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
  35static 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
  51static 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
  58static struct wf_sensor_ops wf_max6690_ops = {
  59        .get_value      = wf_max6690_get,
  60        .release        = wf_max6690_release,
  61        .owner          = THIS_MODULE,
  62};
  63
  64static 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                kfree(max);
  85        }
  86
  87        return rc;
  88}
  89
  90static struct i2c_driver wf_max6690_driver;
  91
  92static struct i2c_client *wf_max6690_create(struct i2c_adapter *adapter,
  93                                            u8 addr, const char *loc)
  94{
  95        struct i2c_board_info info;
  96        struct i2c_client *client;
  97        char *name;
  98
  99        if (!strcmp(loc, "BACKSIDE"))
 100                name = "backside-temp";
 101        else if (!strcmp(loc, "NB Ambient"))
 102                name = "north-bridge-temp";
 103        else if (!strcmp(loc, "GPU Ambient"))
 104                name = "gpu-temp";
 105        else
 106                goto fail;
 107
 108        memset(&info, 0, sizeof(struct i2c_board_info));
 109        info.addr = addr >> 1;
 110        info.platform_data = name;
 111        strlcpy(info.type, "wf_max6690", I2C_NAME_SIZE);
 112
 113        client = i2c_new_device(adapter, &info);
 114        if (client == NULL) {
 115                printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
 116                goto fail;
 117        }
 118
 119        /*
 120         * Let i2c-core delete that device on driver removal.
 121         * This is safe because i2c-core holds the core_lock mutex for us.
 122         */
 123        list_add_tail(&client->detected, &wf_max6690_driver.clients);
 124        return client;
 125
 126 fail:
 127        return NULL;
 128}
 129
 130static int wf_max6690_attach(struct i2c_adapter *adapter)
 131{
 132        struct device_node *busnode, *dev = NULL;
 133        struct pmac_i2c_bus *bus;
 134        const char *loc;
 135
 136        bus = pmac_i2c_adapter_to_bus(adapter);
 137        if (bus == NULL)
 138                return -ENODEV;
 139        busnode = pmac_i2c_get_bus_node(bus);
 140
 141        while ((dev = of_get_next_child(busnode, dev)) != NULL) {
 142                u8 addr;
 143
 144                /* We must re-match the adapter in order to properly check
 145                 * the channel on multibus setups
 146                 */
 147                if (!pmac_i2c_match_adapter(dev, adapter))
 148                        continue;
 149                if (!of_device_is_compatible(dev, "max6690"))
 150                        continue;
 151                addr = pmac_i2c_get_dev_addr(dev);
 152                loc = of_get_property(dev, "hwsensor-location", NULL);
 153                if (loc == NULL || addr == 0)
 154                        continue;
 155                printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
 156                wf_max6690_create(adapter, addr, loc);
 157        }
 158
 159        return 0;
 160}
 161
 162static int wf_max6690_remove(struct i2c_client *client)
 163{
 164        struct wf_6690_sensor *max = i2c_get_clientdata(client);
 165
 166        max->i2c = NULL;
 167        wf_unregister_sensor(&max->sens);
 168
 169        return 0;
 170}
 171
 172static const struct i2c_device_id wf_max6690_id[] = {
 173        { "wf_max6690", 0 },
 174        { }
 175};
 176
 177static struct i2c_driver wf_max6690_driver = {
 178        .driver = {
 179                .name           = "wf_max6690",
 180        },
 181        .attach_adapter = wf_max6690_attach,
 182        .probe          = wf_max6690_probe,
 183        .remove         = wf_max6690_remove,
 184        .id_table       = wf_max6690_id,
 185};
 186
 187static int __init wf_max6690_sensor_init(void)
 188{
 189        /* Don't register on old machines that use therm_pm72 for now */
 190        if (of_machine_is_compatible("PowerMac7,2") ||
 191            of_machine_is_compatible("PowerMac7,3") ||
 192            of_machine_is_compatible("RackMac3,1"))
 193                return -ENODEV;
 194        return i2c_add_driver(&wf_max6690_driver);
 195}
 196
 197static void __exit wf_max6690_sensor_exit(void)
 198{
 199        i2c_del_driver(&wf_max6690_driver);
 200}
 201
 202module_init(wf_max6690_sensor_init);
 203module_exit(wf_max6690_sensor_exit);
 204
 205MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
 206MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
 207MODULE_LICENSE("GPL");
 208