Differential D26250 Diff 76406 sys/dev/backlight/backlight.c

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sys/dev/backlight/backlight.c

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				/*-
				* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
				*
				* Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
				*
				* 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.
				*
				* $FreeBSD$
				*/

				#include <sys/cdefs.h>
				__FBSDID("$FreeBSD$");

				#include <sys/param.h>
				#include <sys/systm.h>
				#include <sys/limits.h>
				#include <sys/bus.h>
				#include <sys/conf.h>
				#include <sys/kernel.h>
				#include <sys/malloc.h>
				#include <sys/module.h>
				#include <sys/lock.h>
				#include <sys/sx.h>

				#include <dev/backlight/backlight.h>

				#include "backlight_if.h"

				static struct sx backlight_sx;
				static MALLOC_DEFINE(M_BACKLIGHT, "BACKLIGHT", "Backlight driver");
				static struct unrhdr *backlight_unit;

				struct backlight_softc {
				struct cdev *cdev;
				struct cdev *alias;
				int unit;
				device_t dev;
				uint32_t cached_brightness;
				};

				static int
				backlight_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
				int fflag, struct thread *td)
				{
				struct backlight_softc *sc;
				struct backlight_props props;
				int error;

				sc = dev->si_drv1;

				switch (cmd) {
				case BACKLIGHTGETSTATUS:
				/* Call the driver function so it fills up the props */
				bcopy(data, &props, sizeof(struct backlight_props));
				error = BACKLIGHT_GET_STATUS(sc->dev, &props);
				if (error == 0)
				bcopy(&props, data, sizeof(struct backlight_props));
				break;
				case BACKLIGHTUPDATESTATUS:
				bcopy(data, &props, sizeof(struct backlight_props));
				if (props.brightness == sc->cached_brightness)
				return (0);
				error = BACKLIGHT_UPDATE_STATUS(sc->dev, &props);
				if (error == 0) {
				bcopy(&props, data, sizeof(struct backlight_props));
				sc->cached_brightness = props.brightness;
				}
				break;
				}

				return (error);
				}

				static struct cdevsw backlight_cdevsw = {
				.d_version = D_VERSION,
				.d_ioctl = backlight_ioctl,
				.d_name = "backlight",
				};

				struct cdev *
				backlight_register(const char *name, device_t dev)
				{
				struct make_dev_args args;
				struct backlight_softc *sc;
				struct backlight_props props;
				int error;

				sc = malloc(sizeof(*sc), M_BACKLIGHT, M_WAITOK \| M_ZERO);

				sx_xlock(&backlight_sx);
				sc->unit = alloc_unr(backlight_unit);
				sc->dev = dev;
				make_dev_args_init(&args);
				args.mda_flags = MAKEDEV_CHECKNAME \| MAKEDEV_WAITOK;
				args.mda_devsw = &backlight_cdevsw;
				args.mda_uid = UID_ROOT;
				args.mda_gid = GID_VIDEO;
				args.mda_mode = 0660;
				args.mda_si_drv1 = sc;
				error = make_dev_s(&args, &sc->cdev, "backlight/backlight%d", sc->unit);

				if (error != 0)
				goto fail;

				error = make_dev_alias_p(MAKEDEV_CHECKNAME \| MAKEDEV_WAITOK,
				&sc->alias, sc->cdev, "backlight/%s%d", name, sc->unit);
				if (error != 0)
				device_printf(dev, "Cannot register with alias %s%d\n", name,
				sc->unit);

				sx_xunlock(&backlight_sx);

				error = BACKLIGHT_GET_STATUS(sc->dev, &props);
				sc->cached_brightness = props.brightness;

				return (sc->cdev);
				fail:
				sx_xunlock(&backlight_sx);
				return (NULL);
				}

				int
				backlight_destroy(struct cdev *dev)
				{
				struct backlight_softc *sc;

				sc = dev->si_drv1;
				sx_xlock(&backlight_sx);
				free_unr(backlight_unit, sc->unit);
				destroy_dev(dev);
				sx_xunlock(&backlight_sx);
				return (0);
				}

				static void
				backlight_drvinit(void *unused)
				{

				backlight_unit = new_unrhdr(0, INT_MAX, NULL);
				sx_init(&backlight_sx, "Backlight sx");
				}

				SYSINIT(backlightdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, backlight_drvinit, NULL);
				MODULE_VERSION(backlight, 1);