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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 "0.2"
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         struct wf_6690_sensor *max;
68         int rc;
69
70         max = kzalloc(sizeof(struct wf_6690_sensor), GFP_KERNEL);
71         if (max == NULL) {
72                 printk(KERN_ERR "windfarm: Couldn't create MAX6690 sensor: "
73                        "no memory\n");
74                 return -ENOMEM;
75         }
76
77         max->i2c = client;
78         max->sens.name = client->dev.platform_data;
79         max->sens.ops = &wf_max6690_ops;
80         i2c_set_clientdata(client, max);
81
82         rc = wf_register_sensor(&max->sens);
83         if (rc) {
84                 i2c_set_clientdata(client, NULL);
85                 kfree(max);
86         }
87
88         return rc;
89 }
90
91 static struct i2c_client *wf_max6690_create(struct i2c_adapter *adapter,
92                                             u8 addr, const char *loc)
93 {
94         struct i2c_board_info info;
95         struct i2c_client *client;
96         char *name;
97
98         if (!strcmp(loc, "BACKSIDE"))
99                 name = "backside-temp";
100         else if (!strcmp(loc, "NB Ambient"))
101                 name = "north-bridge-temp";
102         else if (!strcmp(loc, "GPU Ambient"))
103                 name = "gpu-temp";
104         else
105                 goto fail;
106
107         memset(&info, 0, sizeof(struct i2c_board_info));
108         info.addr = addr >> 1;
109         info.platform_data = name;
110         strlcpy(info.type, "wf_max6690", I2C_NAME_SIZE);
111
112         client = i2c_new_device(adapter, &info);
113         if (client == NULL) {
114                 printk(KERN_ERR "windfarm: failed to attach MAX6690 sensor\n");
115                 goto fail;
116         }
117
118         /*
119          * Let i2c-core delete that device on driver removal.
120          * This is safe because i2c-core holds the core_lock mutex for us.
121          */
122         list_add_tail(&client->detected, &client->driver->clients);
123         return client;
124
125  fail:
126         return NULL;
127 }
128
129 static int wf_max6690_attach(struct i2c_adapter *adapter)
130 {
131         struct device_node *busnode, *dev = NULL;
132         struct pmac_i2c_bus *bus;
133         const char *loc;
134
135         bus = pmac_i2c_adapter_to_bus(adapter);
136         if (bus == NULL)
137                 return -ENODEV;
138         busnode = pmac_i2c_get_bus_node(bus);
139
140         while ((dev = of_get_next_child(busnode, dev)) != NULL) {
141                 u8 addr;
142
143                 /* We must re-match the adapter in order to properly check
144                  * the channel on multibus setups
145                  */
146                 if (!pmac_i2c_match_adapter(dev, adapter))
147                         continue;
148                 if (!of_device_is_compatible(dev, "max6690"))
149                         continue;
150                 addr = pmac_i2c_get_dev_addr(dev);
151                 loc = of_get_property(dev, "hwsensor-location", NULL);
152                 if (loc == NULL || addr == 0)
153                         continue;
154                 printk("found max6690, loc=%s addr=0x%02x\n", loc, addr);
155                 wf_max6690_create(adapter, addr, loc);
156         }
157
158         return 0;
159 }
160
161 static int wf_max6690_remove(struct i2c_client *client)
162 {
163         struct wf_6690_sensor *max = i2c_get_clientdata(client);
164
165         max->i2c = NULL;
166         wf_unregister_sensor(&max->sens);
167
168         return 0;
169 }
170
171 static const struct i2c_device_id wf_max6690_id[] = {
172         { "wf_max6690", 0 },
173         { }
174 };
175
176 static struct i2c_driver wf_max6690_driver = {
177         .driver = {
178                 .name           = "wf_max6690",
179         },
180         .attach_adapter = wf_max6690_attach,
181         .probe          = wf_max6690_probe,
182         .remove         = wf_max6690_remove,
183         .id_table       = wf_max6690_id,
184 };
185
186 static int __init wf_max6690_sensor_init(void)
187 {
188         /* Don't register on old machines that use therm_pm72 for now */
189         if (machine_is_compatible("PowerMac7,2") ||
190             machine_is_compatible("PowerMac7,3") ||
191             machine_is_compatible("RackMac3,1"))
192                 return -ENODEV;
193         return i2c_add_driver(&wf_max6690_driver);
194 }
195
196 static void __exit wf_max6690_sensor_exit(void)
197 {
198         i2c_del_driver(&wf_max6690_driver);
199 }
200
201 module_init(wf_max6690_sensor_init);
202 module_exit(wf_max6690_sensor_exit);
203
204 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
205 MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
206 MODULE_LICENSE("GPL");