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