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 #define i2c_to_6690(x)  container_of((x), struct wf_6690_sensor, i2c)
  35
  36 static int wf_max6690_attach(struct i2c_adapter *adapter);
  37 static int wf_max6690_detach(struct i2c_client *client);
  38
  39 static struct i2c_driver wf_max6690_driver = {
  40         .driver = {
  41                 .name           = "wf_max6690",
  42         },
  43         .attach_adapter = wf_max6690_attach,
  44         .detach_client  = wf_max6690_detach,
  45 };
  46
  47 static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
  48 {
  49         struct wf_6690_sensor *max = wf_to_6690(sr);
  50         s32 data;
  51
  52         if (max->i2c.adapter == NULL)
  53                 return -ENODEV;
  54
  55         /* chip gets initialized by firmware */
  56         data = i2c_smbus_read_byte_data(&max->i2c, MAX6690_EXTERNAL_TEMP);
  57         if (data < 0)
  58                 return data;
  59         *value = data << 16;
  60         return 0;
  61 }
  62
  63 static void wf_max6690_release(struct wf_sensor *sr)
  64 {
  65         struct wf_6690_sensor *max = wf_to_6690(sr);
  66
  67         if (max->i2c.adapter) {
  68                 i2c_detach_client(&max->i2c);
  69                 max->i2c.adapter = NULL;
  70         }
  71         kfree(max);
  72 }
  73
  74 static struct wf_sensor_ops wf_max6690_ops = {
  75         .get_value      = wf_max6690_get,
  76         .release        = wf_max6690_release,
  77         .owner          = THIS_MODULE,
  78 };
  79
  80 static void wf_max6690_create(struct i2c_adapter *adapter, u8 addr,
  81                               const char *loc)
  82 {
  83         struct wf_6690_sensor *max;
  84         char *name;
  85
  86         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  87         if (max == NULL) {
  88                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor %s: "
  89                        "no memory\n", loc);
  90                 return;
  91         }
  92
  93         if (!strcmp(loc, "BACKSIDE"))
  94                 name = "backside-temp";
  95         else if (!strcmp(loc, "NB Ambient"))
  96                 name = "north-bridge-temp";
  97         else if (!strcmp(loc, "GPU Ambient"))
  98                 name = "gpu-temp";
  99         else
 100                 goto fail;
 101
 102         max->sens.ops = &wf_max6690_ops;
 103         max->sens.name = name;
 104         max->i2c.addr = addr >> 1;
 105         max->i2c.adapter = adapter;
 106         max->i2c.driver = &wf_max6690_driver;
 107         strncpy(max->i2c.name, name, I2C_NAME_SIZE-1);
 108
 109         if (i2c_attach_client(&max->i2c)) {
 110                 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
 111                 goto fail;
 112         }
 113
 114         if (wf_register_sensor(&max->sens)) {
 115                 i2c_detach_client(&max->i2c);
 116                 goto fail;
 117         }
 118
 119         return;
 120
 121  fail:
 122         kfree(max);
 123 }
 124
 125 static int wf_max6690_attach(struct i2c_adapter *adapter)
 126 {
 127         struct device_node *busnode, *dev = NULL;
 128         struct pmac_i2c_bus *bus;
 129         const char *loc;
 130
 131         bus = pmac_i2c_adapter_to_bus(adapter);
 132         if (bus == NULL)
 133                 return -ENODEV;
 134         busnode = pmac_i2c_get_bus_node(bus);
 135
 136         while ((dev = of_get_next_child(busnode, dev)) != NULL) {
 137                 u8 addr;
 138
 139                 /* We must re-match the adapter in order to properly check
 140                  * the channel on multibus setups
 141                  */
 142                 if (!pmac_i2c_match_adapter(dev, adapter))
 143                         continue;
 144                 if (!of_device_is_compatible(dev, "max6690"))
 145                         continue;
 146                 addr = pmac_i2c_get_dev_addr(dev);
 147                 loc = of_get_property(dev, "hwsensor-location", NULL);
 148                 if (loc == NULL || addr == 0)
 149                         continue;
 150                 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
 151                 wf_max6690_create(adapter, addr, loc);
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int wf_max6690_detach(struct i2c_client *client)
 158 {
 159         struct wf_6690_sensor *max = i2c_to_6690(client);
 160
 161         max->i2c.adapter = NULL;
 162         wf_unregister_sensor(&max->sens);
 163
 164         return 0;
 165 }
 166
 167 static int __init wf_max6690_sensor_init(void)
 168 {
 169         /* Don't register on old machines that use therm_pm72 for now */
 170         if (machine_is_compatible("PowerMac7,2") ||
 171             machine_is_compatible("PowerMac7,3") ||
 172             machine_is_compatible("RackMac3,1"))
 173                 return -ENODEV;
 174         return i2c_add_driver(&wf_max6690_driver);
 175 }
 176
 177 static void __exit wf_max6690_sensor_exit(void)
 178 {
 179         i2c_del_driver(&wf_max6690_driver);
 180 }
 181
 182 module_init(wf_max6690_sensor_init);
 183 module_exit(wf_max6690_sensor_exit);
 184
 185 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 186 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 187 MODULE_LICENSE("GPL");