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htu21: driver for HTU21D I2C temperature and humidity sensor

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MFC after:	2 weeks
Relnotes:	perhaps
This commit is contained in:
Andriy Gapon 2021-01-19 14:57:24 +02:00
parent 38baca17e0
commit 2c98edd6d6
6 changed files with 676 additions and 1 deletions
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1
share/man/man4/Makefile
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@ -197,6 +197,7 @@ MAN= aac.4 \
${_hptnr.4} \
${_hptrr.4} \
hsctrl.4 \
htu21.4 \
${_hv_kvp.4} \
${_hv_netvsc.4} \
${_hv_storvsc.4} \

134
share/man/man4/htu21.4 Normal file
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@ -0,0 +1,134 @@
.\"
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
.\"
.\" Copyright (c) 2021 Andriy Gapon <avg@FreeBSD.org>
.\"
.\" 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.
.\"
.\" $FreeBSD$
.\"
.Dd January 19, 2021
.Dt HTU21 4
.Os
.Sh NAME
.Nm htu21
.Nd driver for HTU21D and compatible temperature and humidity sensors
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device htu21"
.Cd "device iicbus"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
htu21_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides temperature and relative humidity readings over I2C bus
for the supported sensors:
.Bl -bullet -compact
.It
HTU21D
.It
SHT21
.It
Si7021
.El
.Pp
The
.Nm
driver reports data via
.Xr sysctl 8
entries in the device's node in the
.Xr sysctl 8
tree:
.Bl -tag -width temperature
.It temperature
The temperature, in hundredths of Kelvin.
.It humidity
The relative humidity, in hundredths of a percent.
.It crc_errors
The number of CRC errors in reading the measurements from the device.
.It power
The good power indication.
This can be useful with battery powered sensors.
.It heater
The built-in heater control.
The heater can be used for testing and for recovery from saturation
after high humidity.
.It hold_bus
Whether the sensor should hold SCL low while performing the measurement.
Normally, the sensor releases the bus and NACKs all accessed until the
measurement is completed.
The hold mode may be useful in mult-master environments.
.El
.Pp
On an
.Xr FDT 4
based system the following properties must be set:
.Bl -tag -width "compatible"
.It Va compatible
Must be set to "meas,htu21".
.It Va reg
The I2C address of
.Nm .
Although, it is hard-wired to 0x40 (7-bit) on all supported sensors.
.El
.Pp
The DTS part for a
.Nm
device usually looks like:
.Bd -literal
/ {
...
htu21d {
compatible = "meas,htu21";
reg = <0x40>;
};
};
.Ed
.Sh SEE ALSO
.Xr fdt 4 ,
.Xr iicbus 4 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
driver and this manual page was written by
.An Andriy Gapon Aq Mt avg@FreeBSD.org .
.Sh BUGS
There is no way to control the measurment resolution.
.Pp
Some sensor variants do not provide a serial number or use an incompatible
format.
The
.Nm
driver does not distinguish those variants and may complain about incorrect
serial number checksum.

3
sys/conf/files
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@ -1851,7 +1851,7 @@ dev/iicbus/ds1307.c optional ds1307
dev/iicbus/ds13rtc.c optional ds13rtc | ds133x | ds1374
dev/iicbus/ds1672.c optional ds1672
dev/iicbus/ds3231.c optional ds3231
dev/iicbus/syr827.c optional syr827 ext_resources fdt
dev/iicbus/htu21.c optional htu21
dev/iicbus/icee.c optional icee
dev/iicbus/if_ic.c optional ic
dev/iicbus/iic.c optional iic
@ -1880,6 +1880,7 @@ dev/iicbus/rtc8583.c optional rtc8583
dev/iicbus/rtc/rx8803.c optional rx8803 iicbus fdt
dev/iicbus/s35390a.c optional s35390a
dev/iicbus/sy8106a.c optional sy8106a ext_resources fdt
dev/iicbus/syr827.c optional syr827 ext_resources fdt
dev/iicbus/gpio/tca6416.c optional tca6416 fdt
dev/iir/iir.c optional iir
dev/iir/iir_ctrl.c optional iir

521
sys/dev/iicbus/htu21.c Normal file
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@ -0,0 +1,521 @@
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2021 Andriy Gapon
*
* 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.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <machine/bus.h>
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
/*
* Driver for HTU21D and compatible temperature and humidity sensors.
* Reference documents:
* - Measurement Specialties HTU21D datasheet,
* - Sensirion SHT21 datasheet,
* - Silicon Labs Si7021 datasheet,
* - HTU2X Serial Number Reading application note,
* - Sensirion Electronic Identification Code (How to read-out the serial number
* of SHT2x) application note.
*/
#define HTU21_ADDR 0x40
#define HTU21_GET_TEMP 0xe3
#define HTU21_GET_HUM 0xe5
#define HTU21_GET_TEMP_NH 0xf3
#define HTU21_GET_HUM_NH 0xf5
#define HTU21_WRITE_CFG 0xe6
#define HTU21_READ_CFG 0xe7
#define HTU21_RESET 0xfe
#define HTU2x_SERIAL0_0 0xfa
#define HTU2x_SERIAL0_1 0x0f
#define HTU2x_SERIAL1_0 0xfc
#define HTU2x_SERIAL1_1 0xc9
struct htu21_softc {
device_t sc_dev;
uint32_t sc_addr;
uint8_t sc_serial[8];
int sc_errcount;
bool sc_hold;
};
#ifdef FDT
static struct ofw_compat_data compat_data[] = {
{ "meas,htu21", true },
{ NULL, false }
};
#endif
static uint8_t
calc_crc(uint16_t data)
{
static const uint16_t polynomial = 0x3100;
int i;
for (i = 0; i < 16; i++) {
int msb_neq = data & 0x8000;
data <<= 1;
if (msb_neq)
data ^= polynomial;
}
return (data >> 8);
}
static int
check_crc_16(const uint8_t *data, uint8_t expected)
{
uint8_t crc;
crc = calc_crc(((uint16_t)data[0] << 8) | data[1]);
return (crc == expected);
}
static int
check_crc_8(const uint8_t data, uint8_t expected)
{
uint8_t crc;
crc = calc_crc(data);
return (crc == expected);
}
static int
htu21_get_measurement(device_t dev, uint8_t cmd, uint8_t *data, int count)
{
struct iic_msg msgs[2];
struct htu21_softc *sc;
int error;
sc = device_get_softc(dev);
msgs[0].slave = sc->sc_addr;
msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].slave = sc->sc_addr;
msgs[1].flags = IIC_M_RD;
msgs[1].len = count;
msgs[1].buf = data;
error = iicbus_transfer_excl(dev, msgs, nitems(msgs), IIC_INTRWAIT);
return (error);
}
static int
htu21_get_measurement_nohold(device_t dev, uint8_t cmd,
uint8_t *data, int count)
{
struct iic_msg msgs[2];
struct htu21_softc *sc;
int error;
int i;
sc = device_get_softc(dev);
msgs[0].slave = sc->sc_addr;
msgs[0].flags = IIC_M_WR;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].slave = sc->sc_addr;
msgs[1].flags = IIC_M_RD;
msgs[1].len = count;
msgs[1].buf = data;
error = iicbus_transfer_excl(dev, &msgs[0], 1, IIC_INTRWAIT);
if (error != 0)
return (error);
for (i = 0; i < hz; i++) {
error = iicbus_transfer_excl(dev, &msgs[1], 1, IIC_INTRWAIT);
if (error == 0)
return (0);
if (error != IIC_ENOACK)
break;
pause("htu21", 1);
}
return (error);
}
static int
htu21_temp_sysctl(SYSCTL_HANDLER_ARGS)
{
struct htu21_softc *sc;
device_t dev;
uint8_t raw_data[3];
int error, temp;
dev = arg1;
sc = device_get_softc(dev);
if (sc->sc_hold)
error = htu21_get_measurement(dev, HTU21_GET_TEMP,
raw_data, nitems(raw_data));
else
error = htu21_get_measurement_nohold(dev, HTU21_GET_TEMP_NH,
raw_data, nitems(raw_data));
if (error != 0) {
return (EIO);
} else if (!check_crc_16(raw_data, raw_data[2])) {
temp = -1;
sc->sc_errcount++;
} else {
temp = (((uint16_t)raw_data[0]) << 8) | (raw_data[1] & 0xfc);
temp = ((temp * 17572) >> 16 ) + 27315 - 4685;
}
error = sysctl_handle_int(oidp, &temp, 0, req);
return (error);
}
static int
htu21_rh_sysctl(SYSCTL_HANDLER_ARGS)
{
struct htu21_softc *sc;
device_t dev;
uint8_t raw_data[3];
int error, rh;
dev = arg1;
sc = device_get_softc(dev);
if (sc->sc_hold)
error = htu21_get_measurement(dev, HTU21_GET_HUM,
raw_data, nitems(raw_data));
else
error = htu21_get_measurement_nohold(dev, HTU21_GET_HUM_NH,
raw_data, nitems(raw_data));
if (error != 0) {
return (EIO);
} else if (!check_crc_16(raw_data, raw_data[2])) {
rh = -1;
sc->sc_errcount++;
} else {
rh = (((uint16_t)raw_data[0]) << 8) | (raw_data[1] & 0xfc);
rh = ((rh * 12500) >> 16 ) - 600;
}
error = sysctl_handle_int(oidp, &rh, 0, req);
return (error);
}
static int
htu21_get_cfg(device_t dev, uint8_t *cfg)
{
struct iic_msg msgs[2];
struct htu21_softc *sc;
uint8_t cmd;
int error;
sc = device_get_softc(dev);
cmd = HTU21_READ_CFG;
msgs[0].slave = sc->sc_addr;
msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].slave = sc->sc_addr;
msgs[1].flags = IIC_M_RD;
msgs[1].len = 1;
msgs[1].buf = cfg;
error = iicbus_transfer_excl(dev, msgs, nitems(msgs), IIC_INTRWAIT);
return (error);
}
static int
htu21_set_cfg(device_t dev, uint8_t cfg)
{
struct iic_msg msg;
struct htu21_softc *sc;
uint8_t buf[2];
int error;
sc = device_get_softc(dev);
buf[0] = HTU21_WRITE_CFG;
buf[1] = cfg;
msg.slave = sc->sc_addr;
msg.flags = IIC_M_WR;
msg.len = 2;
msg.buf = buf;
error = iicbus_transfer_excl(dev, &msg, 1, IIC_INTRWAIT);
return (error);
}
static int
htu21_heater_sysctl(SYSCTL_HANDLER_ARGS)
{
struct htu21_softc *sc;
device_t dev;
uint8_t cfg;
int error, heater;
dev = arg1;
sc = device_get_softc(dev);
error = htu21_get_cfg(dev, &cfg);
if (error != 0)
return (EIO);
heater = (cfg & 0x04) != 0;
error = sysctl_handle_int(oidp, &heater, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
cfg &= ~0x04;
cfg |= (heater > 0) << 2;
error = htu21_set_cfg(dev, cfg);
return (error != 0 ? EIO : 0);
}
static int
htu21_power_sysctl(SYSCTL_HANDLER_ARGS)
{
struct htu21_softc *sc;
device_t dev;
uint8_t cfg;
int error, power;
dev = arg1;
sc = device_get_softc(dev);
error = htu21_get_cfg(dev, &cfg);
if (error != 0)
return (EIO);
power = (cfg & 0x40) == 0;
error = sysctl_handle_int(oidp, &power, 0, req);
return (error);
}
/*
* May be incompatible with some chips like SHT21 and Si7021.
*/
static int
htu21_get_serial(device_t dev)
{
struct iic_msg msgs[2];
struct htu21_softc *sc;
uint8_t data[8];
uint8_t cmd[2];
int error, cksum_err;
int i;
sc = device_get_softc(dev);
cmd[0] = HTU2x_SERIAL0_0;
cmd[1] = HTU2x_SERIAL0_1;
msgs[0].slave = sc->sc_addr;
msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
msgs[0].len = nitems(cmd);
msgs[0].buf = cmd;
msgs[1].slave = sc->sc_addr;
msgs[1].flags = IIC_M_RD;
msgs[1].len = nitems(data);
msgs[1].buf = data;
error = iicbus_transfer_excl(dev, msgs, nitems(msgs), IIC_INTRWAIT);
if (error != 0)
return (EIO);
cksum_err = 0;
for (i = 0; i < nitems(data); i += 2) {
if (!check_crc_8(data[i], data[i + 1]))
cksum_err = EINVAL;
sc->sc_serial[2 + i / 2] = data[i];
}
cmd[0] = HTU2x_SERIAL1_0;
cmd[1] = HTU2x_SERIAL1_1;
msgs[0].slave = sc->sc_addr;
msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
msgs[0].len = nitems(cmd);
msgs[0].buf = cmd;
msgs[1].slave = sc->sc_addr;
msgs[1].flags = IIC_M_RD;
msgs[1].len = 6;
msgs[1].buf = data;
error = iicbus_transfer_excl(dev, msgs, nitems(msgs), IIC_INTRWAIT);
if (error != 0)
return (EIO);
if (!check_crc_16(&data[0], data[2]))
cksum_err = EINVAL;
sc->sc_serial[6] = data[0];
sc->sc_serial[7] = data[1];
if (!check_crc_16(&data[3], data[5]))
cksum_err = EINVAL;
sc->sc_serial[0] = data[3];
sc->sc_serial[1] = data[4];
return (cksum_err);
}
static void
htu21_start(void *arg)
{
device_t dev;
struct htu21_softc *sc;
struct sysctl_ctx_list *ctx;
struct sysctl_oid *tree_node;
struct sysctl_oid_list *tree;
int error;
sc = arg;
dev = sc->sc_dev;
for (int i = 0; i < 5; i++) {
error = htu21_get_serial(dev);
if (error == 0)
break;
}
if (error != EIO) {
device_printf(dev, "serial number: %8D (checksum %scorrect)\n",
sc->sc_serial, ":", error == 0 ? "" : "in");
} else {
device_printf(dev, "failed to get serial number, err = %d\n",
error);
}
ctx = device_get_sysctl_ctx(dev);
tree_node = device_get_sysctl_tree(dev);
tree = SYSCTL_CHILDREN(tree_node);
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temperature",
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, 0,
htu21_temp_sysctl, "IK2", "Current temperature");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "humidity",
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, 0,
htu21_rh_sysctl, "I", "Relative humidity in 0.01%% units");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "heater",
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, dev, 0,
htu21_heater_sysctl, "IU", "Enable built-in heater");
SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "power",
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, 0,
htu21_power_sysctl, "IU", "If sensor's power is good");
SYSCTL_ADD_BOOL(ctx, tree, OID_AUTO, "hold_bus",
CTLFLAG_RW, &sc->sc_hold, 0,
"Whether device should hold I2C bus while measuring");
SYSCTL_ADD_INT(ctx, tree, OID_AUTO, "crc_errors",
CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, &sc->sc_errcount, 0,
"Number of checksum errors");
}
static int
htu21_probe(device_t dev)
{
uint8_t addr;
#ifdef FDT
if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
return (ENXIO);
#endif
addr = iicbus_get_addr(dev);
if (addr != (HTU21_ADDR << 1)) {
device_printf(dev, "non-standard slave address 0x%02x\n",
addr >> 1);
}
device_set_desc(dev, "HTU21 temperature and humidity sensor");
return (BUS_PROBE_GENERIC);
}
static int
htu21_attach(device_t dev)
{
struct htu21_softc *sc;
sc = device_get_softc(dev);
sc->sc_dev = dev;
sc->sc_addr = iicbus_get_addr(dev);
/*
* We have to wait until interrupts are enabled. Usually I2C read
* and write only works when the interrupts are available.
*/
config_intrhook_oneshot(htu21_start, sc);
return (0);
}
static int
htu21_detach(device_t dev)
{
return (0);
}
static device_method_t htu21_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, htu21_probe),
DEVMETHOD(device_attach, htu21_attach),
DEVMETHOD(device_detach, htu21_detach),
DEVMETHOD_END
};
static driver_t htu21_driver = {
"htu21",
htu21_methods,
sizeof(struct htu21_softc)
};
static devclass_t htu21_devclass;
DRIVER_MODULE(htu21, iicbus, htu21_driver, htu21_devclass, 0, 0);
MODULE_DEPEND(htu21, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
MODULE_VERSION(htu21, 1);
#ifdef FDT
IICBUS_FDT_PNP_INFO(compat_data);
#endif

1
sys/modules/i2c/Makefile
View File

@ -8,6 +8,7 @@ SUBDIR = \
ds13rtc \
ds1672 \
ds3231 \
htu21 \
icee \
if_ic \
iic \

17
sys/modules/i2c/htu21/Makefile Normal file
View File

@ -0,0 +1,17 @@
# $FreeBSD$
.PATH: ${SRCTOP}/sys/dev/iicbus
KMOD= htu21
SRCS= htu21.c
SRCS+= \
bus_if.h \
device_if.h \
iicbus_if.h \
opt_platform.h
.if !empty(OPT_FDT)
SRCS+= ofw_bus_if.h
.endif
.include <bsd.kmod.mk>