spi_bitbang.h

 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 */