aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/w83l785ts.c
blob: 39dbe990dc102e5638b157cecb1fd3e4a3720a09 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
/*
 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
 *               monitoring
 * Copyright (C) 2003-2009  Jean Delvare <khali@linux-fr.org>
 *
 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
 * by Winbond. It reports a single external temperature with a 1 deg
 * resolution and a 3 deg accuracy. Datasheet can be obtained from
 * Winbond's website at:
 *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
 *
 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
 * <khali@linux-fr.org>.
 *
 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
 * error handling mechanism.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>

/* How many retries on register read error */
#define MAX_RETRIES	5

/*
 * Address to scan
 * Address is fully defined internally and cannot be changed.
 */

static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };

/*
 * The W83L785TS-S registers
 * Manufacturer ID is 0x5CA3 for Winbond.
 */

#define W83L785TS_REG_MAN_ID1		0x4D
#define W83L785TS_REG_MAN_ID2		0x4C
#define W83L785TS_REG_CHIP_ID		0x4E
#define W83L785TS_REG_CONFIG		0x40
#define W83L785TS_REG_TYPE		0x52
#define W83L785TS_REG_TEMP		0x27
#define W83L785TS_REG_TEMP_OVER		0x53 /* not sure about this one */

/*
 * Conversions
 * The W83L785TS-S uses signed 8-bit values.
 */

#define TEMP_FROM_REG(val)	((val) * 1000)

/*
 * Functions declaration
 */

static int w83l785ts_probe(struct i2c_client *client,
			   const struct i2c_device_id *id);
static int w83l785ts_detect(struct i2c_client *client,
			    struct i2c_board_info *info);
static int w83l785ts_remove(struct i2c_client *client);
static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);

/*
 * Driver data (common to all clients)
 */

static const struct i2c_device_id w83l785ts_id[] = {
	{ "w83l785ts", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, w83l785ts_id);

static struct i2c_driver w83l785ts_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "w83l785ts",
	},
	.probe		= w83l785ts_probe,
	.remove		= w83l785ts_remove,
	.id_table	= w83l785ts_id,
	.detect		= w83l785ts_detect,
	.address_list	= normal_i2c,
};

/*
 * Client data (each client gets its own)
 */

struct w83l785ts_data {
	struct device *hwmon_dev;
	struct mutex update_lock;
	char valid; /* zero until following fields are valid */
	unsigned long last_updated; /* in jiffies */

	/* registers values */
	s8 temp[2]; /* 0: input, 1: critical limit */
};

/*
 * Sysfs stuff
 */

static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
	char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
	struct w83l785ts_data *data = w83l785ts_update_device(dev);
	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);

/*
 * Real code
 */

/* Return 0 if detection is successful, -ENODEV otherwise */
static int w83l785ts_detect(struct i2c_client *client,
			    struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;
	u16 man_id;
	u8 chip_id;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

	/* detection */
	if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
	 || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
		dev_dbg(&adapter->dev,
			"W83L785TS-S detection failed at 0x%02x\n",
			client->addr);
		return -ENODEV;
	}

	/* Identification */
	man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
	       + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
	chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);

	if (man_id != 0x5CA3		/* Winbond */
	 || chip_id != 0x70) {		/* W83L785TS-S */
		dev_dbg(&adapter->dev,
			"Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
			man_id, chip_id);
		return -ENODEV;
	}

	strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);

	return 0;
}

static int w83l785ts_probe(struct i2c_client *client,
			   const struct i2c_device_id *id)
{
	struct w83l785ts_data *data;
	struct device *dev = &client->dev;
	int err;

	data = devm_kzalloc(dev, sizeof(struct w83l785ts_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);
	data->valid = 0;
	mutex_init(&data->update_lock);

	/* Default values in case the first read fails (unlikely). */
	data->temp[1] = data->temp[0] = 0;

	/*
	 * Initialize the W83L785TS chip
	 * Nothing yet, assume it is already started.
	 */

	err = device_create_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
	if (err)
		return err;

	err = device_create_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
	if (err)
		goto exit_remove;

	/* Register sysfs hooks */
	data->hwmon_dev = hwmon_device_register(dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return 0;

exit_remove:
	device_remove_file(dev, &sensor_dev_attr_temp1_input.dev_attr);
	device_remove_file(dev, &sensor_dev_attr_temp1_max.dev_attr);
	return err;
}

static int w83l785ts_remove(struct i2c_client *client)
{
	struct w83l785ts_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	device_remove_file(&client->dev,
			   &sensor_dev_attr_temp1_input.dev_attr);
	device_remove_file(&client->dev,
			   &sensor_dev_attr_temp1_max.dev_attr);

	return 0;
}

static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
{
	int value, i;
	struct device *dev;
	const char *prefix;

	/*
	 * We might be called during detection, at which point the client
	 * isn't yet fully initialized, so we can't use dev_dbg on it
	 */
	if (i2c_get_clientdata(client)) {
		dev = &client->dev;
		prefix = "";
	} else {
		dev = &client->adapter->dev;
		prefix = "w83l785ts: ";
	}

	/*
	 * Frequent read errors have been reported on Asus boards, so we
	 * retry on read errors. If it still fails (unlikely), return the
	 * default value requested by the caller.
	 */
	for (i = 1; i <= MAX_RETRIES; i++) {
		value = i2c_smbus_read_byte_data(client, reg);
		if (value >= 0) {
			dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
				prefix, value, reg);
			return value;
		}
		dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
		msleep(i);
	}

	dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
		reg);
	return defval;
}

static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct w83l785ts_data *data = i2c_get_clientdata(client);

	mutex_lock(&data->update_lock);

	if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
		dev_dbg(&client->dev, "Updating w83l785ts data.\n");
		data->temp[0] = w83l785ts_read_value(client,
				W83L785TS_REG_TEMP, data->temp[0]);
		data->temp[1] = w83l785ts_read_value(client,
				W83L785TS_REG_TEMP_OVER, data->temp[1]);

		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

module_i2c_driver(w83l785ts_driver);

MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
MODULE_DESCRIPTION("W83L785TS-S driver");
MODULE_LICENSE("GPL");