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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.
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/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 
37  int ds1775 : 1;
38  int inited : 1;
39  struct i2c_client *i2c;
40  struct wf_sensor sens;
41 };
42 #define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
43 
44 static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
45 {
46  struct wf_lm75_sensor *lm = wf_to_lm75(sr);
47  s32 data;
48 
49  if (lm->i2c == NULL)
50  return -ENODEV;
51 
52  /* Init chip if necessary */
53  if (!lm->inited) {
54  u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
55 
56  DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
57  sr->name, cfg);
58 
59  /* clear shutdown bit, keep other settings as left by
60  * the firmware for now
61  */
62  cfg_new = cfg & ~0x01;
63  i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
64  lm->inited = 1;
65 
66  /* If we just powered it up, let's wait 200 ms */
67  msleep(200);
68  }
69 
70  /* Read temperature register */
72  data <<= 8;
73  *value = data;
74 
75  return 0;
76 }
77 
78 static void wf_lm75_release(struct wf_sensor *sr)
79 {
80  struct wf_lm75_sensor *lm = wf_to_lm75(sr);
81 
82  kfree(lm);
83 }
84 
85 static struct wf_sensor_ops wf_lm75_ops = {
86  .get_value = wf_lm75_get,
87  .release = wf_lm75_release,
88  .owner = THIS_MODULE,
89 };
90 
91 static int wf_lm75_probe(struct i2c_client *client,
92  const struct i2c_device_id *id)
93 {
94  struct wf_lm75_sensor *lm;
95  int rc, ds1775 = id->driver_data;
96  const char *name, *loc;
97 
98  DBG("wf_lm75: creating %s device at address 0x%02x\n",
99  ds1775 ? "ds1775" : "lm75", client->addr);
100 
101  loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
102  if (!loc) {
103  dev_warn(&client->dev, "Missing hwsensor-location property!\n");
104  return -ENXIO;
105  }
106 
107  /* Usual rant about sensor names not beeing very consistent in
108  * the device-tree, oh well ...
109  * Add more entries below as you deal with more setups
110  */
111  if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
112  name = "hd-temp";
113  else if (!strcmp(loc, "Incoming Air Temp"))
114  name = "incoming-air-temp";
115  else if (!strcmp(loc, "ODD Temp"))
116  name = "optical-drive-temp";
117  else if (!strcmp(loc, "HD Temp"))
118  name = "hard-drive-temp";
119  else if (!strcmp(loc, "PCI SLOTS"))
120  name = "slots-temp";
121  else if (!strcmp(loc, "CPU A INLET"))
122  name = "cpu-inlet-temp-0";
123  else if (!strcmp(loc, "CPU B INLET"))
124  name = "cpu-inlet-temp-1";
125  else
126  return -ENXIO;
127 
128 
129  lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
130  if (lm == NULL)
131  return -ENODEV;
132 
133  lm->inited = 0;
134  lm->ds1775 = ds1775;
135  lm->i2c = client;
136  lm->sens.name = (char *)name; /* XXX fix constness in structure */
137  lm->sens.ops = &wf_lm75_ops;
138  i2c_set_clientdata(client, lm);
139 
140  rc = wf_register_sensor(&lm->sens);
141  if (rc)
142  kfree(lm);
143  return rc;
144 }
145 
146 static int wf_lm75_remove(struct i2c_client *client)
147 {
148  struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
149 
150  DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
151 
152  /* Mark client detached */
153  lm->i2c = NULL;
154 
155  /* release sensor */
157 
158  return 0;
159 }
160 
161 static const struct i2c_device_id wf_lm75_id[] = {
162  { "MAC,lm75", 0 },
163  { "MAC,ds1775", 1 },
164  { }
165 };
166 MODULE_DEVICE_TABLE(i2c, wf_lm75_id);
167 
168 static struct i2c_driver wf_lm75_driver = {
169  .driver = {
170  .name = "wf_lm75",
171  },
172  .probe = wf_lm75_probe,
173  .remove = wf_lm75_remove,
174  .id_table = wf_lm75_id,
175 };
176 
177 static int __init wf_lm75_sensor_init(void)
178 {
179  return i2c_add_driver(&wf_lm75_driver);
180 }
181 
182 static void __exit wf_lm75_sensor_exit(void)
183 {
184  i2c_del_driver(&wf_lm75_driver);
185 }
186 
187 
188 module_init(wf_lm75_sensor_init);
189 module_exit(wf_lm75_sensor_exit);
190 
191 MODULE_AUTHOR("Benjamin Herrenschmidt <[email protected]>");
192 MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
193 MODULE_LICENSE("GPL");
194