forked from torvalds/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
rtc-isl12022.c
293 lines (235 loc) · 7.08 KB
/
rtc-isl12022.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
* An I2C driver for the Intersil ISL 12022
*
* Author: Roman Fietze <[email protected]>
*
* Based on the Philips PCF8563 RTC
* by Alessandro Zummo <[email protected]>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*/
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/err.h>
#define DRV_VERSION "0.1"
/* ISL register offsets */
#define ISL12022_REG_SC 0x00
#define ISL12022_REG_MN 0x01
#define ISL12022_REG_HR 0x02
#define ISL12022_REG_DT 0x03
#define ISL12022_REG_MO 0x04
#define ISL12022_REG_YR 0x05
#define ISL12022_REG_DW 0x06
#define ISL12022_REG_SR 0x07
#define ISL12022_REG_INT 0x08
/* ISL register bits */
#define ISL12022_HR_MIL (1 << 7) /* military or 24 hour time */
#define ISL12022_SR_LBAT85 (1 << 2)
#define ISL12022_SR_LBAT75 (1 << 1)
#define ISL12022_INT_WRTC (1 << 6)
static struct i2c_driver isl12022_driver;
struct isl12022 {
struct rtc_device *rtc;
bool write_enabled; /* true if write enable is set */
};
static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
uint8_t *data, size_t n)
{
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 1,
.buf = data
}, /* setup read ptr */
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = n,
.buf = data
}
};
int ret;
data[0] = reg;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret != ARRAY_SIZE(msgs)) {
dev_err(&client->dev, "%s: read error, ret=%d\n",
__func__, ret);
return -EIO;
}
return 0;
}
static int isl12022_write_reg(struct i2c_client *client,
uint8_t reg, uint8_t val)
{
uint8_t data[2] = { reg, val };
int err;
err = i2c_master_send(client, data, sizeof(data));
if (err != sizeof(data)) {
dev_err(&client->dev,
"%s: err=%d addr=%02x, data=%02x\n",
__func__, err, data[0], data[1]);
return -EIO;
}
return 0;
}
/*
* In the routines that deal directly with the isl12022 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
uint8_t buf[ISL12022_REG_INT + 1];
int ret;
ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
if (ret)
return ret;
if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
dev_warn(&client->dev,
"voltage dropped below %u%%, "
"date and time is not reliable.\n",
buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
}
dev_dbg(&client->dev,
"%s: raw data is sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, mon=%02x, year=%02x, wday=%02x, "
"sr=%02x, int=%02x",
__func__,
buf[ISL12022_REG_SC],
buf[ISL12022_REG_MN],
buf[ISL12022_REG_HR],
buf[ISL12022_REG_DT],
buf[ISL12022_REG_MO],
buf[ISL12022_REG_YR],
buf[ISL12022_REG_DW],
buf[ISL12022_REG_SR],
buf[ISL12022_REG_INT]);
tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* The clock can give out invalid datetime, but we cannot return
* -EINVAL otherwise hwclock will refuse to set the time on bootup. */
if (rtc_valid_tm(tm) < 0)
dev_err(&client->dev, "retrieved date and time is invalid.\n");
return 0;
}
static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct isl12022 *isl12022 = i2c_get_clientdata(client);
size_t i;
int ret;
uint8_t buf[ISL12022_REG_DW + 1];
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
if (!isl12022->write_enabled) {
ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
if (ret)
return ret;
/* Check if WRTC (write rtc enable) is set factory default is
* 0 (not set) */
if (!(buf[0] & ISL12022_INT_WRTC)) {
dev_info(&client->dev,
"init write enable and 24 hour format\n");
/* Set the write enable bit. */
ret = isl12022_write_reg(client,
ISL12022_REG_INT,
buf[0] | ISL12022_INT_WRTC);
if (ret)
return ret;
/* Write to any RTC register to start RTC, we use the
* HR register, setting the MIL bit to use the 24 hour
* format. */
ret = isl12022_read_regs(client, ISL12022_REG_HR,
buf, 1);
if (ret)
return ret;
ret = isl12022_write_reg(client,
ISL12022_REG_HR,
buf[0] | ISL12022_HR_MIL);
if (ret)
return ret;
}
isl12022->write_enabled = 1;
}
/* hours, minutes and seconds */
buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
/* month, 1 - 12 */
buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
/* year and century */
buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
/* write register's data */
for (i = 0; i < ARRAY_SIZE(buf); i++) {
ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
buf[ISL12022_REG_SC + i]);
if (ret)
return -EIO;
}
return 0;
}
static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return isl12022_get_datetime(to_i2c_client(dev), tm);
}
static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return isl12022_set_datetime(to_i2c_client(dev), tm);
}
static const struct rtc_class_ops isl12022_rtc_ops = {
.read_time = isl12022_rtc_read_time,
.set_time = isl12022_rtc_set_time,
};
static int isl12022_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct isl12022 *isl12022;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
GFP_KERNEL);
if (!isl12022)
return -ENOMEM;
dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n");
i2c_set_clientdata(client, isl12022);
isl12022->rtc = devm_rtc_device_register(&client->dev,
isl12022_driver.driver.name,
&isl12022_rtc_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(isl12022->rtc);
}
static const struct i2c_device_id isl12022_id[] = {
{ "isl12022", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, isl12022_id);
static struct i2c_driver isl12022_driver = {
.driver = {
.name = "rtc-isl12022",
},
.probe = isl12022_probe,
.id_table = isl12022_id,
};
module_i2c_driver(isl12022_driver);
MODULE_AUTHOR("[email protected]");
MODULE_DESCRIPTION("ISL 12022 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);