diff mbox

[v2] spi: Ensure that CS line is in non-active state after spi_setup()

Message ID 1426265029-12280-1-git-send-email-iivanov@mm-sol.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ivan T. Ivanov March 13, 2015, 4:43 p.m. UTC
Some devices samples state of the chip select signal during power up
and act differently based on this state, so SPI core should ensure
that CS line is driven in non-active state after spi_setup().

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
---
 drivers/spi/spi.c | 2 ++
 1 file changed, 2 insertions(+)

--
1.9.1

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Comments

Ivan T. Ivanov March 20, 2015, 4:14 p.m. UTC | #1
On Fri, 2015-03-13 at 18:43 +0200, Ivan T. Ivanov wrote:
> Some devices samples state of the chip select signal during power up
> and act differently based on this state, so SPI core should ensure
> that CS line is driven in non-active state after spi_setup().
> 
> Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
> ---

Any comments on this one?

Forget to add changes since v1 [1].

CS is set to non-active state unconditionally before
spi->master->setup()

Regards,
Ivan

[1] http://www.spinics.net/lists/linux-spi/msg03056.html

>  drivers/spi/spi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index c64a3e5..4023cc9 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -1893,6 +1893,8 @@ int spi_setup(struct spi_device *spi)
>         if (!spi->max_speed_hz)
>                 spi->max_speed_hz = spi->master->max_speed_hz;
> 
> +       spi_set_cs(spi, false);
> +
>         if (spi->master->setup)
>                 status = spi->master->setup(spi);
> 


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Mark Brown March 20, 2015, 4:17 p.m. UTC | #2
On Fri, Mar 20, 2015 at 06:14:49PM +0200, Ivan T. Ivanov wrote:

> Any comments on this one?

> Forget to add changes since v1 [1].

> CS is set to non-active state unconditionally before
> spi->master->setup()

Please don't send content free quoted pings.
diff mbox

Patch

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index c64a3e5..4023cc9 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1893,6 +1893,8 @@  int spi_setup(struct spi_device *spi)
 	if (!spi->max_speed_hz)
 		spi->max_speed_hz = spi->master->max_speed_hz;

+	spi_set_cs(spi, false);
+
 	if (spi->master->setup)
 		status = spi->master->setup(spi);