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");
207