aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/ds1621.c
blob: 872d76744e30d1a7d603cc6ca332ab2aa76a965f (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
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
 *	      monitoring
 * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
 * the help of Jean Delvare <khali@linux-fr.org>
 *
 * The DS1621 device is a digital temperature/thermometer with 9-bit
 * resolution, a thermal alarm output (Tout), and user-defined minimum
 * and maximum temperature thresholds (TH and TL).
 *
 * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
 * and similar in operation, with slight variations as noted in the device
 * datasheets (please refer to www.maximintegrated.com for specific
 * device information).
 *
 * Since the DS1621 was the first chipset supported by this driver,
 * most comments will refer to this chipset, but are actually general
 * and concern all supported chipsets, unless mentioned otherwise.
 *
 * 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/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>
#include <linux/sysfs.h>
#include <linux/kernel.h>

/* Supported devices */
enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };

/* Insmod parameters */
static int polarity = -1;
module_param(polarity, int, 0);
MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");

/*
 * The Configuration/Status register
 *
 * - DS1621:
 *   7    6    5    4    3    2    1    0
 * |Done|THF |TLF |NVB | X  | X  |POL |1SHOT|
 *
 * - DS1625:
 *   7    6    5    4    3    2    1    0
 * |Done|THF |TLF |NVB | 1  | 0  |POL |1SHOT|
 *
 * - DS1631, DS1731:
 *   7    6    5    4    3    2    1    0
 * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
 *
 * - DS1721:
 *   7    6    5    4    3    2    1    0
 * |Done| X  | X  | U  | R1 | R0 |POL |1SHOT|
 *
 * Where:
 * - 'X' is Reserved
 * - 'U' is Undefined
 */
#define DS1621_REG_CONFIG_NVB		0x10
#define DS1621_REG_CONFIG_RESOL		0x0C
#define DS1621_REG_CONFIG_POLARITY	0x02
#define DS1621_REG_CONFIG_1SHOT		0x01
#define DS1621_REG_CONFIG_DONE		0x80

#define DS1621_REG_CONFIG_RESOL_SHIFT	2

/* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
static const unsigned short ds1721_convrates[] = {
	94,	/*  9-bits (0.5,  93.75, RES[0..1] = 0 */
	188,	/* 10-bits (0.25, 187.5, RES[0..1] = 1 */
	375,	/* 11-bits (0.125,  375, RES[0..1] = 2 */
	750,	/* 12-bits (0.0625, 750, RES[0..1] = 3 */
};

#define DS1621_CONVERSION_MAX	750
#define DS1625_CONVERSION_MAX	500

#define DS1621_TEMP_MAX	125000
#define DS1621_TEMP_MIN	(-55000)

/* The DS1621 temperature registers */
static const u8 DS1621_REG_TEMP[3] = {
	0xAA,		/* input, word, RO */
	0xA2,		/* min, word, RW */
	0xA1,		/* max, word, RW */
};
#define DS1621_REG_CONF			0xAC /* byte, RW */
#define DS1621_COM_START		0xEE /* no data */
#define DS1721_COM_START		0x51 /* no data */
#define DS1621_COM_STOP			0x22 /* no data */

/* The DS1621 configuration register */
#define DS1621_ALARM_TEMP_HIGH		0x40
#define DS1621_ALARM_TEMP_LOW		0x20

/* Conversions */
#define ALARMS_FROM_REG(val) ((val) & \
			(DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))

/* Each client has this additional data */
struct ds1621_data {
	struct i2c_client *client;
	struct mutex update_lock;
	char valid;			/* !=0 if following fields are valid */
	unsigned long last_updated;	/* In jiffies */
	enum chips kind;		/* device type */

	u16 temp[3];			/* Register values, word */
	u8 conf;			/* Register encoding, combined */
	u8 zbits;			/* Resolution encoded as number of
					 * zero bits */
	u16 update_interval;		/* Conversion rate in milliseconds */
};

static inline int DS1621_TEMP_FROM_REG(u16 reg)
{
	return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
}

/*
 * TEMP: 0.001C/bit (-55C to +125C)
 * REG:
 *  - 1621, 1625: 0.5C/bit, 7 zero-bits
 *  - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
 */
static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
{
	temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
	temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
	return temp;
}

static void ds1621_init_client(struct ds1621_data *data,
			       struct i2c_client *client)
{
	u8 conf, new_conf, sreg, resol;

	new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
	/* switch to continuous conversion mode */
	new_conf &= ~DS1621_REG_CONFIG_1SHOT;

	/* setup output polarity */
	if (polarity == 0)
		new_conf &= ~DS1621_REG_CONFIG_POLARITY;
	else if (polarity == 1)
		new_conf |= DS1621_REG_CONFIG_POLARITY;

	if (conf != new_conf)
		i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);

	switch (data->kind) {
	case ds1625:
		data->update_interval = DS1625_CONVERSION_MAX;
		data->zbits = 7;
		sreg = DS1621_COM_START;
		break;
	case ds1631:
	case ds1721:
	case ds1731:
		resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
			 DS1621_REG_CONFIG_RESOL_SHIFT;
		data->update_interval = ds1721_convrates[resol];
		data->zbits = 7 - resol;
		sreg = DS1721_COM_START;
		break;
	default:
		data->update_interval = DS1621_CONVERSION_MAX;
		data->zbits = 7;
		sreg = DS1621_COM_START;
		break;
	}

	/* start conversion */
	i2c_smbus_write_byte(client, sreg);
}

static struct ds1621_data *ds1621_update_client(struct device *dev)
{
	struct ds1621_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	u8 new_conf;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + data->update_interval) ||
	    !data->valid) {
		int i;

		dev_dbg(&client->dev, "Starting ds1621 update\n");

		data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);

		for (i = 0; i < ARRAY_SIZE(data->temp); i++)
			data->temp[i] = i2c_smbus_read_word_swapped(client,
							 DS1621_REG_TEMP[i]);

		/* reset alarms if necessary */
		new_conf = data->conf;
		if (data->temp[0] > data->temp[1])	/* input > min */
			new_conf &= ~DS1621_ALARM_TEMP_LOW;
		if (data->temp[0] < data->temp[2])	/* input < max */
			new_conf &= ~DS1621_ALARM_TEMP_HIGH;
		if (data->conf != new_conf)
			i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
						  new_conf);

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

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t show_temp(struct device *dev, struct device_attribute *da,
			 char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n",
		       DS1621_TEMP_FROM_REG(data->temp[attr->index]));
}

static ssize_t set_temp(struct device *dev, struct device_attribute *da,
			const char *buf, size_t count)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = dev_get_drvdata(dev);
	long val;
	int err;

	err = kstrtol(buf, 10, &val);
	if (err)
		return err;

	mutex_lock(&data->update_lock);
	data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
	i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
				     data->temp[attr->index]);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
			   char *buf)
{
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
			  char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct ds1621_data *data = ds1621_update_client(dev);
	return sprintf(buf, "%d\n", !!(data->conf & attr->index));
}

static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
			  char *buf)
{
	struct ds1621_data *data = dev_get_drvdata(dev);
	return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
}

static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
			    const char *buf, size_t count)
{
	struct ds1621_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	unsigned long convrate;
	s32 err;
	int resol = 0;

	err = kstrtoul(buf, 10, &convrate);
	if (err)
		return err;

	/* Convert rate into resolution bits */
	while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
	       convrate > ds1721_convrates[resol])
		resol++;

	mutex_lock(&data->update_lock);
	data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
	data->conf &= ~DS1621_REG_CONFIG_RESOL;
	data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
	i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
	data->update_interval = ds1721_convrates[resol];
	mutex_unlock(&data->update_lock);

	return count;
}

static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_convrate,
		   set_convrate);

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
		DS1621_ALARM_TEMP_LOW);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
		DS1621_ALARM_TEMP_HIGH);

static struct attribute *ds1621_attributes[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_min.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&dev_attr_alarms.attr,
	&dev_attr_update_interval.attr,
	NULL
};

static umode_t ds1621_attribute_visible(struct kobject *kobj,
					struct attribute *attr, int index)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct ds1621_data *data = dev_get_drvdata(dev);

	if (attr == &dev_attr_update_interval.attr)
		if (data->kind == ds1621 || data->kind == ds1625)
			/* shhh, we're hiding update_interval */
			return 0;
	return attr->mode;
}

static const struct attribute_group ds1621_group = {
	.attrs = ds1621_attributes,
	.is_visible = ds1621_attribute_visible
};
__ATTRIBUTE_GROUPS(ds1621);

static int ds1621_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct ds1621_data *data;
	struct device *hwmon_dev;

	data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	mutex_init(&data->update_lock);

	data->kind = id->driver_data;
	data->client = client;

	/* Initialize the DS1621 chip */
	ds1621_init_client(data, client);

	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
							   client->name, data,
							   ds1621_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id ds1621_id[] = {
	{ "ds1621", ds1621 },
	{ "ds1625", ds1625 },
	{ "ds1631", ds1631 },
	{ "ds1721", ds1721 },
	{ "ds1731", ds1731 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ds1621_id);

/* This is the driver that will be inserted */
static struct i2c_driver ds1621_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "ds1621",
	},
	.probe		= ds1621_probe,
	.id_table	= ds1621_id,
};

module_i2c_driver(ds1621_driver);

MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
MODULE_DESCRIPTION("DS1621 driver");
MODULE_LICENSE("GPL");