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
28struct 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
35static 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
51static 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
58static struct wf_sensor_ops wf_max6690_ops = {
59	.get_value	= wf_max6690_get,
60	.release	= wf_max6690_release,
61	.owner		= THIS_MODULE,
62};
63
64static 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 = name;
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
108static 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
118static const struct i2c_device_id wf_max6690_id[] = {
119	{ "MAC,max6690", 0 },
120	{ }
121};
122MODULE_DEVICE_TABLE(i2c, wf_max6690_id);
123
124static 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
133module_i2c_driver(wf_max6690_driver);
134
135MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
136MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
137MODULE_LICENSE("GPL");
138