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