From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Subject: Re: [PATCH 4/5] spi/mxs: Remove bogus setting of ssp clk rate field Date: Tue, 2 Apr 2013 01:37:38 +0200 Message-ID: <201304020137.39154.marex@denx.de> References: <1364570381-17605-1-git-send-email-tpiepho@gmail.com> <201304020116.04781.marex@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Fabio Estevam , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Shawn Guo , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" To: Trent Piepho Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org Dear Trent Piepho, > On Mon, Apr 1, 2013 at 4:16 PM, Marek Vasut wrote: > >> The ssp struct has a clock rate field, to provide the actual value, in > >> Hz, of the SSP output clock (the rate of SSP_SCK) after > >> mxs_ssp_set_clk_rate() is called. It should be read-only, except for > >> mxs_ssp_set_clk_rate(). > >> > >> For some reason the spi-mxs driver decides to write to this field on > >> init, and sets it to the value of the SSP input clock (clk_sspN, from > >> the MXS clocking block) in kHz. It shouldn't be setting the value, and > >> certainly shouldn't be setting it with the wrong clock in the wrong > >> units. > > > > I suspect this patch should also fix drivers/clk/mxs/clk-ssp.c then? > > Why do you say that? I see no problem with clk-ssp.c, as setting the > clk_rate field in the ssp struct to the actual programmed rate makes > sense. The code in spi-mxs.c just makes no sense. I suspect it was > added by mistake when porting the driver. Either remove it altogether if it's unused OR make sure it's inited to some sane value from the start. Best regards, Marek Vasut ------------------------------------------------------------------------------ Own the Future-Intel® Level Up Game Demo Contest 2013 Rise to greatness in Intel's independent game demo contest. Compete for recognition, cash, and the chance to get your game on Steam. $5K grand prize plus 10 genre and skill prizes. Submit your demo by 6/6/13. http://p.sf.net/sfu/intel_levelupd2d From mboxrd@z Thu Jan 1 00:00:00 1970 From: marex@denx.de (Marek Vasut) Date: Tue, 2 Apr 2013 01:37:38 +0200 Subject: [PATCH 4/5] spi/mxs: Remove bogus setting of ssp clk rate field In-Reply-To: References: <1364570381-17605-1-git-send-email-tpiepho@gmail.com> <201304020116.04781.marex@denx.de> Message-ID: <201304020137.39154.marex@denx.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Dear Trent Piepho, > On Mon, Apr 1, 2013 at 4:16 PM, Marek Vasut wrote: > >> The ssp struct has a clock rate field, to provide the actual value, in > >> Hz, of the SSP output clock (the rate of SSP_SCK) after > >> mxs_ssp_set_clk_rate() is called. It should be read-only, except for > >> mxs_ssp_set_clk_rate(). > >> > >> For some reason the spi-mxs driver decides to write to this field on > >> init, and sets it to the value of the SSP input clock (clk_sspN, from > >> the MXS clocking block) in kHz. It shouldn't be setting the value, and > >> certainly shouldn't be setting it with the wrong clock in the wrong > >> units. > > > > I suspect this patch should also fix drivers/clk/mxs/clk-ssp.c then? > > Why do you say that? I see no problem with clk-ssp.c, as setting the > clk_rate field in the ssp struct to the actual programmed rate makes > sense. The code in spi-mxs.c just makes no sense. I suspect it was > added by mistake when porting the driver. Either remove it altogether if it's unused OR make sure it's inited to some sane value from the start. Best regards, Marek Vasut