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_controller	*ctlr;
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