pwm_backlight.c revision 1.9
1 /* $NetBSD: pwm_backlight.c,v 1.9 2021/01/27 03:10:21 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2018 Jared McNeill <jmcneill (at) 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 1.9 2021/01/27 03:10:21 thorpej 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 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 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; 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 (len < 4) { 111 aprint_error(": couldn't get 'brightness-levels' property\n"); 112 return; 113 } 114 sc->sc_levels = kmem_alloc(len, KM_SLEEP); 115 sc->sc_nlevels = len / 4; 116 for (n = 0; n < sc->sc_nlevels; n++) 117 sc->sc_levels[n] = be32toh(levels[n]); 118 119 aprint_naive("\n"); 120 aprint_normal(": PWM Backlight"); 121 if (sc->sc_nlevels > 1) { 122 aprint_normal(", %u-%u (%u steps)", 123 sc->sc_levels[0], sc->sc_levels[sc->sc_nlevels - 1], 124 sc->sc_nlevels); 125 } 126 aprint_normal("\n"); 127 128 sc->sc_lid_state = true; 129 130 if (of_getprop_uint32(phandle, "default-brightness-level", &default_level) == 0) { 131 /* set the default level now */ 132 pwm_backlight_set(sc, default_level, true); 133 } 134 135 sc->sc_curlevel = pwm_backlight_get(sc); 136 137 pwm_backlight_sysctl_init(sc); 138 pwm_backlight_pmf_init(sc); 139 } 140 141 static void 142 pwm_backlight_set(struct pwm_backlight_softc *sc, u_int index, bool set_cur) 143 { 144 struct pwm_config conf; 145 146 if (index >= sc->sc_nlevels) 147 return; 148 149 KASSERT(sc->sc_levels[sc->sc_nlevels - 1] != 0); 150 aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n", 151 (100 * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]); 152 153 pwm_disable(sc->sc_pwm); 154 pwm_get_config(sc->sc_pwm, &conf); 155 conf.duty_cycle = (conf.period * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]; 156 pwm_set_config(sc->sc_pwm, &conf); 157 pwm_enable(sc->sc_pwm); 158 159 if (set_cur) 160 sc->sc_curlevel = index; 161 } 162 163 static u_int 164 pwm_backlight_get(struct pwm_backlight_softc *sc) 165 { 166 struct pwm_config conf; 167 u_int raw_val, n; 168 169 pwm_get_config(sc->sc_pwm, &conf); 170 171 raw_val = (conf.duty_cycle * sc->sc_levels[sc->sc_nlevels - 1]) / conf.period; 172 173 /* Return the closest setting to the raw value */ 174 for (n = 0; n < sc->sc_nlevels; n++) { 175 if (raw_val <= sc->sc_levels[n]) 176 break; 177 } 178 return n; 179 } 180 181 static int 182 pwm_backlight_sysctl_helper(SYSCTLFN_ARGS) 183 { 184 struct pwm_backlight_softc * const sc = rnode->sysctl_data; 185 struct sysctlnode node; 186 int error; 187 u_int level, n; 188 189 node = *rnode; 190 node.sysctl_data = &level; 191 192 n = pwm_backlight_get(sc); 193 level = sc->sc_levels[n]; 194 195 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 196 if (error || newp == NULL) 197 return error; 198 199 for (n = 0; n < sc->sc_nlevels; n++) { 200 if (sc->sc_levels[n] == level) { 201 pwm_backlight_set(sc, n, true); 202 return 0; 203 } 204 } 205 206 return EINVAL; 207 } 208 209 static void 210 pwm_backlight_sysctl_init(struct pwm_backlight_softc *sc) 211 { 212 const struct sysctlnode *node, *pwmnode; 213 struct sysctllog *log = NULL; 214 int error; 215 u_int n; 216 217 sc->sc_levelstr = kmem_zalloc(strlen("XXXXX ") * sc->sc_nlevels, KM_SLEEP); 218 for (n = 0; n < sc->sc_nlevels; n++) { 219 char buf[7]; 220 snprintf(buf, sizeof(buf), n ? " %u" : "%u", sc->sc_levels[n]); 221 strcat(sc->sc_levelstr, buf); 222 } 223 224 error = sysctl_createv(&log, 0, NULL, &node, 225 CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL, 226 NULL, 0, NULL, 0, CTL_HW, CTL_EOL); 227 if (error) 228 goto failed; 229 230 error = sysctl_createv(&log, 0, &node, &pwmnode, 231 0, CTLTYPE_NODE, device_xname(sc->sc_dev), NULL, 232 NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL); 233 if (error) 234 goto failed; 235 236 error = sysctl_createv(&log, 0, &pwmnode, NULL, 237 0, CTLTYPE_STRING, "levels", NULL, 238 NULL, 0, sc->sc_levelstr, 0, 239 CTL_CREATE, CTL_EOL); 240 if (error) 241 goto failed; 242 243 error = sysctl_createv(&log, 0, &pwmnode, NULL, 244 CTLFLAG_READWRITE, CTLTYPE_INT, "level", NULL, 245 pwm_backlight_sysctl_helper, 0, (void *)sc, 0, 246 CTL_CREATE, CTL_EOL); 247 if (error) 248 goto failed; 249 250 return; 251 252 failed: 253 aprint_error_dev(sc->sc_dev, "couldn't create sysctl nodes: %d\n", error); 254 sysctl_teardown(&log); 255 } 256 257 static void 258 pwm_backlight_enable(struct pwm_backlight_softc *sc, int enable) 259 { 260 if (sc->sc_pin) 261 fdtbus_gpio_write(sc->sc_pin, enable); 262 else 263 pwm_backlight_set(sc, enable ? sc->sc_curlevel : 0, false); 264 } 265 266 static void 267 pwm_backlight_display_on(device_t dev) 268 { 269 struct pwm_backlight_softc * const sc = device_private(dev); 270 271 if (sc->sc_lid_state) 272 pwm_backlight_enable(sc, 1); 273 } 274 275 static void 276 pwm_backlight_display_off(device_t dev) 277 { 278 struct pwm_backlight_softc * const sc = device_private(dev); 279 280 pwm_backlight_enable(sc, 0); 281 } 282 283 static void 284 pwm_backlight_chassis_lid_open(device_t dev) 285 { 286 struct pwm_backlight_softc * const sc = device_private(dev); 287 288 sc->sc_lid_state = true; 289 290 pwm_backlight_enable(sc, 1); 291 } 292 293 static void 294 pwm_backlight_chassis_lid_close(device_t dev) 295 { 296 struct pwm_backlight_softc * const sc = device_private(dev); 297 298 sc->sc_lid_state = false; 299 300 pwm_backlight_enable(sc, 0); 301 } 302 303 static void 304 pwm_backlight_display_brightness_up(device_t dev) 305 { 306 struct pwm_backlight_softc * const sc = device_private(dev); 307 u_int n; 308 309 n = pwm_backlight_get(sc); 310 if (n < sc->sc_nlevels - 1) 311 pwm_backlight_set(sc, n + 1, true); 312 } 313 314 static void 315 pwm_backlight_display_brightness_down(device_t dev) 316 { 317 struct pwm_backlight_softc * const sc = device_private(dev); 318 u_int n; 319 320 n = pwm_backlight_get(sc); 321 if (n > 0) 322 pwm_backlight_set(sc, n - 1, true); 323 } 324 325 static void 326 pwm_backlight_pmf_init(struct pwm_backlight_softc *sc) 327 { 328 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_ON, 329 pwm_backlight_display_on, true); 330 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_OFF, 331 pwm_backlight_display_off, true); 332 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_OPEN, 333 pwm_backlight_chassis_lid_open, true); 334 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_CLOSE, 335 pwm_backlight_chassis_lid_close, true); 336 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_UP, 337 pwm_backlight_display_brightness_up, true); 338 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_DOWN, 339 pwm_backlight_display_brightness_down, true); 340 } 341
Indexes created Mon Sep 29 21:09:56 GMT 2025