From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755409Ab2LSPJh (ORCPT ); Wed, 19 Dec 2012 10:09:37 -0500 Received: from mail-we0-f177.google.com ([74.125.82.177]:55779 "EHLO mail-we0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753221Ab2LSPJ3 (ORCPT ); Wed, 19 Dec 2012 10:09:29 -0500 From: Grant Likely Subject: Re: [PATCH RFC] spidev.c: add sysfs attributes for SPI configuration To: Federico Vaga Cc: spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org, Federico Vaga In-Reply-To: <1353777608-24934-1-git-send-email-federico.vaga@gmail.com> References: <1353777608-24934-1-git-send-email-federico.vaga@gmail.com> Date: Wed, 19 Dec 2012 15:09:25 +0000 Message-Id: <20121219150925.8262E3E0AD7@localhost> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 24 Nov 2012 18:20:08 +0100, Federico Vaga wrote: > This patch introduce the use of the sysfs attribute for the spidev > configuration. This avoid the user to have a specific program which does > ioctl() on spidev. The user can easily does cat (to read) and echo (to > write) on the sysfs file and configure SPI. > > The patch exports the following attributes: bits-per-word, lsb-first, > mode and speed-hz. > > Example: > # cat /sys/bus/spi/devices/spi1.0/speed-hz > 500000 > # echo 450000 > /sys/bus/spi/devices/spi1.0/speed-hz > # dmesg | tail -n 4 > spidev spi1.0: DEactivate 60, mr 000f0011 > spidev spi1.0: setup: 449447 Hz bpw 8 mode 0x0 -> csr0 0000dd02 > spidev spi1.0: setup mode 0, 8 bits/w, 450000 Hz max --> 0 > spidev spi1.0: 450000 Hz (max) > > Signed-off-by: Federico Vaga Not a good idea. sysfs is not a good place for operational interfaces. Please use the spi character devices for direct manipulation of the SPI configuration. g.