drivers/macintosh/windfarm_lm75_sensor.c

   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
  37 struct 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 #define i2c_to_lm75(c) container_of(c, struct wf_lm75_sensor, i2c)
  45
  46 static int wf_lm75_attach(struct i2c_adapter *adapter);
  47 static int wf_lm75_detach(struct i2c_client *client);
  48
  49 static struct i2c_driver wf_lm75_driver = {
  50         .driver = {
  51                 .name   = "wf_lm75",
  52         },
  53         .attach_adapter = wf_lm75_attach,
  54         .detach_client  = wf_lm75_detach,
  55 };
  56
  57 static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
  58 {
  59         struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  60         s32 data;
  61
  62         if (lm->i2c.adapter == NULL)
  63                 return -ENODEV;
  64
  65         /* Init chip if necessary */
  66         if (!lm->inited) {
  67                 u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(&lm->i2c, 1);
  68
  69                 DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
  70                     sr->name, cfg);
  71
  72                 /* clear shutdown bit, keep other settings as left by
  73                  * the firmware for now
  74                  */
  75                 cfg_new = cfg & ~0x01;
  76                 i2c_smbus_write_byte_data(&lm->i2c, 1, cfg_new);
  77                 lm->inited = 1;
  78
  79                 /* If we just powered it up, let's wait 200 ms */
  80                 msleep(200);
  81         }
  82
  83         /* Read temperature register */
  84         data = (s32)le16_to_cpu(i2c_smbus_read_word_data(&lm->i2c, 0));
  85         data <<= 8;
  86         *value = data;
  87
  88         return 0;
  89 }
  90
  91 static void wf_lm75_release(struct wf_sensor *sr)
  92 {
  93         struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  94
  95         /* check if client is registered and detach from i2c */
  96         if (lm->i2c.adapter) {
  97                 i2c_detach_client(&lm->i2c);
  98                 lm->i2c.adapter = NULL;
  99         }
 100
 101         kfree(lm);
 102 }
 103
 104 static struct wf_sensor_ops wf_lm75_ops = {
 105         .get_value      = wf_lm75_get,
 106         .release        = wf_lm75_release,
 107         .owner          = THIS_MODULE,
 108 };
 109
 110 static struct wf_lm75_sensor *wf_lm75_create(struct i2c_adapter *adapter,
 111                                              u8 addr, int ds1775,
 112                                              const char *loc)
 113 {
 114         struct wf_lm75_sensor *lm;
 115         int rc;
 116
 117         DBG("wf_lm75: creating  %s device at address 0x%02x\n",
 118             ds1775 ? "ds1775" : "lm75", addr);
 119
 120         lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
 121         if (lm == NULL)
 122                 return NULL;
 123
 124         /* Usual rant about sensor names not beeing very consistent in
 125          * the device-tree, oh well ...
 126          * Add more entries below as you deal with more setups
 127          */
 128         if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
 129                 lm->sens.name = "hd-temp";
 130         else
 131                 goto fail;
 132
 133         lm->inited = 0;
 134         lm->sens.ops = &wf_lm75_ops;
 135         lm->ds1775 = ds1775;
 136         lm->i2c.addr = (addr >> 1) & 0x7f;
 137         lm->i2c.adapter = adapter;
 138         lm->i2c.driver = &wf_lm75_driver;
 139         strncpy(lm->i2c.name, lm->sens.name, I2C_NAME_SIZE-1);
 140
 141         rc = i2c_attach_client(&lm->i2c);
 142         if (rc) {
 143                 printk(KERN_ERR "windfarm: failed to attach %s %s to i2c,"
 144                        " err %d\n", ds1775 ? "ds1775" : "lm75",
 145                        lm->i2c.name, rc);
 146                 goto fail;
 147         }
 148
 149         if (wf_register_sensor(&lm->sens)) {
 150                 i2c_detach_client(&lm->i2c);
 151                 goto fail;
 152         }
 153
 154         return lm;
 155  fail:
 156         kfree(lm);
 157         return NULL;
 158 }
 159
 160 static int wf_lm75_attach(struct i2c_adapter *adapter)
 161 {
 162         struct device_node *busnode, *dev;
 163         struct pmac_i2c_bus *bus;
 164
 165         DBG("wf_lm75: adapter %s detected\n", adapter->name);
 166
 167         bus = pmac_i2c_adapter_to_bus(adapter);
 168         if (bus == NULL)
 169                 return -ENODEV;
 170         busnode = pmac_i2c_get_bus_node(bus);
 171
 172         DBG("wf_lm75: bus found, looking for device...\n");
 173
 174         /* Now look for lm75(s) in there */
 175         for (dev = NULL;
 176              (dev = of_get_next_child(busnode, dev)) != NULL;) {
 177                 const char *loc =
 178                         of_get_property(dev, "hwsensor-location", NULL);
 179                 u8 addr;
 180
 181                 /* We must re-match the adapter in order to properly check
 182                  * the channel on multibus setups
 183                  */
 184                 if (!pmac_i2c_match_adapter(dev, adapter))
 185                         continue;
 186                 addr = pmac_i2c_get_dev_addr(dev);
 187                 if (loc == NULL || addr == 0)
 188                         continue;
 189                 /* real lm75 */
 190                 if (of_device_is_compatible(dev, "lm75"))
 191                         wf_lm75_create(adapter, addr, 0, loc);
 192                 /* ds1775 (compatible, better resolution */
 193                 else if (of_device_is_compatible(dev, "ds1775"))
 194                         wf_lm75_create(adapter, addr, 1, loc);
 195         }
 196         return 0;
 197 }
 198
 199 static int wf_lm75_detach(struct i2c_client *client)
 200 {
 201         struct wf_lm75_sensor *lm = i2c_to_lm75(client);
 202
 203         DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
 204
 205         /* Mark client detached */
 206         lm->i2c.adapter = NULL;
 207
 208         /* release sensor */
 209         wf_unregister_sensor(&lm->sens);
 210
 211         return 0;
 212 }
 213
 214 static int __init wf_lm75_sensor_init(void)
 215 {
 216         /* Don't register on old machines that use therm_pm72 for now */
 217         if (machine_is_compatible("PowerMac7,2") ||
 218             machine_is_compatible("PowerMac7,3") ||
 219             machine_is_compatible("RackMac3,1"))
 220                 return -ENODEV;
 221         return i2c_add_driver(&wf_lm75_driver);
 222 }
 223
 224 static void __exit wf_lm75_sensor_exit(void)
 225 {
 226         i2c_del_driver(&wf_lm75_driver);
 227 }
 228
 229
 230 module_init(wf_lm75_sensor_init);
 231 module_exit(wf_lm75_sensor_exit);
 232
 233 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 234 MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
 235 MODULE_LICENSE("GPL");
 236