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spi: bitbang: Replace spinlock by mutex

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chipselect (in the case of spi-gpio: spi_gpio_chipselect, which
calls gpiod_set_raw_value_cansleep) can sleep, so we should not
hold a spinlock while calling it from spi_bitbang_setup.

This issue was introduced by this commit, which converted spi-gpio
to cansleep variants:
d9dda5a191 "spi: spi-gpio: Use 'cansleep' variants to access GPIO"

Replacing the lock variable by a mutex fixes the issue: This is
safe as all instances where the lock is used are called from
contexts that can sleep.

Finally, update spi-ppc4xx and and spi-s3c24xx to use mutex
functions, as they directly hold the lock for similar purpose.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Nicolas Boichat
2015-08-17 11:52:54 +08:00
committed by Mark Brown
parent 6ff33f3902
commit c15f6ed3a1
4 changed files with 12 additions and 15 deletions
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4
drivers/spi/spi-s3c24xx.c
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@@ -198,12 +198,12 @@ static int s3c24xx_spi_setup(struct spi_device *spi)
if (ret)
return ret;
spin_lock(&hw->bitbang.lock);
mutex_lock(&hw->bitbang.lock);
if (!hw->bitbang.busy) {
hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
/* need to ndelay for 0.5 clocktick ? */
}
spin_unlock(&hw->bitbang.lock);
mutex_unlock(&hw->bitbang.lock);
return 0;
}