Rework the GPIO framework.  Tie it to the kauth(9) framework to control
access to the GPIO pins.  Device drivers using GPIO pins can now be
attached and detached at runtime.  GPIO pins can be named for easier
reference from userland programs.  Introduce a new gpiosim(4) driver,
which is used for development.

Reviewed by many.


(mbalmer)

/* $NetBSD: gpiosim.c,v 1.1 2009/07/25 16:17:10 mbalmer Exp $ */
/*      $OpenBSD: gpiosim.c,v 1.1 2008/11/23 18:46:49 mbalmer Exp $	*/

/*
 * Copyright (c) 2007, 2008, 2009 Marc Balmer <marc@msys.ch>
 * All rights reserved.
 *
 * 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 MIND, 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.
 */

/* 32 bit wide GPIO simulator  */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/gpio.h>
#include <sys/malloc.h>
#include <sys/sysctl.h>
#include <sys/ioccom.h>

#include <dev/gpio/gpiovar.h>
#include <dev/biovar.h>

#define	GPIOSIM_NPINS	32

struct gpiosim_softc {
	struct device		sc_dev;
	u_int32_t		sc_state;
	struct gpio_chipset_tag	sc_gpio_gc;
	gpio_pin_t		sc_gpio_pins[GPIOSIM_NPINS];
};

struct gpiosim_op {
	void *cookie;
	u_int32_t mask;
	u_int32_t state;
};
#define GPIOSIMREAD	_IOWR('G', 0, struct gpiosim_op)
#define GPIOSIMWRITE	_IOW('G', 1, struct gpiosim_op)

int	gpiosim_match(device_t, cfdata_t, void *);
void	gpiosim_attach(device_t, device_t, void *);
int	gpiosim_detach(device_t, int);
int	gpiosim_ioctl(device_t, u_long cmd, void *);
int	gpiosim_activate(device_t, enum devact);

int	gpiosim_pin_read(void *, int);
void	gpiosim_pin_write(void *, int, int);
void	gpiosim_pin_ctl(void *, int, int);

CFATTACH_DECL_NEW(gpiosim, sizeof(struct gpiosim_softc), gpiosim_match,
    gpiosim_attach, gpiosim_detach, gpiosim_activate);

extern struct cfdriver gpiosim_cd;

int
gpiosim_match(device_t parent, cfdata_t match, void *aux)
{
	return 1;
}

void
gpiosim_attach(device_t parent, device_t self, void *aux)
{
	struct gpiosim_softc *sc = device_private(self);
	struct gpiobus_attach_args gba;
	int i;

	/* initialize pin array */
	for (i = 0; i < GPIOSIM_NPINS; i++) {
		sc->sc_gpio_pins[i].pin_num = i;
		sc->sc_gpio_pins[i].pin_caps = GPIO_PIN_INPUT |
		    GPIO_PIN_OUTPUT | GPIO_PIN_OPENDRAIN |
		    GPIO_PIN_PULLUP | GPIO_PIN_PULLDOWN |
		    GPIO_PIN_INVIN | GPIO_PIN_INVOUT;

		/* read initial state */
		sc->sc_gpio_pins[i].pin_flags = GPIO_PIN_INPUT;
		sc->sc_state = 0;

		/* create controller tag */
		sc->sc_gpio_gc.gp_cookie = sc;
		sc->sc_gpio_gc.gp_pin_read = gpiosim_pin_read;
		sc->sc_gpio_gc.gp_pin_write = gpiosim_pin_write;
		sc->sc_gpio_gc.gp_pin_ctl = gpiosim_pin_ctl;

		/* gba.gba_name = "gpio"; */
		gba.gba_gc = &sc->sc_gpio_gc;
		gba.gba_pins = sc->sc_gpio_pins;
		gba.gba_npins = GPIOSIM_NPINS;
	}
	printf("\n");
	config_found_ia(self, "gpiobus", &gba, gpiobus_print);
	bio_register(&sc->sc_dev, gpiosim_ioctl);
}

int
gpiosim_detach(device_t self, int flags)
{
	return 1;
}

int
gpiosim_activate(device_t self, enum devact act)
{
	switch (act) {
	case DVACT_ACTIVATE:
		return EOPNOTSUPP;
	case DVACT_DEACTIVATE:
		break;
	}

	return 0;
}

int
gpiosim_ioctl(device_t self, u_long cmd, void * data)
{
	struct gpiosim_softc *sc = (void *)self;
	struct gpiosim_op *op = (void *)data;

	switch (cmd) {
		case GPIOSIMREAD:
			op->state = sc->sc_state;
			break;
		case GPIOSIMWRITE:
			sc->sc_state = (sc->sc_state & ~op->mask) |
			    (op->state & op->mask);
			break;
	}
	return 0;
}

int
gpiosim_pin_read(void *arg, int pin)
{
	struct gpiosim_softc *sc = (struct gpiosim_softc *)arg;

	if (sc->sc_state & (1 << pin))
		return GPIO_PIN_HIGH;
	else
		return GPIO_PIN_LOW;
}

void
gpiosim_pin_write(void *arg, int pin, int value)
{
	struct gpiosim_softc *sc = (struct gpiosim_softc *)arg;

	if (value == 0)
		sc->sc_state &= ~(1 << pin);
	else
		sc->sc_state |= (1 << pin);
}

void
gpiosim_pin_ctl(void *arg, int pin, int flags)
{
	struct gpiosim_softc *sc = (struct gpiosim_softc *)arg;

	sc->sc_gpio_pins[pin].pin_flags = flags;
}