include/linux/spi/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
   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         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  */
  42 extern int spi_bitbang_setup(struct spi_device *spi);
  43 extern void spi_bitbang_cleanup(struct spi_device *spi);
  44 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
  45                                       struct spi_transfer *t);
  46
  47 /* start or stop queue processing */
  48 extern int spi_bitbang_start(struct spi_bitbang *spi);
  49 extern int spi_bitbang_init(struct spi_bitbang *spi);
  50 extern void spi_bitbang_stop(struct spi_bitbang *spi);
  51
  52 #endif  /* __SPI_BITBANG_H */