[PATCH v1] spi: davinci: change the lower limit of pre-scale divider to 1

[PATCH v1] spi: davinci: change the lower limit of pre-scale divider to 1

[Murali Karicheri]

SPI hardware spec for Keystone specify a lower value of 0 for pre-scale
divider which determine what max value of spi clock (spi-max-frequency)
the device can support. This translates to a clock divider of 2. So fix
the lower limit value used for the boundary check in
davinci_spi_get_prescale() function to 1 so that a maximum of spi device
clock rate / 2 is possible to be set for spi-max-frequency.

Signed-off-by: Murali Karicheri <m-karicheri2-l0cyMroinI0@public.gmane.org>
Acked-by: Sekhar Nori <nsekhar-l0cyMroinI0@public.gmane.org>
---
 - Re-send with updates to commit log and PATCH prefix
 - Applies to v4.1
 drivers/spi/spi-davinci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 5e99106..987afeb 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -265,7 +265,7 @@ static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
 
 	ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz);
 
-	if (ret < 3 || ret > 256)
+	if (ret < 1 || ret > 256)
 		return -EINVAL;
 
 	return ret - 1;
-- 
1.9.1

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Re: [PATCH v1] spi: davinci: change the lower limit of pre-scale divider to 1

[Mark Brown]

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On Wed, Jun 10, 2015 at 03:23:42AM -0400, Murali Karicheri wrote:
> SPI hardware spec for Keystone specify a lower value of 0 for pre-scale
> divider which determine what max value of spi clock (spi-max-frequency)
> the device can support. This translates to a clock divider of 2. So fix
> the lower limit value used for the boundary check in
> davinci_spi_get_prescale() function to 1 so that a maximum of spi device
> clock rate / 2 is possible to be set for spi-max-frequency.

Applied, thanks.

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