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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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320f669309
Some SPI peripherals may require strict MOSI line state when the controller is not clocking out data. Implement support for MOSI idle state configuration (low or high) by setting the data output line level on controller setup and after transfers. Bitbang operations now call controller specific set_mosi_idle() callback to set MOSI to its idle state. The MOSI line is kept at its idle state if no tx buffer is provided. Acked-by: Nuno Sa <nuno.sa@analog.com> Reviewed-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com> Link: https://patch.msgid.link/de61a600b56ed9cb714d5ea87afa88948e70041e.1720810545.git.marcelo.schmitt@analog.com Signed-off-by: Mark Brown <broonie@kernel.org>
53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
/* 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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typedef u32 (*spi_bb_txrx_word_fn)(struct spi_device *, unsigned int, u32, u8, unsigned int);
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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_controller *ctlr;
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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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void (*set_mosi_idle)(struct spi_device *spi);
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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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spi_bb_txrx_word_fn txrx_word[SPI_MODE_X_MASK + 1];
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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 int spi_bitbang_init(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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