drivers/macintosh/windfarm_max6690_sensor.c

   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
  28 struct 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
  35 static 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
  51 static 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
  58 static struct wf_sensor_ops wf_max6690_ops = {
  59         .get_value      = wf_max6690_get,
  60         .release        = wf_max6690_release,
  61         .owner          = THIS_MODULE,
  62 };
  63
  64 static 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 = name;
  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
 108 static 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
 118 static const struct i2c_device_id wf_max6690_id[] = {
 119         { "MAC,max6690", 0 },
 120         { }
 121 };
 122 MODULE_DEVICE_TABLE(i2c, wf_max6690_id);
 123
 124 static 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
 133 module_i2c_driver(wf_max6690_driver);
 134
 135 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 136 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 137 MODULE_LICENSE("GPL");