summaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/max6642.c
blob: 8326fbd601508d354f5a037aabdc5420b1018670 (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
/*
 * Driver for +/-1 degree C, SMBus-Compatible Remote/Local Temperature Sensor
 * with Overtemperature Alarm
 *
 * Copyright (C) 2011 AppearTV AS
 *
 * Derived from:
 *
 *  Based on the max1619 driver.
 *  Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
 *                          Jean Delvare <khali@linux-fr.org>
 *
 * The MAX6642 is a sensor chip made by Maxim.
 * It reports up to two temperatures (its own plus up to
 * one external one). Complete datasheet can be
 * obtained from Maxim's website at:
 *   http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
 *
 * 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>

static const unsigned short normal_i2c[] = {
	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };

/*
 * The MAX6642 registers
 */

#define MAX6642_REG_R_MAN_ID		0xFE
#define MAX6642_REG_R_CONFIG		0x03
#define MAX6642_REG_W_CONFIG		0x09
#define MAX6642_REG_R_STATUS		0x02
#define MAX6642_REG_R_LOCAL_TEMP	0x00
#define MAX6642_REG_R_LOCAL_TEMPL	0x11
#define MAX6642_REG_R_LOCAL_HIGH	0x05
#define MAX6642_REG_W_LOCAL_HIGH	0x0B
#define MAX6642_REG_R_REMOTE_TEMP	0x01
#define MAX6642_REG_R_REMOTE_TEMPL	0x10
#define MAX6642_REG_R_REMOTE_HIGH	0x07
#define MAX6642_REG_W_REMOTE_HIGH	0x0D

/*
 * Conversions
 */

static int temp_from_reg10(int val)
{
	return val * 250;
}

static int temp_from_reg(int val)
{
	return val * 1000;
}

static int temp_to_reg(int val)
{
	return val / 1000;
}

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

struct max6642_data {
	struct i2c_client *client;
	struct mutex update_lock;
	bool valid; /* zero until following fields are valid */
	unsigned long last_updated; /* in jiffies */

	/* registers values */
	u16 temp_input[2]; /* local/remote */
	u16 temp_high[2]; /* local/remote */
	u8 alarms;
};

/*
 * Real code
 */

static void max6642_init_client(struct max6642_data *data,
				struct i2c_client *client)
{
	u8 config;

	/*
	 * Start the conversions.
	 */
	config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
	if (config & 0x40)
		i2c_smbus_write_byte_data(client, MAX6642_REG_W_CONFIG,
					  config & 0xBF); /* run */

	data->temp_high[0] = i2c_smbus_read_byte_data(client,
				MAX6642_REG_R_LOCAL_HIGH);
	data->temp_high[1] = i2c_smbus_read_byte_data(client,
				MAX6642_REG_R_REMOTE_HIGH);
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int max6642_detect(struct i2c_client *client,
			  struct i2c_board_info *info)
{
	struct i2c_adapter *adapter = client->adapter;
	u8 reg_config, reg_status, man_id;

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

	/* identification */
	man_id = i2c_smbus_read_byte_data(client, MAX6642_REG_R_MAN_ID);
	if (man_id != 0x4D)
		return -ENODEV;

	/* sanity check */
	if (i2c_smbus_read_byte_data(client, 0x04) != 0x4D
	    || i2c_smbus_read_byte_data(client, 0x06) != 0x4D
	    || i2c_smbus_read_byte_data(client, 0xff) != 0x4D)
		return -ENODEV;

	/*
	 * We read the config and status register, the 4 lower bits in the
	 * config register should be zero and bit 5, 3, 1 and 0 should be
	 * zero in the status register.
	 */
	reg_config = i2c_smbus_read_byte_data(client, MAX6642_REG_R_CONFIG);
	if ((reg_config & 0x0f) != 0x00)
		return -ENODEV;

	/* in between, another round of sanity checks */
	if (i2c_smbus_read_byte_data(client, 0x04) != reg_config
	    || i2c_smbus_read_byte_data(client, 0x06) != reg_config
	    || i2c_smbus_read_byte_data(client, 0xff) != reg_config)
		return -ENODEV;

	reg_status = i2c_smbus_read_byte_data(client, MAX6642_REG_R_STATUS);
	if ((reg_status & 0x2b) != 0x00)
		return -ENODEV;

	strlcpy(info->type, "max6642", I2C_NAME_SIZE);

	return 0;
}

static struct max6642_data *max6642_update_device(struct device *dev)
{
	struct max6642_data *data = dev_get_drvdata(dev);
	struct i2c_client *client = data->client;
	u16 val, tmp;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
		dev_dbg(dev, "Updating max6642 data.\n");
		val = i2c_smbus_read_byte_data(client,
					MAX6642_REG_R_LOCAL_TEMPL);
		tmp = (val >> 6) & 3;
		val = i2c_smbus_read_byte_data(client,
					MAX6642_REG_R_LOCAL_TEMP);
		val = (val << 2) | tmp;
		data->temp_input[0] = val;
		val = i2c_smbus_read_byte_data(client,
					MAX6642_REG_R_REMOTE_TEMPL);
		tmp = (val >> 6) & 3;
		val = i2c_smbus_read_byte_data(client,
					MAX6642_REG_R_REMOTE_TEMP);
		val = (val << 2) | tmp;
		data->temp_input[1] = val;
		data->alarms = i2c_smbus_read_byte_data(client,
					MAX6642_REG_R_STATUS);

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

	mutex_unlock(&data->update_lock);

	return data;
}

/*
 * Sysfs stuff
 */

static ssize_t show_temp_max10(struct device *dev,
			       struct device_attribute *dev_attr, char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
	struct max6642_data *data = max6642_update_device(dev);

	return sprintf(buf, "%d\n",
		       temp_from_reg10(data->temp_input[attr->index]));
}

static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
	struct max6642_data *data = max6642_update_device(dev);

	return sprintf(buf, "%d\n", temp_from_reg(data->temp_high[attr2->nr]));
}

static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
	struct max6642_data *data = dev_get_drvdata(dev);
	unsigned long val;
	int err;

	err = kstrtoul(buf, 10, &val);
	if (err < 0)
		return err;

	mutex_lock(&data->update_lock);
	data->temp_high[attr2->nr] = clamp_val(temp_to_reg(val), 0, 255);
	i2c_smbus_write_byte_data(data->client, attr2->index,
				  data->temp_high[attr2->nr]);
	mutex_unlock(&data->update_lock);
	return count;
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	int bitnr = to_sensor_dev_attr(attr)->index;
	struct max6642_data *data = max6642_update_device(dev);
	return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_max10, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_max10, NULL, 1);
static SENSOR_DEVICE_ATTR_2(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
			    set_temp_max, 0, MAX6642_REG_W_LOCAL_HIGH);
static SENSOR_DEVICE_ATTR_2(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
			    set_temp_max, 1, MAX6642_REG_W_REMOTE_HIGH);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);

static struct attribute *max6642_attrs[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp2_input.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp2_max.dev_attr.attr,

	&sensor_dev_attr_temp2_fault.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
	NULL
};
ATTRIBUTE_GROUPS(max6642);

static int max6642_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct max6642_data *data;
	struct device *hwmon_dev;

	data = devm_kzalloc(dev, sizeof(struct max6642_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->client = client;
	mutex_init(&data->update_lock);

	/* Initialize the MAX6642 chip */
	max6642_init_client(data, client);

	hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
							   client->name, data,
							   max6642_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

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

static const struct i2c_device_id max6642_id[] = {
	{ "max6642", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, max6642_id);

static struct i2c_driver max6642_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver = {
		.name	= "max6642",
	},
	.probe		= max6642_probe,
	.id_table	= max6642_id,
	.detect		= max6642_detect,
	.address_list	= normal_i2c,
};

module_i2c_driver(max6642_driver);

MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>");
MODULE_DESCRIPTION("MAX6642 sensor driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud