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 <linux/i2c-dev.h>
  19 #include <asm/prom.h>
  20 #include <asm/machdep.h>
  21 #include <asm/io.h>
  22 #include <asm/system.h>
  23 #include <asm/sections.h>
  24 #include <asm/pmac_low_i2c.h>
  25
  26 #include "windfarm.h"
  27
  28 #define VERSION "0.1"
  29
  30 #undef DEBUG
  31
  32 #ifdef DEBUG
  33 #define DBG(args...)    printk(args)
  34 #else
  35 #define DBG(args...)    do { } while(0)
  36 #endif
  37
  38 struct wf_lm75_sensor {
  39         int                     ds1775 : 1;
  40         int                     inited : 1;
  41         struct  i2c_client      i2c;
  42         struct  wf_sensor       sens;
  43 };
  44 #define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
  45 #define i2c_to_lm75(c) container_of(c, struct wf_lm75_sensor, i2c)
  46
  47 static int wf_lm75_attach(struct i2c_adapter *adapter);
  48 static int wf_lm75_detach(struct i2c_client *client);
  49
  50 static struct i2c_driver wf_lm75_driver = {
  51         .driver = {
  52                 .name   = "wf_lm75",
  53         },
  54         .attach_adapter = wf_lm75_attach,
  55         .detach_client  = wf_lm75_detach,
  56 };
  57
  58 static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
  59 {
  60         struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  61         s32 data;
  62
  63         if (lm->i2c.adapter == NULL)
  64                 return -ENODEV;
  65
  66         /* Init chip if necessary */
  67         if (!lm->inited) {
  68                 u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(&lm->i2c, 1);
  69
  70                 DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
  71                     sr->name, cfg);
  72
  73                 /* clear shutdown bit, keep other settings as left by
  74                  * the firmware for now
  75                  */
  76                 cfg_new = cfg & ~0x01;
  77                 i2c_smbus_write_byte_data(&lm->i2c, 1, cfg_new);
  78                 lm->inited = 1;
  79
  80                 /* If we just powered it up, let's wait 200 ms */
  81                 msleep(200);
  82         }
  83
  84         /* Read temperature register */
  85         data = (s32)le16_to_cpu(i2c_smbus_read_word_data(&lm->i2c, 0));
  86         data <<= 8;
  87         *value = data;
  88
  89         return 0;
  90 }
  91
  92 static void wf_lm75_release(struct wf_sensor *sr)
  93 {
  94         struct wf_lm75_sensor *lm = wf_to_lm75(sr);
  95
  96         /* check if client is registered and detach from i2c */
  97         if (lm->i2c.adapter) {
  98                 i2c_detach_client(&lm->i2c);
  99                 lm->i2c.adapter = NULL;
 100         }
 101
 102         kfree(lm);
 103 }
 104
 105 static struct wf_sensor_ops wf_lm75_ops = {
 106         .get_value      = wf_lm75_get,
 107         .release        = wf_lm75_release,
 108         .owner          = THIS_MODULE,
 109 };
 110
 111 static struct wf_lm75_sensor *wf_lm75_create(struct i2c_adapter *adapter,
 112                                              u8 addr, int ds1775,
 113                                              const char *loc)
 114 {
 115         struct wf_lm75_sensor *lm;
 116
 117         DBG("wf_lm75: creating  %s device at address 0x%02x\n",
 118             ds1775 ? "ds1775" : "lm75", addr);
 119
 120         lm = kmalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
 121         if (lm == NULL)
 122                 return NULL;
 123         memset(lm, 0, sizeof(struct wf_lm75_sensor));
 124
 125         /* Usual rant about sensor names not beeing very consistent in
 126          * the device-tree, oh well ...
 127          * Add more entries below as you deal with more setups
 128          */
 129         if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
 130                 lm->sens.name = "hd-temp";
 131         else
 132                 goto fail;
 133
 134         lm->inited = 0;
 135         lm->sens.ops = &wf_lm75_ops;
 136         lm->ds1775 = ds1775;
 137         lm->i2c.addr = (addr >> 1) & 0x7f;
 138         lm->i2c.adapter = adapter;
 139         lm->i2c.driver = &wf_lm75_driver;
 140         strncpy(lm->i2c.name, lm->sens.name, I2C_NAME_SIZE-1);
 141
 142         if (i2c_attach_client(&lm->i2c)) {
 143                 printk(KERN_ERR "windfarm: failed to attach %s %s to i2c\n",
 144                        ds1775 ? "ds1775" : "lm75", lm->i2c.name);
 145                 goto fail;
 146         }
 147
 148         if (wf_register_sensor(&lm->sens)) {
 149                 i2c_detach_client(&lm->i2c);
 150                 goto fail;
 151         }
 152
 153         return lm;
 154  fail:
 155         kfree(lm);
 156         return NULL;
 157 }
 158
 159 static int wf_lm75_attach(struct i2c_adapter *adapter)
 160 {
 161         struct device_node *busnode, *dev;
 162         struct pmac_i2c_bus *bus;
 163
 164         DBG("wf_lm75: adapter %s detected\n", adapter->name);
 165
 166         bus = pmac_i2c_adapter_to_bus(adapter);
 167         if (bus == NULL)
 168                 return -ENODEV;
 169         busnode = pmac_i2c_get_bus_node(bus);
 170
 171         DBG("wf_lm75: bus found, looking for device...\n");
 172
 173         /* Now look for lm75(s) in there */
 174         for (dev = NULL;
 175              (dev = of_get_next_child(busnode, dev)) != NULL;) {
 176                 const char *loc =
 177                         get_property(dev, "hwsensor-location", NULL);
 178                 u32 *reg = (u32 *)get_property(dev, "reg", NULL);
 179                 DBG(" dev: %s... (loc: %p, reg: %p)\n", dev->name, loc, reg);
 180                 if (loc == NULL || reg == NULL)
 181                         continue;
 182                 /* real lm75 */
 183                 if (device_is_compatible(dev, "lm75"))
 184                         wf_lm75_create(adapter, *reg, 0, loc);
 185                 /* ds1775 (compatible, better resolution */
 186                 else if (device_is_compatible(dev, "ds1775"))
 187                         wf_lm75_create(adapter, *reg, 1, loc);
 188         }
 189         return 0;
 190 }
 191
 192 static int wf_lm75_detach(struct i2c_client *client)
 193 {
 194         struct wf_lm75_sensor *lm = i2c_to_lm75(client);
 195
 196         DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
 197
 198         /* Mark client detached */
 199         lm->i2c.adapter = NULL;
 200
 201         /* release sensor */
 202         wf_unregister_sensor(&lm->sens);
 203
 204         return 0;
 205 }
 206
 207 static int __init wf_lm75_sensor_init(void)
 208 {
 209         return i2c_add_driver(&wf_lm75_driver);
 210 }
 211
 212 static void __exit wf_lm75_sensor_exit(void)
 213 {
 214         i2c_del_driver(&wf_lm75_driver);
 215 }
 216
 217
 218 module_init(wf_lm75_sensor_init);
 219 module_exit(wf_lm75_sensor_exit);
 220
 221 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 222 MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
 223 MODULE_LICENSE("GPL");
 224