1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
5 * Christian W. Zuckschwerdt <zany@triq.net> 2000-11-23
6 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
7 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
8 * the help of Jean Delvare <jdelvare@suse.de>
10 * The DS1621 device is a digital temperature/thermometer with 9-bit
11 * resolution, a thermal alarm output (Tout), and user-defined minimum
12 * and maximum temperature thresholds (TH and TL).
14 * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
15 * and similar in operation, with slight variations as noted in the device
16 * datasheets (please refer to www.maximintegrated.com for specific
17 * device information).
19 * Since the DS1621 was the first chipset supported by this driver,
20 * most comments will refer to this chipset, but are actually general
21 * and concern all supported chipsets, unless mentioned otherwise.
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/slab.h>
27 #include <linux/jiffies.h>
28 #include <linux/i2c.h>
29 #include <linux/hwmon.h>
30 #include <linux/hwmon-sysfs.h>
31 #include <linux/err.h>
32 #include <linux/mutex.h>
33 #include <linux/sysfs.h>
34 #include <linux/kernel.h>
36 /* Supported devices */
37 enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
39 /* Insmod parameters */
40 static int polarity = -1;
41 module_param(polarity, int, 0);
42 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
45 * The Configuration/Status register
49 * |Done|THF |TLF |NVB | X | X |POL |1SHOT|
53 * |Done|THF |TLF |NVB | 1 | 0 |POL |1SHOT|
57 * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
61 * |Done| X | X | U | R1 | R0 |POL |1SHOT|
67 #define DS1621_REG_CONFIG_NVB 0x10
68 #define DS1621_REG_CONFIG_RESOL 0x0C
69 #define DS1621_REG_CONFIG_POLARITY 0x02
70 #define DS1621_REG_CONFIG_1SHOT 0x01
71 #define DS1621_REG_CONFIG_DONE 0x80
73 #define DS1621_REG_CONFIG_RESOL_SHIFT 2
75 /* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
76 static const unsigned short ds1721_convrates[] = {
77 94, /* 9-bits (0.5, 93.75, RES[0..1] = 0 */
78 188, /* 10-bits (0.25, 187.5, RES[0..1] = 1 */
79 375, /* 11-bits (0.125, 375, RES[0..1] = 2 */
80 750, /* 12-bits (0.0625, 750, RES[0..1] = 3 */
83 #define DS1621_CONVERSION_MAX 750
84 #define DS1625_CONVERSION_MAX 500
86 #define DS1621_TEMP_MAX 125000
87 #define DS1621_TEMP_MIN (-55000)
89 /* The DS1621 temperature registers */
90 static const u8 DS1621_REG_TEMP[3] = {
91 0xAA, /* input, word, RO */
92 0xA2, /* min, word, RW */
93 0xA1, /* max, word, RW */
95 #define DS1621_REG_CONF 0xAC /* byte, RW */
96 #define DS1621_COM_START 0xEE /* no data */
97 #define DS1721_COM_START 0x51 /* no data */
98 #define DS1621_COM_STOP 0x22 /* no data */
100 /* The DS1621 configuration register */
101 #define DS1621_ALARM_TEMP_HIGH 0x40
102 #define DS1621_ALARM_TEMP_LOW 0x20
105 #define ALARMS_FROM_REG(val) ((val) & \
106 (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
108 /* Each client has this additional data */
110 struct i2c_client *client;
111 struct mutex update_lock;
112 bool valid; /* true if following fields are valid */
113 unsigned long last_updated; /* In jiffies */
114 enum chips kind; /* device type */
116 u16 temp[3]; /* Register values, word */
117 u8 conf; /* Register encoding, combined */
118 u8 zbits; /* Resolution encoded as number of
120 u16 update_interval; /* Conversion rate in milliseconds */
123 static inline int DS1621_TEMP_FROM_REG(u16 reg)
125 return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
129 * TEMP: 0.001C/bit (-55C to +125C)
131 * - 1621, 1625: 0.5C/bit, 7 zero-bits
132 * - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
134 static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
136 temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
137 temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
141 static void ds1621_init_client(struct ds1621_data *data,
142 struct i2c_client *client)
144 u8 conf, new_conf, sreg, resol;
146 new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
147 /* switch to continuous conversion mode */
148 new_conf &= ~DS1621_REG_CONFIG_1SHOT;
150 /* setup output polarity */
152 new_conf &= ~DS1621_REG_CONFIG_POLARITY;
153 else if (polarity == 1)
154 new_conf |= DS1621_REG_CONFIG_POLARITY;
156 if (conf != new_conf)
157 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
159 switch (data->kind) {
161 data->update_interval = DS1625_CONVERSION_MAX;
163 sreg = DS1621_COM_START;
168 resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
169 DS1621_REG_CONFIG_RESOL_SHIFT;
170 data->update_interval = ds1721_convrates[resol];
171 data->zbits = 7 - resol;
172 sreg = DS1721_COM_START;
175 data->update_interval = DS1621_CONVERSION_MAX;
177 sreg = DS1621_COM_START;
181 /* start conversion */
182 i2c_smbus_write_byte(client, sreg);
185 static struct ds1621_data *ds1621_update_client(struct device *dev)
187 struct ds1621_data *data = dev_get_drvdata(dev);
188 struct i2c_client *client = data->client;
191 mutex_lock(&data->update_lock);
193 if (time_after(jiffies, data->last_updated + data->update_interval) ||
197 dev_dbg(&client->dev, "Starting ds1621 update\n");
199 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
201 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
202 data->temp[i] = i2c_smbus_read_word_swapped(client,
205 /* reset alarms if necessary */
206 new_conf = data->conf;
207 if (data->temp[0] > data->temp[1]) /* input > min */
208 new_conf &= ~DS1621_ALARM_TEMP_LOW;
209 if (data->temp[0] < data->temp[2]) /* input < max */
210 new_conf &= ~DS1621_ALARM_TEMP_HIGH;
211 if (data->conf != new_conf)
212 i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
215 data->last_updated = jiffies;
219 mutex_unlock(&data->update_lock);
224 static ssize_t temp_show(struct device *dev, struct device_attribute *da,
227 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
228 struct ds1621_data *data = ds1621_update_client(dev);
229 return sprintf(buf, "%d\n",
230 DS1621_TEMP_FROM_REG(data->temp[attr->index]));
233 static ssize_t temp_store(struct device *dev, struct device_attribute *da,
234 const char *buf, size_t count)
236 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
237 struct ds1621_data *data = dev_get_drvdata(dev);
241 err = kstrtol(buf, 10, &val);
245 mutex_lock(&data->update_lock);
246 data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
247 i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
248 data->temp[attr->index]);
249 mutex_unlock(&data->update_lock);
253 static ssize_t alarms_show(struct device *dev, struct device_attribute *da,
256 struct ds1621_data *data = ds1621_update_client(dev);
257 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
260 static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
263 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
264 struct ds1621_data *data = ds1621_update_client(dev);
265 return sprintf(buf, "%d\n", !!(data->conf & attr->index));
268 static ssize_t update_interval_show(struct device *dev,
269 struct device_attribute *da, char *buf)
271 struct ds1621_data *data = dev_get_drvdata(dev);
272 return sysfs_emit(buf, "%hu\n", data->update_interval);
275 static ssize_t update_interval_store(struct device *dev,
276 struct device_attribute *da,
277 const char *buf, size_t count)
279 struct ds1621_data *data = dev_get_drvdata(dev);
280 struct i2c_client *client = data->client;
281 unsigned long convrate;
285 err = kstrtoul(buf, 10, &convrate);
289 /* Convert rate into resolution bits */
290 while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
291 convrate > ds1721_convrates[resol])
294 mutex_lock(&data->update_lock);
295 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
296 data->conf &= ~DS1621_REG_CONFIG_RESOL;
297 data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
298 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
299 data->update_interval = ds1721_convrates[resol];
300 data->zbits = 7 - resol;
301 mutex_unlock(&data->update_lock);
306 static DEVICE_ATTR_RO(alarms);
307 static DEVICE_ATTR_RW(update_interval);
309 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
310 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
311 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
312 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS1621_ALARM_TEMP_LOW);
313 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS1621_ALARM_TEMP_HIGH);
315 static struct attribute *ds1621_attributes[] = {
316 &sensor_dev_attr_temp1_input.dev_attr.attr,
317 &sensor_dev_attr_temp1_min.dev_attr.attr,
318 &sensor_dev_attr_temp1_max.dev_attr.attr,
319 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
320 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
321 &dev_attr_alarms.attr,
322 &dev_attr_update_interval.attr,
326 static umode_t ds1621_attribute_visible(struct kobject *kobj,
327 struct attribute *attr, int index)
329 struct device *dev = kobj_to_dev(kobj);
330 struct ds1621_data *data = dev_get_drvdata(dev);
332 if (attr == &dev_attr_update_interval.attr)
333 if (data->kind == ds1621 || data->kind == ds1625)
334 /* shhh, we're hiding update_interval */
339 static const struct attribute_group ds1621_group = {
340 .attrs = ds1621_attributes,
341 .is_visible = ds1621_attribute_visible
343 __ATTRIBUTE_GROUPS(ds1621);
345 static const struct i2c_device_id ds1621_id[];
347 static int ds1621_probe(struct i2c_client *client)
349 struct ds1621_data *data;
350 struct device *hwmon_dev;
352 data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
357 mutex_init(&data->update_lock);
359 data->kind = i2c_match_id(ds1621_id, client)->driver_data;
360 data->client = client;
362 /* Initialize the DS1621 chip */
363 ds1621_init_client(data, client);
365 hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
368 return PTR_ERR_OR_ZERO(hwmon_dev);
371 static const struct i2c_device_id ds1621_id[] = {
372 { "ds1621", ds1621 },
373 { "ds1625", ds1625 },
374 { "ds1631", ds1631 },
375 { "ds1721", ds1721 },
376 { "ds1731", ds1731 },
379 MODULE_DEVICE_TABLE(i2c, ds1621_id);
381 /* This is the driver that will be inserted */
382 static struct i2c_driver ds1621_driver = {
383 .class = I2C_CLASS_HWMON,
387 .probe_new = ds1621_probe,
388 .id_table = ds1621_id,
391 module_i2c_driver(ds1621_driver);
393 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
394 MODULE_DESCRIPTION("DS1621 driver");
395 MODULE_LICENSE("GPL");