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 {
  82         struct wf_6690_sensor *max;
  83         char *name = "backside-temp";
  84
  85         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
  86         if (max == NULL) {
  87                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor %s: "
  88                        "no memory\n", name);
  89                 return;
  90         }
  91
  92         max->sens.ops = &wf_max6690_ops;
  93         max->sens.name = name;
  94         max->i2c.addr = addr >> 1;
  95         max->i2c.adapter = adapter;
  96         max->i2c.driver = &wf_max6690_driver;
  97         strncpy(max->i2c.name, name, I2C_NAME_SIZE-1);
  98
  99         if (i2c_attach_client(&max->i2c)) {
 100                 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
 101                 goto fail;
 102         }
 103
 104         if (wf_register_sensor(&max->sens)) {
 105                 i2c_detach_client(&max->i2c);
 106                 goto fail;
 107         }
 108
 109         return;
 110
 111  fail:
 112         kfree(max);
 113 }
 114
 115 static int wf_max6690_attach(struct i2c_adapter *adapter)
 116 {
 117         struct device_node *busnode, *dev = NULL;
 118         struct pmac_i2c_bus *bus;
 119         const char *loc;
 120
 121         bus = pmac_i2c_adapter_to_bus(adapter);
 122         if (bus == NULL)
 123                 return -ENODEV;
 124         busnode = pmac_i2c_get_bus_node(bus);
 125
 126         while ((dev = of_get_next_child(busnode, dev)) != NULL) {
 127                 u8 addr;
 128
 129                 /* We must re-match the adapter in order to properly check
 130                  * the channel on multibus setups
 131                  */
 132                 if (!pmac_i2c_match_adapter(dev, adapter))
 133                         continue;
 134                 if (!of_device_is_compatible(dev, "max6690"))
 135                         continue;
 136                 addr = pmac_i2c_get_dev_addr(dev);
 137                 loc = of_get_property(dev, "hwsensor-location", NULL);
 138                 if (loc == NULL || addr == 0)
 139                         continue;
 140                 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
 141                 if (strcmp(loc, "BACKSIDE"))
 142                         continue;
 143                 wf_max6690_create(adapter, addr);
 144         }
 145
 146         return 0;
 147 }
 148
 149 static int wf_max6690_detach(struct i2c_client *client)
 150 {
 151         struct wf_6690_sensor *max = i2c_to_6690(client);
 152
 153         max->i2c.adapter = NULL;
 154         wf_unregister_sensor(&max->sens);
 155
 156         return 0;
 157 }
 158
 159 static int __init wf_max6690_sensor_init(void)
 160 {
 161         /* Don't register on old machines that use therm_pm72 for now */
 162         if (machine_is_compatible("PowerMac7,2") ||
 163             machine_is_compatible("PowerMac7,3") ||
 164             machine_is_compatible("RackMac3,1"))
 165                 return -ENODEV;
 166         return i2c_add_driver(&wf_max6690_driver);
 167 }
 168
 169 static void __exit wf_max6690_sensor_exit(void)
 170 {
 171         i2c_del_driver(&wf_max6690_driver);
 172 }
 173
 174 module_init(wf_max6690_sensor_init);
 175 module_exit(wf_max6690_sensor_exit);
 176
 177 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 178 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 179 MODULE_LICENSE("GPL");