drivers/macintosh/windfarm_lm87_sensor.c

   1 /*
   2  * Windfarm PowerMac thermal control. LM87 sensor
   3  *
   4  * Copyright 2012 Benjamin Herrenschmidt, IBM Corp.
   5  *
   6  * Released under the term of the GNU GPL v2.
   7  *
   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/sections.h>
  22 #include <asm/pmac_low_i2c.h>
  23
  24 #include "windfarm.h"
  25
  26 #define VERSION "1.0"
  27
  28 #undef DEBUG
  29
  30 #ifdef DEBUG
  31 #define DBG(args...)    printk(args)
  32 #else
  33 #define DBG(args...)    do { } while(0)
  34 #endif
  35
  36 struct wf_lm87_sensor {
  37         struct i2c_client       *i2c;
  38         struct wf_sensor        sens;
  39 };
  40 #define wf_to_lm87(c) container_of(c, struct wf_lm87_sensor, sens)
  41
  42
  43 static int wf_lm87_read_reg(struct i2c_client *chip, int reg)
  44 {
  45         int rc, tries = 0;
  46         u8 buf;
  47
  48         for (;;) {
  49                 /* Set address */
  50                 buf = (u8)reg;
  51                 rc = i2c_master_send(chip, &buf, 1);
  52                 if (rc <= 0)
  53                         goto error;
  54                 rc = i2c_master_recv(chip, &buf, 1);
  55                 if (rc <= 0)
  56                         goto error;
  57                 return (int)buf;
  58         error:
  59                 DBG("wf_lm87: Error reading LM87, retrying...\n");
  60                 if (++tries > 10) {
  61                         printk(KERN_ERR "wf_lm87: Error reading LM87 !\n");
  62                         return -EIO;
  63                 }
  64                 msleep(10);
  65         }
  66 }
  67
  68 static int wf_lm87_get(struct wf_sensor *sr, s32 *value)
  69 {
  70         struct wf_lm87_sensor *lm = sr->priv;
  71         s32 temp;
  72
  73         if (lm->i2c == NULL)
  74                 return -ENODEV;
  75
  76 #define LM87_INT_TEMP           0x27
  77
  78         /* Read temperature register */
  79         temp = wf_lm87_read_reg(lm->i2c, LM87_INT_TEMP);
  80         if (temp < 0)
  81                 return temp;
  82         *value = temp << 16;
  83
  84         return 0;
  85 }
  86
  87 static void wf_lm87_release(struct wf_sensor *sr)
  88 {
  89         struct wf_lm87_sensor *lm = wf_to_lm87(sr);
  90
  91         kfree(lm);
  92 }
  93
  94 static const struct wf_sensor_ops wf_lm87_ops = {
  95         .get_value      = wf_lm87_get,
  96         .release        = wf_lm87_release,
  97         .owner          = THIS_MODULE,
  98 };
  99
 100 static int wf_lm87_probe(struct i2c_client *client,
 101                          const struct i2c_device_id *id)
 102 {
 103         struct wf_lm87_sensor *lm;
 104         const char *name = NULL, *loc;
 105         struct device_node *np = NULL;
 106         int rc;
 107
 108         /*
 109          * The lm87 contains a whole pile of sensors, additionally,
 110          * the Xserve G5 has several lm87's. However, for now we only
 111          * care about the internal temperature sensor
 112          */
 113         while ((np = of_get_next_child(client->dev.of_node, np)) != NULL) {
 114                 if (strcmp(np->name, "int-temp"))
 115                         continue;
 116                 loc = of_get_property(np, "location", NULL);
 117                 if (!loc)
 118                         continue;
 119                 if (strstr(loc, "DIMM"))
 120                         name = "dimms-temp";
 121                 else if (strstr(loc, "Processors"))
 122                         name = "between-cpus-temp";
 123                 if (name) {
 124                         of_node_put(np);
 125                         break;
 126                 }
 127         }
 128         if (!name) {
 129                 pr_warning("wf_lm87: Unsupported sensor %pOF\n",
 130                            client->dev.of_node);
 131                 return -ENODEV;
 132         }
 133
 134         lm = kzalloc(sizeof(struct wf_lm87_sensor), GFP_KERNEL);
 135         if (lm == NULL)
 136                 return -ENODEV;
 137
 138         lm->i2c = client;
 139         lm->sens.name = name;
 140         lm->sens.ops = &wf_lm87_ops;
 141         lm->sens.priv = lm;
 142         i2c_set_clientdata(client, lm);
 143
 144         rc = wf_register_sensor(&lm->sens);
 145         if (rc)
 146                 kfree(lm);
 147         return rc;
 148 }
 149
 150 static int wf_lm87_remove(struct i2c_client *client)
 151 {
 152         struct wf_lm87_sensor *lm = i2c_get_clientdata(client);
 153
 154         DBG("wf_lm87: i2c detatch called for %s\n", lm->sens.name);
 155
 156         /* Mark client detached */
 157         lm->i2c = NULL;
 158
 159         /* release sensor */
 160         wf_unregister_sensor(&lm->sens);
 161
 162         return 0;
 163 }
 164
 165 static const struct i2c_device_id wf_lm87_id[] = {
 166         { "MAC,lm87cimt", 0 },
 167         { }
 168 };
 169 MODULE_DEVICE_TABLE(i2c, wf_lm87_id);
 170
 171 static struct i2c_driver wf_lm87_driver = {
 172         .driver = {
 173                 .name   = "wf_lm87",
 174         },
 175         .probe          = wf_lm87_probe,
 176         .remove         = wf_lm87_remove,
 177         .id_table       = wf_lm87_id,
 178 };
 179
 180 static int __init wf_lm87_sensor_init(void)
 181 {
 182         /* We only support this on the Xserve */
 183         if (!of_machine_is_compatible("RackMac3,1"))
 184                 return -ENODEV;
 185
 186         return i2c_add_driver(&wf_lm87_driver);
 187 }
 188
 189 static void __exit wf_lm87_sensor_exit(void)
 190 {
 191         i2c_del_driver(&wf_lm87_driver);
 192 }
 193
 194
 195 module_init(wf_lm87_sensor_init);
 196 module_exit(wf_lm87_sensor_exit);
 197
 198 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
 199 MODULE_DESCRIPTION("LM87 sensor objects for PowerMacs thermal control");
 200 MODULE_LICENSE("GPL");
 201