IABSD.fr/src/sys/dev/spi

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• Author : kettenis
  Date : 2021-10-31 15:12:00
  Hash : fe922775
  Message : Extend the SPI bus API a bit. The config structure gets an sc_cs_delay member to allow us to specify a delay between assert the CS# signal and starting the clock. And the transfer function gains a flags argument, which can be used to specify a new SPI_KEEP_CS flag to keep CS# asserted after the transfer. This allows us to do another transfer immediately afterwards without de-asserting CS# which is necessary for sending commands to the upcoming Apple M1 keyboard/touchpad driver. ok patrick@

• spivar.h

• /* $OpenBSD: spivar.h,v 1.2 2021/10/31 15:12:00 kettenis Exp $ */
  /*
   * Copyright (c) 2018 Patrick Wildt <patrick@blueri.se>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  struct spi_config {
  	int		 sc_cs;
  	int		 sc_flags;
  #define SPI_CONFIG_CPOL		(1 << 0)
  #define SPI_CONFIG_CPHA		(1 << 1)
  #define SPI_CONFIG_CS_HIGH	(1 << 2)
  	int		 sc_bpw;
  	uint32_t	 sc_freq;
  	u_int		 sc_cs_delay;
  };
  
  #define SPI_KEEP_CS		(1 << 0)
  
  typedef struct spi_controller {
  	void		*sc_cookie;
  	void		(*sc_config)(void *, struct spi_config *);
  	int		(*sc_transfer)(void *, char *, char *, int, int);
  	int		(*sc_acquire_bus)(void *, int);
  	void		(*sc_release_bus)(void *, int);
  } *spi_tag_t;
  
  struct spi_attach_args {
  	spi_tag_t	 sa_tag;
  	char		*sa_name;
  	void		*sa_cookie;
  };
  
  #define	spi_config(sc, config)						\
  	(*(sc)->sc_config)((sc)->sc_cookie, (config))
  #define	spi_read(sc, data, len)						\
  	(*(sc)->sc_transfer)((sc)->sc_cookie, NULL, (data), (len), 0)
  #define	spi_write(sc, data, len)					\
  	(*(sc)->sc_transfer)((sc)->sc_cookie, (data), NULL, (len), 0)
  #define	spi_transfer(sc, out, in, len, flags)				\
  	(*(sc)->sc_transfer)((sc)->sc_cookie, (out), (in), (len), (flags))
  #define	spi_acquire_bus(sc, flags)					\
  	(*(sc)->sc_acquire_bus)((sc)->sc_cookie, (flags))
  #define	spi_release_bus(sc, flags)					\
  	(*(sc)->sc_release_bus)((sc)->sc_cookie, (flags))