misc: tegra-baseband: Add usb core notification support.
[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/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)
77                 return sprintf(buf, "%llu\n",
78                         ((unsigned long long)le32_to_cpu(val)) * 250);
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  */
143 static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj,
144                                   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 file *filp, struct kobject *kobj,
168                                    struct bin_attribute *attr,
169                                    char *buf, loff_t off, size_t count)
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,
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  */
203 static int ds1682_probe(struct i2c_client *client,
204                         const struct i2c_device_id *id)
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
238 static const struct i2c_device_id ds1682_id[] = {
239         { "ds1682", 0 },
240         { }
241 };
242 MODULE_DEVICE_TABLE(i2c, ds1682_id);
243
244 static struct i2c_driver ds1682_driver = {
245         .driver = {
246                 .name = "ds1682",
247         },
248         .probe = ds1682_probe,
249         .remove = ds1682_remove,
250         .id_table = ds1682_id,
251 };
252
253 static int __init ds1682_init(void)
254 {
255         return i2c_add_driver(&ds1682_driver);
256 }
257
258 static void __exit ds1682_exit(void)
259 {
260         i2c_del_driver(&ds1682_driver);
261 }
262
263 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
264 MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
265 MODULE_LICENSE("GPL");
266
267 module_init(ds1682_init);
268 module_exit(ds1682_exit);