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 struct spi_bitbang { 8 struct mutex lock; 9 u8 busy; 10 u8 use_dma; 11 u16 flags; /* extra spi->mode support */ 12 13 struct spi_master *master; 14 15 /* setup_transfer() changes clock and/or wordsize to match settings 16 * for this transfer; zeroes restore defaults from spi_device. 17 */ 18 int (*setup_transfer)(struct spi_device *spi, 19 struct spi_transfer *t); 20 21 void (*chipselect)(struct spi_device *spi, int is_on); 22 #define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */ 23 #define BITBANG_CS_INACTIVE 0 24 25 /* txrx_bufs() may handle dma mapping for transfers that don't 26 * already have one (transfer.{tx,rx}_dma is zero), or use PIO 27 */ 28 int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t); 29 30 /* txrx_word[SPI_MODE_*]() just looks like a shift register */ 31 u32 (*txrx_word[4])(struct spi_device *spi, 32 unsigned nsecs, 33 u32 word, u8 bits, unsigned flags); 34 int (*set_line_direction)(struct spi_device *spi, bool output); 35 }; 36 37 /* you can call these default bitbang->master methods from your custom 38 * methods, if you like. 39 */ 40 extern int spi_bitbang_setup(struct spi_device *spi); 41 extern void spi_bitbang_cleanup(struct spi_device *spi); 42 extern int spi_bitbang_setup_transfer(struct spi_device *spi, 43 struct spi_transfer *t); 44 45 /* start or stop queue processing */ 46 extern int spi_bitbang_start(struct spi_bitbang *spi); 47 extern int spi_bitbang_init(struct spi_bitbang *spi); 48 extern void spi_bitbang_stop(struct spi_bitbang *spi); 49 50 #endif /* __SPI_BITBANG_H */ 51