Add backlight subsystem

This is a simple subsystem that allow drivers to register as a backlight.
Each backlight creates a device node under /dev/backlight/backlightX and
an alias based on the name provided.

Relnotes:	yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D26250

1 files changed, 61 insertions, 0 deletions

diff --git a/sys/sys/backlight.h b/sys/sys/backlight.h
new file mode 100644
index 000000000000..4742d40e746c
--- /dev/null
+++ b/sys/sys/backlight.h
@@ -0,0 +1,61 @@
+/*-
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __BACKLIGHT_H__
+#define	__BACKLIGHT_H__
+
+#define	BACKLIGHTMAXLEVELS 100
+
+struct backlight_props {
+	uint32_t	brightness;
+	uint32_t	nlevels;
+	uint32_t	levels[BACKLIGHTMAXLEVELS];
+};
+
+enum backlight_info_type {
+	BACKLIGHT_TYPE_PANEL = 0,
+	BACKLIGHT_TYPE_KEYBOARD
+};
+
+#define	BACKLIGHTMAXNAMELENGTH	64
+
+struct backlight_info {
+	char				name[BACKLIGHTMAXNAMELENGTH];
+	enum backlight_info_type	type;
+};
+
+/*
+ * ioctls
+ */
+
+#define BACKLIGHTGETSTATUS	_IOWR('G', 0, struct backlight_props)
+#define BACKLIGHTUPDATESTATUS	_IOWR('G', 1, struct backlight_props)
+#define BACKLIGHTGETINFO	_IOWR('G', 2, struct backlight_info)
+
+#endif	/* __BACKLIGHT_H__ */