1/*
2 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
3 * monitoring
4 * Christian W. Zuckschwerdt <zany@triq.net> 2000-11-23
5 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
6 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
7 * the help of Jean Delvare <jdelvare@suse.de>
8 *
9 * The DS1621 device is a digital temperature/thermometer with 9-bit
10 * resolution, a thermal alarm output (Tout), and user-defined minimum
11 * and maximum temperature thresholds (TH and TL).
12 *
13 * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
14 * and similar in operation, with slight variations as noted in the device
15 * datasheets (please refer to www.maximintegrated.com for specific
16 * device information).
17 *
18 * Since the DS1621 was the first chipset supported by this driver,
19 * most comments will refer to this chipset, but are actually general
20 * and concern all supported chipsets, unless mentioned otherwise.
21 *
22 * This program is free software; you can redistribute it and/or modify
23 * it under the terms of the GNU General Public License as published by
24 * the Free Software Foundation; either version 2 of the License, or
25 * (at your option) any later version.
26 *
27 * This program is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
30 * GNU General Public License for more details.
31 *
32 * You should have received a copy of the GNU General Public License
33 * along with this program; if not, write to the Free Software
34 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
35 */
36
37#include <linux/module.h>
38#include <linux/init.h>
39#include <linux/slab.h>
40#include <linux/jiffies.h>
41#include <linux/i2c.h>
42#include <linux/hwmon.h>
43#include <linux/hwmon-sysfs.h>
44#include <linux/err.h>
45#include <linux/mutex.h>
46#include <linux/sysfs.h>
47#include <linux/kernel.h>
48
49/* Supported devices */
50enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
51
52/* Insmod parameters */
53static int polarity = -1;
54module_param(polarity, int, 0);
55MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
56
57/*
58 * The Configuration/Status register
59 *
60 * - DS1621:
61 * 7 6 5 4 3 2 1 0
62 * |Done|THF |TLF |NVB | X | X |POL |1SHOT|
63 *
64 * - DS1625:
65 * 7 6 5 4 3 2 1 0
66 * |Done|THF |TLF |NVB | 1 | 0 |POL |1SHOT|
67 *
68 * - DS1631, DS1731:
69 * 7 6 5 4 3 2 1 0
70 * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
71 *
72 * - DS1721:
73 * 7 6 5 4 3 2 1 0
74 * |Done| X | X | U | R1 | R0 |POL |1SHOT|
75 *
76 * Where:
77 * - 'X' is Reserved
78 * - 'U' is Undefined
79 */
80#define DS1621_REG_CONFIG_NVB 0x10
81#define DS1621_REG_CONFIG_RESOL 0x0C
82#define DS1621_REG_CONFIG_POLARITY 0x02
83#define DS1621_REG_CONFIG_1SHOT 0x01
84#define DS1621_REG_CONFIG_DONE 0x80
85
86#define DS1621_REG_CONFIG_RESOL_SHIFT 2
87
88/* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
89static const unsigned short ds1721_convrates[] = {
90 94, /* 9-bits (0.5, 93.75, RES[0..1] = 0 */
91 188, /* 10-bits (0.25, 187.5, RES[0..1] = 1 */
92 375, /* 11-bits (0.125, 375, RES[0..1] = 2 */
93 750, /* 12-bits (0.0625, 750, RES[0..1] = 3 */
94};
95
96#define DS1621_CONVERSION_MAX 750
97#define DS1625_CONVERSION_MAX 500
98
99#define DS1621_TEMP_MAX 125000
100#define DS1621_TEMP_MIN (-55000)
101
102/* The DS1621 temperature registers */
103static const u8 DS1621_REG_TEMP[3] = {
104 0xAA, /* input, word, RO */
105 0xA2, /* min, word, RW */
106 0xA1, /* max, word, RW */
107};
108#define DS1621_REG_CONF 0xAC /* byte, RW */
109#define DS1621_COM_START 0xEE /* no data */
110#define DS1721_COM_START 0x51 /* no data */
111#define DS1621_COM_STOP 0x22 /* no data */
112
113/* The DS1621 configuration register */
114#define DS1621_ALARM_TEMP_HIGH 0x40
115#define DS1621_ALARM_TEMP_LOW 0x20
116
117/* Conversions */
118#define ALARMS_FROM_REG(val) ((val) & \
119 (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
120
121/* Each client has this additional data */
122struct ds1621_data {
123 struct i2c_client *client;
124 struct mutex update_lock;
125 char valid; /* !=0 if following fields are valid */
126 unsigned long last_updated; /* In jiffies */
127 enum chips kind; /* device type */
128
129 u16 temp[3]; /* Register values, word */
130 u8 conf; /* Register encoding, combined */
131 u8 zbits; /* Resolution encoded as number of
132 * zero bits */
133 u16 update_interval; /* Conversion rate in milliseconds */
134};
135
136static inline int DS1621_TEMP_FROM_REG(u16 reg)
137{
138 return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
139}
140
141/*
142 * TEMP: 0.001C/bit (-55C to +125C)
143 * REG:
144 * - 1621, 1625: 0.5C/bit, 7 zero-bits
145 * - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
146 */
147static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
148{
149 temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
150 temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
151 return temp;
152}
153
154static void ds1621_init_client(struct ds1621_data *data,
155 struct i2c_client *client)
156{
157 u8 conf, new_conf, sreg, resol;
158
159 new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
160 /* switch to continuous conversion mode */
161 new_conf &= ~DS1621_REG_CONFIG_1SHOT;
162
163 /* setup output polarity */
164 if (polarity == 0)
165 new_conf &= ~DS1621_REG_CONFIG_POLARITY;
166 else if (polarity == 1)
167 new_conf |= DS1621_REG_CONFIG_POLARITY;
168
169 if (conf != new_conf)
170 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
171
172 switch (data->kind) {
173 case ds1625:
174 data->update_interval = DS1625_CONVERSION_MAX;
175 data->zbits = 7;
176 sreg = DS1621_COM_START;
177 break;
178 case ds1631:
179 case ds1721:
180 case ds1731:
181 resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
182 DS1621_REG_CONFIG_RESOL_SHIFT;
183 data->update_interval = ds1721_convrates[resol];
184 data->zbits = 7 - resol;
185 sreg = DS1721_COM_START;
186 break;
187 default:
188 data->update_interval = DS1621_CONVERSION_MAX;
189 data->zbits = 7;
190 sreg = DS1621_COM_START;
191 break;
192 }
193
194 /* start conversion */
195 i2c_smbus_write_byte(client, sreg);
196}
197
198static struct ds1621_data *ds1621_update_client(struct device *dev)
199{
200 struct ds1621_data *data = dev_get_drvdata(dev);
201 struct i2c_client *client = data->client;
202 u8 new_conf;
203
204 mutex_lock(&data->update_lock);
205
206 if (time_after(jiffies, data->last_updated + data->update_interval) ||
207 !data->valid) {
208 int i;
209
210 dev_dbg(&client->dev, "Starting ds1621 update\n");
211
212 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
213
214 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
215 data->temp[i] = i2c_smbus_read_word_swapped(client,
216 DS1621_REG_TEMP[i]);
217
218 /* reset alarms if necessary */
219 new_conf = data->conf;
220 if (data->temp[0] > data->temp[1]) /* input > min */
221 new_conf &= ~DS1621_ALARM_TEMP_LOW;
222 if (data->temp[0] < data->temp[2]) /* input < max */
223 new_conf &= ~DS1621_ALARM_TEMP_HIGH;
224 if (data->conf != new_conf)
225 i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
226 new_conf);
227
228 data->last_updated = jiffies;
229 data->valid = 1;
230 }
231
232 mutex_unlock(&data->update_lock);
233
234 return data;
235}
236
237static ssize_t temp_show(struct device *dev, struct device_attribute *da,
238 char *buf)
239{
240 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
241 struct ds1621_data *data = ds1621_update_client(dev);
242 return sprintf(buf, "%d\n",
243 DS1621_TEMP_FROM_REG(data->temp[attr->index]));
244}
245
246static ssize_t temp_store(struct device *dev, struct device_attribute *da,
247 const char *buf, size_t count)
248{
249 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
250 struct ds1621_data *data = dev_get_drvdata(dev);
251 long val;
252 int err;
253
254 err = kstrtol(buf, 10, &val);
255 if (err)
256 return err;
257
258 mutex_lock(&data->update_lock);
259 data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
260 i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
261 data->temp[attr->index]);
262 mutex_unlock(&data->update_lock);
263 return count;
264}
265
266static ssize_t alarms_show(struct device *dev, struct device_attribute *da,
267 char *buf)
268{
269 struct ds1621_data *data = ds1621_update_client(dev);
270 return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
271}
272
273static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
274 char *buf)
275{
276 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
277 struct ds1621_data *data = ds1621_update_client(dev);
278 return sprintf(buf, "%d\n", !!(data->conf & attr->index));
279}
280
281static ssize_t update_interval_show(struct device *dev,
282 struct device_attribute *da, char *buf)
283{
284 struct ds1621_data *data = dev_get_drvdata(dev);
285 return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
286}
287
288static ssize_t update_interval_store(struct device *dev,
289 struct device_attribute *da,
290 const char *buf, size_t count)
291{
292 struct ds1621_data *data = dev_get_drvdata(dev);
293 struct i2c_client *client = data->client;
294 unsigned long convrate;
295 s32 err;
296 int resol = 0;
297
298 err = kstrtoul(buf, 10, &convrate);
299 if (err)
300 return err;
301
302 /* Convert rate into resolution bits */
303 while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
304 convrate > ds1721_convrates[resol])
305 resol++;
306
307 mutex_lock(&data->update_lock);
308 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
309 data->conf &= ~DS1621_REG_CONFIG_RESOL;
310 data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
311 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
312 data->update_interval = ds1721_convrates[resol];
313 data->zbits = 7 - resol;
314 mutex_unlock(&data->update_lock);
315
316 return count;
317}
318
319static DEVICE_ATTR_RO(alarms);
320static DEVICE_ATTR_RW(update_interval);
321
322static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
323static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
324static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
325static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS1621_ALARM_TEMP_LOW);
326static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS1621_ALARM_TEMP_HIGH);
327
328static struct attribute *ds1621_attributes[] = {
329 &sensor_dev_attr_temp1_input.dev_attr.attr,
330 &sensor_dev_attr_temp1_min.dev_attr.attr,
331 &sensor_dev_attr_temp1_max.dev_attr.attr,
332 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
333 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
334 &dev_attr_alarms.attr,
335 &dev_attr_update_interval.attr,
336 NULL
337};
338
339static umode_t ds1621_attribute_visible(struct kobject *kobj,
340 struct attribute *attr, int index)
341{
342 struct device *dev = container_of(kobj, struct device, kobj);
343 struct ds1621_data *data = dev_get_drvdata(dev);
344
345 if (attr == &dev_attr_update_interval.attr)
346 if (data->kind == ds1621 || data->kind == ds1625)
347 /* shhh, we're hiding update_interval */
348 return 0;
349 return attr->mode;
350}
351
352static const struct attribute_group ds1621_group = {
353 .attrs = ds1621_attributes,
354 .is_visible = ds1621_attribute_visible
355};
356__ATTRIBUTE_GROUPS(ds1621);
357
358static int ds1621_probe(struct i2c_client *client,
359 const struct i2c_device_id *id)
360{
361 struct ds1621_data *data;
362 struct device *hwmon_dev;
363
364 data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
365 GFP_KERNEL);
366 if (!data)
367 return -ENOMEM;
368
369 mutex_init(&data->update_lock);
370
371 data->kind = id->driver_data;
372 data->client = client;
373
374 /* Initialize the DS1621 chip */
375 ds1621_init_client(data, client);
376
377 hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
378 client->name, data,
379 ds1621_groups);
380 return PTR_ERR_OR_ZERO(hwmon_dev);
381}
382
383static const struct i2c_device_id ds1621_id[] = {
384 { "ds1621", ds1621 },
385 { "ds1625", ds1625 },
386 { "ds1631", ds1631 },
387 { "ds1721", ds1721 },
388 { "ds1731", ds1731 },
389 { }
390};
391MODULE_DEVICE_TABLE(i2c, ds1621_id);
392
393/* This is the driver that will be inserted */
394static struct i2c_driver ds1621_driver = {
395 .class = I2C_CLASS_HWMON,
396 .driver = {
397 .name = "ds1621",
398 },
399 .probe = ds1621_probe,
400 .id_table = ds1621_id,
401};
402
403module_i2c_driver(ds1621_driver);
404
405MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
406MODULE_DESCRIPTION("DS1621 driver");
407MODULE_LICENSE("GPL");
408