1/*
2 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
3 *               monitoring
4 * Copyright (C) 2003-2004  Jean Delvare <khali@linux-fr.org>
5 *
6 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
7 * by Winbond. It reports a single external temperature with a 1 deg
8 * resolution and a 3 deg accuracy. Datasheet can be obtained from
9 * Winbond's website at:
10 *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
11 *
12 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
13 * <khali@linux-fr.org>.
14 *
15 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
16 * error handling mechanism.
17 *
18 * This program is free software; you can redistribute it and/or modify
19 * it under the terms of the GNU General Public License as published by
20 * the Free Software Foundation; either version 2 of the License, or
21 * (at your option) any later version.
22 *
23 * This program is distributed in the hope that it will be useful,
24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
26 * GNU General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program; if not, write to the Free Software
30 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
31 */
32
33#include <linux/module.h>
34#include <linux/delay.h>
35#include <linux/init.h>
36#include <linux/slab.h>
37#include <linux/jiffies.h>
38#include <linux/i2c.h>
39#include <linux/hwmon.h>
40#include <linux/hwmon-sysfs.h>
41#include <linux/err.h>
42#include <linux/mutex.h>
43
44/* How many retries on register read error */
45#define MAX_RETRIES	5
46
47/*
48 * Address to scan
49 * Address is fully defined internally and cannot be changed.
50 */
51
52static unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
53
54/*
55 * Insmod parameters
56 */
57
58I2C_CLIENT_INSMOD_1(w83l785ts);
59
60/*
61 * The W83L785TS-S registers
62 * Manufacturer ID is 0x5CA3 for Winbond.
63 */
64
65#define W83L785TS_REG_MAN_ID1		0x4D
66#define W83L785TS_REG_MAN_ID2		0x4C
67#define W83L785TS_REG_CHIP_ID		0x4E
68#define W83L785TS_REG_CONFIG		0x40
69#define W83L785TS_REG_TYPE		0x52
70#define W83L785TS_REG_TEMP		0x27
71#define W83L785TS_REG_TEMP_OVER		0x53 /* not sure about this one */
72
73/*
74 * Conversions
75 * The W83L785TS-S uses signed 8-bit values.
76 */
77
78#define TEMP_FROM_REG(val)	((val) * 1000)
79
80/*
81 * Functions declaration
82 */
83
84static int w83l785ts_attach_adapter(struct i2c_adapter *adapter);
85static int w83l785ts_detect(struct i2c_adapter *adapter, int address,
86	int kind);
87static int w83l785ts_detach_client(struct i2c_client *client);
88static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
89static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
90
91/*
92 * Driver data (common to all clients)
93 */
94
95static struct i2c_driver w83l785ts_driver = {
96	.driver = {
97		.name	= "w83l785ts",
98	},
99	.id		= I2C_DRIVERID_W83L785TS,
100	.attach_adapter	= w83l785ts_attach_adapter,
101	.detach_client	= w83l785ts_detach_client,
102};
103
104/*
105 * Client data (each client gets its own)
106 */
107
108struct w83l785ts_data {
109	struct i2c_client client;
110	struct class_device *class_dev;
111	struct mutex update_lock;
112	char valid; /* zero until following fields are valid */
113	unsigned long last_updated; /* in jiffies */
114
115	/* registers values */
116	s8 temp[2]; /* 0: input
117		       1: critical limit */
118};
119
120/*
121 * Sysfs stuff
122 */
123
124static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
125	char *buf)
126{
127	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
128	struct w83l785ts_data *data = w83l785ts_update_device(dev);
129	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
130}
131
132static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
133static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
134
135/*
136 * Real code
137 */
138
139static int w83l785ts_attach_adapter(struct i2c_adapter *adapter)
140{
141	if (!(adapter->class & I2C_CLASS_HWMON))
142		return 0;
143	return i2c_probe(adapter, &addr_data, w83l785ts_detect);
144}
145
146/*
147 * The following function does more than just detection. If detection
148 * succeeds, it also registers the new chip.
149 */
150static int w83l785ts_detect(struct i2c_adapter *adapter, int address, int kind)
151{
152	struct i2c_client *new_client;
153	struct w83l785ts_data *data;
154	int err = 0;
155
156
157	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
158		goto exit;
159
160	if (!(data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL))) {
161		err = -ENOMEM;
162		goto exit;
163	}
164
165	/* The common I2C client data is placed right before the
166	 * W83L785TS-specific data. */
167	new_client = &data->client;
168	i2c_set_clientdata(new_client, data);
169	new_client->addr = address;
170	new_client->adapter = adapter;
171	new_client->driver = &w83l785ts_driver;
172	new_client->flags = 0;
173
174	/*
175	 * Now we do the remaining detection. A negative kind means that
176	 * the driver was loaded with no force parameter (default), so we
177	 * must both detect and identify the chip (actually there is only
178	 * one possible kind of chip for now, W83L785TS-S). A zero kind means
179	 * that the driver was loaded with the force parameter, the detection
180	 * step shall be skipped. A positive kind means that the driver
181	 * was loaded with the force parameter and a given kind of chip is
182	 * requested, so both the detection and the identification steps
183	 * are skipped.
184	 */
185	if (kind < 0) { /* detection */
186		if (((w83l785ts_read_value(new_client,
187		      W83L785TS_REG_CONFIG, 0) & 0x80) != 0x00)
188		 || ((w83l785ts_read_value(new_client,
189		      W83L785TS_REG_TYPE, 0) & 0xFC) != 0x00)) {
190			dev_dbg(&adapter->dev,
191				"W83L785TS-S detection failed at 0x%02x.\n",
192				address);
193			goto exit_free;
194		}
195	}
196
197	if (kind <= 0) { /* identification */
198		u16 man_id;
199		u8 chip_id;
200
201		man_id = (w83l785ts_read_value(new_client,
202			 W83L785TS_REG_MAN_ID1, 0) << 8) +
203			 w83l785ts_read_value(new_client,
204			 W83L785TS_REG_MAN_ID2, 0);
205		chip_id = w83l785ts_read_value(new_client,
206			  W83L785TS_REG_CHIP_ID, 0);
207
208		if (man_id == 0x5CA3) { /* Winbond */
209			if (chip_id == 0x70) { /* W83L785TS-S */
210				kind = w83l785ts;
211			}
212		}
213
214		if (kind <= 0) { /* identification failed */
215			dev_info(&adapter->dev,
216				 "Unsupported chip (man_id=0x%04X, "
217				 "chip_id=0x%02X).\n", man_id, chip_id);
218			goto exit_free;
219		}
220	}
221
222	/* We can fill in the remaining client fields. */
223	strlcpy(new_client->name, "w83l785ts", I2C_NAME_SIZE);
224	data->valid = 0;
225	mutex_init(&data->update_lock);
226
227	/* Default values in case the first read fails (unlikely). */
228	data->temp[1] = data->temp[0] = 0;
229
230	/* Tell the I2C layer a new client has arrived. */
231	if ((err = i2c_attach_client(new_client)))
232		goto exit_free;
233
234	/*
235	 * Initialize the W83L785TS chip
236	 * Nothing yet, assume it is already started.
237	 */
238
239	err = device_create_file(&new_client->dev,
240				 &sensor_dev_attr_temp1_input.dev_attr);
241	if (err)
242		goto exit_remove;
243
244	err = device_create_file(&new_client->dev,
245				 &sensor_dev_attr_temp1_max.dev_attr);
246	if (err)
247		goto exit_remove;
248
249	/* Register sysfs hooks */
250	data->class_dev = hwmon_device_register(&new_client->dev);
251	if (IS_ERR(data->class_dev)) {
252		err = PTR_ERR(data->class_dev);
253		goto exit_remove;
254	}
255
256	return 0;
257
258exit_remove:
259	device_remove_file(&new_client->dev,
260			   &sensor_dev_attr_temp1_input.dev_attr);
261	device_remove_file(&new_client->dev,
262			   &sensor_dev_attr_temp1_max.dev_attr);
263	i2c_detach_client(new_client);
264exit_free:
265	kfree(data);
266exit:
267	return err;
268}
269
270static int w83l785ts_detach_client(struct i2c_client *client)
271{
272	struct w83l785ts_data *data = i2c_get_clientdata(client);
273	int err;
274
275	hwmon_device_unregister(data->class_dev);
276	device_remove_file(&client->dev,
277			   &sensor_dev_attr_temp1_input.dev_attr);
278	device_remove_file(&client->dev,
279			   &sensor_dev_attr_temp1_max.dev_attr);
280	if ((err = i2c_detach_client(client)))
281		return err;
282
283	kfree(data);
284	return 0;
285}
286
287static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
288{
289	int value, i;
290
291	/* Frequent read errors have been reported on Asus boards, so we
292	 * retry on read errors. If it still fails (unlikely), return the
293	 * default value requested by the caller. */
294	for (i = 1; i <= MAX_RETRIES; i++) {
295		value = i2c_smbus_read_byte_data(client, reg);
296		if (value >= 0) {
297			dev_dbg(&client->dev, "Read 0x%02x from register "
298				"0x%02x.\n", value, reg);
299			return value;
300		}
301		dev_dbg(&client->dev, "Read failed, will retry in %d.\n", i);
302		msleep(i);
303	}
304
305	dev_err(&client->dev, "Couldn't read value from register 0x%02x. "
306		"Please report.\n", reg);
307	return defval;
308}
309
310static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
311{
312	struct i2c_client *client = to_i2c_client(dev);
313	struct w83l785ts_data *data = i2c_get_clientdata(client);
314
315	mutex_lock(&data->update_lock);
316
317	if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
318		dev_dbg(&client->dev, "Updating w83l785ts data.\n");
319		data->temp[0] = w83l785ts_read_value(client,
320				W83L785TS_REG_TEMP, data->temp[0]);
321		data->temp[1] = w83l785ts_read_value(client,
322				W83L785TS_REG_TEMP_OVER, data->temp[1]);
323
324		data->last_updated = jiffies;
325		data->valid = 1;
326	}
327
328	mutex_unlock(&data->update_lock);
329
330	return data;
331}
332
333static int __init sensors_w83l785ts_init(void)
334{
335	return i2c_add_driver(&w83l785ts_driver);
336}
337
338static void __exit sensors_w83l785ts_exit(void)
339{
340	i2c_del_driver(&w83l785ts_driver);
341}
342
343MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
344MODULE_DESCRIPTION("W83L785TS-S driver");
345MODULE_LICENSE("GPL");
346
347module_init(sensors_w83l785ts_init);
348module_exit(sensors_w83l785ts_exit);
349