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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1#ifndef __SPI_BITBANG_H
2#define __SPI_BITBANG_H
3
4#include <linux/workqueue.h>
5
6struct spi_bitbang {
7 struct workqueue_struct *workqueue;
8 struct work_struct work;
9
10 spinlock_t lock;
11 struct list_head queue;
12 u8 busy;
13 u8 use_dma;
14 u8 flags; /* extra spi->mode support */
15
16 struct spi_master *master;
17
18 /* setup_transfer() changes clock and/or wordsize to match settings
19 * for this transfer; zeroes restore defaults from spi_device.
20 */
21 int (*setup_transfer)(struct spi_device *spi,
22 struct spi_transfer *t);
23
24 void (*chipselect)(struct spi_device *spi, int is_on);
25#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
26#define BITBANG_CS_INACTIVE 0
27
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 u32 (*txrx_word[4])(struct spi_device *spi,
35 unsigned nsecs,
36 u32 word, u8 bits);
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_transfer(struct spi_device *spi, struct spi_message *m);
45extern int spi_bitbang_setup_transfer(struct spi_device *spi,
46 struct spi_transfer *t);
47
48/* start or stop queue processing */
49extern int spi_bitbang_start(struct spi_bitbang *spi);
50extern int spi_bitbang_stop(struct spi_bitbang *spi);
51
52#endif /* __SPI_BITBANG_H */