linux/drivers/macintosh/windfarm_max6690_sensor.c
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   1/*
   2 * Windfarm PowerMac thermal control.  MAX6690 sensor.
   3 *
   4 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
   5 *
   6 * Use and redistribute under the terms of the GNU GPL v2.
   7 */
   8#include <linux/types.h>
   9#include <linux/errno.h>
  10#include <linux/kernel.h>
  11#include <linux/init.h>
  12#include <linux/slab.h>
  13#include <linux/i2c.h>
  14#include <asm/prom.h>
  15#include <asm/pmac_low_i2c.h>
  16
  17#include "windfarm.h"
  18
  19#define VERSION "1.0"
  20
  21/* This currently only exports the external temperature sensor,
  22   since that's all the control loops need. */
  23
  24/* Some MAX6690 register numbers */
  25#define MAX6690_INTERNAL_TEMP   0
  26#define MAX6690_EXTERNAL_TEMP   1
  27
  28struct wf_6690_sensor {
  29        struct i2c_client       *i2c;
  30        struct wf_sensor        sens;
  31};
  32
  33#define wf_to_6690(x)   container_of((x), struct wf_6690_sensor, sens)
  34
  35static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
  36{
  37        struct wf_6690_sensor *max = wf_to_6690(sr);
  38        s32 data;
  39
  40        if (max->i2c == NULL)
  41                return -ENODEV;
  42
  43        /* chip gets initialized by firmware */
  44        data = i2c_smbus_read_byte_data(max->i2c, MAX6690_EXTERNAL_TEMP);
  45        if (data < 0)
  46                return data;
  47        *value = data << 16;
  48        return 0;
  49}
  50
  51static void wf_max6690_release(struct wf_sensor *sr)
  52{
  53        struct wf_6690_sensor *max = wf_to_6690(sr);
  54
  55        kfree(max);
  56}
  57
  58static struct wf_sensor_ops wf_max6690_ops = {
  59        .get_value      = wf_max6690_get,
  60        .release        = wf_max6690_release,
  61        .owner          = THIS_MODULE,
  62};
  63
  64static int wf_max6690_probe(struct i2c_client *client,
  65                            const struct i2c_device_id *id)
  66{
  67        const char *name, *loc;
  68        struct wf_6690_sensor *max;
  69        int rc;
  70
  71        loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
  72        if (!loc) {
  73                dev_warn(&client->dev, "Missing hwsensor-location property!\n");
  74                return -ENXIO;
  75        }
  76
  77        /*
  78         * We only expose the external temperature register for
  79         * now as this is all we need for our control loops
  80         */
  81        if (!strcmp(loc, "BACKSIDE") || !strcmp(loc, "SYS CTRLR AMBIENT"))
  82                name = "backside-temp";
  83        else if (!strcmp(loc, "NB Ambient"))
  84                name = "north-bridge-temp";
  85        else if (!strcmp(loc, "GPU Ambient"))
  86                name = "gpu-temp";
  87        else
  88                return -ENXIO;
  89
  90        max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  91        if (max == NULL) {
  92                printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
  93                       "no memory\n");
  94                return -ENOMEM;
  95        }
  96
  97        max->i2c = client;
  98        max->sens.name = (char *)name; /* XXX fix constness in structure */
  99        max->sens.ops = &wf_max6690_ops;
 100        i2c_set_clientdata(client, max);
 101
 102        rc = wf_register_sensor(&max->sens);
 103        if (rc)
 104                kfree(max);
 105        return rc;
 106}
 107
 108static int wf_max6690_remove(struct i2c_client *client)
 109{
 110        struct wf_6690_sensor *max = i2c_get_clientdata(client);
 111
 112        max->i2c = NULL;
 113        wf_unregister_sensor(&max->sens);
 114
 115        return 0;
 116}
 117
 118static const struct i2c_device_id wf_max6690_id[] = {
 119        { "MAC,max6690", 0 },
 120        { }
 121};
 122MODULE_DEVICE_TABLE(i2c, wf_max6690_id);
 123
 124static struct i2c_driver wf_max6690_driver = {
 125        .driver = {
 126                .name           = "wf_max6690",
 127        },
 128        .probe          = wf_max6690_probe,
 129        .remove         = wf_max6690_remove,
 130        .id_table       = wf_max6690_id,
 131};
 132
 133module_i2c_driver(wf_max6690_driver);
 134
 135MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 136MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 137MODULE_LICENSE("GPL");
 138
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