From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753885AbbJPO2C (ORCPT ); Fri, 16 Oct 2015 10:28:02 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:37814 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752243AbbJPO2A (ORCPT ); Fri, 16 Oct 2015 10:28:00 -0400 From: "Franklin S Cooper Jr." To: Mark Brown CC: , , , , , , , , , Subject: Re: [PATCH] spi: Setup the master controller driver before setting the chipselect References: <1444942305-24038-1-git-send-email-fcooper@ti.com> <20151016102846.GJ14956@sirena.org.uk> Message-ID: <56210966.3040501@ti.com> Date: Fri, 16 Oct 2015 09:27:50 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151016102846.GJ14956@sirena.org.uk> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16/2015 05:28 AM, Mark Brown wrote: > On Thu, Oct 15, 2015 at 03:51:45PM -0500, Franklin S Cooper Jr wrote: >> Some devices depend on the master controller driver setup function being >> called before calling any chipselect functions. >> >> Insure that this is done otherwise uninitialized structures may be >> accessed causing a kernel panic. > I think this is a sensible change but can we please have a better > changelog - why is this the best thing to do rather than fixing the > driver to not crash? There are a bunch of good reasons to do the master > setup before asserting chip select but a driver crashing isn't one of > them, it's not clear that this isn't a bug in the driver. Mark, Makes sense. How about something like this? SPI controllers may need to be properly setup before chip selects can be used. Therefore, wait until the spi controller has a chance to perform their setup procedure before trying to use the chip select.