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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
5162b75b GL |
2 | /* |
3 | * Dallas Semiconductor DS1682 Elapsed Time Recorder device driver | |
4 | * | |
5 | * Written by: Grant Likely <grant.likely@secretlab.ca> | |
6 | * | |
7 | * Copyright (C) 2007 Secret Lab Technologies Ltd. | |
5162b75b GL |
8 | */ |
9 | ||
10 | /* | |
11 | * The DS1682 elapsed timer recorder is a simple device that implements | |
12 | * one elapsed time counter, one event counter, an alarm signal and 10 | |
13 | * bytes of general purpose EEPROM. | |
14 | * | |
15 | * This driver provides access to the DS1682 counters and user data via | |
16 | * the sysfs. The following attributes are added to the device node: | |
17 | * elapsed_time (u32): Total elapsed event time in ms resolution | |
18 | * alarm_time (u32): When elapsed time exceeds the value in alarm_time, | |
19 | * then the alarm pin is asserted. | |
20 | * event_count (u16): number of times the event pin has gone low. | |
21 | * eeprom (u8[10]): general purpose EEPROM | |
22 | * | |
23 | * Counter registers and user data are both read/write unless the device | |
24 | * has been write protected. This driver does not support turning off write | |
25 | * protection. Once write protection is turned on, it is impossible to | |
26 | * turn it off again, so I have left the feature out of this driver to avoid | |
27 | * accidental enabling, but it is trivial to add write protect support. | |
28 | * | |
29 | */ | |
30 | ||
31 | #include <linux/module.h> | |
5162b75b GL |
32 | #include <linux/i2c.h> |
33 | #include <linux/string.h> | |
34 | #include <linux/list.h> | |
35 | #include <linux/sysfs.h> | |
36 | #include <linux/ctype.h> | |
37 | #include <linux/hwmon-sysfs.h> | |
38 | ||
39 | /* Device registers */ | |
40 | #define DS1682_REG_CONFIG 0x00 | |
41 | #define DS1682_REG_ALARM 0x01 | |
42 | #define DS1682_REG_ELAPSED 0x05 | |
43 | #define DS1682_REG_EVT_CNTR 0x09 | |
44 | #define DS1682_REG_EEPROM 0x0b | |
45 | #define DS1682_REG_RESET 0x1d | |
46 | #define DS1682_REG_WRITE_DISABLE 0x1e | |
47 | #define DS1682_REG_WRITE_MEM_DISABLE 0x1f | |
48 | ||
49 | #define DS1682_EEPROM_SIZE 10 | |
50 | ||
51 | /* | |
52 | * Generic counter attributes | |
53 | */ | |
54 | static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr, | |
55 | char *buf) | |
56 | { | |
57 | struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); | |
58 | struct i2c_client *client = to_i2c_client(dev); | |
066ed427 | 59 | unsigned long long val, check; |
2fa065fd | 60 | __le32 val_le = 0; |
5162b75b GL |
61 | int rc; |
62 | ||
63 | dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name); | |
64 | ||
65 | /* Read the register */ | |
66 | rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr, | |
2fa065fd | 67 | (u8 *)&val_le); |
5162b75b GL |
68 | if (rc < 0) |
69 | return -EIO; | |
70 | ||
2fa065fd | 71 | val = le32_to_cpu(val_le); |
5162b75b | 72 | |
066ed427 TV |
73 | if (sattr->index == DS1682_REG_ELAPSED) { |
74 | int retries = 5; | |
75 | ||
76 | /* Detect and retry when a tick occurs mid-read */ | |
77 | do { | |
78 | rc = i2c_smbus_read_i2c_block_data(client, sattr->index, | |
79 | sattr->nr, | |
80 | (u8 *)&val_le); | |
81 | if (rc < 0 || retries <= 0) | |
82 | return -EIO; | |
83 | ||
84 | check = val; | |
85 | val = le32_to_cpu(val_le); | |
86 | retries--; | |
87 | } while (val != check && val != (check + 1)); | |
88 | } | |
89 | ||
2fa065fd AS |
90 | /* Format the output string and return # of bytes |
91 | * Special case: the 32 bit regs are time values with 1/4s | |
92 | * resolution, scale them up to milliseconds | |
93 | */ | |
94 | return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : val); | |
5162b75b GL |
95 | } |
96 | ||
97 | static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr, | |
98 | const char *buf, size_t count) | |
99 | { | |
100 | struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr); | |
101 | struct i2c_client *client = to_i2c_client(dev); | |
5162b75b GL |
102 | u64 val; |
103 | __le32 val_le; | |
104 | int rc; | |
105 | ||
106 | dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name); | |
107 | ||
108 | /* Decode input */ | |
40300745 SB |
109 | rc = kstrtoull(buf, 0, &val); |
110 | if (rc < 0) { | |
5162b75b GL |
111 | dev_dbg(dev, "input string not a number\n"); |
112 | return -EINVAL; | |
113 | } | |
114 | ||
115 | /* Special case: the 32 bit regs are time values with 1/4s | |
116 | * resolution, scale input down to quarter-seconds */ | |
117 | if (sattr->nr == 4) | |
118 | do_div(val, 250); | |
119 | ||
120 | /* write out the value */ | |
121 | val_le = cpu_to_le32(val); | |
122 | rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr, | |
123 | (u8 *) & val_le); | |
124 | if (rc < 0) { | |
125 | dev_err(dev, "register write failed; reg=0x%x, size=%i\n", | |
126 | sattr->index, sattr->nr); | |
127 | return -EIO; | |
128 | } | |
129 | ||
130 | return count; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Simple register attributes | |
135 | */ | |
136 | static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show, | |
137 | ds1682_store, 4, DS1682_REG_ELAPSED); | |
138 | static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show, | |
139 | ds1682_store, 4, DS1682_REG_ALARM); | |
140 | static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show, | |
141 | ds1682_store, 2, DS1682_REG_EVT_CNTR); | |
142 | ||
143 | static const struct attribute_group ds1682_group = { | |
144 | .attrs = (struct attribute *[]) { | |
145 | &sensor_dev_attr_elapsed_time.dev_attr.attr, | |
146 | &sensor_dev_attr_alarm_time.dev_attr.attr, | |
147 | &sensor_dev_attr_event_count.dev_attr.attr, | |
148 | NULL, | |
149 | }, | |
150 | }; | |
151 | ||
152 | /* | |
153 | * User data attribute | |
154 | */ | |
2c3c8bea CW |
155 | static ssize_t ds1682_eeprom_read(struct file *filp, struct kobject *kobj, |
156 | struct bin_attribute *attr, | |
05bd711e | 157 | char *buf, loff_t off, size_t count) |
5162b75b GL |
158 | { |
159 | struct i2c_client *client = kobj_to_i2c_client(kobj); | |
160 | int rc; | |
161 | ||
162 | dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n", | |
163 | buf, off, count); | |
164 | ||
5162b75b GL |
165 | rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off, |
166 | count, buf); | |
167 | if (rc < 0) | |
168 | return -EIO; | |
169 | ||
170 | return count; | |
171 | } | |
172 | ||
2c3c8bea CW |
173 | static ssize_t ds1682_eeprom_write(struct file *filp, struct kobject *kobj, |
174 | struct bin_attribute *attr, | |
05bd711e | 175 | char *buf, loff_t off, size_t count) |
5162b75b GL |
176 | { |
177 | struct i2c_client *client = kobj_to_i2c_client(kobj); | |
178 | ||
179 | dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n", | |
180 | buf, off, count); | |
181 | ||
5162b75b GL |
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 | ||
57daedf8 | 190 | static const struct bin_attribute ds1682_eeprom_attr = { |
5162b75b GL |
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 | */ | |
3127a86a | 203 | static int ds1682_probe(struct i2c_client *client) |
5162b75b GL |
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 | ||
ed5c2f5f | 230 | static void ds1682_remove(struct i2c_client *client) |
5162b75b GL |
231 | { |
232 | sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr); | |
233 | sysfs_remove_group(&client->dev.kobj, &ds1682_group); | |
5162b75b GL |
234 | } |
235 | ||
3760f736 JD |
236 | static const struct i2c_device_id ds1682_id[] = { |
237 | { "ds1682", 0 }, | |
238 | { } | |
239 | }; | |
240 | MODULE_DEVICE_TABLE(i2c, ds1682_id); | |
241 | ||
5ef16854 JMC |
242 | static const struct of_device_id ds1682_of_match[] = { |
243 | { .compatible = "dallas,ds1682", }, | |
244 | {} | |
245 | }; | |
246 | MODULE_DEVICE_TABLE(of, ds1682_of_match); | |
247 | ||
5162b75b GL |
248 | static struct i2c_driver ds1682_driver = { |
249 | .driver = { | |
250 | .name = "ds1682", | |
5ef16854 | 251 | .of_match_table = ds1682_of_match, |
5162b75b | 252 | }, |
f050bb8f | 253 | .probe = ds1682_probe, |
5162b75b | 254 | .remove = ds1682_remove, |
3760f736 | 255 | .id_table = ds1682_id, |
5162b75b GL |
256 | }; |
257 | ||
a64fe2ed | 258 | module_i2c_driver(ds1682_driver); |
5162b75b GL |
259 | |
260 | MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>"); | |
261 | MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver"); | |
262 | MODULE_LICENSE("GPL"); |