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 = (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
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
133static int __init wf_max6690_sensor_init(void)
134{
135	return i2c_add_driver(&wf_max6690_driver);
136}
137
138static void __exit wf_max6690_sensor_exit(void)
139{
140	i2c_del_driver(&wf_max6690_driver);
141}
142
143module_init(wf_max6690_sensor_init);
144module_exit(wf_max6690_sensor_exit);
145
146MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
147MODULE_DESCRIPTION("MAX6690 sensor objects for PowerMac thermal control");
148MODULE_LICENSE("GPL");