LXR linux/include/linux/spi/spi

   1#ifndef __SPI_BITBANG_H
   2#define __SPI_BITBANG_H
   3
   4#include <linux/workqueue.h>
   5
   6struct spi_bitbang {
   7        spinlock_t              lock;
   8        u8                      busy;
   9        u8                      use_dma;
  10        u8                      flags;          /* extra spi->mode support */
  11
  12        struct spi_master       *master;
  13
  14        /* setup_transfer() changes clock and/or wordsize to match settings
  15         * for this transfer; zeroes restore defaults from spi_device.
  16         */
  17        int     (*setup_transfer)(struct spi_device *spi,
  18                        struct spi_transfer *t);
  19
  20        void    (*chipselect)(struct spi_device *spi, int is_on);
  21#define BITBANG_CS_ACTIVE       1       /* normally nCS, active low */
  22#define BITBANG_CS_INACTIVE     0
  23
  24        /* txrx_bufs() may handle dma mapping for transfers that don't
  25         * already have one (transfer.{tx,rx}_dma is zero), or use PIO
  26         */
  27        int     (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
  28
  29        /* txrx_word[SPI_MODE_*]() just looks like a shift register */
  30        u32     (*txrx_word[4])(struct spi_device *spi,
  31                        unsigned nsecs,
  32                        u32 word, u8 bits);
  33};
  34
  35/* you can call these default bitbang->master methods from your custom
  36 * methods, if you like.
  37 */
  38extern int spi_bitbang_setup(struct spi_device *spi);
  39extern void spi_bitbang_cleanup(struct spi_device *spi);
  40extern int spi_bitbang_setup_transfer(struct spi_device *spi,
  41                                      struct spi_transfer *t);
  42
  43/* start or stop queue processing */
  44extern int spi_bitbang_start(struct spi_bitbang *spi);
  45extern void spi_bitbang_stop(struct spi_bitbang *spi);
  46
  47#endif  /* __SPI_BITBANG_H */
  48