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authorNicolas Boichat <drinkcat@chromium.org>2015-08-17 11:52:54 +0800
committerMark Brown <broonie@kernel.org>2015-09-17 12:13:40 +0100
commitc15f6ed3a18f10cdc33f64906ab353f17a6df114 (patch)
treed31632b7d325d16e602437062832c01eabae2451 /drivers/spi/spi-bitbang.c
parent6ff33f3902c3b1c5d0db6b1e2c70b6d76fba357f (diff)
spi: bitbang: Replace spinlock by mutex
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>
Diffstat (limited to 'drivers/spi/spi-bitbang.c')
-rw-r--r--drivers/spi/spi-bitbang.c17
1 files changed, 7 insertions, 10 deletions
diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 840a4984d365..ef43ef507c9a 100644
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -180,7 +180,6 @@ int spi_bitbang_setup(struct spi_device *spi)
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi->master);
@@ -210,12 +209,12 @@ int spi_bitbang_setup(struct spi_device *spi)
*/
/* deselect chip (low or high) */
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
if (!bitbang->busy) {
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(cs->nsecs);
}
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
@@ -255,13 +254,12 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
static int spi_bitbang_prepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi);
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
bitbang->busy = 1;
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
@@ -378,13 +376,12 @@ static int spi_bitbang_transfer_one(struct spi_master *master,
static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi);
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
bitbang->busy = 0;
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
@@ -427,7 +424,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)
if (!master || !bitbang->chipselect)
return -EINVAL;
- spin_lock_init(&bitbang->lock);
+ mutex_init(&bitbang->lock);
if (!master->mode_bits)
master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;