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[karo-tx-linux.git] / drivers / macintosh / windfarm_max6690_sensor.c
1 /*
2  * Windfarm PowerMac thermal control.  MAX6690 sensor.
3  *
4  * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
5  *
6  * Use and redistribute under the terms of the GNU GPL v2.
7  */
8 #include <linux/types.h>
9 #include <linux/errno.h>
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/i2c.h>
14 #include <asm/prom.h>
15 #include <asm/pmac_low_i2c.h>
16
17 #include "windfarm.h"
18
19 #define VERSION "1.0"
20
21 /* This currently only exports the external temperature sensor,
22    since that's all the control loops need. */
23
24 /* Some MAX6690 register numbers */
25 #define MAX6690_INTERNAL_TEMP   0
26 #define MAX6690_EXTERNAL_TEMP   1
27
28 struct wf_6690_sensor {
29         struct i2c_client       *i2c;
30         struct wf_sensor        sens;
31 };
32
33 #define wf_to_6690(x)   container_of((x), struct wf_6690_sensor, sens)
34
35 static int wf_max6690_get(struct wf_sensor *sr, s32 *value)
36 {
37         struct wf_6690_sensor *max = wf_to_6690(sr);
38         s32 data;
39
40         if (max->i2c == NULL)
41                 return -ENODEV;
42
43         /* chip gets initialized by firmware */
44         data = i2c_smbus_read_byte_data(max->i2c, MAX6690_EXTERNAL_TEMP);
45         if (data < 0)
46                 return data;
47         *value = data << 16;
48         return 0;
49 }
50
51 static void wf_max6690_release(struct wf_sensor *sr)
52 {
53         struct wf_6690_sensor *max = wf_to_6690(sr);
54
55         kfree(max);
56 }
57
58 static struct wf_sensor_ops wf_max6690_ops = {
59         .get_value      = wf_max6690_get,
60         .release        = wf_max6690_release,
61         .owner          = THIS_MODULE,
62 };
63
64 static int wf_max6690_probe(struct i2c_client *client,
65                             const struct i2c_device_id *id)
66 {
67         const char *name, *loc;
68         struct wf_6690_sensor *max;
69         int rc;
70
71         loc = of_get_property(client->dev.of_node, "hwsensor-location", NULL);
72         if (!loc) {
73                 dev_warn(&client->dev, "Missing hwsensor-location property!\n");
74                 return -ENXIO;
75         }
76
77         /*
78          * We only expose the external temperature register for
79          * now as this is all we need for our control loops
80          */
81         if (!strcmp(loc, "BACKSIDE") || !strcmp(loc, "SYS CTRLR AMBIENT"))
82                 name = "backside-temp";
83         else if (!strcmp(loc, "NB Ambient"))
84                 name = "north-bridge-temp";
85         else if (!strcmp(loc, "GPU Ambient"))
86                 name = "gpu-temp";
87         else
88                 return -ENXIO;
89
90         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
91         if (max == NULL) {
92                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
93                        "no memory\n");
94                 return -ENOMEM;
95         }
96
97         max->i2c = client;
98         max->sens.name = (char *)name; /* XXX fix constness in structure */
99         max->sens.ops = &wf_max6690_ops;
100         i2c_set_clientdata(client, max);
101
102         rc = wf_register_sensor(&max->sens);
103         if (rc)
104                 kfree(max);
105         return rc;
106 }
107
108 static int wf_max6690_remove(struct i2c_client *client)
109 {
110         struct wf_6690_sensor *max = i2c_get_clientdata(client);
111
112         max->i2c = NULL;
113         wf_unregister_sensor(&max->sens);
114
115         return 0;
116 }
117
118 static const struct i2c_device_id wf_max6690_id[] = {
119         { "MAC,max6690", 0 },
120         { }
121 };
122 MODULE_DEVICE_TABLE(i2c, wf_max6690_id);
123
124 static struct i2c_driver wf_max6690_driver = {
125         .driver = {
126                 .name           = "wf_max6690",
127         },
128         .probe          = wf_max6690_probe,
129         .remove         = wf_max6690_remove,
130         .id_table       = wf_max6690_id,
131 };
132
133 static int __init wf_max6690_sensor_init(void)
134 {
135         return i2c_add_driver(&wf_max6690_driver);
136 }
137
138 static void __exit wf_max6690_sensor_exit(void)
139 {
140         i2c_del_driver(&wf_max6690_driver);
141 }
142
143 module_init(wf_max6690_sensor_init);
144 module_exit(wf_max6690_sensor_exit);
145
146 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
147 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
148 MODULE_LICENSE("GPL");