1 /* $NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $ */
2
3 /*-
4 * Copyright (c) 2018 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: pwm_backlight.c,v 1.10 2021/11/07 17:14:09 jmcneill Exp $");
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/device.h>
35 #include <sys/systm.h>
36 #include <sys/sysctl.h>
37 #include <sys/kmem.h>
38 #include <sys/gpio.h>
39
40 #include <dev/pwm/pwmvar.h>
41
42 #include <dev/fdt/fdtvar.h>
43
44 struct pwm_backlight_softc {
45 device_t sc_dev;
46 pwm_tag_t sc_pwm;
47 struct fdtbus_gpio_pin *sc_pin;
48
49 u_int *sc_levels;
50 u_int sc_nlevels;
51 u_int sc_curlevel;
52
53 char *sc_levelstr;
54
55 bool sc_lid_state;
56 };
57
58 static int pwm_backlight_match(device_t, cfdata_t, void *);
59 static void pwm_backlight_attach(device_t, device_t, void *);
60
61 static void pwm_backlight_sysctl_init(struct pwm_backlight_softc *);
62 static void pwm_backlight_pmf_init(struct pwm_backlight_softc *);
63 static void pwm_backlight_set(struct pwm_backlight_softc *, u_int, bool);
64 static u_int pwm_backlight_get(struct pwm_backlight_softc *);
65
66 static const struct device_compatible_entry compat_data[] = {
67 { .compat = "pwm-backlight" },
68 DEVICE_COMPAT_EOL
69 };
70
71 CFATTACH_DECL_NEW(pwmbacklight, sizeof(struct pwm_backlight_softc),
72 pwm_backlight_match, pwm_backlight_attach, NULL, NULL);
73
74 static int
pwm_backlight_match(device_t parent,cfdata_t cf,void * aux)75 pwm_backlight_match(device_t parent, cfdata_t cf, void *aux)
76 {
77 struct fdt_attach_args * const faa = aux;
78
79 return of_compatible_match(faa->faa_phandle, compat_data);
80 }
81
82 static void
pwm_backlight_attach(device_t parent,device_t self,void * aux)83 pwm_backlight_attach(device_t parent, device_t self, void *aux)
84 {
85 struct pwm_backlight_softc * const sc = device_private(self);
86 struct fdt_attach_args * const faa = aux;
87 const int phandle = faa->faa_phandle;
88 const u_int *levels;
89 u_int default_level = 0;
90 u_int n;
91 int len;
92
93 sc->sc_dev = self;
94 sc->sc_pwm = fdtbus_pwm_acquire(phandle, "pwms");
95 if (sc->sc_pwm == NULL) {
96 aprint_error(": couldn't acquire pwm\n");
97 return;
98 }
99 if (of_hasprop(phandle, "enable-gpios")) {
100 sc->sc_pin = fdtbus_gpio_acquire(phandle, "enable-gpios",
101 GPIO_PIN_OUTPUT);
102 if (!sc->sc_pin) {
103 aprint_error(": couldn't acquire enable gpio\n");
104 return;
105 }
106 fdtbus_gpio_write(sc->sc_pin, 1);
107 }
108
109 levels = fdtbus_get_prop(phandle, "brightness-levels", &len);
110 if (levels != NULL) {
111 sc->sc_nlevels = len / 4;
112 sc->sc_levels = kmem_alloc(len, KM_SLEEP);
113 for (n = 0; n < sc->sc_nlevels; n++)
114 sc->sc_levels[n] = be32toh(levels[n]);
115 } else {
116 sc->sc_nlevels = 256;
117 sc->sc_levels = kmem_alloc(sc->sc_nlevels * 4, KM_SLEEP);
118 for (n = 0; n < sc->sc_nlevels; n++)
119 sc->sc_levels[n] = n;
120 default_level = 200;
121 }
122
123 aprint_naive("\n");
124 aprint_normal(": PWM Backlight");
125 if (sc->sc_nlevels > 1) {
126 aprint_normal(", %u-%u (%u steps)",
127 sc->sc_levels[0], sc->sc_levels[sc->sc_nlevels - 1],
128 sc->sc_nlevels);
129 }
130 aprint_normal("\n");
131
132 sc->sc_lid_state = true;
133
134 of_getprop_uint32(phandle, "default-brightness-level", &default_level);
135 if (default_level != 0) {
136 /* set the default level now */
137 pwm_backlight_set(sc, default_level, true);
138 }
139
140 sc->sc_curlevel = pwm_backlight_get(sc);
141
142 pwm_backlight_sysctl_init(sc);
143 pwm_backlight_pmf_init(sc);
144 }
145
146 static void
pwm_backlight_set(struct pwm_backlight_softc * sc,u_int index,bool set_cur)147 pwm_backlight_set(struct pwm_backlight_softc *sc, u_int index, bool set_cur)
148 {
149 struct pwm_config conf;
150
151 if (index >= sc->sc_nlevels)
152 return;
153
154 KASSERT(sc->sc_levels[sc->sc_nlevels - 1] != 0);
155 aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n",
156 (100 * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]);
157
158 pwm_disable(sc->sc_pwm);
159 pwm_get_config(sc->sc_pwm, &conf);
160 conf.duty_cycle = (conf.period * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1];
161 pwm_set_config(sc->sc_pwm, &conf);
162 pwm_enable(sc->sc_pwm);
163
164 if (set_cur)
165 sc->sc_curlevel = index;
166 }
167
168 static u_int
pwm_backlight_get(struct pwm_backlight_softc * sc)169 pwm_backlight_get(struct pwm_backlight_softc *sc)
170 {
171 struct pwm_config conf;
172 u_int raw_val, n;
173
174 pwm_get_config(sc->sc_pwm, &conf);
175
176 raw_val = (conf.duty_cycle * sc->sc_levels[sc->sc_nlevels - 1]) / conf.period;
177
178 /* Return the closest setting to the raw value */
179 for (n = 0; n < sc->sc_nlevels; n++) {
180 if (raw_val <= sc->sc_levels[n])
181 break;
182 }
183 return n;
184 }
185
186 static int
pwm_backlight_sysctl_helper(SYSCTLFN_ARGS)187 pwm_backlight_sysctl_helper(SYSCTLFN_ARGS)
188 {
189 struct pwm_backlight_softc * const sc = rnode->sysctl_data;
190 struct sysctlnode node;
191 int error;
192 u_int level, n;
193
194 node = *rnode;
195 node.sysctl_data = &level;
196
197 n = pwm_backlight_get(sc);
198 level = sc->sc_levels[n];
199
200 error = sysctl_lookup(SYSCTLFN_CALL(&node));
201 if (error || newp == NULL)
202 return error;
203
204 for (n = 0; n < sc->sc_nlevels; n++) {
205 if (sc->sc_levels[n] == level) {
206 pwm_backlight_set(sc, n, true);
207 return 0;
208 }
209 }
210
211 return EINVAL;
212 }
213
214 static void
pwm_backlight_sysctl_init(struct pwm_backlight_softc * sc)215 pwm_backlight_sysctl_init(struct pwm_backlight_softc *sc)
216 {
217 const struct sysctlnode *node, *pwmnode;
218 struct sysctllog *log = NULL;
219 int error;
220 u_int n;
221
222 sc->sc_levelstr = kmem_zalloc(strlen("XXXXX ") * sc->sc_nlevels, KM_SLEEP);
223 for (n = 0; n < sc->sc_nlevels; n++) {
224 char buf[7];
225 snprintf(buf, sizeof(buf), n ? " %u" : "%u", sc->sc_levels[n]);
226 strcat(sc->sc_levelstr, buf);
227 }
228
229 error = sysctl_createv(&log, 0, NULL, &node,
230 CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL,
231 NULL, 0, NULL, 0, CTL_HW, CTL_EOL);
232 if (error)
233 goto failed;
234
235 error = sysctl_createv(&log, 0, &node, &pwmnode,
236 0, CTLTYPE_NODE, device_xname(sc->sc_dev), NULL,
237 NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL);
238 if (error)
239 goto failed;
240
241 error = sysctl_createv(&log, 0, &pwmnode, NULL,
242 0, CTLTYPE_STRING, "levels", NULL,
243 NULL, 0, sc->sc_levelstr, 0,
244 CTL_CREATE, CTL_EOL);
245 if (error)
246 goto failed;
247
248 error = sysctl_createv(&log, 0, &pwmnode, NULL,
249 CTLFLAG_READWRITE, CTLTYPE_INT, "level", NULL,
250 pwm_backlight_sysctl_helper, 0, (void *)sc, 0,
251 CTL_CREATE, CTL_EOL);
252 if (error)
253 goto failed;
254
255 return;
256
257 failed:
258 aprint_error_dev(sc->sc_dev, "couldn't create sysctl nodes: %d\n", error);
259 sysctl_teardown(&log);
260 }
261
262 static void
pwm_backlight_enable(struct pwm_backlight_softc * sc,int enable)263 pwm_backlight_enable(struct pwm_backlight_softc *sc, int enable)
264 {
265 if (sc->sc_pin)
266 fdtbus_gpio_write(sc->sc_pin, enable);
267 else
268 pwm_backlight_set(sc, enable ? sc->sc_curlevel : 0, false);
269 }
270
271 static void
pwm_backlight_display_on(device_t dev)272 pwm_backlight_display_on(device_t dev)
273 {
274 struct pwm_backlight_softc * const sc = device_private(dev);
275
276 if (sc->sc_lid_state)
277 pwm_backlight_enable(sc, 1);
278 }
279
280 static void
pwm_backlight_display_off(device_t dev)281 pwm_backlight_display_off(device_t dev)
282 {
283 struct pwm_backlight_softc * const sc = device_private(dev);
284
285 pwm_backlight_enable(sc, 0);
286 }
287
288 static void
pwm_backlight_chassis_lid_open(device_t dev)289 pwm_backlight_chassis_lid_open(device_t dev)
290 {
291 struct pwm_backlight_softc * const sc = device_private(dev);
292
293 sc->sc_lid_state = true;
294
295 pwm_backlight_enable(sc, 1);
296 }
297
298 static void
pwm_backlight_chassis_lid_close(device_t dev)299 pwm_backlight_chassis_lid_close(device_t dev)
300 {
301 struct pwm_backlight_softc * const sc = device_private(dev);
302
303 sc->sc_lid_state = false;
304
305 pwm_backlight_enable(sc, 0);
306 }
307
308 static void
pwm_backlight_display_brightness_up(device_t dev)309 pwm_backlight_display_brightness_up(device_t dev)
310 {
311 struct pwm_backlight_softc * const sc = device_private(dev);
312 u_int n;
313
314 n = pwm_backlight_get(sc);
315 if (n < sc->sc_nlevels - 1)
316 pwm_backlight_set(sc, n + 1, true);
317 }
318
319 static void
pwm_backlight_display_brightness_down(device_t dev)320 pwm_backlight_display_brightness_down(device_t dev)
321 {
322 struct pwm_backlight_softc * const sc = device_private(dev);
323 u_int n;
324
325 n = pwm_backlight_get(sc);
326 if (n > 0)
327 pwm_backlight_set(sc, n - 1, true);
328 }
329
330 static void
pwm_backlight_pmf_init(struct pwm_backlight_softc * sc)331 pwm_backlight_pmf_init(struct pwm_backlight_softc *sc)
332 {
333 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_ON,
334 pwm_backlight_display_on, true);
335 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_OFF,
336 pwm_backlight_display_off, true);
337 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_OPEN,
338 pwm_backlight_chassis_lid_open, true);
339 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_CLOSE,
340 pwm_backlight_chassis_lid_close, true);
341 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_UP,
342 pwm_backlight_display_brightness_up, true);
343 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_DOWN,
344 pwm_backlight_display_brightness_down, true);
345 }
346