/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2016 Michael Zhilin All rights reserved. * Copyright (c) 2019 Ian Lepore * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * GPIOTHS - Temp/Humidity sensor over GPIO. * * This is driver for Temperature & Humidity sensor which provides digital * output over single-wire protocol from embedded 8-bit microcontroller. * Note that it uses a custom single-wire protocol, it is not 1-wire(tm). * * This driver supports the following chips: * DHT11: Temp 0c to 50c +-2.0c, Humidity 20% to 90% +-5% * DHT12: Temp -20c to 60c +-0.5c, Humidity 20% to 95% +-5% * DHT21: Temp -40c to 80c +-0.3c, Humidity 0% to 100% +-3% * DHT22: Temp -40c to 80c +-0.3c, Humidity 0% to 100% +-2% * AM2301: Same as DHT21, but also supports i2c interface. * AM2302: Same as DHT22, but also supports i2c interface. * * Temp/Humidity sensor can't be discovered automatically, please specify hints * as part of loader or kernel configuration: * hint.gpioths.0.at="gpiobus0" * hint.gpioths.0.pins= * * Or configure via FDT data. */ #include #include #include #include #include #include #include #include #include #include #include #ifdef FDT #include #include static struct ofw_compat_data compat_data[] = { {"dht11", true}, {NULL, false} }; OFWBUS_PNP_INFO(compat_data); SIMPLEBUS_PNP_INFO(compat_data); #endif /* FDT */ #define PIN_IDX 0 /* Use the first/only configured pin. */ #define GPIOTHS_POLLTIME 5 /* in seconds */ #define GPIOTHS_DHT_STARTCYCLE 20000 /* 20ms = 20000us */ #define GPIOTHS_DHT_TIMEOUT 1000 /* 1ms = 1000us */ #define GPIOTHS_DHT_CYCLES 41 #define GPIOTHS_DHT_ONEBYTEMASK 0xFF struct gpioths_softc { device_t dev; gpio_pin_t pin; int temp; int hum; int fails; struct timeout_task task; bool detaching; }; static int gpioths_probe(device_t dev) { int rv; /* * By default we only bid to attach if specifically added by our parent * (usually via hint.gpioths.#.at=busname). On FDT systems we bid as * the default driver based on being configured in the FDT data. */ rv = BUS_PROBE_NOWILDCARD; #ifdef FDT if (ofw_bus_status_okay(dev) && ofw_bus_search_compatible(dev, compat_data)->ocd_data) rv = BUS_PROBE_DEFAULT; #endif device_set_desc(dev, "DHT11/DHT22 Temperature and Humidity Sensor"); return (rv); } static int gpioths_dht_timeuntil(struct gpioths_softc *sc, bool lev, uint32_t *time) { bool cur_level; int i; for (i = 0; i < GPIOTHS_DHT_TIMEOUT; i++) { gpio_pin_is_active(sc->pin, &cur_level); if (cur_level == lev) { if (time != NULL) *time = i; return (0); } DELAY(1); } /* Timeout */ return (ETIMEDOUT); } static void gpioths_dht_initread(struct gpioths_softc *sc) { /* * According to specifications we need to drive the data line low for at * least 20ms then drive it high, to wake up the chip and signal it to * send a measurement. After sending this start signal, we switch the * pin back to input so the device can begin talking to us. */ gpio_pin_setflags(sc->pin, GPIO_PIN_OUTPUT); gpio_pin_set_active(sc->pin, false); pause_sbt("gpioths", ustosbt(GPIOTHS_DHT_STARTCYCLE), C_PREL(2), 0); gpio_pin_set_active(sc->pin, true); gpio_pin_setflags(sc->pin, GPIO_PIN_INPUT); } static int gpioths_dht_readbytes(struct gpioths_softc *sc) { uint32_t calibrations[GPIOTHS_DHT_CYCLES]; uint32_t intervals[GPIOTHS_DHT_CYCLES]; uint32_t err, avglen, value; uint8_t crc, calc; int i, negmul, offset, size, tmphi, tmplo; gpioths_dht_initread(sc); err = gpioths_dht_timeuntil(sc, false, NULL); if (err) { device_printf(sc->dev, "err(START) = %d\n", err); goto error; } /* reading - 41 cycles */ for (i = 0; i < GPIOTHS_DHT_CYCLES; i++) { err = gpioths_dht_timeuntil(sc, true, &calibrations[i]); if (err) { device_printf(sc->dev, "err(CAL, %d) = %d\n", i, err); goto error; } err = gpioths_dht_timeuntil(sc, false, &intervals[i]); if (err) { device_printf(sc->dev, "err(INTERVAL, %d) = %d\n", i, err); goto error; } } /* Calculate average data calibration cycle length */ avglen = 0; for (i = 1; i < GPIOTHS_DHT_CYCLES; i++) avglen += calibrations[i]; avglen = avglen / (GPIOTHS_DHT_CYCLES - 1); /* Calculate data */ value = 0; offset = 1; size = sizeof(value) * 8; for (i = offset; i < size + offset; i++) { value <<= 1; if (intervals[i] > avglen) value += 1; } /* Calculate CRC */ crc = 0; offset = sizeof(value) * 8 + 1; size = sizeof(crc) * 8; for (i = offset; i < size + offset; i++) { crc <<= 1; if (intervals[i] > avglen) crc += 1; } calc = 0; for (i = 0; i < sizeof(value); i++) calc += (value >> (8*i)) & GPIOTHS_DHT_ONEBYTEMASK; #ifdef GPIOTHS_DEBUG /* Debug bits */ for (i = 0; i < GPIOTHS_DHT_CYCLES; i++) device_printf(sc->dev, "%d: %d %d\n", i, calibrations[i], intervals[i]); device_printf(sc->dev, "len=%d, data=%x, crc=%x/%x\n", avglen, value, crc, calc); #endif /* GPIOTHS_DEBUG */ /* CRC check */ if (calc != crc) { err = -1; goto error; } /* * For DHT11/12, the values are split into 8 bits of integer and 8 bits * of fractional tenths. On DHT11 the fraction bytes are always zero. * On DHT12 the sign bit is in the high bit of the fraction byte. * - DHT11: 0HHHHHHH 00000000 00TTTTTT 00000000 * - DHT12: 0HHHHHHH 0000hhhh 00TTTTTT s000tttt * * For DHT21/21, the values are are encoded in 16 bits each, with the * temperature sign bit in the high bit. The values are tenths of a * degree C and tenths of a percent RH. * - DHT21: 000000HH HHHHHHHH s00000TT TTTTTTTT * - DHT22: 000000HH HHHHHHHH s00000TT TTTTTTTT * * For all devices, some bits are always zero because of the range of * values supported by the device. * * We figure out how to decode things based on the high byte of the * humidity. A DHT21/22 cannot report a value greater than 3 in * the upper bits of its 16-bit humidity. A DHT11/12 should not report * a value lower than 20. To allow for the possibility that a device * could report a value slightly out of its sensitivity range, we split * the difference and say if the value is greater than 10 it must be a * DHT11/12 (that would be a humidity over 256% on a DHT21/22). */ #define DK_OFFSET 2731 /* Offset between K and C, in decikelvins. */ if ((value >> 24) > 10) { /* DHT11 or DHT12 */ tmphi = (value >> 8) & 0x3f; tmplo = value & 0x0f; negmul = (value & 0x80) ? -1 : 1; sc->temp = DK_OFFSET + (negmul * (tmphi * 10 + tmplo)); sc->hum = (value >> 24) & 0x7f; } else { /* DHT21 or DHT22 */ negmul = (value & 0x8000) ? -1 : 1; sc->temp = DK_OFFSET + (negmul * (value & 0x03ff)); sc->hum = ((value >> 16) & 0x03ff) / 10; } sc->fails = 0; #ifdef GPIOTHS_DEBUG /* Debug bits */ device_printf(dev, "fails=%d, temp=%d, hum=%d\n", sc->fails, sc->temp, sc->hum); #endif /* GPIOTHS_DEBUG */ return (0); error: sc->fails++; return (err); } static void gpioths_poll(void *arg, int pending __unused) { struct gpioths_softc *sc; sc = (struct gpioths_softc *)arg; gpioths_dht_readbytes(sc); if (!sc->detaching) taskqueue_enqueue_timeout_sbt(taskqueue_thread, &sc->task, GPIOTHS_POLLTIME * SBT_1S, 0, C_PREL(3)); } static int gpioths_attach(device_t dev) { struct gpioths_softc *sc; struct sysctl_ctx_list *ctx; struct sysctl_oid *tree; int err; sc = device_get_softc(dev); ctx = device_get_sysctl_ctx(dev); tree = device_get_sysctl_tree(dev); sc->dev = dev; TIMEOUT_TASK_INIT(taskqueue_thread, &sc->task, 0, gpioths_poll, sc); #ifdef FDT /* Try to configure our pin from fdt data on fdt-based systems. */ err = gpio_pin_get_by_ofw_idx(dev, ofw_bus_get_node(dev), PIN_IDX, &sc->pin); #else err = ENOENT; #endif /* * If we didn't get configured by fdt data and our parent is gpiobus, * see if we can be configured by the bus (allows hinted attachment even * on fdt-based systems). */ if (err != 0 && strcmp("gpiobus", device_get_name(device_get_parent(dev))) == 0) err = gpio_pin_get_by_child_index(dev, PIN_IDX, &sc->pin); /* If we didn't get configured by either method, whine and punt. */ if (err != 0) { device_printf(sc->dev, "cannot acquire gpio pin (config error)\n"); return (err); } /* * Ensure we have control of our pin, and preset the data line to its * idle condition (high). Leave the line in input mode, relying on the * external pullup to keep the line high while idle. */ err = gpio_pin_setflags(sc->pin, GPIO_PIN_OUTPUT); if (err != 0) { device_printf(dev, "gpio_pin_setflags(OUT) = %d\n", err); return (err); } err = gpio_pin_set_active(sc->pin, true); if (err != 0) { device_printf(dev, "gpio_pin_set_active(false) = %d\n", err); return (err); } err = gpio_pin_setflags(sc->pin, GPIO_PIN_INPUT); if (err != 0) { device_printf(dev, "gpio_pin_setflags(IN) = %d\n", err); return (err); } /* * Do an initial read so we have correct values for reporting before * registering the sysctls that can access those values. This also * schedules the periodic polling the driver does every few seconds to * update the sysctl variables. */ gpioths_poll(sc, 0); sysctl_add_oid(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "temperature", \ CTLFLAG_RD | CTLTYPE_INT | CTLFLAG_MPSAFE, &sc->temp, 0, sysctl_handle_int, "IK", "temperature", NULL); SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "humidity", CTLFLAG_RD, &sc->hum, 0, "relative humidity(%)"); SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, "fails", CTLFLAG_RD, &sc->fails, 0, "failures since last successful read"); return (0); } static int gpioths_detach(device_t dev) { struct gpioths_softc *sc; sc = device_get_softc(dev); gpio_pin_release(sc->pin); sc->detaching = true; while (taskqueue_cancel_timeout(taskqueue_thread, &sc->task, NULL) != 0) taskqueue_drain_timeout(taskqueue_thread, &sc->task); return (0); } /* Driver bits */ static device_method_t gpioths_methods[] = { /* Device interface */ DEVMETHOD(device_probe, gpioths_probe), DEVMETHOD(device_attach, gpioths_attach), DEVMETHOD(device_detach, gpioths_detach), DEVMETHOD_END }; DEFINE_CLASS_0(gpioths, gpioths_driver, gpioths_methods, sizeof(struct gpioths_softc)); #ifdef FDT DRIVER_MODULE(gpioths, simplebus, gpioths_driver, 0, 0); #endif DRIVER_MODULE(gpioths, gpiobus, gpioths_driver, 0, 0); MODULE_DEPEND(gpioths, gpiobus, 1, 1, 1);