text: /*-
   * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
   * Copyright (c) 2010 Luiz Otavio O Souza
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: releng/9.3/sys/dev/gpio/gpioiic.c 213277 2010-09-29 20:53:33Z gonzo $");
  
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/bio.h>
  #include <sys/bus.h>
  #include <sys/conf.h>
  #include <sys/kernel.h>
  #include <sys/kthread.h>
  #include <sys/lock.h>
  #include <sys/malloc.h>
  #include <sys/module.h>
  #include <sys/mutex.h>
  
  #include <sys/gpio.h>
  #include "gpiobus_if.h"
  
  #include <dev/iicbus/iiconf.h>
  #include <dev/iicbus/iicbus.h>
  
  #include "iicbb_if.h"
  
  #define	SCL_PIN		0	/* gpiobus mapped pin 6 */
  #define	SDA_PIN		1	/* gpiobus mapped pin 7 */
  
  struct gpioiic_softc 
  {
  	device_t	sc_dev;
  	device_t	sc_busdev;
  	struct mtx	sc_mtx;
  	struct cdev	*sc_leddev;
  };
  
  static int gpioiic_probe(device_t);
  static int gpioiic_attach(device_t);
  
  /* iicbb interface */
  static void gpioiic_reset_bus(device_t);
  static int gpioiic_callback(device_t, int, caddr_t);
  static void gpioiic_setsda(device_t, int);
  static void gpioiic_setscl(device_t, int);
  static int gpioiic_getsda(device_t);
  static int gpioiic_getscl(device_t);
  static int gpioiic_reset(device_t, u_char, u_char, u_char *);
  
  
  static int
  gpioiic_probe(device_t dev)
  {
  
  	device_set_desc(dev, "GPIO I2C bit-banging driver");
  	return (0);
  }
  
  static int
  gpioiic_attach(device_t dev)
  {
  	struct gpioiic_softc	*sc = device_get_softc(dev);
  	device_t		bitbang;
  
  	sc->sc_dev = dev;
  	sc->sc_busdev = device_get_parent(dev);
  
  	/* add generic bit-banging code */
  	bitbang = device_add_child(dev, "iicbb", -1);
  	device_probe_and_attach(bitbang);
  
  	return (0);
  }
  
  /*
   * Reset bus by setting SDA first and then SCL. 
   * Must always be called with gpio bus locked.
   */
  static void
  gpioiic_reset_bus(device_t dev)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  
  	GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
  	    GPIO_PIN_INPUT);
  	GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
  	    GPIO_PIN_INPUT);
  }
  
  static int
  gpioiic_callback(device_t dev, int index, caddr_t data)
  {
  	struct gpioiic_softc	*sc = device_get_softc(dev);
  	int			error = 0;
  
  	switch (index) {
  	case IIC_REQUEST_BUS:
  		GPIOBUS_LOCK_BUS(sc->sc_busdev);
  		GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
  		GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  		break;
  	case IIC_RELEASE_BUS:
  		GPIOBUS_LOCK_BUS(sc->sc_busdev);
  		GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
  		GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  		break;
  	default:
  		error = EINVAL;
  	}
  
  	return(error);
  }
  
  static void
  gpioiic_setsda(device_t dev, int val)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  
  	GPIOBUS_LOCK_BUS(sc->sc_busdev);
  	if (val == 0) {
  		GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, SDA_PIN, 0);
  		GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
  		    GPIO_PIN_OUTPUT);
  	} else {
  		GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
  		    GPIO_PIN_INPUT);
  	}
  	GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  }
  
  static void
  gpioiic_setscl(device_t dev, int val)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  
  	GPIOBUS_LOCK_BUS(sc->sc_busdev);
  	if (val == 0) {
  		GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, SCL_PIN, 0);
  		GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
  		    GPIO_PIN_OUTPUT);
  	} else {
  		GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
  		    GPIO_PIN_INPUT);
  	}
  	GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  }
  
  static int
  gpioiic_getscl(device_t dev)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  	unsigned int			val;
  
  	GPIOBUS_LOCK_BUS(sc->sc_busdev);
  	GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
  	    GPIO_PIN_INPUT);
  	GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, SCL_PIN, &val);
  	GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  
  	return ((int)val);
  }
  
  static int
  gpioiic_getsda(device_t dev)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  	unsigned int			val;
  
  	GPIOBUS_LOCK_BUS(sc->sc_busdev);
  	GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
  	    GPIO_PIN_INPUT);
  	GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, SDA_PIN, &val);
  	GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  
  	return ((int)val);
  }
  
  static int
  gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
  {
  	struct gpioiic_softc		*sc = device_get_softc(dev);
  
  	GPIOBUS_LOCK_BUS(sc->sc_busdev);
  	GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
  
  	gpioiic_reset_bus(sc->sc_dev);
  
  	GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
  	GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
  
  	return (IIC_ENOADDR);
  }
  
  static devclass_t gpioiic_devclass;
  
  static device_method_t gpioiic_methods[] = {
  	/* Device interface */
  	DEVMETHOD(device_probe,		gpioiic_probe),
  	DEVMETHOD(device_attach,	gpioiic_attach),
  	DEVMETHOD(device_detach,	bus_generic_detach),
  
  	/* iicbb interface */
  	DEVMETHOD(iicbb_callback,	gpioiic_callback),
  	DEVMETHOD(iicbb_setsda,		gpioiic_setsda),
  	DEVMETHOD(iicbb_setscl,		gpioiic_setscl),
  	DEVMETHOD(iicbb_getsda,		gpioiic_getsda),
  	DEVMETHOD(iicbb_getscl,		gpioiic_getscl),
  	DEVMETHOD(iicbb_reset,		gpioiic_reset),
  
  	{ 0, 0 }
  };
  
  static driver_t gpioiic_driver = {
  	"gpioiic",
  	gpioiic_methods,
  	sizeof(struct gpioiic_softc),
  };
  
  DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, gpioiic_devclass, 0, 0);
  DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, iicbb_devclass, 0, 0);
  MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
  MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1);
  