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Diffstat (limited to 'kernel/include/linux/spi/spi_bitbang.h')
-rw-r--r--kernel/include/linux/spi/spi_bitbang.h47
1 files changed, 47 insertions, 0 deletions
diff --git a/kernel/include/linux/spi/spi_bitbang.h b/kernel/include/linux/spi/spi_bitbang.h
new file mode 100644
index 000000000..85578d4be
--- /dev/null
+++ b/kernel/include/linux/spi/spi_bitbang.h
@@ -0,0 +1,47 @@
+#ifndef __SPI_BITBANG_H
+#define __SPI_BITBANG_H
+
+#include <linux/workqueue.h>
+
+struct spi_bitbang {
+ spinlock_t lock;
+ u8 busy;
+ u8 use_dma;
+ u8 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);
+};
+
+/* 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 void spi_bitbang_stop(struct spi_bitbang *spi);
+
+#endif /* __SPI_BITBANG_H */