1/*
2 * Windfarm PowerMac thermal control. LM75 sensor
3 *
4 * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
5 *                    <benh@kernel.crashing.org>
6 *
7 * Released under the term of the GNU GPL v2.
8 */
9
10#include <linux/types.h>
11#include <linux/errno.h>
12#include <linux/kernel.h>
13#include <linux/delay.h>
14#include <linux/slab.h>
15#include <linux/init.h>
16#include <linux/wait.h>
17#include <linux/i2c.h>
18#include <asm/prom.h>
19#include <asm/machdep.h>
20#include <asm/io.h>
21#include <asm/sections.h>
22#include <asm/pmac_low_i2c.h>
23
24#include "windfarm.h"
25
26#define VERSION "0.2"
27
28#undef DEBUG
29
30#ifdef DEBUG
31#define DBG(args...)	printk(args)
32#else
33#define DBG(args...)	do { } while(0)
34#endif
35
36struct wf_lm75_sensor {
37	int			ds1775 : 1;
38	int			inited : 1;
39	struct 	i2c_client	*i2c;
40	struct 	wf_sensor	sens;
41};
42#define wf_to_lm75(c) container_of(c, struct wf_lm75_sensor, sens)
43
44static int wf_lm75_get(struct wf_sensor *sr, s32 *value)
45{
46	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
47	s32 data;
48
49	if (lm->i2c == NULL)
50		return -ENODEV;
51
52	/* Init chip if necessary */
53	if (!lm->inited) {
54		u8 cfg_new, cfg = (u8)i2c_smbus_read_byte_data(lm->i2c, 1);
55
56		DBG("wf_lm75: Initializing %s, cfg was: %02x\n",
57		    sr->name, cfg);
58
59		/* clear shutdown bit, keep other settings as left by
60		 * the firmware for now
61		 */
62		cfg_new = cfg & ~0x01;
63		i2c_smbus_write_byte_data(lm->i2c, 1, cfg_new);
64		lm->inited = 1;
65
66		/* If we just powered it up, let's wait 200 ms */
67		msleep(200);
68	}
69
70	/* Read temperature register */
71	data = (s32)le16_to_cpu(i2c_smbus_read_word_data(lm->i2c, 0));
72	data <<= 8;
73	*value = data;
74
75	return 0;
76}
77
78static void wf_lm75_release(struct wf_sensor *sr)
79{
80	struct wf_lm75_sensor *lm = wf_to_lm75(sr);
81
82	kfree(lm);
83}
84
85static struct wf_sensor_ops wf_lm75_ops = {
86	.get_value	= wf_lm75_get,
87	.release	= wf_lm75_release,
88	.owner		= THIS_MODULE,
89};
90
91static int wf_lm75_probe(struct i2c_client *client,
92			 const struct i2c_device_id *id)
93{
94	struct wf_lm75_sensor *lm;
95	int rc;
96
97	lm = kzalloc(sizeof(struct wf_lm75_sensor), GFP_KERNEL);
98	if (lm == NULL)
99		return -ENODEV;
100
101	lm->inited = 0;
102	lm->ds1775 = id->driver_data;
103	lm->i2c = client;
104	lm->sens.name = client->dev.platform_data;
105	lm->sens.ops = &wf_lm75_ops;
106	i2c_set_clientdata(client, lm);
107
108	rc = wf_register_sensor(&lm->sens);
109	if (rc)
110		kfree(lm);
111
112	return rc;
113}
114
115static struct i2c_driver wf_lm75_driver;
116
117static struct i2c_client *wf_lm75_create(struct i2c_adapter *adapter,
118					     u8 addr, int ds1775,
119					     const char *loc)
120{
121	struct i2c_board_info info;
122	struct i2c_client *client;
123	char *name;
124
125	DBG("wf_lm75: creating  %s device at address 0x%02x\n",
126	    ds1775 ? "ds1775" : "lm75", addr);
127
128	/* Usual rant about sensor names not beeing very consistent in
129	 * the device-tree, oh well ...
130	 * Add more entries below as you deal with more setups
131	 */
132	if (!strcmp(loc, "Hard drive") || !strcmp(loc, "DRIVE BAY"))
133		name = "hd-temp";
134	else if (!strcmp(loc, "Incoming Air Temp"))
135		name = "incoming-air-temp";
136	else if (!strcmp(loc, "ODD Temp"))
137		name = "optical-drive-temp";
138	else if (!strcmp(loc, "HD Temp"))
139		name = "hard-drive-temp";
140	else
141		goto fail;
142
143	memset(&info, 0, sizeof(struct i2c_board_info));
144	info.addr = (addr >> 1) & 0x7f;
145	info.platform_data = name;
146	strlcpy(info.type, ds1775 ? "wf_ds1775" : "wf_lm75", I2C_NAME_SIZE);
147
148	client = i2c_new_device(adapter, &info);
149	if (client == NULL) {
150		printk(KERN_ERR "windfarm: failed to attach %s %s to i2c\n",
151		       ds1775 ? "ds1775" : "lm75", name);
152		goto fail;
153	}
154
155	/*
156	 * Let i2c-core delete that device on driver removal.
157	 * This is safe because i2c-core holds the core_lock mutex for us.
158	 */
159	list_add_tail(&client->detected, &wf_lm75_driver.clients);
160	return client;
161 fail:
162	return NULL;
163}
164
165static int wf_lm75_attach(struct i2c_adapter *adapter)
166{
167	struct device_node *busnode, *dev;
168	struct pmac_i2c_bus *bus;
169
170	DBG("wf_lm75: adapter %s detected\n", adapter->name);
171
172	bus = pmac_i2c_adapter_to_bus(adapter);
173	if (bus == NULL)
174		return -ENODEV;
175	busnode = pmac_i2c_get_bus_node(bus);
176
177	DBG("wf_lm75: bus found, looking for device...\n");
178
179	/* Now look for lm75(s) in there */
180	for (dev = NULL;
181	     (dev = of_get_next_child(busnode, dev)) != NULL;) {
182		const char *loc =
183			of_get_property(dev, "hwsensor-location", NULL);
184		u8 addr;
185
186		/* We must re-match the adapter in order to properly check
187		 * the channel on multibus setups
188		 */
189		if (!pmac_i2c_match_adapter(dev, adapter))
190			continue;
191		addr = pmac_i2c_get_dev_addr(dev);
192		if (loc == NULL || addr == 0)
193			continue;
194		/* real lm75 */
195		if (of_device_is_compatible(dev, "lm75"))
196			wf_lm75_create(adapter, addr, 0, loc);
197		/* ds1775 (compatible, better resolution */
198		else if (of_device_is_compatible(dev, "ds1775"))
199			wf_lm75_create(adapter, addr, 1, loc);
200	}
201	return 0;
202}
203
204static int wf_lm75_remove(struct i2c_client *client)
205{
206	struct wf_lm75_sensor *lm = i2c_get_clientdata(client);
207
208	DBG("wf_lm75: i2c detatch called for %s\n", lm->sens.name);
209
210	/* Mark client detached */
211	lm->i2c = NULL;
212
213	/* release sensor */
214	wf_unregister_sensor(&lm->sens);
215
216	return 0;
217}
218
219static const struct i2c_device_id wf_lm75_id[] = {
220	{ "wf_lm75", 0 },
221	{ "wf_ds1775", 1 },
222	{ }
223};
224
225static struct i2c_driver wf_lm75_driver = {
226	.driver = {
227		.name	= "wf_lm75",
228	},
229	.attach_adapter	= wf_lm75_attach,
230	.probe		= wf_lm75_probe,
231	.remove		= wf_lm75_remove,
232	.id_table	= wf_lm75_id,
233};
234
235static int __init wf_lm75_sensor_init(void)
236{
237	/* Don't register on old machines that use therm_pm72 for now */
238	if (of_machine_is_compatible("PowerMac7,2") ||
239	    of_machine_is_compatible("PowerMac7,3") ||
240	    of_machine_is_compatible("RackMac3,1"))
241		return -ENODEV;
242	return i2c_add_driver(&wf_lm75_driver);
243}
244
245static void __exit wf_lm75_sensor_exit(void)
246{
247	i2c_del_driver(&wf_lm75_driver);
248}
249
250
251module_init(wf_lm75_sensor_init);
252module_exit(wf_lm75_sensor_exit);
253
254MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
255MODULE_DESCRIPTION("LM75 sensor objects for PowerMacs thermal control");
256MODULE_LICENSE("GPL");
257
258