linux/drivers/macintosh/windfarm_max6690_sensor.c
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   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
  28struct 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
  36static int wf_max6690_attach(struct i2c_adapter *adapter);
  37static int wf_max6690_detach(struct i2c_client *client);
  38
  39static 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
  47static 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
  63static 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
  74static struct wf_sensor_ops wf_max6690_ops = {
  75        .get_value      = wf_max6690_get,
  76        .release        = wf_max6690_release,
  77        .owner          = THIS_MODULE,
  78};
  79
  80static 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
 125static 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
 157static 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
 167static 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
 177static void __exit wf_max6690_sensor_exit(void)
 178{
 179        i2c_del_driver(&wf_max6690_driver);
 180}
 181
 182module_init(wf_max6690_sensor_init);
 183module_exit(wf_max6690_sensor_exit);
 184
 185MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 186MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 187MODULE_LICENSE("GPL");
 188