[gpioths] new driver for temperature/humidity sensor DHT11
This patch adds driver for temperature/humidity sensor connected via GPIO. To compile it into kernel add "device gpioths". To activate driver, use hints (.at and .pins) for gpiobus. As result it will provide temperature & humidity values via sysctl. DHT11 is cheap & popular temperature/humidity sensor used via GPIO on ARM or MIPS devices like Raspberry Pi or Onion Omega. Reviewed by: adrian Approved by: adrian (mentor) Differential Revision: https://reviews.freebsd.org/D9185
This commit is contained in:
Michael Zhilin
parent
f73628e7b1
commit
662e30fca3
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=312290
@ -1714,6 +1714,7 @@ dev/gpio/gpioled_fdt.c optional gpioled fdt
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dev/gpio/gpiopower.c optional gpiopower fdt
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dev/gpio/gpioregulator.c optional gpioregulator fdt ext_resources
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dev/gpio/gpiospi.c optional gpiospi
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dev/gpio/gpioths.c optional gpioths
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dev/gpio/gpio_if.m optional gpio
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dev/gpio/gpiobus_if.m optional gpio
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dev/gpio/gpiopps.c optional gpiopps
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405
sys/dev/gpio/gpioths.c
Normal file
405
sys/dev/gpio/gpioths.c
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@ -0,0 +1,405 @@
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/*-
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* Copyright (c) 2016 Michael Zhilin <mizhka@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/bus.h>
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#include <sys/module.h>
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#include <sys/errno.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <machine/bus.h>
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#include <sys/rman.h>
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#include <sys/gpio.h>
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#include <machine/resource.h>
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#include "gpiobus_if.h"
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/*
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* GPIOTHS - Temp/Humidity sensor over GPIO, e.g. DHT11/DHT22
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* This is driver for Temperature & Humidity sensor which provides digital
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* output over single-wire protocol from embedded 8-bit microcontroller.
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*
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* Temp/Humidity sensor can't be discovered automatically, please specify hints
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* as part of loader or kernel configuration:
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* hint.gpioths.0.at="gpiobus0"
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* hint.gpioths.0.pins=<PIN>
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*/
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#define GPIOTHS_POLLTIME 5 /* in seconds */
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#define GPIOTHS_DHT_STARTCYCLE 20000 /* 20ms = 20000us */
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#define GPIOTHS_DHT_TIMEOUT 1000 /* 1ms = 1000us */
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#define GPIOTHS_DHT_CYCLES 41
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#define GPIOTHS_DHT_ONEBYTEMASK 0xFF
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#define GPIOTHS_DHT_TEMP_SHIFT 8
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#define GPIOTHS_DHT_HUM_SHIFT 24
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struct gpioths_softc {
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device_t dev;
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int temp;
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int hum;
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int fails;
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struct sysctl_oid *temp_oid;
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struct sysctl_oid *hum_oid;
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struct sysctl_oid *fails_oid;
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struct callout callout;
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};
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static devclass_t gpioths_devclass;
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/* Prototypes */
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static int gpioths_probe(device_t dev);
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static int gpioths_attach(device_t dev);
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static int gpioths_detach(device_t dev);
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static void gpioths_poll(void *arg);
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static int gpioths_temp_sysctl(SYSCTL_HANDLER_ARGS);
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static int gpioths_hum_sysctl(SYSCTL_HANDLER_ARGS);
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static int gpioths_fails_sysctl(SYSCTL_HANDLER_ARGS);
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/* DHT-specific methods */
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static int gpioths_dht_initread(device_t bus, device_t dev);
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static int gpioths_dht_readbytes(device_t bus, device_t dev);
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static int gpioths_dht_timeuntil(device_t bus, device_t dev,
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uint32_t lev, uint32_t *time);
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/* Implementation */
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static int
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gpioths_probe(device_t dev)
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{
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device_set_desc(dev, "Temperature and Humidity Sensor over GPIO");
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return (0);
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}
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static int
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gpioths_dht_timeuntil(device_t bus, device_t dev, uint32_t lev, uint32_t *time)
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{
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uint32_t cur_level;
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int i;
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for (i = 0; i < GPIOTHS_DHT_TIMEOUT; i++) {
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GPIOBUS_PIN_GET(bus, dev, 0, &cur_level);
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if (cur_level == lev) {
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if (time != NULL)
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*time = i;
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return (0);
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}
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DELAY(1);
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}
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/* Timeout */
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return (ETIMEDOUT);
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}
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static int
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gpioths_dht_initread(device_t bus, device_t dev)
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{
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int err;
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err = GPIOBUS_PIN_SETFLAGS(bus, dev, 0, GPIO_PIN_OUTPUT);
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if (err != 0) {
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device_printf(dev, "err(GPIOBUS_PIN_SETFLAGS, OUT) = %d\n", err);
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return (err);
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}
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DELAY(1);
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err = GPIOBUS_PIN_SET(bus, dev, 0, GPIO_PIN_LOW);
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if (err != 0) {
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device_printf(dev, "err(GPIOBUS_PIN_SET, LOW) = %d\n", err);
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return (err);
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}
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/*
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* According to specifications we need to wait no more than 18ms
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* to start data transfer
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*/
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DELAY(GPIOTHS_DHT_STARTCYCLE);
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err = GPIOBUS_PIN_SET(bus, dev, 0, GPIO_PIN_HIGH);
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if (err != 0) {
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device_printf(dev, "err(GPIOBUS_PIN_SET, HIGH) = %d\n", err);
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return (err);
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}
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DELAY(1);
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err = GPIOBUS_PIN_SETFLAGS(bus, dev, 0, GPIO_PIN_INPUT) ;
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if (err != 0) {
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device_printf(dev, "err(GPIOBUS_PIN_SETFLAGS, IN) = %d\n", err);
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return (err);
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}
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DELAY(1);
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return (0);
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}
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static int
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gpioths_dht_readbytes(device_t bus, device_t dev)
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{
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struct gpioths_softc *sc;
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uint32_t calibrations[GPIOTHS_DHT_CYCLES];
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uint32_t intervals[GPIOTHS_DHT_CYCLES];
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uint32_t err, avglen, value;
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uint8_t crc, calc;
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int i, offset, size;
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sc = device_get_softc(dev);
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err = gpioths_dht_initread(bus,dev);
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if (err) {
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device_printf(dev, "gpioths_dht_initread error = %d\n", err);
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goto error;
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}
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err = gpioths_dht_timeuntil(bus, dev, GPIO_PIN_LOW, NULL);
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if (err) {
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device_printf(dev, "err(START) = %d\n", err);
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goto error;
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}
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/* reading - 41 cycles */
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for (i = 0; i < GPIOTHS_DHT_CYCLES; i++) {
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err = gpioths_dht_timeuntil(bus, dev, GPIO_PIN_HIGH,
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&calibrations[i]);
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if (err) {
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device_printf(dev, "err(CAL, %d) = %d\n", i, err);
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goto error;
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}
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err = gpioths_dht_timeuntil(bus, dev, GPIO_PIN_LOW,
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&intervals[i]);
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if (err) {
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device_printf(dev, "err(INTERVAL, %d) = %d\n", i, err);
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goto error;
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}
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}
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err = GPIOBUS_PIN_SETFLAGS(bus, dev, 0, GPIO_PIN_OUTPUT);
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if (err != 0) {
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device_printf(dev, "err(FINAL_SETFLAGS, OUT) = %d\n", err);
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goto error;
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}
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DELAY(1);
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/* Calculate average data calibration cycle length */
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avglen = 0;
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for (i = 1; i < GPIOTHS_DHT_CYCLES; i++)
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avglen += calibrations[i];
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avglen = avglen / (GPIOTHS_DHT_CYCLES - 1);
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/* Calculate data */
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value = 0;
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offset = 1;
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size = sizeof(value) * 8;
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for (i = offset; i < size + offset; i++) {
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value <<= 1;
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if (intervals[i] > avglen)
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value += 1;
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}
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/* Calculate CRC */
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crc = 0;
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offset = sizeof(value) * 8 + 1;
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size = sizeof(crc) * 8;
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for (i = offset; i < size + offset; i++) {
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crc <<= 1;
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if (intervals[i] > avglen)
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crc += 1;
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}
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calc = 0;
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for (i = 0; i < sizeof(value); i++)
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calc += (value >> (8*i)) & GPIOTHS_DHT_ONEBYTEMASK;
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#ifdef GPIOTHS_DEBUG
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/* Debug bits */
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for (i = 0; i < GPIOTHS_DHT_CYCLES; i++)
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device_printf(dev, "%d: %d %d\n", i, calibrations[i],
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intervals[i]);
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device_printf(dev, "len=%d, data=%x, crc=%x/%x\n", avglen, value, crc,
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calc);
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#endif /* GPIOTHS_DEBUG */
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/* CRC check */
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if (calc != crc) {
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err = -1;
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goto error;
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}
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sc->fails = 0;
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sc->temp = (value >> GPIOTHS_DHT_TEMP_SHIFT) & GPIOTHS_DHT_ONEBYTEMASK;
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sc->hum = (value >> GPIOTHS_DHT_HUM_SHIFT) & GPIOTHS_DHT_ONEBYTEMASK;
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#ifdef GPIOTHS_DEBUG
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/* Debug bits */
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device_printf(dev, "fails=%d, temp=%d, hum=%d\n", sc->fails,
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sc->temp, sc->hum);
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#endif /* GPIOTHS_DEBUG */
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return (0);
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error:
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sc->fails++;
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return (err);
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}
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static void
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gpioths_poll(void *arg)
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{
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struct gpioths_softc *sc;
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device_t dev;
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dev = (device_t)arg;
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sc = device_get_softc(dev);
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gpioths_dht_readbytes(device_get_parent(dev), dev);
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callout_schedule(&sc->callout, GPIOTHS_POLLTIME * hz);
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}
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static int
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gpioths_temp_sysctl(SYSCTL_HANDLER_ARGS)
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{
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struct gpioths_softc *sc;
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int value;
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sc = (struct gpioths_softc*)arg1;
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value = sc->temp;
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return (sysctl_handle_int(oidp, &value, 0, req));
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}
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static int
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gpioths_hum_sysctl(SYSCTL_HANDLER_ARGS)
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{
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struct gpioths_softc *sc;
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int value;
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sc = (struct gpioths_softc*)arg1;
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value = sc->hum;
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return (sysctl_handle_int(oidp, &value, 0, req));
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}
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static int
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gpioths_fails_sysctl(SYSCTL_HANDLER_ARGS)
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{
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struct gpioths_softc *sc;
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int value;
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sc = (struct gpioths_softc*)arg1;
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value = sc->fails;
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return (sysctl_handle_int(oidp, &value, 0, req));
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}
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static int
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gpioths_attach(device_t dev)
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{
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struct gpioths_softc *sc;
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struct sysctl_ctx_list *ctx;
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struct sysctl_oid *tree;
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sc = device_get_softc(dev);
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ctx = device_get_sysctl_ctx(dev);
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tree = device_get_sysctl_tree(dev);
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sc->dev = dev;
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callout_init(&sc->callout, 1);
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callout_reset(&sc->callout, GPIOTHS_POLLTIME * hz, gpioths_poll, dev);
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sc->temp_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
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"temperature", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
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gpioths_temp_sysctl, "I", "temperature(C)");
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sc->hum_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
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"humidity", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
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gpioths_hum_sysctl, "I", "humidity(%)");
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sc->fails_oid = SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
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"fails", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
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gpioths_fails_sysctl, "I", "fails since last successful read");
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return (0);
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}
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static int
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gpioths_detach(device_t dev)
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{
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return (0);
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}
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/* DDB bits */
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#include "opt_ddb.h"
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#ifdef DDB
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#include <ddb/ddb.h>
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#include <ddb/db_lex.h>
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#include <sys/cons.h>
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static struct command_table db_gpioths_table = LIST_HEAD_INITIALIZER(db_t4_table);
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_DB_SET(_show, gpioths, NULL, db_show_table, 0, &db_gpioths_table);
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DB_FUNC(read, db_show_gpiothsread, db_gpioths_table, CS_OWN, NULL)
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{
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device_t dev;
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int t;
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int init;
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init = 0;
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t = db_read_token();
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if (t == tIDENT) {
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dev = device_lookup_by_name(db_tok_string);
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init = 1;
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}
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db_skip_to_eol();
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if (init)
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db_printf("read: 0x%x\n",
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gpioths_dht_readbytes(dev, device_get_parent(dev)));
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else
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db_printf("usage: show gpioths read <gpiothsdevice>\n");
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return;
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}
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#endif /* DDB */
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/* Driver bits */
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static device_method_t gpioths_methods[] = {
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/* Device interface */
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DEVMETHOD(device_probe, gpioths_probe),
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DEVMETHOD(device_attach, gpioths_attach),
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DEVMETHOD(device_detach, gpioths_detach),
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DEVMETHOD_END
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};
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DEFINE_CLASS_0(gpioths, gpioths_driver, gpioths_methods, sizeof(struct gpioths_softc));
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DRIVER_MODULE(gpioths, gpiobus, gpioths_driver, gpioths_devclass, 0, 0);
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