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 typedef u32 (*spi_bb_txrx_word_fn)(struct spi_device *, unsigned int, u32, u8, unsigned int);
8
9 struct 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 /* txrx_bufs() may handle dma mapping for transfers that don't
28 * already have one (transfer.{tx,rx}_dma is zero), or use PIO
29 */
30 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
31
32 /* txrx_word[SPI_MODE_*]() just looks like a shift register */
33 spi_bb_txrx_word_fn txrx_word[SPI_MODE_X_MASK + 1];
34
35 int (*set_line_direction)(struct spi_device *spi, bool output);
36 };
37
38 /* you can call these default bitbang->master methods from your custom
39 * methods, if you like.
40 */
41 extern int spi_bitbang_setup(struct spi_device *spi);
42 extern void spi_bitbang_cleanup(struct spi_device *spi);
43 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
44 struct spi_transfer *t);
45
46 /* start or stop queue processing */
47 extern int spi_bitbang_start(struct spi_bitbang *spi);
48 extern int spi_bitbang_init(struct spi_bitbang *spi);
49 extern void spi_bitbang_stop(struct spi_bitbang *spi);
50
51 #endif /* __SPI_BITBANG_H */
52
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