gpiobacklight.c revision 302408 
1/*-
2 * Copyright (c) 2015-2016 Oleksandr Tymoshenko <gonzo@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/sys/dev/gpio/gpiobacklight.c 299395 2016-05-11 00:26:52Z gonzo $");
29
30#include "opt_platform.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/bus.h>
35#include <sys/gpio.h>
36#include <sys/kernel.h>
37#include <sys/lock.h>
38#include <sys/malloc.h>
39#include <sys/module.h>
40#include <sys/mutex.h>
41#include <sys/sysctl.h>
42
43#include <dev/fdt/fdt_common.h>
44#include <dev/ofw/ofw_bus.h>
45
46#include <dev/gpio/gpiobusvar.h>
47
48struct gpiobacklight_softc
49{
50	gpio_pin_t		sc_pin;
51	struct sysctl_oid	*sc_oid;
52	bool			sc_brightness;
53};
54
55static int gpiobacklight_sysctl(SYSCTL_HANDLER_ARGS);
56static void gpiobacklight_update_brightness(struct gpiobacklight_softc *);
57static int gpiobacklight_probe(device_t);
58static int gpiobacklight_attach(device_t);
59static int gpiobacklight_detach(device_t);
60
61static void
62gpiobacklight_update_brightness(struct gpiobacklight_softc *sc)
63{
64
65	if (sc->sc_pin)
66		gpio_pin_set_active(sc->sc_pin, sc->sc_brightness);
67}
68
69static int
70gpiobacklight_sysctl(SYSCTL_HANDLER_ARGS)
71{
72	struct gpiobacklight_softc *sc;
73	int error;
74	int brightness;
75
76	sc = (struct gpiobacklight_softc*)arg1;
77
78	brightness = sc->sc_brightness;
79	error = sysctl_handle_int(oidp, &brightness, 0, req);
80
81	if (error != 0 || req->newptr == NULL)
82		return (error);
83
84	sc->sc_brightness = (brightness > 0);
85	gpiobacklight_update_brightness(sc);
86
87	return (0);
88}
89
90static int
91gpiobacklight_probe(device_t dev)
92{
93
94	if (!ofw_bus_is_compatible(dev, "gpio-backlight"))
95		return (ENXIO);
96
97	device_set_desc(dev, "GPIO backlight");
98
99	return (0);
100}
101
102static int
103gpiobacklight_attach(device_t dev)
104{
105	struct gpiobacklight_softc *sc;
106	struct sysctl_ctx_list *ctx;
107	struct sysctl_oid *tree;
108	phandle_t node;
109
110	sc = device_get_softc(dev);
111
112	if ((node = ofw_bus_get_node(dev)) == -1)
113		return (ENXIO);
114
115	if (OF_hasprop(node, "default-on"))
116		sc->sc_brightness = true;
117	else
118		sc->sc_brightness = false;
119
120	gpio_pin_get_by_ofw_idx(dev, node, 0, &sc->sc_pin);
121	if (sc->sc_pin == NULL) {
122		device_printf(dev, "failed to map GPIO pin\n");
123		return (ENXIO);
124	}
125
126	gpio_pin_setflags(sc->sc_pin, GPIO_PIN_OUTPUT);
127
128	gpiobacklight_update_brightness(sc);
129
130	/* Init backlight interface */
131	ctx = device_get_sysctl_ctx(dev);
132	tree = device_get_sysctl_tree(dev);
133	sc->sc_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
134	    "brightness", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
135	    gpiobacklight_sysctl, "I", "backlight brightness");
136
137	return (0);
138}
139
140static int
141gpiobacklight_detach(device_t dev)
142{
143	struct gpiobacklight_softc *sc;
144
145	sc = device_get_softc(dev);
146
147	if (sc->sc_pin)
148		gpio_pin_release(sc->sc_pin);
149
150	return (0);
151}
152
153static devclass_t gpiobacklight_devclass;
154
155static device_method_t gpiobacklight_methods[] = {
156	/* Device interface */
157	DEVMETHOD(device_probe,		gpiobacklight_probe),
158	DEVMETHOD(device_attach,	gpiobacklight_attach),
159	DEVMETHOD(device_detach,	gpiobacklight_detach),
160
161	DEVMETHOD_END
162};
163
164static driver_t gpiobacklight_driver = {
165	"gpiobacklight",
166	gpiobacklight_methods,
167	sizeof(struct gpiobacklight_softc),
168};
169
170DRIVER_MODULE(gpiobacklight, simplebus, gpiobacklight_driver,
171    gpiobacklight_devclass, 0, 0);
172MODULE_DEPEND(gpiobacklight, gpiobus, 1, 1, 1);
173