doing that. The diffstat is not in > > favor of this conversion, but I find the resulting code cleaner and more > > future proof. > > Thanks, seems to work fine, with the 512-byte 25LC040 I have! > > Tested-by: Geert Uytterhoeven > > I did notice that the first two-byte transfer (command+offset) of each > message is now split in two one-byte transfers, though. That's something we can optimize in drivers/spi/spi-mem.c if you think it makes a difference.