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/* $OpenBSD: owsbm.c,v 1.1 2007/02/28 21:54:43 grange Exp $ */
/*
* Copyright (c) 2007 Aaron Linville <aaron@linville.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* 1-Wire Smart Battery Monitor family type device driver.
* Provides on-board temperature, an A/D converter for voltage/current,
* current accumulator, elapsed time metter, and 40 bytes of nonvolatile
* memory.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/sensors.h>
#include <dev/onewire/onewiredevs.h>
#include <dev/onewire/onewirereg.h>
#include <dev/onewire/onewirevar.h>
/* Commands */
#define DSSBM_CMD_READ_SCRATCHPAD 0xbe
#define DSSBM_CMD_WRITE_SCRATCHPAD 0x4e
#define DSSBM_CMD_COPY_SCRATCHPAD 0x48
#define DSSBM_CMD_RECALL_MEMORY 0xb8
#define DSSBM_CMD_CONVERT_T 0x44
#define DSSBM_CMD_CONVERT_V 0xb4
/* Scratchpad layout */
#define DS2438_SP_STATUS 0
#define DS2438_SP_TEMP_LSB 1
#define DS2438_SP_TEMP_MSB 2
#define DS2438_SP_VOLT_LSB 3
#define DS2438_SP_VOLT_MSB 4
#define DS2438_SP_CURRENT_LSB 5
#define DS2438_SP_CURRENT_MSB 6
#define DS2438_SP_THRESHOLD 7
#define DS2438_SP_CRC 8
struct owsbm_softc {
struct device sc_dev;
void * sc_onewire;
u_int64_t sc_rom;
struct sensordev sc_sensordev;
struct sensor sc_temp;
struct sensor sc_voltage_vdd; /* Battery, AD = 1*/
struct sensor sc_voltage_vad; /* General purpose, AD = 0 */
struct sensor sc_voltage_cr; /* Current Register */
struct rwlock sc_lock;
};
int owsbm_match(struct device *, void *, void *);
void owsbm_attach(struct device *, struct device *, void *);
int owsbm_detach(struct device *, int);
int owsbm_activate(struct device *, enum devact);
void owsbm_update(void *);
struct cfattach owsbm_ca = {
sizeof(struct owsbm_softc),
owsbm_match,
owsbm_attach,
owsbm_detach,
owsbm_activate
};
struct cfdriver owsbm_cd = {
NULL, "owsbm", DV_DULL
};
static const struct onewire_matchfam owsbm_fams[] = {
{ ONEWIRE_FAMILY_DS2438 }
};
int
owsbm_match(struct device *parent, void *match, void *aux)
{
return (onewire_matchbyfam(aux, owsbm_fams,
sizeof(owsbm_fams) /sizeof(owsbm_fams[0])));
}
void
owsbm_attach(struct device *parent, struct device *self, void *aux)
{
struct owsbm_softc *sc = (struct owsbm_softc *)self;
struct onewire_attach_args *oa = aux;
sc->sc_onewire = oa->oa_onewire;
sc->sc_rom = oa->oa_rom;
/* Initialize temp sensor */
strlcpy(sc->sc_sensordev.xname, sc->sc_dev.dv_xname,
sizeof(sc->sc_sensordev.xname));
sc->sc_temp.type = SENSOR_TEMP;
strlcpy(sc->sc_temp.desc, "Temp", sizeof(sc->sc_temp.desc));
sensor_attach(&sc->sc_sensordev, &sc->sc_temp);
/* Initialize voltage sensor */
sc->sc_voltage_vdd.type = SENSOR_VOLTS_DC;
strlcpy(sc->sc_voltage_vdd.desc, "VDD", sizeof(sc->sc_voltage_vdd.desc));
sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vdd);
/* Initialize voltage sensor */
sc->sc_voltage_vad.type = SENSOR_VOLTS_DC;
strlcpy(sc->sc_voltage_vad.desc, "VAD", sizeof(sc->sc_voltage_vad.desc));
sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_vad);
/* Initialize the current sensor */
sc->sc_voltage_cr.type = SENSOR_VOLTS_DC;
strlcpy(sc->sc_voltage_cr.desc, "CR", sizeof(sc->sc_voltage_cr.desc));
sensor_attach(&sc->sc_sensordev, &sc->sc_voltage_cr);
if (sensor_task_register(sc, owsbm_update, 10)) {
printf(": unable to register owsbm update task\n");
return;
}
sensordev_install(&sc->sc_sensordev);
rw_init(&sc->sc_lock, sc->sc_dev.dv_xname);
printf("\n");
}
int
owsbm_detach(struct device *self, int flags)
{
struct owsbm_softc *sc = (struct owsbm_softc *)self;
rw_enter_write(&sc->sc_lock);
sensordev_deinstall(&sc->sc_sensordev);
sensor_task_unregister(sc);
rw_exit_write(&sc->sc_lock);
return (0);
}
int
owsbm_activate(struct device *self, enum devact act)
{
return (0);
}
void
owsbm_update(void *arg)
{
struct owsbm_softc *sc = arg;
u_int8_t data[9];
rw_enter_write(&sc->sc_lock);
onewire_lock(sc->sc_onewire, 0);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_T);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
/* Issue Recall Memory page 00h cmd */
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
onewire_write_byte(sc->sc_onewire, 0);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
/* Read page 0 of Memory Map from Scratchpad */
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
onewire_write_byte(sc->sc_onewire, 0);
onewire_read_block(sc->sc_onewire, data, 9);
if (onewire_crc(data, 8) == data[DS2438_SP_CRC]) {
sc->sc_temp.value = 273150000 +
(int)(((u_int16_t)data[DS2438_SP_TEMP_MSB] << 5) |
((u_int16_t)data[DS2438_SP_TEMP_LSB] >> 3)) * 31250;
sc->sc_voltage_vdd.value =
(int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
data[DS2438_SP_VOLT_LSB]) * 10000;
sc->sc_voltage_cr.value =
(int)(((u_int16_t)data[DS2438_SP_CURRENT_MSB] << 8) |
data[DS2438_SP_CURRENT_LSB]) * 244;
}
/* Reconfigure DS2438 to measure VAD */
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
onewire_write_byte(sc->sc_onewire, 0);
onewire_write_byte(sc->sc_onewire, 0x7); /* AD = 0 */
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_CONVERT_V);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
/* Issue Recall Memory page 00h cmd */
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_RECALL_MEMORY);
onewire_write_byte(sc->sc_onewire, 0);
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_READ_SCRATCHPAD);
onewire_write_byte(sc->sc_onewire, 0);
onewire_read_block(sc->sc_onewire, data, 9);
if (onewire_crc(data, 8) == data[8]) {
sc->sc_voltage_vad.value =
(int)(((u_int16_t)data[DS2438_SP_VOLT_MSB] << 8) |
data[DS2438_SP_VOLT_LSB]) * 10000;
}
/* Reconfigure back DS2438 to measure VDD (default) */
if (onewire_reset(sc->sc_onewire) != 0)
goto done;
onewire_matchrom(sc->sc_onewire, sc->sc_rom);
onewire_write_byte(sc->sc_onewire, DSSBM_CMD_WRITE_SCRATCHPAD);
onewire_write_byte(sc->sc_onewire, 0);
onewire_write_byte(sc->sc_onewire, 0xf); /* AD = 1 */
onewire_reset(sc->sc_onewire);
done:
onewire_unlock(sc->sc_onewire);
rw_exit_write(&sc->sc_lock);
}
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