diff options
Diffstat (limited to 'include/linux/spi/spi_bitbang.h')
| -rw-r--r-- | include/linux/spi/spi_bitbang.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h new file mode 100644 index 000000000..b7e021b27 --- /dev/null +++ b/include/linux/spi/spi_bitbang.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __SPI_BITBANG_H +#define __SPI_BITBANG_H + +#include <linux/workqueue.h> + +struct spi_bitbang { + struct mutex lock; + u8 busy; + u8 use_dma; + u16 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, unsigned flags); + int (*set_line_direction)(struct spi_device *spi, bool output); +}; + +/* 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 */ |