Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / drivers / misc / ds1682.c
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>
36 #include <linux/slab.h>
37 #include <linux/i2c.h>
38 #include <linux/string.h>
39 #include <linux/list.h>
40 #include <linux/sysfs.h>
41 #include <linux/ctype.h>
42 #include <linux/hwmon-sysfs.h>
43
44 /* Device registers */
45 #define DS1682_REG_CONFIG               0x00
46 #define DS1682_REG_ALARM                0x01
47 #define DS1682_REG_ELAPSED              0x05
48 #define DS1682_REG_EVT_CNTR             0x09
49 #define DS1682_REG_EEPROM               0x0b
50 #define DS1682_REG_RESET                0x1d
51 #define DS1682_REG_WRITE_DISABLE        0x1e
52 #define DS1682_REG_WRITE_MEM_DISABLE    0x1f
53
54 #define DS1682_EEPROM_SIZE              10
55
56 /*
57  * Generic counter attributes
58  */
59 static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
60                            char *buf)
61 {
62         struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
63         struct i2c_client *client = to_i2c_client(dev);
64         __le32 val = 0;
65         int rc;
66
67         dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
68
69         /* Read the register */
70         rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
71                                            (u8 *) & val);
72         if (rc < 0)
73                 return -EIO;
74
75         /* Special case: the 32 bit regs are time values with 1/4s
76          * resolution, scale them up to milliseconds */
77         if (sattr->nr == 4)
78                 return sprintf(buf, "%llu\n",
79                         ((unsigned long long)le32_to_cpu(val)) * 250);
80
81         /* Format the output string and return # of bytes */
82         return sprintf(buf, "%li\n", (long)le32_to_cpu(val));
83 }
84
85 static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
86                             const char *buf, size_t count)
87 {
88         struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
89         struct i2c_client *client = to_i2c_client(dev);
90         char *endp;
91         u64 val;
92         __le32 val_le;
93         int rc;
94
95         dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
96
97         /* Decode input */
98         val = simple_strtoull(buf, &endp, 0);
99         if (buf == endp) {
100                 dev_dbg(dev, "input string not a number\n");
101                 return -EINVAL;
102         }
103
104         /* Special case: the 32 bit regs are time values with 1/4s
105          * resolution, scale input down to quarter-seconds */
106         if (sattr->nr == 4)
107                 do_div(val, 250);
108
109         /* write out the value */
110         val_le = cpu_to_le32(val);
111         rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
112                                             (u8 *) & val_le);
113         if (rc < 0) {
114                 dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
115                         sattr->index, sattr->nr);
116                 return -EIO;
117         }
118
119         return count;
120 }
121
122 /*
123  * Simple register attributes
124  */
125 static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
126                             ds1682_store, 4, DS1682_REG_ELAPSED);
127 static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
128                             ds1682_store, 4, DS1682_REG_ALARM);
129 static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
130                             ds1682_store, 2, DS1682_REG_EVT_CNTR);
131
132 static const struct attribute_group ds1682_group = {
133         .attrs = (struct attribute *[]) {
134                 &sensor_dev_attr_elapsed_time.dev_attr.attr,
135                 &sensor_dev_attr_alarm_time.dev_attr.attr,
136                 &sensor_dev_attr_event_count.dev_attr.attr,
137                 NULL,
138         },
139 };
140
141 /*
142  * User data attribute
143  */
144 static ssize_t ds1682_eeprom_read(struct kobject *kobj, struct bin_attribute *attr,
145                                   char *buf, loff_t off, size_t count)
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
167 static ssize_t ds1682_eeprom_write(struct kobject *kobj, struct bin_attribute *attr,
168                                    char *buf, loff_t off, size_t count)
169 {
170         struct i2c_client *client = kobj_to_i2c_client(kobj);
171
172         dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
173                 buf, off, count);
174
175         if (off >= DS1682_EEPROM_SIZE)
176                 return -ENOSPC;
177
178         if (off + count > DS1682_EEPROM_SIZE)
179                 count = DS1682_EEPROM_SIZE - off;
180
181         /* Write out to the device */
182         if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
183                                            count, buf) < 0)
184                 return -EIO;
185
186         return count;
187 }
188
189 static struct bin_attribute ds1682_eeprom_attr = {
190         .attr = {
191                 .name = "eeprom",
192                 .mode = S_IRUGO | S_IWUSR,
193         },
194         .size = DS1682_EEPROM_SIZE,
195         .read = ds1682_eeprom_read,
196         .write = ds1682_eeprom_write,
197 };
198
199 /*
200  * Called when a ds1682 device is matched with this driver
201  */
202 static int ds1682_probe(struct i2c_client *client,
203                         const struct i2c_device_id *id)
204 {
205         int rc;
206
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");
210                 rc = -ENODEV;
211                 goto exit;
212         }
213
214         rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
215         if (rc)
216                 goto exit;
217
218         rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
219         if (rc)
220                 goto exit_bin_attr;
221
222         return 0;
223
224  exit_bin_attr:
225         sysfs_remove_group(&client->dev.kobj, &ds1682_group);
226  exit:
227         return rc;
228 }
229
230 static int ds1682_remove(struct i2c_client *client)
231 {
232         sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
233         sysfs_remove_group(&client->dev.kobj, &ds1682_group);
234         return 0;
235 }
236
237 static const struct i2c_device_id ds1682_id[] = {
238         { "ds1682", 0 },
239         { }
240 };
241 MODULE_DEVICE_TABLE(i2c, ds1682_id);
242
243 static struct i2c_driver ds1682_driver = {
244         .driver = {
245                 .name = "ds1682",
246         },
247         .probe = ds1682_probe,
248         .remove = ds1682_remove,
249         .id_table = ds1682_id,
250 };
251
252 static int __init ds1682_init(void)
253 {
254         return i2c_add_driver(&ds1682_driver);
255 }
256
257 static void __exit ds1682_exit(void)
258 {
259         i2c_del_driver(&ds1682_driver);
260 }
261
262 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
263 MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
264 MODULE_LICENSE("GPL");
265
266 module_init(ds1682_init);
267 module_exit(ds1682_exit);