sys/dev/pwm/pwm_backlight.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2020 Emmanuel Vadot <manu@FreeBSD.org>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD$
  28  */
  29
  30 #include <sys/cdefs.h>
  31 __FBSDID("$FreeBSD$");
  32
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/bio.h>
  37 #include <sys/bus.h>
  38 #include <sys/conf.h>
  39 #include <sys/endian.h>
  40 #include <sys/fcntl.h>
  41 #include <sys/ioccom.h>
  42 #include <sys/kernel.h>
  43 #include <sys/kthread.h>
  44 #include <sys/lock.h>
  45 #include <sys/malloc.h>
  46 #include <sys/module.h>
  47 #include <sys/mutex.h>
  48 #include <sys/priv.h>
  49 #include <sys/slicer.h>
  50 #include <sys/sysctl.h>
  51 #include <sys/time.h>
  52
  53 #include <dev/ofw/ofw_bus.h>
  54 #include <dev/ofw/ofw_bus_subr.h>
  55
  56 #include <dev/extres/regulator/regulator.h>
  57
  58 #include <dev/backlight/backlight.h>
  59
  60 #include <dev/pwm/ofw_pwm.h>
  61
  62 #include "backlight_if.h"
  63 #include "pwmbus_if.h"
  64
  65 struct pwm_backlight_softc {
  66         device_t        pwmdev;
  67         struct cdev     *cdev;
  68
  69         pwm_channel_t   channel;
  70         uint32_t        *levels;
  71         ssize_t         nlevels;
  72         int             default_level;
  73         ssize_t         current_level;
  74
  75         regulator_t     power_supply;
  76         uint64_t        period;
  77         uint64_t        duty;
  78         bool            enabled;
  79 };
  80
  81 static int pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent);
  82
  83 static struct ofw_compat_data compat_data[] = {
  84         { "pwm-backlight",      1 },
  85         { NULL,                 0 }
  86 };
  87
  88 static int
  89 pwm_backlight_probe(device_t dev)
  90 {
  91
  92         if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
  93                 return (ENXIO);
  94
  95         device_set_desc(dev, "PWM Backlight");
  96         return (BUS_PROBE_DEFAULT);
  97 }
  98
  99 static int
 100 pwm_backlight_attach(device_t dev)
 101 {
 102         struct pwm_backlight_softc *sc;
 103         phandle_t node;
 104         int rv;
 105
 106         sc = device_get_softc(dev);
 107         node = ofw_bus_get_node(dev);
 108
 109         rv = pwm_get_by_ofw_propidx(dev, node, "pwms", 0, &sc->channel);
 110         if (rv != 0) {
 111                 device_printf(dev, "Cannot map pwm channel %d\n", rv);
 112                 return (ENXIO);
 113         }
 114
 115         if (regulator_get_by_ofw_property(dev, 0, "power-supply",
 116             &sc->power_supply) != 0) {
 117                 device_printf(dev, "No power-supply property\n");
 118                 return (ENXIO);
 119         }
 120
 121         if (OF_hasprop(node, "brightness-levels")) {
 122                 sc->nlevels = OF_getencprop_alloc(node, "brightness-levels",
 123                     (void **)&sc->levels);
 124                 if (sc->nlevels <= 0) {
 125                         device_printf(dev, "Cannot parse brightness levels\n");
 126                         return (ENXIO);
 127                 }
 128                 sc->nlevels /= sizeof(uint32_t);
 129
 130                 if (OF_getencprop(node, "default-brightness-level",
 131                     &sc->default_level, sizeof(uint32_t)) <= 0) {
 132                         device_printf(dev, "No default-brightness-level while brightness-levels is specified\n");
 133                         return (ENXIO);
 134                 } else {
 135                         if (sc->default_level > sc->nlevels) {
 136                                 device_printf(dev, "default-brightness-level isn't present in brightness-levels range\n");
 137                                 return (ENXIO);
 138                         }
 139                         sc->channel->duty = sc->channel->period * sc->levels[sc->default_level] / 100;
 140                 }
 141
 142                 if (bootverbose) {
 143                         device_printf(dev, "Number of levels: %zd\n", sc->nlevels);
 144                         device_printf(dev, "Configured period time: %ju\n", (uintmax_t)sc->channel->period);
 145                         device_printf(dev, "Default duty cycle: %ju\n", (uintmax_t)sc->channel->duty);
 146                 }
 147         } else {
 148                 /* Get the current backlight level */
 149                 PWMBUS_CHANNEL_GET_CONFIG(sc->channel->dev,
 150                     sc->channel->channel,
 151                     (unsigned int *)&sc->channel->period,
 152                     (unsigned int *)&sc->channel->duty);
 153                 if (sc->channel->duty > sc->channel->period)
 154                         sc->channel->duty = sc->channel->period;
 155                 if (bootverbose) {
 156                         device_printf(dev, "Configured period time: %ju\n", (uintmax_t)sc->channel->period);
 157                         device_printf(dev, "Default duty cycle: %ju\n", (uintmax_t)sc->channel->duty);
 158                 }
 159         }
 160
 161         regulator_enable(sc->power_supply);
 162         sc->channel->enabled = true;
 163         PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
 164             sc->channel->period, sc->channel->duty);
 165         PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
 166             sc->channel->enabled);
 167
 168         sc->current_level = pwm_backlight_find_level_per_percent(sc,
 169             sc->channel->period / sc->channel->duty);
 170         sc->cdev = backlight_register("pwm_backlight", dev);
 171         if (sc->cdev == NULL)
 172                 device_printf(dev, "Cannot register as a backlight\n");
 173
 174         return (0);
 175 }
 176
 177 static int
 178 pwm_backlight_detach(device_t dev)
 179 {
 180         struct pwm_backlight_softc *sc;
 181
 182         sc = device_get_softc(dev);
 183         if (sc->nlevels > 0)
 184                 OF_prop_free(sc->levels);
 185         regulator_disable(sc->power_supply);
 186         backlight_destroy(sc->cdev);
 187         return (0);
 188 }
 189
 190 static int
 191 pwm_backlight_find_level_per_percent(struct pwm_backlight_softc *sc, int percent)
 192 {
 193         int i;
 194         int diff;
 195
 196         if (percent < 0 || percent > 100)
 197                 return (-1);
 198
 199         for (i = 0, diff = 0; i < sc->nlevels; i++) {
 200                 if (sc->levels[i] == percent)
 201                         return (i);
 202                 else if (sc->levels[i] < percent)
 203                         diff = percent - sc->levels[i];
 204                 else {
 205                         if (diff < abs((percent - sc->levels[i])))
 206                                 return (i - 1);
 207                         else
 208                                 return (i);
 209                 }
 210         }
 211
 212         return (-1);
 213 }
 214
 215 static int
 216 pwm_backlight_update_status(device_t dev, struct backlight_props *props)
 217 {
 218         struct pwm_backlight_softc *sc;
 219         int reg_status;
 220         int error;
 221
 222         sc = device_get_softc(dev);
 223
 224         if (sc->nlevels != 0) {
 225                 error = pwm_backlight_find_level_per_percent(sc,
 226                     props->brightness);
 227                 if (error < 0)
 228                         return (ERANGE);
 229                 sc->current_level = error;
 230                 sc->channel->duty = sc->channel->period *
 231                         sc->levels[sc->current_level] / 100;
 232         } else {
 233                 if (props->brightness > 100 || props->brightness < 0)
 234                         return (ERANGE);
 235                 sc->channel->duty = sc->channel->period *
 236                         props->brightness / 100;
 237         }
 238         sc->channel->enabled = true;
 239         PWMBUS_CHANNEL_CONFIG(sc->channel->dev, sc->channel->channel,
 240             sc->channel->period, sc->channel->duty);
 241         PWMBUS_CHANNEL_ENABLE(sc->channel->dev, sc->channel->channel,
 242             sc->channel->enabled);
 243         error = regulator_status(sc->power_supply, &reg_status);
 244         if (error != 0)
 245                 device_printf(dev,
 246                     "Cannot get power-supply status: %d\n", error);
 247         else {
 248                 if (props->brightness > 0) {
 249                         if (reg_status != REGULATOR_STATUS_ENABLED)
 250                                 regulator_enable(sc->power_supply);
 251                 } else {
 252                         if (reg_status == REGULATOR_STATUS_ENABLED)
 253                                 regulator_disable(sc->power_supply);
 254                 }
 255         }
 256
 257         return (0);
 258 }
 259
 260 static int
 261 pwm_backlight_get_status(device_t dev, struct backlight_props *props)
 262 {
 263         struct pwm_backlight_softc *sc;
 264         int i;
 265
 266         sc = device_get_softc(dev);
 267
 268         if (sc->nlevels != 0) {
 269                 props->brightness = sc->levels[sc->current_level];
 270                 props->nlevels = sc->nlevels;
 271                 for (i = 0; i < sc->nlevels; i++)
 272                         props->levels[i] = sc->levels[i];
 273         } else {
 274                 props->brightness = sc->channel->duty * 100 / sc->channel->period;
 275                 props->nlevels = 0;
 276         }
 277         return (0);
 278 }
 279
 280 static int
 281 pwm_backlight_get_info(device_t dev, struct backlight_info *info)
 282 {
 283
 284         info->type = BACKLIGHT_TYPE_PANEL;
 285         strlcpy(info->name, "pwm-backlight", BACKLIGHTMAXNAMELENGTH);
 286         return (0);
 287 }
 288
 289 static device_method_t pwm_backlight_methods[] = {
 290         /* device_if */
 291         DEVMETHOD(device_probe, pwm_backlight_probe),
 292         DEVMETHOD(device_attach, pwm_backlight_attach),
 293         DEVMETHOD(device_detach, pwm_backlight_detach),
 294
 295         /* backlight interface */
 296         DEVMETHOD(backlight_update_status, pwm_backlight_update_status),
 297         DEVMETHOD(backlight_get_status, pwm_backlight_get_status),
 298         DEVMETHOD(backlight_get_info, pwm_backlight_get_info),
 299         DEVMETHOD_END
 300 };
 301
 302 driver_t pwm_backlight_driver = {
 303         "pwm_backlight",
 304         pwm_backlight_methods,
 305         sizeof(struct pwm_backlight_softc),
 306 };
 307 devclass_t pwm_backlight_devclass;
 308
 309 DRIVER_MODULE(pwm_backlight, simplebus, pwm_backlight_driver,
 310     pwm_backlight_devclass, 0, 0);
 311 OFWBUS_PNP_INFO(compat_data);