linux_dsm_epyc7002/include/linux/spi/spi_bitbang.h
Lorenzo Bianconi 4b859db2c6
spi: spi-gpio: add SPI_3WIRE support
Add SPI_3WIRE support to spi-gpio controller introducing
set_line_direction function pointer in spi_bitbang data structure.
Spi-gpio controller has been tested using hts221 temp/rh iio sensor
running in 3wire mode and lsm6dsm running in 4wire mode

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-08-01 14:50:28 +01:00

50 lines
1.5 KiB
C

/* 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 */