On 21.09.2012 09:54, Uwe Kleine-K?nig wrote:

On Fri, Sep 21, 2012 at 09:36:51AM +0200, Dirk Behme wrote:

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On 31.08.2012 04:35, Shawn Guo wrote:

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Copy Uwe ...

Copy our kernel mailing list ...

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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

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On Fri, Aug 31, 2012 at 10:55:11AM +0200, Dirk Behme wrote:

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From: Knut Wohlrab<redacted>

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<redacted>

If you forward a patch you must add your S-o-b.

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---

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?

yes.

Thanks
Uwe

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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

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