linux-kernel - Re: [RFC][PATCH] spi: Setup the master controller driver before setting the chipselect

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Date:	Wed, 14 Oct 2015 14:08:12 +0300
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	"Ivan T. Ivanov" <iivanov.xz@...il.com>,
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Cc:	Franklin S Cooper Jr <fcooper@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-spi@...r.kernel.org, Mark Brown <broonie@...nel.org>,
	Sekhar Nori <nsekhar@...com>, ssantosh@...nel.org,
	"Ivan T. Ivanov" <iivanov@...sol.com>, m-karicheri2@...com
Subject: Re: [RFC][PATCH] spi: Setup the master controller driver before
 setting the chipselect

+Cc: Jarkko to see from spi-pxa2xx prospective

On Wed, Oct 14, 2015 at 12:47 PM, Ivan T. Ivanov <iivanov.xz@...il.com> wrote:
> Adding Andy.
>
>
>> On Oct 13, 2015, at 12:01 AM, Franklin S Cooper Jr <fcooper@...com> wrote:
>>
>> Some devices depend on the master controller driver setup function being
>> called before calling any chipselect functions.
>>
>> Insure that this is done otherwise uninitialized structures may be
>> accessed causing a kernel panic.

As far as I understand my concern should be about spi-dw driver.

So, I have just tested yesterday's linux-next with and without
proposed patch. Works for me:
Tested-by: Andy Shevchenko <andy.shevchenko@...il.com>

>>
>> Signed-off-by: Franklin S Cooper Jr <fcooper@...com>
>> ---
>> drivers/spi/spi.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
>> index 38006cc..9374d82 100644
>> --- a/drivers/spi/spi.c
>> +++ b/drivers/spi/spi.c
>> @@ -2053,11 +2053,11 @@ 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);
>>
>> +     spi_set_cs(spi, false);
>> +
>>       dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
>>                       (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
>>                       (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
>> --
>> 2.6.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-spi" in
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>



-- 
With Best Regards,
Andy Shevchenko
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