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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> | |
5162b75b GL |
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> | |
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 | */ | |
57 | static 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) | |
f52e0ef4 AM |
76 | return sprintf(buf, "%llu\n", |
77 | ((unsigned long long)le32_to_cpu(val)) * 250); | |
5162b75b GL |
78 | |
79 | /* Format the output string and return # of bytes */ | |
80 | return sprintf(buf, "%li\n", (long)le32_to_cpu(val)); | |
81 | } | |
82 | ||
83 | static 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); | |
5162b75b GL |
88 | 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 */ | |
40300745 SB |
95 | rc = kstrtoull(buf, 0, &val); |
96 | if (rc < 0) { | |
5162b75b GL |
97 | 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 | */ | |
122 | static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show, | |
123 | ds1682_store, 4, DS1682_REG_ELAPSED); | |
124 | static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show, | |
125 | ds1682_store, 4, DS1682_REG_ALARM); | |
126 | static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show, | |
127 | ds1682_store, 2, DS1682_REG_EVT_CNTR); | |
128 | ||
129 | static 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 | */ | |
2c3c8bea CW |
141 | static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj, |
142 | struct bin_attribute *attr, | |
05bd711e | 143 | char *buf, loff_t off, size_t count) |
5162b75b GL |
144 | { |
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 | ||
5162b75b GL |
151 | rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off, |
152 | count, buf); | |
153 | if (rc < 0) | |
154 | return -EIO; | |
155 | ||
156 | return count; | |
157 | } | |
158 | ||
2c3c8bea CW |
159 | static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj, |
160 | struct bin_attribute *attr, | |
05bd711e | 161 | char *buf, loff_t off, size_t count) |
5162b75b GL |
162 | { |
163 | struct i2c_client *client = kobj_to_i2c_client(kobj); | |
164 | ||
165 | dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n", | |
166 | buf, off, count); | |
167 | ||
5162b75b GL |
168 | /* Write out to the device */ |
169 | if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off, | |
170 | count, buf) < 0) | |
171 | return -EIO; | |
172 | ||
173 | return count; | |
174 | } | |
175 | ||
176 | static struct bin_attribute ds1682_eeprom_attr = { | |
177 | .attr = { | |
178 | .name = "eeprom", | |
179 | .mode = S_IRUGO | S_IWUSR, | |
5162b75b GL |
180 | }, |
181 | .size = DS1682_EEPROM_SIZE, | |
182 | .read = ds1682_eeprom_read, | |
183 | .write = ds1682_eeprom_write, | |
184 | }; | |
185 | ||
186 | /* | |
187 | * Called when a ds1682 device is matched with this driver | |
188 | */ | |
d2653e92 JD |
189 | static int ds1682_probe(struct i2c_client *client, |
190 | const struct i2c_device_id *id) | |
5162b75b GL |
191 | { |
192 | int rc; | |
193 | ||
194 | if (!i2c_check_functionality(client->adapter, | |
195 | I2C_FUNC_SMBUS_I2C_BLOCK)) { | |
196 | dev_err(&client->dev, "i2c bus does not support the ds1682\n"); | |
197 | rc = -ENODEV; | |
198 | goto exit; | |
199 | } | |
200 | ||
201 | rc = sysfs_create_group(&client->dev.kobj, &ds1682_group); | |
202 | if (rc) | |
203 | goto exit; | |
204 | ||
205 | rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); | |
206 | if (rc) | |
207 | goto exit_bin_attr; | |
208 | ||
209 | return 0; | |
210 | ||
211 | exit_bin_attr: | |
212 | sysfs_remove_group(&client->dev.kobj, &ds1682_group); | |
213 | exit: | |
214 | return rc; | |
215 | } | |
216 | ||
217 | static int ds1682_remove(struct i2c_client *client) | |
218 | { | |
219 | sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); | |
220 | sysfs_remove_group(&client->dev.kobj, &ds1682_group); | |
221 | return 0; | |
222 | } | |
223 | ||
3760f736 JD |
224 | static const struct i2c_device_id ds1682_id[] = { |
225 | { "ds1682", 0 }, | |
226 | { } | |
227 | }; | |
228 | MODULE_DEVICE_TABLE(i2c, ds1682_id); | |
229 | ||
5162b75b GL |
230 | static struct i2c_driver ds1682_driver = { |
231 | .driver = { | |
232 | .name = "ds1682", | |
233 | }, | |
234 | .probe = ds1682_probe, | |
235 | .remove = ds1682_remove, | |
3760f736 | 236 | .id_table = ds1682_id, |
5162b75b GL |
237 | }; |
238 | ||
a64fe2ed | 239 | module_i2c_driver(ds1682_driver); |
5162b75b GL |
240 | |
241 | MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>"); | |
242 | MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver"); | |
243 | MODULE_LICENSE("GPL"); |