kernel

linux-6.8.1/include/linux/spi/spi_bitbang.h

@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef	__SPI_BITBANG_H
+#define	__SPI_BITBANG_H
+
+#include <linux/workqueue.h>
+
+struct spi_bitbang {
+	struct mutex		lock;
+	u8			busy;
+	u8			use_dma;
+	u16			flags;		/* extra spi->mode support */
+
+	struct spi_master	*master;
+
+	/* 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
+
+	/* 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 */
+	u32	(*txrx_word[4])(struct spi_device *spi,
+			unsigned nsecs,
+			u32 word, u8 bits, unsigned flags);
+	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 */