mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 17:08:10 +00:00
c15f6ed3a1
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>
47 lines
1.4 KiB
C
47 lines
1.4 KiB
C
#ifndef __SPI_BITBANG_H
|
|
#define __SPI_BITBANG_H
|
|
|
|
#include <linux/workqueue.h>
|
|
|
|
struct spi_bitbang {
|
|
struct mutex lock;
|
|
u8 busy;
|
|
u8 use_dma;
|
|
u8 flags; /* extra spi->mode support */
|
|
|
|
struct spi_master *master;
|
|
|
|
/* setup_transfer() changes clock and/or wordsize to match settings
|
|
* for this transfer; zeroes restore defaults from spi_device.
|
|
*/
|
|
int (*setup_transfer)(struct spi_device *spi,
|
|
struct spi_transfer *t);
|
|
|
|
void (*chipselect)(struct spi_device *spi, int is_on);
|
|
#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
|
|
#define BITBANG_CS_INACTIVE 0
|
|
|
|
/* txrx_bufs() may handle dma mapping for transfers that don't
|
|
* already have one (transfer.{tx,rx}_dma is zero), or use PIO
|
|
*/
|
|
int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
|
|
|
|
/* txrx_word[SPI_MODE_*]() just looks like a shift register */
|
|
u32 (*txrx_word[4])(struct spi_device *spi,
|
|
unsigned nsecs,
|
|
u32 word, u8 bits);
|
|
};
|
|
|
|
/* you can call these default bitbang->master methods from your custom
|
|
* methods, if you like.
|
|
*/
|
|
extern int spi_bitbang_setup(struct spi_device *spi);
|
|
extern void spi_bitbang_cleanup(struct spi_device *spi);
|
|
extern int spi_bitbang_setup_transfer(struct spi_device *spi,
|
|
struct spi_transfer *t);
|
|
|
|
/* start or stop queue processing */
|
|
extern int spi_bitbang_start(struct spi_bitbang *spi);
|
|
extern void spi_bitbang_stop(struct spi_bitbang *spi);
|
|
|
|
#endif /* __SPI_BITBANG_H */
|