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 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 = 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 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 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 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 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 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 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 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 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 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 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 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 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