1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2016 Michael Zhilin <mizhka@freebsd.org> All rights reserved. 5 * Copyright (c) 2019 Ian Lepore <ian@freebsd.org> 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 AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, 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/* 30 * GPIOTHS - Temp/Humidity sensor over GPIO. 31 * 32 * This is driver for Temperature & Humidity sensor which provides digital 33 * output over single-wire protocol from embedded 8-bit microcontroller. 34 * Note that it uses a custom single-wire protocol, it is not 1-wire(tm). 35 * 36 * This driver supports the following chips: 37 * DHT11: Temp 0c to 50c +-2.0c, Humidity 20% to 90% +-5% 38 * DHT12: Temp -20c to 60c +-0.5c, Humidity 20% to 95% +-5% 39 * DHT21: Temp -40c to 80c +-0.3c, Humidity 0% to 100% +-3% 40 * DHT22: Temp -40c to 80c +-0.3c, Humidity 0% to 100% +-2% 41 * AM2301: Same as DHT21, but also supports i2c interface. 42 * AM2302: Same as DHT22, but also supports i2c interface. 43 * 44 * Temp/Humidity sensor can't be discovered automatically, please specify hints 45 * as part of loader or kernel configuration: 46 * hint.gpioths.0.at="gpiobus0" 47 * hint.gpioths.0.pins=<PIN> 48 * 49 * Or configure via FDT data. 50 */ 51 52#include <sys/param.h> 53#include <sys/kernel.h> 54#include <sys/bus.h> 55#include <sys/gpio.h> 56#include <sys/module.h> 57#include <sys/errno.h> 58#include <sys/systm.h> 59#include <sys/sysctl.h> 60#include <sys/taskqueue.h> 61 62#include <dev/gpio/gpiobusvar.h> 63 64#ifdef FDT 65#include <dev/ofw/ofw_bus.h> 66#include <dev/ofw/ofw_bus_subr.h> 67 68static struct ofw_compat_data compat_data[] = { 69 {"dht11", true}, 70 {NULL, false} 71}; 72OFWBUS_PNP_INFO(compat_data); 73SIMPLEBUS_PNP_INFO(compat_data); 74#endif /* FDT */ 75 76#define PIN_IDX 0 /* Use the first/only configured pin. */ 77 78#define GPIOTHS_POLLTIME 5 /* in seconds */ 79 80#define GPIOTHS_DHT_STARTCYCLE 20000 /* 20ms = 20000us */ 81#define GPIOTHS_DHT_TIMEOUT 1000 /* 1ms = 1000us */ 82#define GPIOTHS_DHT_CYCLES 41 83#define GPIOTHS_DHT_ONEBYTEMASK 0xFF 84 85struct gpioths_softc { 86 device_t dev; 87 gpio_pin_t pin; 88 int temp; 89 int hum; 90 int fails; 91 struct timeout_task task; 92 bool detaching; 93}; 94 95static int 96gpioths_probe(device_t dev) 97{ 98 int rv; 99 100 /* 101 * By default we only bid to attach if specifically added by our parent 102 * (usually via hint.gpioths.#.at=busname). On FDT systems we bid as 103 * the default driver based on being configured in the FDT data. 104 */ 105 rv = BUS_PROBE_NOWILDCARD; 106 107#ifdef FDT 108 if (ofw_bus_status_okay(dev) && 109 ofw_bus_search_compatible(dev, compat_data)->ocd_data) 110 rv = BUS_PROBE_DEFAULT; 111#endif 112 113 device_set_desc(dev, "DHT11/DHT22 Temperature and Humidity Sensor"); 114 115 return (rv); 116} 117 118static int 119gpioths_dht_timeuntil(struct gpioths_softc *sc, bool lev, uint32_t *time) 120{ 121 bool cur_level; 122 int i; 123 124 for (i = 0; i < GPIOTHS_DHT_TIMEOUT; i++) { 125 gpio_pin_is_active(sc->pin, &cur_level); 126 if (cur_level == lev) { 127 if (time != NULL) 128 *time = i; 129 return (0); 130 } 131 DELAY(1); 132 } 133 134 /* Timeout */ 135 return (ETIMEDOUT); 136} 137 138static void 139gpioths_dht_initread(struct gpioths_softc *sc) 140{ 141 142 /* 143 * According to specifications we need to drive the data line low for at 144 * least 20ms then drive it high, to wake up the chip and signal it to 145 * send a measurement. After sending this start signal, we switch the 146 * pin back to input so the device can begin talking to us. 147 */ 148 gpio_pin_setflags(sc->pin, GPIO_PIN_OUTPUT); 149 gpio_pin_set_active(sc->pin, false); 150 pause_sbt("gpioths", ustosbt(GPIOTHS_DHT_STARTCYCLE), C_PREL(2), 0); 151 gpio_pin_set_active(sc->pin, true); 152 gpio_pin_setflags(sc->pin, GPIO_PIN_INPUT); 153} 154 155static int 156gpioths_dht_readbytes(struct gpioths_softc *sc) 157{ 158 uint32_t calibrations[GPIOTHS_DHT_CYCLES]; 159 uint32_t intervals[GPIOTHS_DHT_CYCLES]; 160 uint32_t err, avglen, value; 161 uint8_t crc, calc; 162 int i, negmul, offset, size, tmphi, tmplo; 163 164 gpioths_dht_initread(sc); 165 166 err = gpioths_dht_timeuntil(sc, false, NULL); 167 if (err) { 168 device_printf(sc->dev, "err(START) = %d\n", err); 169 goto error; 170 } 171 172 /* reading - 41 cycles */ 173 for (i = 0; i < GPIOTHS_DHT_CYCLES; i++) { 174 err = gpioths_dht_timeuntil(sc, true, &calibrations[i]); 175 if (err) { 176 device_printf(sc->dev, "err(CAL, %d) = %d\n", i, err); 177 goto error; 178 } 179 err = gpioths_dht_timeuntil(sc, false, &intervals[i]); 180 if (err) { 181 device_printf(sc->dev, "err(INTERVAL, %d) = %d\n", i, err); 182 goto error; 183 } 184 } 185 186 /* Calculate average data calibration cycle length */ 187 avglen = 0; 188 for (i = 1; i < GPIOTHS_DHT_CYCLES; i++) 189 avglen += calibrations[i]; 190 191 avglen = avglen / (GPIOTHS_DHT_CYCLES - 1); 192 193 /* Calculate data */ 194 value = 0; 195 offset = 1; 196 size = sizeof(value) * 8; 197 for (i = offset; i < size + offset; i++) { 198 value <<= 1; 199 if (intervals[i] > avglen) 200 value += 1; 201 } 202 203 /* Calculate CRC */ 204 crc = 0; 205 offset = sizeof(value) * 8 + 1; 206 size = sizeof(crc) * 8; 207 for (i = offset; i < size + offset; i++) { 208 crc <<= 1; 209 if (intervals[i] > avglen) 210 crc += 1; 211 } 212 213 calc = 0; 214 for (i = 0; i < sizeof(value); i++) 215 calc += (value >> (8*i)) & GPIOTHS_DHT_ONEBYTEMASK; 216 217#ifdef GPIOTHS_DEBUG 218 /* Debug bits */ 219 for (i = 0; i < GPIOTHS_DHT_CYCLES; i++) 220 device_printf(sc->dev, "%d: %d %d\n", i, calibrations[i], 221 intervals[i]); 222 223 device_printf(sc->dev, "len=%d, data=%x, crc=%x/%x\n", avglen, value, crc, 224 calc); 225#endif /* GPIOTHS_DEBUG */ 226 227 /* CRC check */ 228 if (calc != crc) { 229 err = -1; 230 goto error; 231 } 232 233 /* 234 * For DHT11/12, the values are split into 8 bits of integer and 8 bits 235 * of fractional tenths. On DHT11 the fraction bytes are always zero. 236 * On DHT12 the sign bit is in the high bit of the fraction byte. 237 * - DHT11: 0HHHHHHH 00000000 00TTTTTT 00000000 238 * - DHT12: 0HHHHHHH 0000hhhh 00TTTTTT s000tttt 239 * 240 * For DHT21/21, the values are are encoded in 16 bits each, with the 241 * temperature sign bit in the high bit. The values are tenths of a 242 * degree C and tenths of a percent RH. 243 * - DHT21: 000000HH HHHHHHHH s00000TT TTTTTTTT 244 * - DHT22: 000000HH HHHHHHHH s00000TT TTTTTTTT 245 * 246 * For all devices, some bits are always zero because of the range of 247 * values supported by the device. 248 * 249 * We figure out how to decode things based on the high byte of the 250 * humidity. A DHT21/22 cannot report a value greater than 3 in 251 * the upper bits of its 16-bit humidity. A DHT11/12 should not report 252 * a value lower than 20. To allow for the possibility that a device 253 * could report a value slightly out of its sensitivity range, we split 254 * the difference and say if the value is greater than 10 it must be a 255 * DHT11/12 (that would be a humidity over 256% on a DHT21/22). 256 */ 257#define DK_OFFSET 2731 /* Offset between K and C, in decikelvins. */ 258 if ((value >> 24) > 10) { 259 /* DHT11 or DHT12 */ 260 tmphi = (value >> 8) & 0x3f; 261 tmplo = value & 0x0f; 262 negmul = (value & 0x80) ? -1 : 1; 263 sc->temp = DK_OFFSET + (negmul * (tmphi * 10 + tmplo)); 264 sc->hum = (value >> 24) & 0x7f; 265 } else { 266 /* DHT21 or DHT22 */ 267 negmul = (value & 0x8000) ? -1 : 1; 268 sc->temp = DK_OFFSET + (negmul * (value & 0x03ff)); 269 sc->hum = ((value >> 16) & 0x03ff) / 10; 270 } 271 272 sc->fails = 0; 273 274#ifdef GPIOTHS_DEBUG 275 /* Debug bits */ 276 device_printf(dev, "fails=%d, temp=%d, hum=%d\n", sc->fails, 277 sc->temp, sc->hum); 278#endif /* GPIOTHS_DEBUG */ 279 280 return (0); 281error: 282 sc->fails++; 283 return (err); 284} 285 286static void 287gpioths_poll(void *arg, int pending __unused) 288{ 289 struct gpioths_softc *sc; 290 291 sc = (struct gpioths_softc *)arg; 292 293 gpioths_dht_readbytes(sc); 294 if (!sc->detaching) 295 taskqueue_enqueue_timeout_sbt(taskqueue_thread, &sc->task, 296 GPIOTHS_POLLTIME * SBT_1S, 0, C_PREL(3)); 297} 298 299static int 300gpioths_attach(device_t dev) 301{ 302 struct gpioths_softc *sc; 303 struct sysctl_ctx_list *ctx; 304 struct sysctl_oid *tree; 305 int err; 306 307 sc = device_get_softc(dev); 308 ctx = device_get_sysctl_ctx(dev); 309 tree = device_get_sysctl_tree(dev); 310 311 sc->dev = dev; 312 313 TIMEOUT_TASK_INIT(taskqueue_thread, &sc->task, 0, gpioths_poll, sc); 314 315#ifdef FDT 316 /* Try to configure our pin from fdt data on fdt-based systems. */ 317 err = gpio_pin_get_by_ofw_idx(dev, ofw_bus_get_node(dev), PIN_IDX, 318 &sc->pin); 319#else 320 err = ENOENT; 321#endif 322 /* 323 * If we didn't get configured by fdt data and our parent is gpiobus, 324 * see if we can be configured by the bus (allows hinted attachment even 325 * on fdt-based systems). 326 */ 327 if (err != 0 && 328 strcmp("gpiobus", device_get_name(device_get_parent(dev))) == 0) 329 err = gpio_pin_get_by_child_index(dev, PIN_IDX, &sc->pin); 330 331 /* If we didn't get configured by either method, whine and punt. */ 332 if (err != 0) { 333 device_printf(sc->dev, 334 "cannot acquire gpio pin (config error)\n"); 335 return (err); 336 } 337 338 /* 339 * Ensure we have control of our pin, and preset the data line to its 340 * idle condition (high). Leave the line in input mode, relying on the 341 * external pullup to keep the line high while idle. 342 */ 343 err = gpio_pin_setflags(sc->pin, GPIO_PIN_OUTPUT); 344 if (err != 0) { 345 device_printf(dev, "gpio_pin_setflags(OUT) = %d\n", err); 346 return (err); 347 } 348 err = gpio_pin_set_active(sc->pin, true); 349 if (err != 0) { 350 device_printf(dev, "gpio_pin_set_active(false) = %d\n", err); 351 return (err); 352 } 353 err = gpio_pin_setflags(sc->pin, GPIO_PIN_INPUT); 354 if (err != 0) { 355 device_printf(dev, "gpio_pin_setflags(IN) = %d\n", err); 356 return (err); 357 } 358 359 /* 360 * Do an initial read so we have correct values for reporting before 361 * registering the sysctls that can access those values. This also 362 * schedules the periodic polling the driver does every few seconds to 363 * update the sysctl variables. 364 */ 365 gpioths_poll(sc, 0); 366 367 sysctl_add_oid(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "temperature", \ 368 CTLFLAG_RD | CTLTYPE_INT | CTLFLAG_MPSAFE, 369 &sc->temp, 0, sysctl_handle_int, "IK", "temperature", NULL); 370 371 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "humidity", 372 CTLFLAG_RD, &sc->hum, 0, "relative humidity(%)"); 373 374 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "fails", 375 CTLFLAG_RD, &sc->fails, 0, 376 "failures since last successful read"); 377 378 return (0); 379} 380 381static int 382gpioths_detach(device_t dev) 383{ 384 struct gpioths_softc *sc; 385 386 sc = device_get_softc(dev); 387 gpio_pin_release(sc->pin); 388 sc->detaching = true; 389 while (taskqueue_cancel_timeout(taskqueue_thread, &sc->task, NULL) != 0) 390 taskqueue_drain_timeout(taskqueue_thread, &sc->task); 391 392 return (0); 393} 394 395/* Driver bits */ 396static device_method_t gpioths_methods[] = { 397 /* Device interface */ 398 DEVMETHOD(device_probe, gpioths_probe), 399 DEVMETHOD(device_attach, gpioths_attach), 400 DEVMETHOD(device_detach, gpioths_detach), 401 402 DEVMETHOD_END 403}; 404 405DEFINE_CLASS_0(gpioths, gpioths_driver, gpioths_methods, sizeof(struct gpioths_softc)); 406 407#ifdef FDT 408DRIVER_MODULE(gpioths, simplebus, gpioths_driver, 0, 0); 409#endif 410 411DRIVER_MODULE(gpioths, gpiobus, gpioths_driver, 0, 0); 412MODULE_DEPEND(gpioths, gpiobus, 1, 1, 1); 413