windfarm_lm75_sensor.c

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/*
 * Windfarm PowerMac thermal control. LM75 sensor
 *
 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
 *                    <[email protected]>
 *
 * Released under the term of the GNU GPL v2.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/i2c.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/sections.h>
#include <asm/pmac_low_i2c.h>

#include "windfarm.h"

#define VERSION "1.0"

#undef DEBUG

#ifdef DEBUG
#define DBG(args...)    printk(args)
#else
#define DBG(args...)    do { } while(0)
#endif

struct wf_lm75_sensor {
    int         ds1775 : 1;
    int         inited : 1;
    struct i2c_client   *i2c;
    struct wf_sensor    sens;
};
#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)

static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
{
    struct wf_lm75_sensor *lm = wf_to_lm75(sr);
    s32 data;

    if (lm->i2c == NULL)
        return -ENODEV;

    /* Init chip if necessary */
    if (!lm->inited) {
        u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);

        DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
            sr->name, cfg);

        /* clear shutdown bit, keep other settings as left by
         * the firmware for now
         */
        cfg_new = cfg & ~0x01;
        i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
        lm->inited = 1;

        /* If we just powered it up, let's wait 200 ms */
        msleep(200);
    }

    /* Read temperature register */
    data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
    data <<= 8;
    *value = data;

    return 0;
}

static void wf_lm75_release(struct wf_sensor *sr)
{
    struct wf_lm75_sensor *lm = wf_to_lm75(sr);

    kfree(lm);
}

static struct wf_sensor_ops wf_lm75_ops = {
    .get_value  = wf_lm75_get,
    .release    = wf_lm75_release,
    .owner      = THIS_MODULE,
};

static int wf_lm75_probe(struct i2c_client *client,
             const struct i2c_device_id *id)
{   
    struct wf_lm75_sensor *lm;
    int rc, ds1775 = id->driver_data;
    const char *name, *loc;

    DBG("wf_lm75: creating  %s device at address 0x%02x\n",
        ds1775 ? "ds1775" : "lm75", client->addr);

    loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
    if (!loc) {
        dev_warn(&client->dev, "Missing hwsensor-location property!\n");
        return -ENXIO;
    }

    /* Usual rant about sensor names not beeing very consistent in
     * the device-tree, oh well ...
     * Add more entries below as you deal with more setups
     */
    if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
        name = "hd-temp";
    else if (!strcmp(loc, "Incoming Air Temp"))
        name = "incoming-air-temp";
    else if (!strcmp(loc, "ODD Temp"))
        name = "optical-drive-temp";
    else if (!strcmp(loc, "HD Temp"))
        name = "hard-drive-temp";
    else if (!strcmp(loc, "PCI SLOTS"))
        name = "slots-temp";
    else if (!strcmp(loc, "CPU A INLET"))
        name = "cpu-inlet-temp-0";
    else if (!strcmp(loc, "CPU B INLET"))
        name = "cpu-inlet-temp-1";
    else
        return -ENXIO;
    

    lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
    if (lm == NULL)
        return -ENODEV;

    lm->inited = 0;
    lm->ds1775 = ds1775;
    lm->i2c = client;
    lm->sens.name = (char *)name; /* XXX fix constness in structure */
    lm->sens.ops = &wf_lm75_ops;
    i2c_set_clientdata(client, lm);

    rc = wf_register_sensor(&lm->sens);
    if (rc)
        kfree(lm);
    return rc;
}

static int wf_lm75_remove(struct i2c_client *client)
{
    struct wf_lm75_sensor *lm = i2c_get_clientdata(client);

    DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);

    /* Mark client detached */
    lm->i2c = NULL;

    /* release sensor */
    wf_unregister_sensor(&lm->sens);

    return 0;
}

static const struct i2c_device_id wf_lm75_id[] = {
    { "MAC,lm75", 0 },
    { "MAC,ds1775", 1 },
    { }
};
MODULE_DEVICE_TABLE(i2c, wf_lm75_id);

static struct i2c_driver wf_lm75_driver = {
    .driver = {
        .name   = "wf_lm75",
    },
    .probe      = wf_lm75_probe,
    .remove     = wf_lm75_remove,
    .id_table   = wf_lm75_id,
};

static int __init wf_lm75_sensor_init(void)
{
    return i2c_add_driver(&wf_lm75_driver);
}

static void __exit wf_lm75_sensor_exit(void)
{
    i2c_del_driver(&wf_lm75_driver);
}


module_init(wf_lm75_sensor_init);
module_exit(wf_lm75_sensor_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
MODULE_LICENSE("GPL");