50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __SPI_BITBANG_H
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#define __SPI_BITBANG_H
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#include <linux/workqueue.h>
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struct spi_bitbang {
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struct mutex lock;
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u8 busy;
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u8 use_dma;
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u16 flags; /* extra spi->mode support */
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struct spi_master *master;
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/* setup_transfer() changes clock and/or wordsize to match settings
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* for this transfer; zeroes restore defaults from spi_device.
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*/
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int (*setup_transfer)(struct spi_device *spi,
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struct spi_transfer *t);
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void (*chipselect)(struct spi_device *spi, int is_on);
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#define BITBANG_CS_ACTIVE 1 /* normally nCS, active low */
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#define BITBANG_CS_INACTIVE 0
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/* txrx_bufs() may handle dma mapping for transfers that don't
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* already have one (transfer.{tx,rx}_dma is zero), or use PIO
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*/
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int (*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
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/* txrx_word[SPI_MODE_*]() just looks like a shift register */
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u32 (*txrx_word[4])(struct spi_device *spi,
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unsigned nsecs,
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u32 word, u8 bits, unsigned flags);
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int (*set_line_direction)(struct spi_device *spi, bool output);
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};
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/* you can call these default bitbang->master methods from your custom
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* methods, if you like.
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*/
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extern int spi_bitbang_setup(struct spi_device *spi);
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extern void spi_bitbang_cleanup(struct spi_device *spi);
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extern int spi_bitbang_setup_transfer(struct spi_device *spi,
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struct spi_transfer *t);
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/* start or stop queue processing */
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extern int spi_bitbang_start(struct spi_bitbang *spi);
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extern void spi_bitbang_stop(struct spi_bitbang *spi);
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#endif /* __SPI_BITBANG_H */
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