/*	$OpenBSD: gpio.c,v 1.17 2022/04/11 14:30:05 visa Exp $	*/

/*
 * Copyright (c) 2008 Marc Balmer <mbalmer@openbsd.org>
 * Copyright (c) 2004, 2006 Alexander Yurchenko <grange@openbsd.org>
 *
 * 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.
 */

/*
 * General Purpose Input/Output framework.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/gpio.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/queue.h>

#include <dev/gpio/gpiovar.h>

struct gpio_softc {
	struct device sc_dev;

	gpio_chipset_tag_t		 sc_gc;		/* GPIO controller */
	gpio_pin_t			*sc_pins;	/* pins array */
	int				 sc_npins;	/* number of pins */

	int sc_opened;
	LIST_HEAD(, gpio_dev)		 sc_devs;	/* devices */
	LIST_HEAD(, gpio_name) 	 	 sc_names;	/* named pins */
};

int	gpio_match(struct device *, void *, void *);
int	gpio_submatch(struct device *, void *, void *);
void	gpio_attach(struct device *, struct device *, void *);
int	gpio_detach(struct device *, int);
int	gpio_search(struct device *, void *, void *);
int	gpio_print(void *, const char *);
int	gpio_pinbyname(struct gpio_softc *, char *gp_name);
int	gpio_ioctl(struct gpio_softc *, u_long, caddr_t, int);

const struct cfattach gpio_ca = {
	sizeof (struct gpio_softc),
	gpio_match,
	gpio_attach,
	gpio_detach
};

struct cfdriver gpio_cd = {
	NULL, "gpio", DV_DULL
};

int
gpio_match(struct device *parent, void *match, void *aux)
{
	struct cfdata *cf = match;
	struct gpiobus_attach_args *gba = aux;

	return (strcmp(gba->gba_name, cf->cf_driver->cd_name) == 0);
}

int
gpio_submatch(struct device *parent, void *match, void *aux)
{
	struct cfdata *cf = match;
	struct gpio_attach_args *ga = aux;

	if (strcmp(ga->ga_dvname, cf->cf_driver->cd_name) != 0)
		return (0);

	return ((*cf->cf_attach->ca_match)(parent, match, aux));
}

void
gpio_attach(struct device *parent, struct device *self, void *aux)
{
	struct gpio_softc *sc = (struct gpio_softc *)self;
	struct gpiobus_attach_args *gba = aux;

	sc->sc_gc = gba->gba_gc;
	sc->sc_pins = gba->gba_pins;
	sc->sc_npins = gba->gba_npins;

	printf(": %d pins\n", sc->sc_npins);

	/*
	 * Attach all devices that can be connected to the GPIO pins
	 * described in the kernel configuration file.
	 */
	config_search(gpio_search, self, sc);
}

int
gpio_detach(struct device *self, int flags)
{
	int maj, mn;

	/* Locate the major number */
	for (maj = 0; maj < nchrdev; maj++)
		if (cdevsw[maj].d_open == gpioopen)
			break;

	/* Nuke the vnodes for any open instances (calls close) */
	mn = self->dv_unit;
	vdevgone(maj, mn, mn, VCHR);

	return (0);
}

int
gpio_search(struct device *parent, void *arg, void *aux)
{
	struct cfdata *cf = arg;
	struct gpio_attach_args ga;

	ga.ga_gpio = aux;
	ga.ga_offset = cf->cf_loc[0];
	ga.ga_mask = cf->cf_loc[1];
	ga.ga_flags = cf->cf_loc[2];

	if (cf->cf_attach->ca_match(parent, cf, &ga) > 0)
		config_attach(parent, cf, &ga, gpio_print);

	return (0);
}

int
gpio_print(void *aux, const char *pnp)
{
	struct gpio_attach_args *ga = aux;
	int i;

	printf(" pins");
	for (i = 0; i < 32; i++)
		if (ga->ga_mask & (1 << i))
			printf(" %d", ga->ga_offset + i);

	return (UNCONF);
}

int
gpiobus_print(void *aux, const char *pnp)
{
	struct gpiobus_attach_args *gba = aux;

	if (pnp != NULL)
		printf("%s at %s", gba->gba_name, pnp);

	return (UNCONF);
}

int
gpio_pin_map(void *gpio, int offset, u_int32_t mask, struct gpio_pinmap *map)
{
	struct gpio_softc *sc = gpio;
	int npins, pin, i;

	npins = gpio_npins(mask);
	if (npins > sc->sc_npins)
		return (1);

	for (npins = 0, i = 0; i < 32; i++)
		if (mask & (1 << i)) {
			pin = offset + i;
			if (pin < 0 || pin >= sc->sc_npins)
				return (1);
			if (sc->sc_pins[pin].pin_mapped)
				return (1);
			sc->sc_pins[pin].pin_mapped = 1;
			map->pm_map[npins++] = pin;
		}
	map->pm_size = npins;

	return (0);
}

void
gpio_pin_unmap(void *gpio, struct gpio_pinmap *map)
{
	struct gpio_softc *sc = gpio;
	int pin, i;

	for (i = 0; i < map->pm_size; i++) {
		pin = map->pm_map[i];
		sc->sc_pins[pin].pin_mapped = 0;
	}
}

int
gpio_pin_read(void *gpio, struct gpio_pinmap *map, int pin)
{
	struct gpio_softc *sc = gpio;

	return (gpiobus_pin_read(sc->sc_gc, map->pm_map[pin]));
}

void
gpio_pin_write(void *gpio, struct gpio_pinmap *map, int pin, int value)
{
	struct gpio_softc *sc = gpio;

	return (gpiobus_pin_write(sc->sc_gc, map->pm_map[pin], value));
}

void
gpio_pin_ctl(void *gpio, struct gpio_pinmap *map, int pin, int flags)
{
	struct gpio_softc *sc = gpio;

	return (gpiobus_pin_ctl(sc->sc_gc, map->pm_map[pin], flags));
}

int
gpio_pin_caps(void *gpio, struct gpio_pinmap *map, int pin)
{
	struct gpio_softc *sc = gpio;

	return (sc->sc_pins[map->pm_map[pin]].pin_caps);
}

int
gpio_npins(u_int32_t mask)
{
	int npins, i;

	for (npins = 0, i = 0; i < 32; i++)
		if (mask & (1 << i))
			npins++;

	return (npins);
}

int
gpioopen(dev_t dev, int flag, int mode, struct proc *p)
{
	struct gpio_softc *sc;
	int error = 0;

	sc = (struct gpio_softc *)device_lookup(&gpio_cd, minor(dev));
	if (sc == NULL)
		return (ENXIO);

	if (sc->sc_opened)
		error = EBUSY;
	else
		sc->sc_opened = 1;

	device_unref(&sc->sc_dev);

	return (error);
}

int
gpioclose(dev_t dev, int flag, int mode, struct proc *p)
{
	struct gpio_softc *sc;

	sc = (struct gpio_softc *)device_lookup(&gpio_cd, minor(dev));
	if (sc == NULL)
		return (ENXIO);

	sc->sc_opened = 0;

	device_unref(&sc->sc_dev);

	return (0);
}

int
gpio_pinbyname(struct gpio_softc *sc, char *gp_name)
{
	struct gpio_name *nm;

	LIST_FOREACH(nm, &sc->sc_names, gp_next)
		if (!strcmp(nm->gp_name, gp_name))
			return (nm->gp_pin);
	return (-1);
}

int
gpio_ioctl(struct gpio_softc *sc, u_long cmd, caddr_t data, int flag)
{
	gpio_chipset_tag_t gc;
	struct gpio_info *info;
	struct gpio_pin_op *op;
	struct gpio_attach *attach;
	struct gpio_attach_args ga;
	struct gpio_dev *gdev;
	struct gpio_name *nm;
	struct gpio_pin_set *set;
	struct device *dv;
	int pin, value, flags, npins, found;

	gc = sc->sc_gc;

	switch (cmd) {
	case GPIOINFO:
		info = (struct gpio_info *)data;
		if (securelevel < 1)
			info->gpio_npins = sc->sc_npins;
		else {
			for (pin = npins = 0; pin < sc->sc_npins; pin++)
				if (sc->sc_pins[pin].pin_flags & GPIO_PIN_SET)
					++npins;
			info->gpio_npins = npins;
		}
		break;
	case GPIOPINREAD:
		op = (struct gpio_pin_op *)data;

		if (op->gp_name[0] != '\0') {
			pin = gpio_pinbyname(sc, op->gp_name);
			if (pin == -1)
				return (EINVAL);
		} else
			pin = op->gp_pin;

		if (pin < 0 || pin >= sc->sc_npins)
			return (EINVAL);

		if (!(sc->sc_pins[pin].pin_flags & GPIO_PIN_SET) &&
		    securelevel > 0)
			return (EPERM);

		/* return read value */
		op->gp_value = gpiobus_pin_read(gc, pin);
		break;
	case GPIOPINWRITE:
		if ((flag & FWRITE) == 0)
			return (EBADF);

		op = (struct gpio_pin_op *)data;

		if (op->gp_name[0] != '\0') {
			pin = gpio_pinbyname(sc, op->gp_name);
			if (pin == -1)
				return (EINVAL);
		} else
			pin = op->gp_pin;

		if (pin < 0 || pin >= sc->sc_npins)
			return (EINVAL);

		if (sc->sc_pins[pin].pin_mapped)
			return (EBUSY);

		if (!(sc->sc_pins[pin].pin_flags & GPIO_PIN_SET) &&
		    securelevel > 0)
			return (EPERM);

		value = op->gp_value;
		if (value != GPIO_PIN_LOW && value != GPIO_PIN_HIGH)
			return (EINVAL);

		gpiobus_pin_write(gc, pin, value);
		/* return old value */
		op->gp_value = sc->sc_pins[pin].pin_state;
		/* update current value */
		sc->sc_pins[pin].pin_state = value;
		break;
	case GPIOPINTOGGLE:
		if ((flag & FWRITE) == 0)
			return (EBADF);

		op = (struct gpio_pin_op *)data;

		if (op->gp_name[0] != '\0') {
			pin = gpio_pinbyname(sc, op->gp_name);
			if (pin == -1)
				return (EINVAL);
		} else
			pin = op->gp_pin;

		if (pin < 0 || pin >= sc->sc_npins)
			return (EINVAL);

		if (sc->sc_pins[pin].pin_mapped)
			return (EBUSY);

		if (!(sc->sc_pins[pin].pin_flags & GPIO_PIN_SET) &&
		    securelevel > 0)
			return (EPERM);

		value = (sc->sc_pins[pin].pin_state == GPIO_PIN_LOW ?
		    GPIO_PIN_HIGH : GPIO_PIN_LOW);
		gpiobus_pin_write(gc, pin, value);
		/* return old value */
		op->gp_value = sc->sc_pins[pin].pin_state;
		/* update current value */
		sc->sc_pins[pin].pin_state = value;
		break;
	case GPIOATTACH:
		if (securelevel > 0)
			return (EPERM);

		attach = (struct gpio_attach *)data;
		bzero(&ga, sizeof(ga));
		ga.ga_gpio = sc;
		ga.ga_dvname = attach->ga_dvname;
		ga.ga_offset = attach->ga_offset;
		ga.ga_mask = attach->ga_mask;
		ga.ga_flags = attach->ga_flags;
		dv = config_found_sm((struct device *)sc, &ga, gpiobus_print,
		    gpio_submatch);
		if (dv != NULL) {
			gdev = malloc(sizeof(*gdev), M_DEVBUF,
			    M_WAITOK);
			gdev->sc_dev = dv;
			LIST_INSERT_HEAD(&sc->sc_devs, gdev, sc_next);
		}
		break;
	case GPIODETACH:
		if (securelevel > 0)
			return (EPERM);

		attach = (struct gpio_attach *)data;
		LIST_FOREACH(gdev, &sc->sc_devs, sc_next) {
			if (strcmp(gdev->sc_dev->dv_xname, attach->ga_dvname)
			    == 0) {
				if (config_detach(gdev->sc_dev, 0) == 0) {
					LIST_REMOVE(gdev, sc_next);
					free(gdev, M_DEVBUF, sizeof(*gdev));
				}
				break;
			}
		}
		break;
	case GPIOPINSET:
		if (securelevel > 0)
			return (EPERM);

		set = (struct gpio_pin_set *)data;

		if (set->gp_name[0] != '\0') {
			pin = gpio_pinbyname(sc, set->gp_name);
			if (pin == -1)
				return (EINVAL);
		} else
			pin = set->gp_pin;
		if (pin < 0 || pin >= sc->sc_npins)
			return (EINVAL);
		flags = set->gp_flags;
		/* check that the controller supports all requested flags */
		if ((flags & sc->sc_pins[pin].pin_caps) != flags)
			return (ENODEV);
		flags = set->gp_flags | GPIO_PIN_SET;

		set->gp_caps = sc->sc_pins[pin].pin_caps;
		/* return old value */
		set->gp_flags = sc->sc_pins[pin].pin_flags;
		if (flags > 0) {
			gpiobus_pin_ctl(gc, pin, flags);
			/* update current value */
			sc->sc_pins[pin].pin_flags = flags;
		}

		/* rename pin or new pin? */
		if (set->gp_name2[0] != '\0') {
			found = 0;
			LIST_FOREACH(nm, &sc->sc_names, gp_next)
				if (nm->gp_pin == pin) {
					strlcpy(nm->gp_name, set->gp_name2,
					    sizeof(nm->gp_name));
					found = 1;
					break;
				}
			if (!found) {
				nm = malloc(sizeof(*nm), M_DEVBUF, M_WAITOK);
				strlcpy(nm->gp_name, set->gp_name2,
				    sizeof(nm->gp_name));
				nm->gp_pin = set->gp_pin;
				LIST_INSERT_HEAD(&sc->sc_names, nm, gp_next);
			}
		}
		break;
	case GPIOPINUNSET:
		if (securelevel > 0)
			return (EPERM);

		set = (struct gpio_pin_set *)data;
		if (set->gp_name[0] != '\0') {
			pin = gpio_pinbyname(sc, set->gp_name);
			if (pin == -1)
				return (EINVAL);
		} else
			pin = set->gp_pin;
		
		if (pin < 0 || pin >= sc->sc_npins)
			return (EINVAL);
		if (sc->sc_pins[pin].pin_mapped)
			return (EBUSY);
		if (!(sc->sc_pins[pin].pin_flags & GPIO_PIN_SET))
			return (EINVAL);

		LIST_FOREACH(nm, &sc->sc_names, gp_next) {
			if (nm->gp_pin == pin) {
				LIST_REMOVE(nm, gp_next);
				free(nm, M_DEVBUF, sizeof(*nm));
				break;
			}
		}
		sc->sc_pins[pin].pin_flags &= ~GPIO_PIN_SET;
		break;
	default:
		return (ENOTTY);
	}

	return (0);
}

int
gpioioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
	struct gpio_softc *sc;
	int error;

	sc = (struct gpio_softc *)device_lookup(&gpio_cd, minor(dev));
	if (sc == NULL)
		return (ENXIO);

	error = gpio_ioctl(sc, cmd, data, flag);

	device_unref(&sc->sc_dev);

	return (error);
}