pwm_backlight.c revision 1.4
1 /* $NetBSD: pwm_backlight.c,v 1.4 2018/05/10 13:11:21 jmcneill 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 1.4 2018/05/10 13:11:21 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 52 char *sc_levelstr; 53 54 bool sc_lid_state; 55 }; 56 57 static int pwm_backlight_match(device_t, cfdata_t, void *); 58 static void pwm_backlight_attach(device_t, device_t, void *); 59 60 static void pwm_backlight_sysctl_init(struct pwm_backlight_softc *); 61 static void pwm_backlight_pmf_init(struct pwm_backlight_softc *); 62 static void pwm_backlight_set(struct pwm_backlight_softc *, u_int); 63 static u_int pwm_backlight_get(struct pwm_backlight_softc *); 64 65 static const char *compatible[] = { 66 "pwm-backlight", 67 NULL 68 }; 69 70 CFATTACH_DECL_NEW(pwmbacklight, sizeof(struct pwm_backlight_softc), 71 pwm_backlight_match, pwm_backlight_attach, NULL, NULL); 72 73 static int 74 pwm_backlight_match(device_t parent, cfdata_t cf, void *aux) 75 { 76 struct fdt_attach_args * const faa = aux; 77 78 return of_match_compatible(faa->faa_phandle, compatible); 79 } 80 81 static void 82 pwm_backlight_attach(device_t parent, device_t self, void *aux) 83 { 84 struct pwm_backlight_softc * const sc = device_private(self); 85 struct fdt_attach_args * const faa = aux; 86 const int phandle = faa->faa_phandle; 87 const u_int *levels; 88 u_int default_level; 89 u_int n; 90 int len; 91 92 sc->sc_dev = self; 93 sc->sc_pwm = fdtbus_pwm_acquire(phandle, "pwms"); 94 if (sc->sc_pwm == NULL) { 95 aprint_error(": couldn't acquire pwm\n"); 96 return; 97 } 98 if (of_hasprop(phandle, "enable-gpios")) { 99 sc->sc_pin = fdtbus_gpio_acquire(phandle, "enable-gpios", 100 GPIO_PIN_OUTPUT); 101 if (!sc->sc_pin) { 102 aprint_error(": couldn't acquire enable gpio\n"); 103 return; 104 } 105 fdtbus_gpio_write(sc->sc_pin, 1); 106 } 107 108 levels = fdtbus_get_prop(phandle, "brightness-levels", &len); 109 if (len < 4) { 110 aprint_error(": couldn't get 'brightness-levels' property\n"); 111 return; 112 } 113 sc->sc_levels = kmem_alloc(len, KM_SLEEP); 114 sc->sc_nlevels = len / 4; 115 for (n = 0; n < sc->sc_nlevels; n++) 116 sc->sc_levels[n] = be32toh(levels[n]); 117 118 aprint_naive("\n"); 119 aprint_normal(": PWM Backlight"); 120 aprint_verbose(" <"); 121 for (n = 0; n < sc->sc_nlevels; n++) { 122 aprint_verbose("%s%u", n ? " " : "", sc->sc_levels[n]); 123 } 124 aprint_verbose(">"); 125 aprint_normal("\n"); 126 127 sc->sc_lid_state = true; 128 129 if (of_getprop_uint32(phandle, "default-brightness-level", &default_level) == 0) { 130 /* set the default level now */ 131 pwm_backlight_set(sc, default_level); 132 } 133 134 pwm_backlight_sysctl_init(sc); 135 pwm_backlight_pmf_init(sc); 136 } 137 138 static void 139 pwm_backlight_set(struct pwm_backlight_softc *sc, u_int index) 140 { 141 struct pwm_config conf; 142 143 if (index >= sc->sc_nlevels) 144 return; 145 146 aprint_debug_dev(sc->sc_dev, "set duty cycle to %u%%\n", sc->sc_levels[index]); 147 148 pwm_disable(sc->sc_pwm); 149 pwm_get_config(sc->sc_pwm, &conf); 150 conf.duty_cycle = (conf.period * sc->sc_levels[index]) / sc->sc_levels[sc->sc_nlevels - 1]; 151 pwm_set_config(sc->sc_pwm, &conf); 152 pwm_enable(sc->sc_pwm); 153 } 154 155 static u_int 156 pwm_backlight_get(struct pwm_backlight_softc *sc) 157 { 158 struct pwm_config conf; 159 u_int raw_val, n; 160 161 pwm_get_config(sc->sc_pwm, &conf); 162 163 raw_val = (conf.duty_cycle * sc->sc_levels[sc->sc_nlevels - 1]) / conf.period; 164 165 /* Return the closest setting to the raw value */ 166 for (n = 0; n < sc->sc_nlevels; n++) { 167 if (raw_val <= sc->sc_levels[n]) 168 break; 169 } 170 return n; 171 } 172 173 static int 174 pwm_backlight_sysctl_helper(SYSCTLFN_ARGS) 175 { 176 struct pwm_backlight_softc * const sc = rnode->sysctl_data; 177 struct sysctlnode node; 178 int error; 179 u_int level, n; 180 181 node = *rnode; 182 node.sysctl_data = &level; 183 184 n = pwm_backlight_get(sc); 185 level = sc->sc_levels[n]; 186 187 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 188 if (error || newp == NULL) 189 return error; 190 191 for (n = 0; n < sc->sc_nlevels; n++) { 192 if (sc->sc_levels[n] == level) { 193 pwm_backlight_set(sc, n); 194 return 0; 195 } 196 } 197 198 return EINVAL; 199 } 200 201 static void 202 pwm_backlight_sysctl_init(struct pwm_backlight_softc *sc) 203 { 204 const struct sysctlnode *node, *pwmnode; 205 struct sysctllog *log = NULL; 206 int error; 207 u_int n; 208 209 sc->sc_levelstr = kmem_zalloc(strlen("XXXXX ") * sc->sc_nlevels, KM_SLEEP); 210 for (n = 0; n < sc->sc_nlevels; n++) { 211 char buf[7]; 212 snprintf(buf, sizeof(buf), n ? " %u" : "%u", sc->sc_levels[n]); 213 strcat(sc->sc_levelstr, buf); 214 } 215 216 error = sysctl_createv(&log, 0, NULL, &node, 217 CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL, 218 NULL, 0, NULL, 0, CTL_HW, CTL_EOL); 219 if (error) 220 goto failed; 221 222 error = sysctl_createv(&log, 0, &node, &pwmnode, 223 0, CTLTYPE_NODE, device_xname(sc->sc_dev), NULL, 224 NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL); 225 if (error) 226 goto failed; 227 228 error = sysctl_createv(&log, 0, &pwmnode, NULL, 229 0, CTLTYPE_STRING, "levels", NULL, 230 NULL, 0, sc->sc_levelstr, 0, 231 CTL_CREATE, CTL_EOL); 232 if (error) 233 goto failed; 234 235 error = sysctl_createv(&log, 0, &pwmnode, NULL, 236 CTLFLAG_READWRITE, CTLTYPE_INT, "level", NULL, 237 pwm_backlight_sysctl_helper, 0, (void *)sc, 0, 238 CTL_CREATE, CTL_EOL); 239 if (error) 240 goto failed; 241 242 return; 243 244 failed: 245 aprint_error_dev(sc->sc_dev, "couldn't create sysctl nodes: %d\n", error); 246 sysctl_teardown(&log); 247 } 248 249 static void 250 pwm_backlight_display_on(device_t dev) 251 { 252 struct pwm_backlight_softc * const sc = device_private(dev); 253 254 if (sc->sc_pin && sc->sc_lid_state) 255 fdtbus_gpio_write(sc->sc_pin, 1); 256 } 257 258 static void 259 pwm_backlight_display_off(device_t dev) 260 { 261 struct pwm_backlight_softc * const sc = device_private(dev); 262 263 if (sc->sc_pin) 264 fdtbus_gpio_write(sc->sc_pin, 0); 265 } 266 267 static void 268 pwm_backlight_chassis_lid_open(device_t dev) 269 { 270 struct pwm_backlight_softc * const sc = device_private(dev); 271 272 sc->sc_lid_state = true; 273 274 if (sc->sc_pin) 275 fdtbus_gpio_write(sc->sc_pin, 1); 276 } 277 278 static void 279 pwm_backlight_chassis_lid_close(device_t dev) 280 { 281 struct pwm_backlight_softc * const sc = device_private(dev); 282 283 sc->sc_lid_state = false; 284 285 if (sc->sc_pin) 286 fdtbus_gpio_write(sc->sc_pin, 0); 287 } 288 289 static void 290 pwm_backlight_display_brightness_up(device_t dev) 291 { 292 struct pwm_backlight_softc * const sc = device_private(dev); 293 u_int n; 294 295 n = pwm_backlight_get(sc); 296 if (n < sc->sc_nlevels - 1) 297 pwm_backlight_set(sc, n + 1); 298 } 299 300 static void 301 pwm_backlight_display_brightness_down(device_t dev) 302 { 303 struct pwm_backlight_softc * const sc = device_private(dev); 304 u_int n; 305 306 n = pwm_backlight_get(sc); 307 if (n > 0) 308 pwm_backlight_set(sc, n - 1); 309 } 310 311 static void 312 pwm_backlight_pmf_init(struct pwm_backlight_softc *sc) 313 { 314 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_ON, 315 pwm_backlight_display_on, true); 316 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_OFF, 317 pwm_backlight_display_off, true); 318 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_OPEN, 319 pwm_backlight_chassis_lid_open, true); 320 pmf_event_register(sc->sc_dev, PMFE_CHASSIS_LID_CLOSE, 321 pwm_backlight_chassis_lid_close, true); 322 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_UP, 323 pwm_backlight_display_brightness_up, true); 324 pmf_event_register(sc->sc_dev, PMFE_DISPLAY_BRIGHTNESS_DOWN, 325 pwm_backlight_display_brightness_down, true); 326 } 327
Indexes created Mon Sep 29 21:09:56 GMT 2025