NetBSD/sys/dev/i2c/mcp980x.c

229 lines
6.1 KiB
C

/* $NetBSD: mcp980x.c,v 1.1 2013/05/06 22:04:12 rkujawa Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Radoslaw Kujawa.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*
* Microchip MCP9800/1/2/3 2-Wire High-Accuracy Temperature Sensor driver.
* TODO: everything besides simple temperature read with default configuration.
*
* Note: MCP9805 is different and is supported by the sdtemp(4) driver.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mcp980x.c,v 1.1 2013/05/06 22:04:12 rkujawa Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/mutex.h>
#include <sys/endian.h>
#include <sys/bus.h>
#include <dev/i2c/i2cvar.h>
#include <dev/sysmon/sysmonvar.h>
#include <dev/i2c/mcp980xreg.h>
struct mcp980x_softc {
device_t sc_dev;
i2c_tag_t sc_tag;
i2c_addr_t sc_addr;
/* envsys(4) stuff */
struct sysmon_envsys *sc_sme;
envsys_data_t sc_sensor;
kmutex_t sc_lock;
};
static int mcp980x_match(device_t, cfdata_t, void *);
static void mcp980x_attach(device_t, device_t, void *);
/*static uint8_t mcp980x_reg_read_1(struct mcp980x_softc *sc, uint8_t);*/
static uint16_t mcp980x_reg_read_2(struct mcp980x_softc *sc, uint8_t reg);
static uint32_t mcp980x_temperature(struct mcp980x_softc *sc);
static void mcp980x_envsys_register(struct mcp980x_softc *);
static void mcp980x_envsys_refresh(struct sysmon_envsys *, envsys_data_t *);
CFATTACH_DECL_NEW(mcp980x, sizeof (struct mcp980x_softc),
mcp980x_match, mcp980x_attach, NULL, NULL);
static int
mcp980x_match(device_t parent, cfdata_t cf, void *aux)
{
/*
* No sane way to probe? Perhaps at least try to match constant part
* of the I2Caddress.
*/
return 1;
}
static void
mcp980x_attach(device_t parent, device_t self, void *aux)
{
struct mcp980x_softc *sc = device_private(self);
struct i2c_attach_args *ia = aux;
sc->sc_dev = self;
sc->sc_addr = ia->ia_addr;
sc->sc_tag = ia->ia_tag;
aprint_normal(": Microchip MCP980x Temperature Sensor\n");
mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
mcp980x_envsys_register(sc);
}
static uint16_t
mcp980x_reg_read_2(struct mcp980x_softc *sc, uint8_t reg)
{
uint8_t wbuf[2];
uint16_t rv;
if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL) != 0) {
aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n");
return 0;
}
wbuf[0] = reg;
if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf,
1, &rv, 2, I2C_F_POLL)) {
aprint_error_dev(sc->sc_dev, "cannot execute operation\n");
iic_release_bus(sc->sc_tag, I2C_F_POLL);
return 0;
}
iic_release_bus(sc->sc_tag, I2C_F_POLL);
return be16toh(rv);
}
/* Will need that later for reading config register. */
/*
static uint8_t
mcp980x_reg_read_1(struct mcp980x_softc *sc, uint8_t reg)
{
uint8_t rv, wbuf[2];
if (iic_acquire_bus(sc->sc_tag, I2C_F_POLL) != 0) {
aprint_error_dev(sc->sc_dev, "cannot acquire bus for read\n");
return 0;
}
wbuf[0] = reg;
if (iic_exec(sc->sc_tag, I2C_OP_READ_WITH_STOP, sc->sc_addr, wbuf,
1, &rv, 1, I2C_F_POLL)) {
aprint_error_dev(sc->sc_dev, "cannot execute operation\n");
iic_release_bus(sc->sc_tag, I2C_F_POLL);
return 0;
}
iic_release_bus(sc->sc_tag, I2C_F_POLL);
return rv;
}*/
/* Get temperature in microKelvins. */
static uint32_t
mcp980x_temperature(struct mcp980x_softc *sc)
{
uint16_t raw;
uint32_t rv, uk, basedegc;
raw = mcp980x_reg_read_2(sc, MCP980X_AMBIENT_TEMP);
basedegc = (raw & MCP980X_AMBIENT_TEMP_DEGREES) >>
MCP980X_AMBIENT_TEMP_DEGREES_SHIFT;
uk = 1000000 * basedegc;
if (raw & MCP980X_AMBIENT_TEMP_05DEGREE)
uk += 500000;
if (raw & MCP980X_AMBIENT_TEMP_025DEGREE)
uk += 250000;
if (raw & MCP980X_AMBIENT_TEMP_0125DEGREE)
uk += 125000;
if (raw & MCP980X_AMBIENT_TEMP_00625DEGREE)
uk += 62500;
if (raw & MCP980X_AMBIENT_TEMP_SIGN)
rv = 273150000U - uk;
else
rv = 273150000U + uk;
return rv;
}
static void
mcp980x_envsys_register(struct mcp980x_softc *sc)
{
sc->sc_sme = sysmon_envsys_create();
strlcpy(sc->sc_sensor.desc, "Ambient temp",
sizeof(sc->sc_sensor.desc));
sc->sc_sensor.units = ENVSYS_STEMP;
sc->sc_sensor.state = ENVSYS_SINVALID;
if (sysmon_envsys_sensor_attach(sc->sc_sme, &sc->sc_sensor)) {
aprint_error_dev(sc->sc_dev,
"error attaching sensor\n");
return;
}
sc->sc_sme->sme_name = device_xname(sc->sc_dev);
sc->sc_sme->sme_cookie = sc;
sc->sc_sme->sme_refresh = mcp980x_envsys_refresh;
if (sysmon_envsys_register(sc->sc_sme)) {
aprint_error_dev(sc->sc_dev, "unable to register in sysmon\n");
sysmon_envsys_destroy(sc->sc_sme);
}
}
static void
mcp980x_envsys_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
{
struct mcp980x_softc *sc = sme->sme_cookie;
mutex_enter(&sc->sc_lock);
edata->value_cur = mcp980x_temperature(sc);
edata->state = ENVSYS_SVALID;
mutex_exit(&sc->sc_lock);
}