2 * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
4 * Written by: Grant Likely <grant.likely@secretlab.ca>
6 * Copyright (C) 2007 Secret Lab Technologies Ltd.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
14 * The DS1682 elapsed timer recorder is a simple device that implements
15 * one elapsed time counter, one event counter, an alarm signal and 10
16 * bytes of general purpose EEPROM.
18 * This driver provides access to the DS1682 counters and user data via
19 * the sysfs. The following attributes are added to the device node:
20 * elapsed_time (u32): Total elapsed event time in ms resolution
21 * alarm_time (u32): When elapsed time exceeds the value in alarm_time,
22 * then the alarm pin is asserted.
23 * event_count (u16): number of times the event pin has gone low.
24 * eeprom (u8[10]): general purpose EEPROM
26 * Counter registers and user data are both read/write unless the device
27 * has been write protected. This driver does not support turning off write
28 * protection. Once write protection is turned on, it is impossible to
29 * turn it off again, so I have left the feature out of this driver to avoid
30 * accidental enabling, but it is trivial to add write protect support.
34 #include <linux/module.h>
35 #include <linux/i2c.h>
36 #include <linux/string.h>
37 #include <linux/list.h>
38 #include <linux/sysfs.h>
39 #include <linux/ctype.h>
40 #include <linux/hwmon-sysfs.h>
42 /* Device registers */
43 #define DS1682_REG_CONFIG 0x00
44 #define DS1682_REG_ALARM 0x01
45 #define DS1682_REG_ELAPSED 0x05
46 #define DS1682_REG_EVT_CNTR 0x09
47 #define DS1682_REG_EEPROM 0x0b
48 #define DS1682_REG_RESET 0x1d
49 #define DS1682_REG_WRITE_DISABLE 0x1e
50 #define DS1682_REG_WRITE_MEM_DISABLE 0x1f
52 #define DS1682_EEPROM_SIZE 10
55 * Generic counter attributes
57 static ssize_t
ds1682_show(struct device
*dev
, struct device_attribute
*attr
,
60 struct sensor_device_attribute_2
*sattr
= to_sensor_dev_attr_2(attr
);
61 struct i2c_client
*client
= to_i2c_client(dev
);
65 dev_dbg(dev
, "ds1682_show() called on %s\n", attr
->attr
.name
);
67 /* Read the register */
68 rc
= i2c_smbus_read_i2c_block_data(client
, sattr
->index
, sattr
->nr
,
73 /* Special case: the 32 bit regs are time values with 1/4s
74 * resolution, scale them up to milliseconds */
76 return sprintf(buf
, "%llu\n",
77 ((unsigned long long)le32_to_cpu(val
)) * 250);
79 /* Format the output string and return # of bytes */
80 return sprintf(buf
, "%li\n", (long)le32_to_cpu(val
));
83 static ssize_t
ds1682_store(struct device
*dev
, struct device_attribute
*attr
,
84 const char *buf
, size_t count
)
86 struct sensor_device_attribute_2
*sattr
= to_sensor_dev_attr_2(attr
);
87 struct i2c_client
*client
= to_i2c_client(dev
);
93 dev_dbg(dev
, "ds1682_store() called on %s\n", attr
->attr
.name
);
96 val
= simple_strtoull(buf
, &endp
, 0);
98 dev_dbg(dev
, "input string not a number\n");
102 /* Special case: the 32 bit regs are time values with 1/4s
103 * resolution, scale input down to quarter-seconds */
107 /* write out the value */
108 val_le
= cpu_to_le32(val
);
109 rc
= i2c_smbus_write_i2c_block_data(client
, sattr
->index
, sattr
->nr
,
112 dev_err(dev
, "register write failed; reg=0x%x, size=%i\n",
113 sattr
->index
, sattr
->nr
);
121 * Simple register attributes
123 static SENSOR_DEVICE_ATTR_2(elapsed_time
, S_IRUGO
| S_IWUSR
, ds1682_show
,
124 ds1682_store
, 4, DS1682_REG_ELAPSED
);
125 static SENSOR_DEVICE_ATTR_2(alarm_time
, S_IRUGO
| S_IWUSR
, ds1682_show
,
126 ds1682_store
, 4, DS1682_REG_ALARM
);
127 static SENSOR_DEVICE_ATTR_2(event_count
, S_IRUGO
| S_IWUSR
, ds1682_show
,
128 ds1682_store
, 2, DS1682_REG_EVT_CNTR
);
130 static const struct attribute_group ds1682_group
= {
131 .attrs
= (struct attribute
*[]) {
132 &sensor_dev_attr_elapsed_time
.dev_attr
.attr
,
133 &sensor_dev_attr_alarm_time
.dev_attr
.attr
,
134 &sensor_dev_attr_event_count
.dev_attr
.attr
,
140 * User data attribute
142 static ssize_t
ds1682_eeprom_read(struct file
*filp
, struct kobject
*kobj
,
143 struct bin_attribute
*attr
,
144 char *buf
, loff_t off
, size_t count
)
146 struct i2c_client
*client
= kobj_to_i2c_client(kobj
);
149 dev_dbg(&client
->dev
, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
152 if (off
>= DS1682_EEPROM_SIZE
)
155 if (off
+ count
> DS1682_EEPROM_SIZE
)
156 count
= DS1682_EEPROM_SIZE
- off
;
158 rc
= i2c_smbus_read_i2c_block_data(client
, DS1682_REG_EEPROM
+ off
,
166 static ssize_t
ds1682_eeprom_write(struct file
*filp
, struct kobject
*kobj
,
167 struct bin_attribute
*attr
,
168 char *buf
, loff_t off
, size_t count
)
170 struct i2c_client
*client
= kobj_to_i2c_client(kobj
);
172 dev_dbg(&client
->dev
, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
175 if (off
>= DS1682_EEPROM_SIZE
)
178 if (off
+ count
> DS1682_EEPROM_SIZE
)
179 count
= DS1682_EEPROM_SIZE
- off
;
181 /* Write out to the device */
182 if (i2c_smbus_write_i2c_block_data(client
, DS1682_REG_EEPROM
+ off
,
189 static struct bin_attribute ds1682_eeprom_attr
= {
192 .mode
= S_IRUGO
| S_IWUSR
,
194 .size
= DS1682_EEPROM_SIZE
,
195 .read
= ds1682_eeprom_read
,
196 .write
= ds1682_eeprom_write
,
200 * Called when a ds1682 device is matched with this driver
202 static int ds1682_probe(struct i2c_client
*client
,
203 const struct i2c_device_id
*id
)
207 if (!i2c_check_functionality(client
->adapter
,
208 I2C_FUNC_SMBUS_I2C_BLOCK
)) {
209 dev_err(&client
->dev
, "i2c bus does not support the ds1682\n");
214 rc
= sysfs_create_group(&client
->dev
.kobj
, &ds1682_group
);
218 rc
= sysfs_create_bin_file(&client
->dev
.kobj
, &ds1682_eeprom_attr
);
225 sysfs_remove_group(&client
->dev
.kobj
, &ds1682_group
);
230 static int ds1682_remove(struct i2c_client
*client
)
232 sysfs_remove_bin_file(&client
->dev
.kobj
, &ds1682_eeprom_attr
);
233 sysfs_remove_group(&client
->dev
.kobj
, &ds1682_group
);
237 static const struct i2c_device_id ds1682_id
[] = {
241 MODULE_DEVICE_TABLE(i2c
, ds1682_id
);
243 static struct i2c_driver ds1682_driver
= {
247 .probe
= ds1682_probe
,
248 .remove
= ds1682_remove
,
249 .id_table
= ds1682_id
,
252 module_i2c_driver(ds1682_driver
);
254 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
255 MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
256 MODULE_LICENSE("GPL");