lm75.c

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/*-
 * Copyright (c) 2010 Andreas Tobler.
 * Copyright (c) 2013-2014 Luiz Otavio O Souza <loos@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, 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 "opt_platform.h"
 
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/endian.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/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
 
/* LM75 registers. */
#define LM75_TEMP       0x0
#define LM75_TEMP_MASK          0xff80
#define LM75A_TEMP_MASK         0xffe0
#define LM75_CONF       0x1
#define LM75_CONF_FSHIFT        3
#define LM75_CONF_FAULT         0x18
#define LM75_CONF_POL           0x04
#define LM75_CONF_MODE          0x02
#define LM75_CONF_SHUTD         0x01
#define LM75_CONF_MASK          0x1f
#define LM75_THYST      0x2
#define LM75_TOS        0x3
 
/* LM75 constants. */
#define LM75_TEST_PATTERN       0xa
#define LM75_MIN_TEMP           -55
#define LM75_MAX_TEMP           125
#define LM75_0500C              0x80
#define LM75_0250C              0x40
#define LM75_0125C              0x20
#define LM75_MSB                0x8000
#define LM75_NEG_BIT            LM75_MSB
#define TZ_ZEROC                2731
 
/* LM75 supported models. */
#define HWTYPE_LM75             1
#define HWTYPE_LM75A            2
 
/* Regular bus attachment functions */
static int  lm75_probe(device_t);
static int  lm75_attach(device_t);
 
struct lm75_softc {
        device_t                sc_dev;
        struct intr_config_hook enum_hook;
        int32_t                 sc_hwtype;
        uint32_t                sc_addr;
        uint32_t                sc_conf;
};
 
/* Utility functions */
static int  lm75_conf_read(struct lm75_softc *);
static int  lm75_conf_write(struct lm75_softc *);
static int  lm75_temp_read(struct lm75_softc *, uint8_t, int *);
static int  lm75_temp_write(struct lm75_softc *, uint8_t, int);
static void lm75_start(void *);
static int  lm75_read(device_t, uint32_t, uint8_t, uint8_t *, size_t);
static int  lm75_write(device_t, uint32_t, uint8_t *, size_t);
static int  lm75_str_mode(char *);
static int  lm75_str_pol(char *);
static int  lm75_temp_sysctl(SYSCTL_HANDLER_ARGS);
static int  lm75_faults_sysctl(SYSCTL_HANDLER_ARGS);
static int  lm75_mode_sysctl(SYSCTL_HANDLER_ARGS);
static int  lm75_pol_sysctl(SYSCTL_HANDLER_ARGS);
static int  lm75_shutdown_sysctl(SYSCTL_HANDLER_ARGS);
 
static device_method_t  lm75_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         lm75_probe),
        DEVMETHOD(device_attach,        lm75_attach),
 
        DEVMETHOD_END
};
 
static driver_t lm75_driver = {
        "lm75",
        lm75_methods,
        sizeof(struct lm75_softc)
};
 
static devclass_t lm75_devclass;
 
DRIVER_MODULE(lm75, iicbus, lm75_driver, lm75_devclass, 0, 0);
 
static int
lm75_read(device_t dev, uint32_t addr, uint8_t reg, uint8_t *data, size_t len)
{
        struct iic_msg msg[2] = {
            { addr, IIC_M_WR | IIC_M_NOSTOP, 1, &reg },
            { addr, IIC_M_RD, len, data },
        };
 
        if (iicbus_transfer(dev, msg, nitems(msg)) != 0)
                return (-1);
 
        return (0);
}
 
static int
lm75_write(device_t dev, uint32_t addr, uint8_t *data, size_t len)
{
        struct iic_msg msg[1] = {
            { addr, IIC_M_WR, len, data },
        };
 
        if (iicbus_transfer(dev, msg, nitems(msg)) != 0)
                return (-1);
 
        return (0);
}
 
static int
lm75_probe(device_t dev)
{
        struct lm75_softc *sc;
 
        sc = device_get_softc(dev);
        sc->sc_hwtype = HWTYPE_LM75;
#ifdef FDT
        if (!ofw_bus_is_compatible(dev, "national,lm75"))
                return (ENXIO);
#endif
        device_set_desc(dev, "LM75 temperature sensor");
 
        return (BUS_PROBE_GENERIC);
}
 
static int
lm75_attach(device_t dev)
{
        struct lm75_softc *sc;
 
        sc = device_get_softc(dev);
        sc->sc_dev = dev;
        sc->sc_addr = iicbus_get_addr(dev);
 
        sc->enum_hook.ich_func = lm75_start;
        sc->enum_hook.ich_arg = dev;
 
        /*
         * We have to wait until interrupts are enabled.  Usually I2C read
         * and write only works when the interrupts are available.
         */
        if (config_intrhook_establish(&sc->enum_hook) != 0)
                return (ENOMEM);
 
        return (0);
}
 
static int
lm75_type_detect(struct lm75_softc *sc)
{
        int i, lm75a;
        uint8_t buf8;
        uint32_t conf;
 
        /* Save the contents of the configuration register. */
        if (lm75_conf_read(sc) != 0)
                return (-1);
        conf = sc->sc_conf;
 
        /*
         * Just write some pattern at configuration register so we can later
         * verify.  The test pattern should be pretty harmless.
         */
        sc->sc_conf = LM75_TEST_PATTERN;
        if (lm75_conf_write(sc) != 0)
                return (-1);
 
        /*
         * Read the configuration register again and check for our test
         * pattern.
         */
        if (lm75_conf_read(sc) != 0)
                return (-1);
        if (sc->sc_conf != LM75_TEST_PATTERN)
                return (-1);
 
        /*
         * Read from nonexistent registers (0x4 ~ 0x6).
         * LM75A always return 0xff for nonexistent registers.
         * LM75 will return the last read value - our test pattern written to
         * configuration register.
         */
        lm75a = 0;
        for (i = 4; i <= 6; i++) {
                if (lm75_read(sc->sc_dev, sc->sc_addr, i,
                    &buf8, sizeof(buf8)) < 0)
                        return (-1);
                if (buf8 != LM75_TEST_PATTERN && buf8 != 0xff)
                        return (-1);
                if (buf8 == 0xff)
                        lm75a++;
        }
        if (lm75a == 3)
                sc->sc_hwtype = HWTYPE_LM75A;
 
        /* Restore the configuration register. */
        sc->sc_conf = conf;
        if (lm75_conf_write(sc) != 0)
                return (-1);
 
        return (0);
}
 
static void
lm75_start(void *xdev)
{
        device_t dev;
        struct lm75_softc *sc;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *tree_node;
        struct sysctl_oid_list *tree;
 
        dev = (device_t)xdev;
        sc = device_get_softc(dev);
        ctx = device_get_sysctl_ctx(dev);
        tree_node = device_get_sysctl_tree(dev);
        tree = SYSCTL_CHILDREN(tree_node);
 
        config_intrhook_disestablish(&sc->enum_hook);
 
        /*
         * Detect the kind of chip we are attaching to.
         * This may not work for LM75 clones.
         */
        if (lm75_type_detect(sc) != 0) {
                device_printf(dev, "cannot read from sensor.\n");
                return;
        }
        if (sc->sc_hwtype == HWTYPE_LM75A)
                device_printf(dev,
                    "LM75A type sensor detected (11bits resolution).\n");
 
        /* Temperature. */
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temperature",
            CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, LM75_TEMP,
            lm75_temp_sysctl, "IK", "Current temperature");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "thyst",
            CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, dev, LM75_THYST,
            lm75_temp_sysctl, "IK", "Hysteresis temperature");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "tos",
            CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, dev, LM75_TOS,
            lm75_temp_sysctl, "IK", "Overtemperature");
 
        /* Configuration parameters. */
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "faults",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, dev, 0,
            lm75_faults_sysctl, "IU", "LM75 fault queue");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "mode",
            CTLFLAG_RW | CTLTYPE_STRING | CTLFLAG_MPSAFE, dev, 0,
            lm75_mode_sysctl, "A", "LM75 mode");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "polarity",
            CTLFLAG_RW | CTLTYPE_STRING | CTLFLAG_MPSAFE, dev, 0,
            lm75_pol_sysctl, "A", "LM75 OS polarity");
        SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "shutdown",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, dev, 0,
            lm75_shutdown_sysctl, "IU", "LM75 shutdown");
}
 
static int
lm75_conf_read(struct lm75_softc *sc)
{
        uint8_t buf8;
 
        if (lm75_read(sc->sc_dev, sc->sc_addr, LM75_CONF,
            &buf8, sizeof(buf8)) < 0)
                return (-1);
        sc->sc_conf = (uint32_t)buf8;
 
        return (0);
}
 
static int
lm75_conf_write(struct lm75_softc *sc)
{
        uint8_t buf8[2];
 
        buf8[0] = LM75_CONF;
        buf8[1] = (uint8_t)sc->sc_conf & LM75_CONF_MASK;
        if (lm75_write(sc->sc_dev, sc->sc_addr, buf8, sizeof(buf8)) < 0)
                return (-1);
 
        return (0);
}
 
static int
lm75_temp_read(struct lm75_softc *sc, uint8_t reg, int *temp)
{
        uint8_t buf8[2];
        uint16_t buf;
        int neg, t;
 
        if (lm75_read(sc->sc_dev, sc->sc_addr, reg, buf8, sizeof(buf8)) < 0)
                return (-1);
        buf = (uint16_t)((buf8[0] << 8) | (buf8[1] & 0xff));
        /*
         * LM75 has a 9 bit ADC with resolution of 0.5 C per bit.
         * LM75A has an 11 bit ADC with resolution of 0.125 C per bit.
         * Temperature is stored with two's complement.
         */
        neg = 0;
        if (buf & LM75_NEG_BIT) {
                if (sc->sc_hwtype == HWTYPE_LM75A)
                        buf = ~(buf & LM75A_TEMP_MASK) + 1;
                else
                        buf = ~(buf & LM75_TEMP_MASK) + 1;
                neg = 1;
        }
        *temp = ((int16_t)buf >> 8) * 10;
        t = 0;
        if (sc->sc_hwtype == HWTYPE_LM75A) {
                if (buf & LM75_0125C)
                        t += 125;
                if (buf & LM75_0250C)
                        t += 250;
        }
        if (buf & LM75_0500C)
                t += 500;
        t /= 100;
        *temp += t;
        if (neg)
                *temp = -(*temp);
        *temp += TZ_ZEROC;
 
        return (0);
}
 
static int
lm75_temp_write(struct lm75_softc *sc, uint8_t reg, int temp)
{
        uint8_t buf8[3];
        uint16_t buf;
 
        temp = (temp - TZ_ZEROC) / 10;
        if (temp > LM75_MAX_TEMP)
                temp = LM75_MAX_TEMP;
        if (temp < LM75_MIN_TEMP)
                temp = LM75_MIN_TEMP;
 
        buf = (uint16_t)temp;
        buf <<= 8;
 
        buf8[0] = reg;
        buf8[1] = buf >> 8;
        buf8[2] = buf & 0xff;
        if (lm75_write(sc->sc_dev, sc->sc_addr, buf8, sizeof(buf8)) < 0)
                return (-1);
 
        return (0);
}
 
static int
lm75_str_mode(char *buf)
{
        int len, rtrn;
 
        rtrn = -1;
        len = strlen(buf);
        if (len > 2 && strncasecmp("interrupt", buf, len) == 0)
                rtrn = 1;
        else if (len > 2 && strncasecmp("comparator", buf, len) == 0)
                rtrn = 0;
 
        return (rtrn);
}
 
static int
lm75_str_pol(char *buf)
{
        int len, rtrn;
 
        rtrn = -1;
        len = strlen(buf);
        if (len > 1 && strncasecmp("high", buf, len) == 0)
                rtrn = 1;
        else if (len > 1 && strncasecmp("low", buf, len) == 0)
                rtrn = 0;
        else if (len > 8 && strncasecmp("active-high", buf, len) == 0)
                rtrn = 1;
        else if (len > 8 && strncasecmp("active-low", buf, len) == 0)
                rtrn = 0;
 
        return (rtrn);
}
 
static int
lm75_temp_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        int error, temp;
        struct lm75_softc *sc;
        uint8_t reg;
 
        dev = (device_t)arg1;
        reg = (uint8_t)arg2;
        sc = device_get_softc(dev);
 
        if (lm75_temp_read(sc, reg, &temp) != 0)
                return (EIO);
 
        error = sysctl_handle_int(oidp, &temp, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
 
        if (lm75_temp_write(sc, reg, temp) != 0)
                return (EIO);
 
        return (error);
}
 
static int
lm75_faults_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        int lm75_faults[] = { 1, 2, 4, 6 };
        int error, faults, i, newf, tmp;
        struct lm75_softc *sc;
 
        dev = (device_t)arg1;
        sc = device_get_softc(dev);
        tmp = (sc->sc_conf & LM75_CONF_FAULT) >> LM75_CONF_FSHIFT;
        if (tmp >= nitems(lm75_faults))
                tmp = nitems(lm75_faults) - 1;
        faults = lm75_faults[tmp];
 
        error = sysctl_handle_int(oidp, &faults, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
 
        if (faults != lm75_faults[tmp]) {
                newf = 0;
                for (i = 0; i < nitems(lm75_faults); i++)
                        if (faults >= lm75_faults[i])
                                newf = i;
                sc->sc_conf &= ~LM75_CONF_FAULT;
                sc->sc_conf |= newf << LM75_CONF_FSHIFT;
                if (lm75_conf_write(sc) != 0)
                        return (EIO);
        }
 
        return (error);
}
 
static int
lm75_mode_sysctl(SYSCTL_HANDLER_ARGS)
{
        char buf[16];
        device_t dev;
        int error, mode, newm;
        struct lm75_softc *sc;
 
        dev = (device_t)arg1;
        sc = device_get_softc(dev);
        if (sc->sc_conf & LM75_CONF_MODE) {
                mode = 1;
                strlcpy(buf, "interrupt", sizeof(buf));
        } else {
                mode = 0;
                strlcpy(buf, "comparator", sizeof(buf));
        }
 
        error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
        if (error != 0 || req->newptr == NULL)
                return (error);
 
        newm = lm75_str_mode(buf);
        if (newm != -1 && mode != newm) {
                sc->sc_conf &= ~LM75_CONF_MODE;
                if (newm == 1)
                        sc->sc_conf |= LM75_CONF_MODE;
                if (lm75_conf_write(sc) != 0)
                        return (EIO);
        }
 
        return (error);
}
 
static int
lm75_pol_sysctl(SYSCTL_HANDLER_ARGS)
{
        char buf[16];
        device_t dev;
        int error, newp, pol;
        struct lm75_softc *sc;
 
        dev = (device_t)arg1;
        sc = device_get_softc(dev);
        if (sc->sc_conf & LM75_CONF_POL) {
                pol = 1;
                strlcpy(buf, "active-high", sizeof(buf));
        } else {
                pol = 0;
                strlcpy(buf, "active-low", sizeof(buf));
        }
 
        error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
        if (error != 0 || req->newptr == NULL)
                return (error);
 
        newp = lm75_str_pol(buf);
        if (newp != -1 && pol != newp) {
                sc->sc_conf &= ~LM75_CONF_POL;
                if (newp == 1)
                        sc->sc_conf |= LM75_CONF_POL;
                if (lm75_conf_write(sc) != 0)
                        return (EIO);
        }
 
        return (error);
}
 
static int
lm75_shutdown_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        int error, shutdown, tmp;
        struct lm75_softc *sc;
 
        dev = (device_t)arg1;
        sc = device_get_softc(dev);
        tmp = shutdown = (sc->sc_conf & LM75_CONF_SHUTD) ? 1 : 0;
 
        error = sysctl_handle_int(oidp, &shutdown, 0, req);
        if (error != 0 || req->newptr == NULL)
                return (error);
 
        if (shutdown != tmp) {
                sc->sc_conf &= ~LM75_CONF_SHUTD;
                if (shutdown)
                        sc->sc_conf |= LM75_CONF_SHUTD;
                if (lm75_conf_write(sc) != 0)
                        return (EIO);
        }
 
        return (error);
}