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5162b75b GL |
1 | /* |
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> | |
35 | #include <linux/init.h> | |
5162b75b GL |
36 | #include <linux/i2c.h> |
37 | #include <linux/string.h> | |
38 | #include <linux/list.h> | |
39 | #include <linux/sysfs.h> | |
40 | #include <linux/ctype.h> | |
41 | #include <linux/hwmon-sysfs.h> | |
42 | ||
43 | /* Device registers */ | |
44 | #define DS1682_REG_CONFIG 0x00 | |
45 | #define DS1682_REG_ALARM 0x01 | |
46 | #define DS1682_REG_ELAPSED 0x05 | |
47 | #define DS1682_REG_EVT_CNTR 0x09 | |
48 | #define DS1682_REG_EEPROM 0x0b | |
49 | #define DS1682_REG_RESET 0x1d | |
50 | #define DS1682_REG_WRITE_DISABLE 0x1e | |
51 | #define DS1682_REG_WRITE_MEM_DISABLE 0x1f | |
52 | ||
53 | #define DS1682_EEPROM_SIZE 10 | |
54 | ||
55 | /* | |
56 | * Generic counter attributes | |
57 | */ | |
58 | static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr, | |
59 | char *buf) | |
60 | { | |
61 | struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); | |
62 | struct i2c_client *client = to_i2c_client(dev); | |
63 | __le32 val = 0; | |
64 | int rc; | |
65 | ||
66 | dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name); | |
67 | ||
68 | /* Read the register */ | |
69 | rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr, | |
70 | (u8 *) & val); | |
71 | if (rc < 0) | |
72 | return -EIO; | |
73 | ||
74 | /* Special case: the 32 bit regs are time values with 1/4s | |
75 | * resolution, scale them up to milliseconds */ | |
76 | if (sattr->nr == 4) | |
f52e0ef4 AM |
77 | return sprintf(buf, "%llu\n", |
78 | ((unsigned long long)le32_to_cpu(val)) * 250); | |
5162b75b GL |
79 | |
80 | /* Format the output string and return # of bytes */ | |
81 | return sprintf(buf, "%li\n", (long)le32_to_cpu(val)); | |
82 | } | |
83 | ||
84 | static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr, | |
85 | const char *buf, size_t count) | |
86 | { | |
87 | struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); | |
88 | struct i2c_client *client = to_i2c_client(dev); | |
89 | char *endp; | |
90 | u64 val; | |
91 | __le32 val_le; | |
92 | int rc; | |
93 | ||
94 | dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name); | |
95 | ||
96 | /* Decode input */ | |
97 | val = simple_strtoull(buf, &endp, 0); | |
98 | if (buf == endp) { | |
99 | dev_dbg(dev, "input string not a number\n"); | |
100 | return -EINVAL; | |
101 | } | |
102 | ||
103 | /* Special case: the 32 bit regs are time values with 1/4s | |
104 | * resolution, scale input down to quarter-seconds */ | |
105 | if (sattr->nr == 4) | |
106 | do_div(val, 250); | |
107 | ||
108 | /* write out the value */ | |
109 | val_le = cpu_to_le32(val); | |
110 | rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr, | |
111 | (u8 *) & val_le); | |
112 | if (rc < 0) { | |
113 | dev_err(dev, "register write failed; reg=0x%x, size=%i\n", | |
114 | sattr->index, sattr->nr); | |
115 | return -EIO; | |
116 | } | |
117 | ||
118 | return count; | |
119 | } | |
120 | ||
121 | /* | |
122 | * Simple register attributes | |
123 | */ | |
124 | static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show, | |
125 | ds1682_store, 4, DS1682_REG_ELAPSED); | |
126 | static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show, | |
127 | ds1682_store, 4, DS1682_REG_ALARM); | |
128 | static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show, | |
129 | ds1682_store, 2, DS1682_REG_EVT_CNTR); | |
130 | ||
131 | static const struct attribute_group ds1682_group = { | |
132 | .attrs = (struct attribute *[]) { | |
133 | &sensor_dev_attr_elapsed_time.dev_attr.attr, | |
134 | &sensor_dev_attr_alarm_time.dev_attr.attr, | |
135 | &sensor_dev_attr_event_count.dev_attr.attr, | |
136 | NULL, | |
137 | }, | |
138 | }; | |
139 | ||
140 | /* | |
141 | * User data attribute | |
142 | */ | |
2c3c8bea CW |
143 | static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj, |
144 | struct bin_attribute *attr, | |
05bd711e | 145 | char *buf, loff_t off, size_t count) |
5162b75b GL |
146 | { |
147 | struct i2c_client *client = kobj_to_i2c_client(kobj); | |
148 | int rc; | |
149 | ||
150 | dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n", | |
151 | buf, off, count); | |
152 | ||
153 | if (off >= DS1682_EEPROM_SIZE) | |
154 | return 0; | |
155 | ||
156 | if (off + count > DS1682_EEPROM_SIZE) | |
157 | count = DS1682_EEPROM_SIZE - off; | |
158 | ||
159 | rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off, | |
160 | count, buf); | |
161 | if (rc < 0) | |
162 | return -EIO; | |
163 | ||
164 | return count; | |
165 | } | |
166 | ||
2c3c8bea CW |
167 | static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj, |
168 | struct bin_attribute *attr, | |
05bd711e | 169 | char *buf, loff_t off, size_t count) |
5162b75b GL |
170 | { |
171 | struct i2c_client *client = kobj_to_i2c_client(kobj); | |
172 | ||
173 | dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n", | |
174 | buf, off, count); | |
175 | ||
176 | if (off >= DS1682_EEPROM_SIZE) | |
177 | return -ENOSPC; | |
178 | ||
179 | if (off + count > DS1682_EEPROM_SIZE) | |
180 | count = DS1682_EEPROM_SIZE - off; | |
181 | ||
182 | /* Write out to the device */ | |
183 | if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off, | |
184 | count, buf) < 0) | |
185 | return -EIO; | |
186 | ||
187 | return count; | |
188 | } | |
189 | ||
190 | static struct bin_attribute ds1682_eeprom_attr = { | |
191 | .attr = { | |
192 | .name = "eeprom", | |
193 | .mode = S_IRUGO | S_IWUSR, | |
5162b75b GL |
194 | }, |
195 | .size = DS1682_EEPROM_SIZE, | |
196 | .read = ds1682_eeprom_read, | |
197 | .write = ds1682_eeprom_write, | |
198 | }; | |
199 | ||
200 | /* | |
201 | * Called when a ds1682 device is matched with this driver | |
202 | */ | |
d2653e92 JD |
203 | static int ds1682_probe(struct i2c_client *client, |
204 | const struct i2c_device_id *id) | |
5162b75b GL |
205 | { |
206 | int rc; | |
207 | ||
208 | if (!i2c_check_functionality(client->adapter, | |
209 | I2C_FUNC_SMBUS_I2C_BLOCK)) { | |
210 | dev_err(&client->dev, "i2c bus does not support the ds1682\n"); | |
211 | rc = -ENODEV; | |
212 | goto exit; | |
213 | } | |
214 | ||
215 | rc = sysfs_create_group(&client->dev.kobj, &ds1682_group); | |
216 | if (rc) | |
217 | goto exit; | |
218 | ||
219 | rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); | |
220 | if (rc) | |
221 | goto exit_bin_attr; | |
222 | ||
223 | return 0; | |
224 | ||
225 | exit_bin_attr: | |
226 | sysfs_remove_group(&client->dev.kobj, &ds1682_group); | |
227 | exit: | |
228 | return rc; | |
229 | } | |
230 | ||
231 | static int ds1682_remove(struct i2c_client *client) | |
232 | { | |
233 | sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); | |
234 | sysfs_remove_group(&client->dev.kobj, &ds1682_group); | |
235 | return 0; | |
236 | } | |
237 | ||
3760f736 JD |
238 | static const struct i2c_device_id ds1682_id[] = { |
239 | { "ds1682", 0 }, | |
240 | { } | |
241 | }; | |
242 | MODULE_DEVICE_TABLE(i2c, ds1682_id); | |
243 | ||
5162b75b GL |
244 | static struct i2c_driver ds1682_driver = { |
245 | .driver = { | |
246 | .name = "ds1682", | |
247 | }, | |
248 | .probe = ds1682_probe, | |
249 | .remove = ds1682_remove, | |
3760f736 | 250 | .id_table = ds1682_id, |
5162b75b GL |
251 | }; |
252 | ||
a64fe2ed | 253 | module_i2c_driver(ds1682_driver); |
5162b75b GL |
254 | |
255 | MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>"); | |
256 | MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver"); | |
257 | MODULE_LICENSE("GPL"); |