ds1621.c 11.8 KB
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
/*
 * 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 <jdelvare@suse.de>
 *
 * 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];
	data->zbits = 7 - 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");