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Grant Likely5162b752007-07-12 14:12:29 +02001/*
2 * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
3 *
4 * Written by: Grant Likely <grant.likely@secretlab.ca>
5 *
6 * Copyright (C) 2007 Secret Lab Technologies Ltd.
7 *
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.
11 */
12
13/*
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.
17 *
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
25 *
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.
31 *
32 */
33
34#include <linux/module.h>
Grant Likely5162b752007-07-12 14:12:29 +020035#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>
41
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
51
52#define DS1682_EEPROM_SIZE 10
53
54/*
55 * Generic counter attributes
56 */
57static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
58 char *buf)
59{
60 struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
61 struct i2c_client *client = to_i2c_client(dev);
62 __le32 val = 0;
63 int rc;
64
65 dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
66
67 /* Read the register */
68 rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
69 (u8 *) & val);
70 if (rc < 0)
71 return -EIO;
72
73 /* Special case: the 32 bit regs are time values with 1/4s
74 * resolution, scale them up to milliseconds */
75 if (sattr->nr == 4)
Andrew Mortonf52e0ef2007-07-26 10:41:09 -070076 return sprintf(buf, "%llu\n",
77 ((unsigned long long)le32_to_cpu(val)) * 250);
Grant Likely5162b752007-07-12 14:12:29 +020078
79 /* Format the output string and return # of bytes */
80 return sprintf(buf, "%li\n", (long)le32_to_cpu(val));
81}
82
83static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
84 const char *buf, size_t count)
85{
86 struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
87 struct i2c_client *client = to_i2c_client(dev);
Grant Likely5162b752007-07-12 14:12:29 +020088 u64 val;
89 __le32 val_le;
90 int rc;
91
92 dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
93
94 /* Decode input */
Sebastien Bourdelin40300742014-04-01 11:04:28 -040095 rc = kstrtoull(buf, 0, &val);
96 if (rc < 0) {
Grant Likely5162b752007-07-12 14:12:29 +020097 dev_dbg(dev, "input string not a number\n");
98 return -EINVAL;
99 }
100
101 /* Special case: the 32 bit regs are time values with 1/4s
102 * resolution, scale input down to quarter-seconds */
103 if (sattr->nr == 4)
104 do_div(val, 250);
105
106 /* write out the value */
107 val_le = cpu_to_le32(val);
108 rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
109 (u8 *) & val_le);
110 if (rc < 0) {
111 dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
112 sattr->index, sattr->nr);
113 return -EIO;
114 }
115
116 return count;
117}
118
119/*
120 * Simple register attributes
121 */
122static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
123 ds1682_store, 4, DS1682_REG_ELAPSED);
124static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
125 ds1682_store, 4, DS1682_REG_ALARM);
126static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
127 ds1682_store, 2, DS1682_REG_EVT_CNTR);
128
129static const struct attribute_group ds1682_group = {
130 .attrs = (struct attribute *[]) {
131 &sensor_dev_attr_elapsed_time.dev_attr.attr,
132 &sensor_dev_attr_alarm_time.dev_attr.attr,
133 &sensor_dev_attr_event_count.dev_attr.attr,
134 NULL,
135 },
136};
137
138/*
139 * User data attribute
140 */
Chris Wright2c3c8be2010-05-12 18:28:57 -0700141static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj,
142 struct bin_attribute *attr,
Al Viro05bd7112007-07-15 21:01:22 +0100143 char *buf, loff_t off, size_t count)
Grant Likely5162b752007-07-12 14:12:29 +0200144{
145 struct i2c_client *client = kobj_to_i2c_client(kobj);
146 int rc;
147
148 dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
149 buf, off, count);
150
151 if (off >= DS1682_EEPROM_SIZE)
152 return 0;
153
154 if (off + count > DS1682_EEPROM_SIZE)
155 count = DS1682_EEPROM_SIZE - off;
156
157 rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
158 count, buf);
159 if (rc < 0)
160 return -EIO;
161
162 return count;
163}
164
Chris Wright2c3c8be2010-05-12 18:28:57 -0700165static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj,
166 struct bin_attribute *attr,
Al Viro05bd7112007-07-15 21:01:22 +0100167 char *buf, loff_t off, size_t count)
Grant Likely5162b752007-07-12 14:12:29 +0200168{
169 struct i2c_client *client = kobj_to_i2c_client(kobj);
170
171 dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
172 buf, off, count);
173
174 if (off >= DS1682_EEPROM_SIZE)
175 return -ENOSPC;
176
177 if (off + count > DS1682_EEPROM_SIZE)
178 count = DS1682_EEPROM_SIZE - off;
179
180 /* Write out to the device */
181 if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
182 count, buf) < 0)
183 return -EIO;
184
185 return count;
186}
187
188static struct bin_attribute ds1682_eeprom_attr = {
189 .attr = {
190 .name = "eeprom",
191 .mode = S_IRUGO | S_IWUSR,
Grant Likely5162b752007-07-12 14:12:29 +0200192 },
193 .size = DS1682_EEPROM_SIZE,
194 .read = ds1682_eeprom_read,
195 .write = ds1682_eeprom_write,
196};
197
198/*
199 * Called when a ds1682 device is matched with this driver
200 */
Jean Delvared2653e92008-04-29 23:11:39 +0200201static int ds1682_probe(struct i2c_client *client,
202 const struct i2c_device_id *id)
Grant Likely5162b752007-07-12 14:12:29 +0200203{
204 int rc;
205
206 if (!i2c_check_functionality(client->adapter,
207 I2C_FUNC_SMBUS_I2C_BLOCK)) {
208 dev_err(&client->dev, "i2c bus does not support the ds1682\n");
209 rc = -ENODEV;
210 goto exit;
211 }
212
213 rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
214 if (rc)
215 goto exit;
216
217 rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
218 if (rc)
219 goto exit_bin_attr;
220
221 return 0;
222
223 exit_bin_attr:
224 sysfs_remove_group(&client->dev.kobj, &ds1682_group);
225 exit:
226 return rc;
227}
228
229static int ds1682_remove(struct i2c_client *client)
230{
231 sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
232 sysfs_remove_group(&client->dev.kobj, &ds1682_group);
233 return 0;
234}
235
Jean Delvare3760f732008-04-29 23:11:40 +0200236static const struct i2c_device_id ds1682_id[] = {
237 { "ds1682", 0 },
238 { }
239};
240MODULE_DEVICE_TABLE(i2c, ds1682_id);
241
Grant Likely5162b752007-07-12 14:12:29 +0200242static struct i2c_driver ds1682_driver = {
243 .driver = {
244 .name = "ds1682",
245 },
246 .probe = ds1682_probe,
247 .remove = ds1682_remove,
Jean Delvare3760f732008-04-29 23:11:40 +0200248 .id_table = ds1682_id,
Grant Likely5162b752007-07-12 14:12:29 +0200249};
250
Axel Lina64fe2e2012-01-22 15:36:45 +0800251module_i2c_driver(ds1682_driver);
Grant Likely5162b752007-07-12 14:12:29 +0200252
253MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
254MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
255MODULE_LICENSE("GPL");