From: dirk.behme@de•bosch.com (Dirk Behme)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] spi/imx: set the inactive state of the clock according to the clock polarity
Date: Fri, 21 Sep 2012 09:36:51 +0200 [thread overview]
Message-ID: <505C1913.1090004@de.bosch.com> (raw)
In-Reply-To: <20120831023518.GE7726@r65073-Latitude-D630>
On 31.08.2012 04:35, Shawn Guo wrote:
> Copy Uwe ...
Ping ;)
Any opinions on this?
Thanks
Dirk
> On Fri, Aug 31, 2012 at 10:55:11AM +0200, Dirk Behme wrote:
>> From: Knut Wohlrab <knut.wohlrab@de•bosch.com>
>>
>> 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" = 0 = clock active high polarity = inactive state low
>> DT with "spi-cpol" = 1 = clock active low polarity = inactive state high
>>
>> Signed-off-by: Knut Wohlrab <knut.wohlrab@de•bosch.com>
>> ---
>>
>> Question: Are there real world examples for a need of an individual setting of
>> clock polarity/inactive state?
>
> I'm less concerned about that. We can always patch the driver when
> the real world example occurs?
>
> Regards,
> Shawn
>
>> 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(struct spi_imx_data *spi_imx,
>> if (config->mode & SPI_CPHA)
>> cfg |= MX51_ECSPI_CONFIG_SCLKPHA(config->cs);
>>
>> - if (config->mode & SPI_CPOL)
>> + if (config->mode & SPI_CPOL) {
>> cfg |= MX51_ECSPI_CONFIG_SCLKPOL(config->cs);
>> -
>> + cfg |= MX51_ECSPI_CONFIG_SCLKCTL(config->cs);
>> + }
>> if (config->mode & SPI_CS_HIGH)
>> cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
>>
>> --
>> 1.7.0.4
next prev parent reply other threads:[~2012-09-21 7:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-31 8:55 [PATCH] spi/imx: set the inactive state of the clock according to the clock polarity Dirk Behme
2012-08-31 2:35 ` Shawn Guo
2012-09-21 7:36 ` Dirk Behme [this message]
2012-09-21 7:54 ` Uwe Kleine-König
2012-09-22 6:10 ` Dirk Behme
2012-09-22 13:44 ` Fabio Estevam
2012-09-24 5:06 ` Shawn Guo
2012-09-24 6:34 ` Dirk Behme
2012-09-24 10:02 ` Mark Brown
2012-09-24 11:31 ` Dirk Behme
2012-09-25 11:08 ` Mark Brown
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