/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SPI_BITBANG_H
#define __SPI_BITBANG_H

#include <linux/workqueue.h>

typedef u32 (*spi_bb_txrx_word_fn)(struct spi_device *, unsigned int, u32, u8, unsigned int);

struct spi_bitbang {
        struct mutex            lock;
        u8                      busy;
        u8                      use_dma;
        u16                     flags;          /* extra spi->mode support */

        struct spi_controller   *ctlr;

        /* setup_transfer() changes clock and/or wordsize to match settings
         * for this transfer; zeroes restore defaults from spi_device.
         */
        int     (*setup_transfer)(struct spi_device *spi,
                        struct spi_transfer *t);

        void    (*chipselect)(struct spi_device *spi, int is_on);
#define BITBANG_CS_ACTIVE       1       /* normally nCS, active low */
#define BITBANG_CS_INACTIVE     0

        void    (*set_mosi_idle)(struct spi_device *spi);
        /* txrx_bufs() may handle dma mapping for transfers that don't
         * already have one (transfer.{tx,rx}_dma is zero), or use PIO
         */
        int     (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);

        /* txrx_word[SPI_MODE_*]() just looks like a shift register */
        spi_bb_txrx_word_fn txrx_word[SPI_MODE_X_MASK + 1];

        int     (*set_line_direction)(struct spi_device *spi, bool output);
};

/* you can call these default bitbang->master methods from your custom
 * methods, if you like.
 */
extern int spi_bitbang_setup(struct spi_device *spi);
extern void spi_bitbang_cleanup(struct spi_device *spi);
extern int spi_bitbang_setup_transfer(struct spi_device *spi,
                                      struct spi_transfer *t);

/* start or stop queue processing */
extern int spi_bitbang_start(struct spi_bitbang *spi);
extern int spi_bitbang_init(struct spi_bitbang *spi);
extern void spi_bitbang_stop(struct spi_bitbang *spi);

#endif  /* __SPI_BITBANG_H */