1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef	__SPI_BITBANG_H
3 #define	__SPI_BITBANG_H
4 
5 #include <linux/workqueue.h>
6 
7 struct 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  */
40 extern int spi_bitbang_setup(struct spi_device *spi);
41 extern void spi_bitbang_cleanup(struct spi_device *spi);
42 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
43 				      struct spi_transfer *t);
44 
45 /* start or stop queue processing */
46 extern int spi_bitbang_start(struct spi_bitbang *spi);
47 extern int spi_bitbang_init(struct spi_bitbang *spi);
48 extern void spi_bitbang_stop(struct spi_bitbang *spi);
49 
50 #endif	/* __SPI_BITBANG_H */
51