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

From: Ivan T. Ivanov
Date: Fri Mar 20 2015 - 12:15:00 EST



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@xxxxxxxxxx>
> ---

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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