tmp461.c

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/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2021 Alstom Group.
 * Copyright (c) 2021 Semihalf.
 *
 * 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/module.h>
#include <sys/ctype.h>
#include <sys/kernel.h>
#include <sys/libkern.h>
#include <sys/sysctl.h>
 
#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
 
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/ofw_bus.h>
 
#define BIT(x)                                  (1UL << (x))
 
#define TMP461_LOCAL_TEMP_REG_MSB               0x0
#define TMP461_LOCAL_TEMP_REG_LSB               0x15
#define TMP461_GLOBAL_TEMP_REG_MSB              0x1
#define TMP461_GLOBAL_TEMP_REG_LSB              0x10
#define TMP461_CONFIG_REG                       0x3
#define TMP461_CONFIG_REG_TEMP_RANGE_BIT        BIT(2)
 
#define TMP461_EXTENDED_TEMP_MODIFIER           64
/* 28.4 fixed point representation of 273.15f */
#define TMP461_C_TO_K_FIX                       4370
#define TMP461_TEMP_LSB                         0
 
static int tmp461_probe(device_t dev);
static int tmp461_attach(device_t dev);
static int tmp461_read_1(device_t dev, uint8_t reg, uint8_t *data);
static int tmp461_read_temp(device_t dev, int32_t *temp);
static int tmp461_detach(device_t dev);
static int tmp461_sensor_sysctl(SYSCTL_HANDLER_ARGS);
static int32_t tmp461_signed_extend32(uint32_t value, int sign_pos);
 
static device_method_t tmp461_methods[] = {
        DEVMETHOD(device_probe,         tmp461_probe),
        DEVMETHOD(device_attach,        tmp461_attach),
        DEVMETHOD(device_detach,        tmp461_detach),
 
        DEVMETHOD_END
};
 
static driver_t tmp461_driver = {
        "tmp461_dev",
        tmp461_methods,
        0
};
 
static devclass_t tmp461_devclass;
 
static struct ofw_compat_data tmp461_compat_data[] = {
        { "ti,tmp461",          1 },
        { NULL,                 0 }
};
 
DRIVER_MODULE(tmp461, iicbus, tmp461_driver, tmp461_devclass, 0, 0);
IICBUS_FDT_PNP_INFO(tmp461_compat_data);
 
static int
tmp461_attach(device_t dev)
{
        struct sysctl_oid *sensor_root_oid;
        struct sysctl_ctx_list *ctx;
 
        ctx = device_get_sysctl_ctx(dev);
        
        sensor_root_oid = SYSCTL_ADD_NODE(ctx, SYSCTL_STATIC_CHILDREN(_hw),
            OID_AUTO, "temperature", CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
            "TMP 461 Thermal Sensor Information");
        if (sensor_root_oid == NULL)
                return (ENXIO);
 
        SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(sensor_root_oid), OID_AUTO,
            "tmp461", CTLTYPE_INT | CTLFLAG_RD, dev, 0,
            tmp461_sensor_sysctl, "IK0", "TMP461 Thermal Sensor");
 
        return (0);
}
 
static int
tmp461_probe(device_t dev)
{
 
        if (!ofw_bus_status_okay(dev))
                return (ENXIO);
 
        if (!ofw_bus_search_compatible(dev, tmp461_compat_data)->ocd_data)
                return (ENXIO);
 
        device_set_desc(dev, "TMP461 Thermal Sensor");
 
        return (BUS_PROBE_GENERIC);
}
 
static int
tmp461_detach(device_t dev)
{
 
        return (0);
}
 
static int
tmp461_read_1(device_t dev,  uint8_t reg, uint8_t *data)
{
        int error;
 
        error = iicdev_readfrom(dev, reg, (void *) data, 1, IIC_WAIT);
        if (error != 0)
                device_printf(dev, "Failed to read from device\n");
 
        return (error);
}
 
static int
tmp461_read_temp(device_t dev, int32_t *temp)
{
        bool extended_mode;
        uint8_t data;
        int error;
 
        /* read temperature range */
        error = tmp461_read_1(dev, TMP461_CONFIG_REG, &data);
        if (error != 0)
                return (ENXIO);
 
        extended_mode = data & TMP461_CONFIG_REG_TEMP_RANGE_BIT;
 
        /* read temp MSB */
        error = tmp461_read_1(dev, TMP461_LOCAL_TEMP_REG_MSB, &data);
        if (error != 0)
                return (ENXIO);
 
        *temp = signed_extend32(data, TMP461_TEMP_LSB, 8) -
            (extended_mode ? TMP461_EXTENDED_TEMP_MODIFIER : 0);
 
        error = tmp461_read_1(dev, TMP461_LOCAL_TEMP_REG_LSB, &data);
        if (error != 0)
                return (ENXIO);
 
        *temp = (((*temp << 4) | (data >> 4)) + TMP461_C_TO_K_FIX) >> 4;
 
        return (0);
}
 
static int
tmp461_sensor_sysctl(SYSCTL_HANDLER_ARGS)
{
        device_t dev;
        int32_t temp;
        int error;
 
        dev = arg1;
 
        error = tmp461_read_temp(dev, &temp);
        if (error != 0)
                return (error);
 
        return (sysctl_handle_int(oidp, &temp, 0, req));
}