1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __SPI_BITBANG_H
3#define __SPI_BITBANG_H
4
5#include <linux/workqueue.h>
6
7struct spi_bitbang {
8 struct mutex lock;
9 u8 busy;
10 u8 use_dma;
11 u16 flags; /* extra spi->mode support */
12
13 struct spi_master *master;
14
15 /* setup_transfer() changes clock and/or wordsize to match settings
16 * for this transfer; zeroes restore defaults from spi_device.
17 */
18 int (*setup_transfer)(struct spi_device *spi,
19 struct spi_transfer *t);
20
21 void (*chipselect)(struct spi_device *spi, int is_on);
22#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
23#define BITBANG_CS_INACTIVE 0
24
25 /* txrx_bufs() may handle dma mapping for transfers that don't
26 * already have one (transfer.{tx,rx}_dma is zero), or use PIO
27 */
28 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
29
30 /* txrx_word[SPI_MODE_*]() just looks like a shift register */
31 u32 (*txrx_word[4])(struct spi_device *spi,
32 unsigned nsecs,
33 u32 word, u8 bits, unsigned flags);
34 int (*set_line_direction)(struct spi_device *spi, bool output);
35};
36
37/* you can call these default bitbang->master methods from your custom
38 * methods, if you like.
39 */
40extern int spi_bitbang_setup(struct spi_device *spi);
41extern void spi_bitbang_cleanup(struct spi_device *spi);
42extern int spi_bitbang_setup_transfer(struct spi_device *spi,
43 struct spi_transfer *t);
44
45/* start or stop queue processing */
46extern int spi_bitbang_start(struct spi_bitbang *spi);
47extern int spi_bitbang_init(struct spi_bitbang *spi);
48extern void spi_bitbang_stop(struct spi_bitbang *spi);
49
50#endif /* __SPI_BITBANG_H */
51

source code of linux/include/linux/spi/spi_bitbang.h