From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754545Ab3I0SpP (ORCPT ); Fri, 27 Sep 2013 14:45:15 -0400 Received: from smtp-out-093.synserver.de ([212.40.185.93]:1046 "EHLO smtp-out-091.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754341Ab3I0SpN (ORCPT ); Fri, 27 Sep 2013 14:45:13 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 2125 Message-ID: <5245D2A0.4090909@metafoo.de> Date: Fri, 27 Sep 2013 20:46:56 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130922 Icedove/17.0.9 MIME-Version: 1.0 To: Mark Brown CC: Jean Delvare , Guenter Roeck , Jonathan Cameron , lm-sensors@lm-sensors.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, linux-spi@vger.kernel.org Subject: Re: [PATCH 1/3] spi: Add a spi_w8r16be() helper References: <1380292469-17347-1-git-send-email-lars@metafoo.de> <20130927183456.GM19304@sirena.org.uk> In-Reply-To: <20130927183456.GM19304@sirena.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/27/2013 08:34 PM, Mark Brown wrote: > On Fri, Sep 27, 2013 at 04:34:27PM +0200, Lars-Peter Clausen wrote: >> This patch adds a new spi_w8r16be() helper, which is similar to spi_w8r16() >> except that it converts the read data word from big endian to native endianness >> before returning it. The reason for introducing this new helper is that for SPI > > This actually feels like a bug in spi_w8r16() - I'd expect it to be > returning native endian in the first place since in SPI a word is by > default big endian so I'd expect this to have more of a register I/O > model. It certainly seems to match what almost all of the users are > doing. According to the documentation of spi_w8r16() it is a feature. * The number is returned in wire-order, which is at least sometimes * big-endian. There seem to be at least two users though which assume that the result is in native endianness drivers/hwmon/ads7871.c and drivers/mfd/stmpe-spi.c > > That said I'm not sure this is worth fixing in which case the new API > makes sense. Or converting the users to regmap I guess. > regmap is always my first choice, but the users are all devices having varying register sizes, so regmap is not working that nicely. - Lars