linux/drivers/macintosh/windfarm_lm75_sensor.c
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   1/*
   2 * Windfarm PowerMac thermal control. LM75 sensor
   3 *
   4 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
   5 *                    <benh@kernel.crashing.org>
   6 *
   7 * Released under the term of the GNU GPL v2.
   8 */
   9
  10#include <linux/types.h>
  11#include <linux/errno.h>
  12#include <linux/kernel.h>
  13#include <linux/delay.h>
  14#include <linux/slab.h>
  15#include <linux/init.h>
  16#include <linux/wait.h>
  17#include <linux/i2c.h>
  18#include <asm/prom.h>
  19#include <asm/machdep.h>
  20#include <asm/io.h>
  21#include <asm/system.h>
  22#include <asm/sections.h>
  23#include <asm/pmac_low_i2c.h>
  24
  25#include "windfarm.h"
  26
  27#define VERSION "0.2"
  28
  29#undef DEBUG
  30
  31#ifdef DEBUG
  32#define DBG(args...)    printk(args)
  33#else
  34#define DBG(args...)    do { } while(0)
  35#endif
  36
  37struct wf_lm75_sensor {
  38        int                     ds1775 : 1;
  39        int                     inited : 1;
  40        struct  i2c_client      *i2c;
  41        struct  wf_sensor       sens;
  42};
  43#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
  44
  45static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
  46{
  47        struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  48        s32 data;
  49
  50        if (lm->i2c == NULL)
  51                return -ENODEV;
  52
  53        /* Init chip if necessary */
  54        if (!lm->inited) {
  55                u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
  56
  57                DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
  58                    sr->name, cfg);
  59
  60                /* clear shutdown bit, keep other settings as left by
  61                 * the firmware for now
  62                 */
  63                cfg_new = cfg & ~0x01;
  64                i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
  65                lm->inited = 1;
  66
  67                /* If we just powered it up, let's wait 200 ms */
  68                msleep(200);
  69        }
  70
  71        /* Read temperature register */
  72        data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
  73        data <<= 8;
  74        *value = data;
  75
  76        return 0;
  77}
  78
  79static void wf_lm75_release(struct wf_sensor *sr)
  80{
  81        struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  82
  83        kfree(lm);
  84}
  85
  86static struct wf_sensor_ops wf_lm75_ops = {
  87        .get_value      = wf_lm75_get,
  88        .release        = wf_lm75_release,
  89        .owner          = THIS_MODULE,
  90};
  91
  92static int wf_lm75_probe(struct i2c_client *client,
  93                         const struct i2c_device_id *id)
  94{
  95        struct wf_lm75_sensor *lm;
  96        int rc;
  97
  98        lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
  99        if (lm == NULL)
 100                return -ENODEV;
 101
 102        lm->inited = 0;
 103        lm->ds1775 = id->driver_data;
 104        lm->i2c = client;
 105        lm->sens.name = client->dev.platform_data;
 106        lm->sens.ops = &wf_lm75_ops;
 107        i2c_set_clientdata(client, lm);
 108
 109        rc = wf_register_sensor(&lm->sens);
 110        if (rc)
 111                kfree(lm);
 112
 113        return rc;
 114}
 115
 116static struct i2c_driver wf_lm75_driver;
 117
 118static struct i2c_client *wf_lm75_create(struct i2c_adapter *adapter,
 119                                             u8 addr, int ds1775,
 120                                             const char *loc)
 121{
 122        struct i2c_board_info info;
 123        struct i2c_client *client;
 124        char *name;
 125
 126        DBG("wf_lm75: creating  %s device at address 0x%02x\n",
 127            ds1775 ? "ds1775" : "lm75", addr);
 128
 129        /* Usual rant about sensor names not beeing very consistent in
 130         * the device-tree, oh well ...
 131         * Add more entries below as you deal with more setups
 132         */
 133        if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
 134                name = "hd-temp";
 135        else if (!strcmp(loc, "Incoming Air Temp"))
 136                name = "incoming-air-temp";
 137        else if (!strcmp(loc, "ODD Temp"))
 138                name = "optical-drive-temp";
 139        else if (!strcmp(loc, "HD Temp"))
 140                name = "hard-drive-temp";
 141        else
 142                goto fail;
 143
 144        memset(&info, 0, sizeof(struct i2c_board_info));
 145        info.addr = (addr >> 1) & 0x7f;
 146        info.platform_data = name;
 147        strlcpy(info.type, ds1775 ? "wf_ds1775" : "wf_lm75", I2C_NAME_SIZE);
 148
 149        client = i2c_new_device(adapter, &info);
 150        if (client == NULL) {
 151                printk(KERN_ERR "windfarm: failed to attach %s %s to i2c\n",
 152                       ds1775 ? "ds1775" : "lm75", name);
 153                goto fail;
 154        }
 155
 156        /*
 157         * Let i2c-core delete that device on driver removal.
 158         * This is safe because i2c-core holds the core_lock mutex for us.
 159         */
 160        list_add_tail(&client->detected, &wf_lm75_driver.clients);
 161        return client;
 162 fail:
 163        return NULL;
 164}
 165
 166static int wf_lm75_attach(struct i2c_adapter *adapter)
 167{
 168        struct device_node *busnode, *dev;
 169        struct pmac_i2c_bus *bus;
 170
 171        DBG("wf_lm75: adapter %s detected\n", adapter->name);
 172
 173        bus = pmac_i2c_adapter_to_bus(adapter);
 174        if (bus == NULL)
 175                return -ENODEV;
 176        busnode = pmac_i2c_get_bus_node(bus);
 177
 178        DBG("wf_lm75: bus found, looking for device...\n");
 179
 180        /* Now look for lm75(s) in there */
 181        for (dev = NULL;
 182             (dev = of_get_next_child(busnode, dev)) != NULL;) {
 183                const char *loc =
 184                        of_get_property(dev, "hwsensor-location", NULL);
 185                u8 addr;
 186
 187                /* We must re-match the adapter in order to properly check
 188                 * the channel on multibus setups
 189                 */
 190                if (!pmac_i2c_match_adapter(dev, adapter))
 191                        continue;
 192                addr = pmac_i2c_get_dev_addr(dev);
 193                if (loc == NULL || addr == 0)
 194                        continue;
 195                /* real lm75 */
 196                if (of_device_is_compatible(dev, "lm75"))
 197                        wf_lm75_create(adapter, addr, 0, loc);
 198                /* ds1775 (compatible, better resolution */
 199                else if (of_device_is_compatible(dev, "ds1775"))
 200                        wf_lm75_create(adapter, addr, 1, loc);
 201        }
 202        return 0;
 203}
 204
 205static int wf_lm75_remove(struct i2c_client *client)
 206{
 207        struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
 208
 209        DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
 210
 211        /* Mark client detached */
 212        lm->i2c = NULL;
 213
 214        /* release sensor */
 215        wf_unregister_sensor(&lm->sens);
 216
 217        return 0;
 218}
 219
 220static const struct i2c_device_id wf_lm75_id[] = {
 221        { "wf_lm75", 0 },
 222        { "wf_ds1775", 1 },
 223        { }
 224};
 225
 226static struct i2c_driver wf_lm75_driver = {
 227        .driver = {
 228                .name   = "wf_lm75",
 229        },
 230        .attach_adapter = wf_lm75_attach,
 231        .probe          = wf_lm75_probe,
 232        .remove         = wf_lm75_remove,
 233        .id_table       = wf_lm75_id,
 234};
 235
 236static int __init wf_lm75_sensor_init(void)
 237{
 238        /* Don't register on old machines that use therm_pm72 for now */
 239        if (of_machine_is_compatible("PowerMac7,2") ||
 240            of_machine_is_compatible("PowerMac7,3") ||
 241            of_machine_is_compatible("RackMac3,1"))
 242                return -ENODEV;
 243        return i2c_add_driver(&wf_lm75_driver);
 244}
 245
 246static void __exit wf_lm75_sensor_exit(void)
 247{
 248        i2c_del_driver(&wf_lm75_driver);
 249}
 250
 251
 252module_init(wf_lm75_sensor_init);
 253module_exit(wf_lm75_sensor_exit);
 254
 255MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 256MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
 257MODULE_LICENSE("GPL");
 258
 259