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 <linux/i2c-dev.h>
  15 #include <asm/prom.h>
  16 #include <asm/pmac_low_i2c.h>
  17
  18 #include "windfarm.h"
  19
  20 #define VERSION "0.2"
  21
  22 /* This currently only exports the external temperature sensor,
  23    since that's all the control loops need. */
  24
  25 /* Some MAX6690 register numbers */
  26 #define MAX6690_INTERNAL_TEMP   0
  27 #define MAX6690_EXTERNAL_TEMP   1
  28
  29 struct wf_6690_sensor {
  30         struct i2c_client       i2c;
  31         struct wf_sensor        sens;
  32 };
  33
  34 #define wf_to_6690(x)   container_of((x), struct wf_6690_sensor, sens)
  35 #define i2c_to_6690(x)  container_of((x), struct wf_6690_sensor, i2c)
  36
  37 static int wf_max6690_attach(struct i2c_adapter *adapter);
  38 static int wf_max6690_detach(struct i2c_client *client);
  39
  40 static struct i2c_driver wf_max6690_driver = {
  41         .driver = {
  42                 .name           = "wf_max6690",
  43         },
  44         .attach_adapter = wf_max6690_attach,
  45         .detach_client  = wf_max6690_detach,
  46 };
  47
  48 static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
  49 {
  50         struct wf_6690_sensor *max = wf_to_6690(sr);
  51         s32 data;
  52
  53         if (max->i2c.adapter == NULL)
  54                 return -ENODEV;
  55
  56         /* chip gets initialized by firmware */
  57         data = i2c_smbus_read_byte_data(&max->i2c, MAX6690_EXTERNAL_TEMP);
  58         if (data < 0)
  59                 return data;
  60         *value = data << 16;
  61         return 0;
  62 }
  63
  64 static void wf_max6690_release(struct wf_sensor *sr)
  65 {
  66         struct wf_6690_sensor *max = wf_to_6690(sr);
  67
  68         if (max->i2c.adapter) {
  69                 i2c_detach_client(&max->i2c);
  70                 max->i2c.adapter = NULL;
  71         }
  72         kfree(max);
  73 }
  74
  75 static struct wf_sensor_ops wf_max6690_ops = {
  76         .get_value      = wf_max6690_get,
  77         .release        = wf_max6690_release,
  78         .owner          = THIS_MODULE,
  79 };
  80
  81 static void wf_max6690_create(struct i2c_adapter *adapter, u8 addr)
  82 {
  83         struct wf_6690_sensor *max;
  84         char *name = "backside-temp";
  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", name);
  90                 return;
  91         }
  92
  93         max->sens.ops = &wf_max6690_ops;
  94         max->sens.name = name;
  95         max->i2c.addr = addr >> 1;
  96         max->i2c.adapter = adapter;
  97         max->i2c.driver = &wf_max6690_driver;
  98         strncpy(max->i2c.name, name, I2C_NAME_SIZE-1);
  99
 100         if (i2c_attach_client(&max->i2c)) {
 101                 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
 102                 goto fail;
 103         }
 104
 105         if (wf_register_sensor(&max->sens)) {
 106                 i2c_detach_client(&max->i2c);
 107                 goto fail;
 108         }
 109
 110         return;
 111
 112  fail:
 113         kfree(max);
 114 }
 115
 116 static int wf_max6690_attach(struct i2c_adapter *adapter)
 117 {
 118         struct device_node *busnode, *dev = NULL;
 119         struct pmac_i2c_bus *bus;
 120         const char *loc;
 121
 122         bus = pmac_i2c_adapter_to_bus(adapter);
 123         if (bus == NULL)
 124                 return -ENODEV;
 125         busnode = pmac_i2c_get_bus_node(bus);
 126
 127         while ((dev = of_get_next_child(busnode, dev)) != NULL) {
 128                 u8 addr;
 129
 130                 /* We must re-match the adapter in order to properly check
 131                  * the channel on multibus setups
 132                  */
 133                 if (!pmac_i2c_match_adapter(dev, adapter))
 134                         continue;
 135                 if (!device_is_compatible(dev, "max6690"))
 136                         continue;
 137                 addr = pmac_i2c_get_dev_addr(dev);
 138                 loc = get_property(dev, "hwsensor-location", NULL);
 139                 if (loc == NULL || addr == 0)
 140                         continue;
 141                 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
 142                 if (strcmp(loc, "BACKSIDE"))
 143                         continue;
 144                 wf_max6690_create(adapter, addr);
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int wf_max6690_detach(struct i2c_client *client)
 151 {
 152         struct wf_6690_sensor *max = i2c_to_6690(client);
 153
 154         max->i2c.adapter = NULL;
 155         wf_unregister_sensor(&max->sens);
 156
 157         return 0;
 158 }
 159
 160 static int __init wf_max6690_sensor_init(void)
 161 {
 162         /* Don't register on old machines that use therm_pm72 for now */
 163         if (machine_is_compatible("PowerMac7,2") ||
 164             machine_is_compatible("PowerMac7,3") ||
 165             machine_is_compatible("RackMac3,1"))
 166                 return -ENODEV;
 167         return i2c_add_driver(&wf_max6690_driver);
 168 }
 169
 170 static void __exit wf_max6690_sensor_exit(void)
 171 {
 172         i2c_del_driver(&wf_max6690_driver);
 173 }
 174
 175 module_init(wf_max6690_sensor_init);
 176 module_exit(wf_max6690_sensor_exit);
 177
 178 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 179 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 180 MODULE_LICENSE("GPL");