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
  25 #include "windfarm.h"
  26
  27 #define VERSION "0.1"
  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         .owner          = THIS_MODULE,
  51         .name           = "wf_lm75",
  52         .flags          = I2C_DF_NOTIFY,
  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
 116         DBG("wf_lm75: creating  %s device at address 0x%02x\n",
 117             ds1775 ? "ds1775" : "lm75", addr);
 118
 119         lm = kmalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
 120         if (lm == NULL)
 121                 return NULL;
 122         memset(lm, 0, sizeof(struct wf_lm75_sensor));
 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         if (i2c_attach_client(&lm->i2c)) {
 142                 printk(KERN_ERR "windfarm: failed to attach %s %s to i2c\n",
 143                        ds1775 ? "ds1775" : "lm75", lm->i2c.name);
 144                 goto fail;
 145         }
 146
 147         if (wf_register_sensor(&lm->sens)) {
 148                 i2c_detach_client(&lm->i2c);
 149                 goto fail;
 150         }
 151
 152         return lm;
 153  fail:
 154         kfree(lm);
 155         return NULL;
 156 }
 157
 158 static int wf_lm75_attach(struct i2c_adapter *adapter)
 159 {
 160         u8 bus_id;
 161         struct device_node *smu, *bus, *dev;
 162
 163         /* We currently only deal with LM75's hanging off the SMU
 164          * i2c busses. If we extend that driver to other/older
 165          * machines, we should split this function into SMU-i2c,
 166          * keywest-i2c, PMU-i2c, ...
 167          */
 168
 169         DBG("wf_lm75: adapter %s detected\n", adapter->name);
 170
 171         if (strncmp(adapter->name, "smu-i2c-", 8) != 0)
 172                 return 0;
 173         smu = of_find_node_by_type(NULL, "smu");
 174         if (smu == NULL)
 175                 return 0;
 176
 177         /* Look for the bus in the device-tree */
 178         bus_id = (u8)simple_strtoul(adapter->name + 8, NULL, 16);
 179
 180         DBG("wf_lm75: bus ID is %x\n", bus_id);
 181
 182         /* Look for sensors subdir */
 183         for (bus = NULL;
 184              (bus = of_get_next_child(smu, bus)) != NULL;) {
 185                 u32 *reg;
 186
 187                 if (strcmp(bus->name, "i2c"))
 188                         continue;
 189                 reg = (u32 *)get_property(bus, "reg", NULL);
 190                 if (reg == NULL)
 191                         continue;
 192                 if (bus_id == *reg)
 193                         break;
 194         }
 195         of_node_put(smu);
 196         if (bus == NULL) {
 197                 printk(KERN_WARNING "windfarm: SMU i2c bus 0x%x not found"
 198                        " in device-tree !\n", bus_id);
 199                 return 0;
 200         }
 201
 202         DBG("wf_lm75: bus found, looking for device...\n");
 203
 204         /* Now look for lm75(s) in there */
 205         for (dev = NULL;
 206              (dev = of_get_next_child(bus, dev)) != NULL;) {
 207                 const char *loc =
 208                         get_property(dev, "hwsensor-location", NULL);
 209                 u32 *reg = (u32 *)get_property(dev, "reg", NULL);
 210                 DBG(" dev: %s... (loc: %p, reg: %p)\n", dev->name, loc, reg);
 211                 if (loc == NULL || reg == NULL)
 212                         continue;
 213                 /* real lm75 */
 214                 if (device_is_compatible(dev, "lm75"))
 215                         wf_lm75_create(adapter, *reg, 0, loc);
 216                 /* ds1775 (compatible, better resolution */
 217                 else if (device_is_compatible(dev, "ds1775"))
 218                         wf_lm75_create(adapter, *reg, 1, loc);
 219         }
 220
 221         of_node_put(bus);
 222
 223         return 0;
 224 }
 225
 226 static int wf_lm75_detach(struct i2c_client *client)
 227 {
 228         struct wf_lm75_sensor *lm = i2c_to_lm75(client);
 229
 230         DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
 231
 232         /* Mark client detached */
 233         lm->i2c.adapter = NULL;
 234
 235         /* release sensor */
 236         wf_unregister_sensor(&lm->sens);
 237
 238         return 0;
 239 }
 240
 241 static int __init wf_lm75_sensor_init(void)
 242 {
 243         int rc;
 244
 245         rc = i2c_add_driver(&wf_lm75_driver);
 246         if (rc < 0)
 247                 return rc;
 248         return 0;
 249 }
 250
 251 static void __exit wf_lm75_sensor_exit(void)
 252 {
 253         i2c_del_driver(&wf_lm75_driver);
 254 }
 255
 256
 257 module_init(wf_lm75_sensor_init);
 258 module_exit(wf_lm75_sensor_exit);
 259
 260 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 261 MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
 262 MODULE_LICENSE("GPL");
 263