From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Behme Subject: Re: [PATCH] spi/imx: set the inactive state of the clock according to the clock polarity Date: Sat, 22 Sep 2012 08:10:48 +0200 Message-ID: <505D5668.4040209@gmail.com> References: <1346403311-25080-1-git-send-email-dirk.behme@de.bosch.com> <20120831023518.GE7726@r65073-Latitude-D630> <505C1913.1090004@de.bosch.com> <20120921075431.GS5525@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: Hui Wang , Rob Herring , Dirk Behme , "Wohlrab Knut \(CM-AI/PJ-CF31\)" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" To: =?ISO-8859-1?Q?Uwe_Kleine-K=F6nig?= , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, "spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , Shawn Guo Return-path: In-Reply-To: <20120921075431.GS5525-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 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 On 21.09.2012 09:54, Uwe Kleine-K=F6nig wrote: > On Fri, Sep 21, 2012 at 09:36:51AM +0200, Dirk Behme wrote: >> On 31.08.2012 04:35, Shawn Guo wrote: >>> Copy Uwe ... > Copy our kernel mailing list ... > >> Ping ;) >> >> Any opinions on this? > Assuming it fixes access to a device I'm ok with your patch, but I don't > really feel responsible for the driver (i.e. me not acking shouldn't > have a negative influence on getting the patch in). Ok, thanks. I'm not so familiar with the SPI world: Who would be the best person = to ack this, and in case it's ok finally apply it, then? Thanks Dirk >>> On Fri, Aug 31, 2012 at 10:55:11AM +0200, Dirk Behme wrote: >>>> From: Knut Wohlrab >>>> >>>> There are SPI devices which need a SPI clock with active low polarity = and >>>> high inactive state. >>>> >>>> Add the setting of the inactive state ECSPIx_CONFIGREG:SCLK CTL >>>> according to the clock polarity ECSPIx_CONFIGREG:SCLK POL: >>>> >>>> DT without "spi-cpol" =3D 0 =3D clock active high polarity =3D inactiv= e state low >>>> DT with "spi-cpol" =3D 1 =3D clock active low polarity =3D inactiv= e state high >>>> >>>> Signed-off-by: Knut Wohlrab > If you forward a patch you must add your S-o-b. > >>>> --- >>>> >>>> Question: Are there real world examples for a need of an individual se= tting of >>>> clock polarity/inactive state? >>> >>> I'm less concerned about that. We can always patch the driver when >>> the real world example occurs? > yes. > > Thanks > Uwe > >>>> drivers/spi/spi-imx.c | 6 ++++-- >>>> 1 files changed, 4 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c >>>> index e834ff8..d64655b 100644 >>>> --- a/drivers/spi/spi-imx.c >>>> +++ b/drivers/spi/spi-imx.c >>>> @@ -197,6 +197,7 @@ static unsigned int spi_imx_clkdiv_2(unsigned int = fin, >>>> #define MX51_ECSPI_CONFIG_SCLKPOL(cs) (1<< ((cs) + 4)) >>>> #define MX51_ECSPI_CONFIG_SBBCTRL(cs) (1<< ((cs) + 8)) >>>> #define MX51_ECSPI_CONFIG_SSBPOL(cs) (1<< ((cs) + 12)) >>>> +#define MX51_ECSPI_CONFIG_SCLKCTL(cs) (1<< ((cs) + 20)) >>>> #define MX51_ECSPI_INT 0x10 >>>> #define MX51_ECSPI_INT_TEEN (1<< 0) >>>> @@ -287,9 +288,10 @@ static int __maybe_unused mx51_ecspi_config(struc= t spi_imx_data *spi_imx, >>>> if (config->mode& SPI_CPHA) >>>> cfg |=3D MX51_ECSPI_CONFIG_SCLKPHA(config->cs); >>>> - if (config->mode& SPI_CPOL) >>>> + if (config->mode& SPI_CPOL) { >>>> cfg |=3D MX51_ECSPI_CONFIG_SCLKPOL(config->cs); >>>> - >>>> + cfg |=3D MX51_ECSPI_CONFIG_SCLKCTL(config->cs); >>>> + } >>>> if (config->mode& SPI_CS_HIGH) >>>> cfg |=3D MX51_ECSPI_CONFIG_SSBPOL(config->cs); >>>> -- >>>> 1.7.0.4 >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> > ---------------------------------------------------------------------------= --- How fast is your code? 3 out of 4 devs don\\\'t know how their code performs in production. Find out how slow your code is with AppDynamics Lite. http://ad.doubleclick.net/clk;262219672;13503038;z? http://info.appdynamics.com/FreeJavaPerformanceDownload.html