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 "0.2"
  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         struct wf_6690_sensor *max;
  68         int rc;
  69
  70         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  71         if (max == NULL) {
  72                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
  73                        "no memory\n");
  74                 return -ENOMEM;
  75         }
  76
  77         max->i2c = client;
  78         max->sens.name = client->dev.platform_data;
  79         max->sens.ops = &wf_max6690_ops;
  80         i2c_set_clientdata(client, max);
  81
  82         rc = wf_register_sensor(&max->sens);
  83         if (rc) {
  84                 i2c_set_clientdata(client, NULL);
  85                 kfree(max);
  86         }
  87
  88         return rc;
  89 }
  90
  91 static struct i2c_driver wf_max6690_driver;
  92
  93 static struct i2c_client *wf_max6690_create(struct i2c_adapter *adapter,
  94                                             u8 addr, const char *loc)
  95 {
  96         struct i2c_board_info info;
  97         struct i2c_client *client;
  98         char *name;
  99
 100         if (!strcmp(loc, "BACKSIDE"))
 101                 name = "backside-temp";
 102         else if (!strcmp(loc, "NB Ambient"))
 103                 name = "north-bridge-temp";
 104         else if (!strcmp(loc, "GPU Ambient"))
 105                 name = "gpu-temp";
 106         else
 107                 goto fail;
 108
 109         memset(&info, 0, sizeof(struct i2c_board_info));
 110         info.addr = addr >> 1;
 111         info.platform_data = name;
 112         strlcpy(info.type, "wf_max6690", I2C_NAME_SIZE);
 113
 114         client = i2c_new_device(adapter, &info);
 115         if (client == NULL) {
 116                 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
 117                 goto fail;
 118         }
 119
 120         /*
 121          * Let i2c-core delete that device on driver removal.
 122          * This is safe because i2c-core holds the core_lock mutex for us.
 123          */
 124         list_add_tail(&client->detected, &wf_max6690_driver.clients);
 125         return client;
 126
 127  fail:
 128         return NULL;
 129 }
 130
 131 static int wf_max6690_attach(struct i2c_adapter *adapter)
 132 {
 133         struct device_node *busnode, *dev = NULL;
 134         struct pmac_i2c_bus *bus;
 135         const char *loc;
 136
 137         bus = pmac_i2c_adapter_to_bus(adapter);
 138         if (bus == NULL)
 139                 return -ENODEV;
 140         busnode = pmac_i2c_get_bus_node(bus);
 141
 142         while ((dev = of_get_next_child(busnode, dev)) != NULL) {
 143                 u8 addr;
 144
 145                 /* We must re-match the adapter in order to properly check
 146                  * the channel on multibus setups
 147                  */
 148                 if (!pmac_i2c_match_adapter(dev, adapter))
 149                         continue;
 150                 if (!of_device_is_compatible(dev, "max6690"))
 151                         continue;
 152                 addr = pmac_i2c_get_dev_addr(dev);
 153                 loc = of_get_property(dev, "hwsensor-location", NULL);
 154                 if (loc == NULL || addr == 0)
 155                         continue;
 156                 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
 157                 wf_max6690_create(adapter, addr, loc);
 158         }
 159
 160         return 0;
 161 }
 162
 163 static int wf_max6690_remove(struct i2c_client *client)
 164 {
 165         struct wf_6690_sensor *max = i2c_get_clientdata(client);
 166
 167         max->i2c = NULL;
 168         wf_unregister_sensor(&max->sens);
 169
 170         return 0;
 171 }
 172
 173 static const struct i2c_device_id wf_max6690_id[] = {
 174         { "wf_max6690", 0 },
 175         { }
 176 };
 177
 178 static struct i2c_driver wf_max6690_driver = {
 179         .driver = {
 180                 .name           = "wf_max6690",
 181         },
 182         .attach_adapter = wf_max6690_attach,
 183         .probe          = wf_max6690_probe,
 184         .remove         = wf_max6690_remove,
 185         .id_table       = wf_max6690_id,
 186 };
 187
 188 static int __init wf_max6690_sensor_init(void)
 189 {
 190         /* Don't register on old machines that use therm_pm72 for now */
 191         if (of_machine_is_compatible("PowerMac7,2") ||
 192             of_machine_is_compatible("PowerMac7,3") ||
 193             of_machine_is_compatible("RackMac3,1"))
 194                 return -ENODEV;
 195         return i2c_add_driver(&wf_max6690_driver);
 196 }
 197
 198 static void __exit wf_max6690_sensor_exit(void)
 199 {
 200         i2c_del_driver(&wf_max6690_driver);
 201 }
 202
 203 module_init(wf_max6690_sensor_init);
 204 module_exit(wf_max6690_sensor_exit);
 205
 206 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 207 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 208 MODULE_LICENSE("GPL");