freebsd-dev/sys/dev/ow/ow_temp.c
Warner Losh ae1f3df434 New 1-Wire bus implementation. 1-Wire controller is abstracted, though
only gpiobus configured via FDT is supported. Bus enumeration is
supported. Devices are created for each device found. 1-Wire
temperature controllers are supported, but other drivers could be
written. Temperatures are polled and reported via a sysctl.  Errors
are reported via sysctl counters. Mis-wired bus detection is included
for more trouble shooting. See ow(4), owc(4) and ow_temp(4) for
details of what's supported and known issues.

This has been tested on Raspberry Pi-B, Pi2 and Beagle Bone Black
with up to 7 devices.

Differential Revision: https://reviews.freebsd.org/D2956
Relnotes: yes
MFC after: 2 weeks
Reviewed by: loos@ (with many insightful comments)
2015-08-27 23:33:38 +00:00

286 lines
7.7 KiB
C

/*-
* Copyright (c) 2015 M. Warner Losh <imp@freebsd.org>
* All rights reserved.
*
* 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 unmodified, 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 ``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 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 <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/errno.h>
#include <sys/libkern.h>
#include <sys/kthread.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <dev/ow/ow.h>
#include <dev/ow/own.h>
#define OWT_DS1820 0x10 /* Also 18S20 */
#define OWT_DS1822 0x22 /* Very close to 18B20 */
#define OWT_DS18B20 0x28 /* Also MAX31820 */
#define OWT_DS1825 0x3B /* Just like 18B20 with address bits */
#define CONVERT_T 0x44
#define COPY_SCRATCHPAD 0x48
#define WRITE_SCRATCHPAD 0x4e
#define READ_POWER_SUPPLY 0xb4
#define RECALL_EE 0xb8
#define READ_SCRATCHPAD 0xbe
#define OW_TEMP_DONE 0x01
#define OW_TEMP_RUNNING 0x02
struct ow_temp_softc
{
device_t dev;
int type;
int temp;
int flags;
int bad_crc;
int bad_reads;
int reading_interval;
int parasite;
struct mtx temp_lock;
struct proc *event_thread;
};
static int
ow_temp_probe(device_t dev)
{
switch (ow_get_family(dev)) {
case OWT_DS1820:
device_set_desc(dev, "One Wire Temperature");
return BUS_PROBE_DEFAULT;
case OWT_DS1822:
case OWT_DS1825:
case OWT_DS18B20:
device_set_desc(dev, "Advanced One Wire Temperature");
return BUS_PROBE_DEFAULT;
default:
return ENXIO;
}
}
static int
ow_temp_read_scratchpad(device_t dev, uint8_t *scratch, int len)
{
struct ow_cmd cmd;
own_self_command(dev, &cmd, READ_SCRATCHPAD);
cmd.xpt_read_len = len;
own_command_wait(dev, &cmd);
memcpy(scratch, cmd.xpt_read, len);
return 0;
}
static int
ow_temp_convert_t(device_t dev)
{
struct ow_cmd cmd;
own_self_command(dev, &cmd, CONVERT_T);
own_command_wait(dev, &cmd);
return 0;
}
static int
ow_temp_read_power_supply(device_t dev, int *parasite)
{
struct ow_cmd cmd;
own_self_command(dev, &cmd, READ_POWER_SUPPLY);
cmd.flags |= OW_FLAG_READ_BIT;
cmd.xpt_read_len = 1;
own_command_wait(dev, &cmd);
*parasite = !cmd.xpt_read[0]; /* parasites pull bus low */
return 0;
}
static void
ow_temp_event_thread(void *arg)
{
struct ow_temp_softc *sc;
uint8_t scratch[8 + 1];
uint8_t crc;
int retries, rv;
sc = arg;
pause("owtstart", device_get_unit(sc->dev) * hz / 100); // 10ms stagger
mtx_lock(&sc->temp_lock);
sc->flags |= OW_TEMP_RUNNING;
ow_temp_read_power_supply(sc->dev, &sc->parasite);
if (sc->parasite)
device_printf(sc->dev, "Running in parasitic mode unsupported\n");
while ((sc->flags & OW_TEMP_DONE) == 0) {
mtx_unlock(&sc->temp_lock);
ow_temp_convert_t(sc->dev);
mtx_lock(&sc->temp_lock);
msleep(sc, &sc->temp_lock, 0, "owtcvt", hz);
if (sc->flags & OW_TEMP_DONE)
break;
for (retries = 5; retries > 0; retries--) {
mtx_unlock(&sc->temp_lock);
rv = ow_temp_read_scratchpad(sc->dev, scratch, sizeof(scratch));
mtx_lock(&sc->temp_lock);
if (rv == 0) {
crc = own_crc(sc->dev, scratch, sizeof(scratch) - 1);
if (crc == scratch[8]) {
if (sc->type == OWT_DS1820) {
if (scratch[7]) {
/*
* Formula from DS18S20 datasheet, page 6
* DS18S20 datahseet says count_per_c is 16, DS1820 does not
*/
sc->temp = (int16_t)((scratch[0] & 0xfe) |
(scratch[1] << 8)) << 3;
sc->temp += 16 - scratch[6] - 4; /* count_per_c == 16 */
} else
sc->temp = (int16_t)(scratch[0] | (scratch[1] << 8)) << 3;
} else
sc->temp = (int16_t)(scratch[0] | (scratch[1] << 8));
sc->temp = sc->temp * 1000 / 16 + 273150;
break;
}
sc->bad_crc++;
} else
sc->bad_reads++;
}
msleep(sc, &sc->temp_lock, 0, "owtcvt", sc->reading_interval);
}
sc->flags &= ~OW_TEMP_RUNNING;
mtx_unlock(&sc->temp_lock);
kproc_exit(0);
}
static int
ow_temp_attach(device_t dev)
{
struct ow_temp_softc *sc;
sc = device_get_softc(dev);
sc->dev = dev;
sc->type = ow_get_family(dev);
SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
OID_AUTO, "temperature", CTLFLAG_RD | CTLTYPE_INT,
&sc->temp, 0, sysctl_handle_int,
"IK3", "Current Temperature");
SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
OID_AUTO, "badcrc", CTLFLAG_RD,
&sc->bad_crc, 0,
"Number of Bad CRC on reading scratchpad");
SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
OID_AUTO, "badread", CTLFLAG_RD,
&sc->bad_reads, 0,
"Number of errors on reading scratchpad");
SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
OID_AUTO, "reading_interval", CTLFLAG_RW,
&sc->reading_interval, 0,
"ticks between reads");
SYSCTL_ADD_INT(device_get_sysctl_ctx(dev),
SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
OID_AUTO, "parasite", CTLFLAG_RW,
&sc->parasite, 0,
"In Parasite mode");
/*
* Just do this for unit 0 to avoid locking
* the ow bus until that code can be put
* into place.
*/
sc->temp = -1;
sc->reading_interval = 10 * hz;
mtx_init(&sc->temp_lock, "lock for doing temperature", NULL, MTX_DEF);
/* Start the thread */
if (kproc_create(ow_temp_event_thread, sc, &sc->event_thread, 0, 0,
"%s event thread", device_get_nameunit(dev))) {
device_printf(dev, "unable to create event thread.\n");
panic("cbb_create_event_thread");
}
return 0;
}
static int
ow_temp_detach(device_t dev)
{
struct ow_temp_softc *sc;
sc = device_get_softc(dev);
/*
* Wait for the thread to die. kproc_exit will do a wakeup
* on the event thread's struct thread * so that we know it is
* safe to proceed. IF the thread is running, set the please
* die flag and wait for it to comply. Since the wakeup on
* the event thread happens only in kproc_exit, we don't
* need to loop here.
*/
mtx_lock(&sc->temp_lock);
sc->flags |= OW_TEMP_DONE;
while (sc->flags & OW_TEMP_RUNNING) {
wakeup(sc);
msleep(sc->event_thread, &sc->temp_lock, PWAIT, "owtun", 0);
}
mtx_destroy(&sc->temp_lock);
return 0;
}
devclass_t ow_temp_devclass;
static device_method_t ow_temp_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, ow_temp_probe),
DEVMETHOD(device_attach, ow_temp_attach),
DEVMETHOD(device_detach, ow_temp_detach),
{ 0, 0 }
};
static driver_t ow_temp_driver = {
"ow_temp",
ow_temp_methods,
sizeof(struct ow_temp_softc),
};
DRIVER_MODULE(ow_temp, ow, ow_temp_driver, ow_temp_devclass, 0, 0);
MODULE_DEPEND(ow_temp, ow, 1, 1, 1);