1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __SPI_BITBANG_H
3#define __SPI_BITBANG_H
4
5#include <linux/workqueue.h>
6
7typedef u32 (*spi_bb_txrx_word_fn)(struct spi_device *, unsigned int, u32, u8, unsigned int);
8
9struct spi_bitbang {
10 struct mutex lock;
11 u8 busy;
12 u8 use_dma;
13 u16 flags; /* extra spi->mode support */
14
15 struct spi_controller *ctlr;
16
17 /* setup_transfer() changes clock and/or wordsize to match settings
18 * for this transfer; zeroes restore defaults from spi_device.
19 */
20 int (*setup_transfer)(struct spi_device *spi,
21 struct spi_transfer *t);
22
23 void (*chipselect)(struct spi_device *spi, int is_on);
24#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
25#define BITBANG_CS_INACTIVE 0
26
27 void (*set_mosi_idle)(struct spi_device *spi);
28 /* txrx_bufs() may handle dma mapping for transfers that don't
29 * already have one (transfer.{tx,rx}_dma is zero), or use PIO
30 */
31 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
32
33 /* txrx_word[SPI_MODE_*]() just looks like a shift register */
34 spi_bb_txrx_word_fn txrx_word[SPI_MODE_X_MASK + 1];
35
36 int (*set_line_direction)(struct spi_device *spi, bool output);
37};
38
39/* you can call these default bitbang->master methods from your custom
40 * methods, if you like.
41 */
42extern int spi_bitbang_setup(struct spi_device *spi);
43extern void spi_bitbang_cleanup(struct spi_device *spi);
44extern int spi_bitbang_setup_transfer(struct spi_device *spi,
45 struct spi_transfer *t);
46
47/* start or stop queue processing */
48extern int spi_bitbang_start(struct spi_bitbang *spi);
49extern int spi_bitbang_init(struct spi_bitbang *spi);
50extern void spi_bitbang_stop(struct spi_bitbang *spi);
51
52#endif /* __SPI_BITBANG_H */
53

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