1
2
3
4
5
6
7
8
9
10
11
12
13
14#include <linux/i2c.h>
15#include <linux/bcd.h>
16#include <linux/rtc.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/err.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22
23#define DRV_VERSION "0.1"
24
25
26#define ISL12022_REG_SC 0x00
27#define ISL12022_REG_MN 0x01
28#define ISL12022_REG_HR 0x02
29#define ISL12022_REG_DT 0x03
30#define ISL12022_REG_MO 0x04
31#define ISL12022_REG_YR 0x05
32#define ISL12022_REG_DW 0x06
33
34#define ISL12022_REG_SR 0x07
35#define ISL12022_REG_INT 0x08
36
37
38#define ISL12022_HR_MIL (1 << 7)
39
40#define ISL12022_SR_LBAT85 (1 << 2)
41#define ISL12022_SR_LBAT75 (1 << 1)
42
43#define ISL12022_INT_WRTC (1 << 6)
44
45
46static struct i2c_driver isl12022_driver;
47
48struct isl12022 {
49 struct rtc_device *rtc;
50
51 bool write_enabled;
52};
53
54
55static int isl12022_read_regs(struct i2c_client *client, uint8_t reg,
56 uint8_t *data, size_t n)
57{
58 struct i2c_msg msgs[] = {
59 {
60 .addr = client->addr,
61 .flags = 0,
62 .len = 1,
63 .buf = data
64 },
65 {
66 .addr = client->addr,
67 .flags = I2C_M_RD,
68 .len = n,
69 .buf = data
70 }
71 };
72
73 int ret;
74
75 data[0] = reg;
76 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
77 if (ret != ARRAY_SIZE(msgs)) {
78 dev_err(&client->dev, "%s: read error, ret=%d\n",
79 __func__, ret);
80 return -EIO;
81 }
82
83 return 0;
84}
85
86
87static int isl12022_write_reg(struct i2c_client *client,
88 uint8_t reg, uint8_t val)
89{
90 uint8_t data[2] = { reg, val };
91 int err;
92
93 err = i2c_master_send(client, data, sizeof(data));
94 if (err != sizeof(data)) {
95 dev_err(&client->dev,
96 "%s: err=%d addr=%02x, data=%02x\n",
97 __func__, err, data[0], data[1]);
98 return -EIO;
99 }
100
101 return 0;
102}
103
104
105
106
107
108
109static int isl12022_get_datetime(struct i2c_client *client, struct rtc_time *tm)
110{
111 uint8_t buf[ISL12022_REG_INT + 1];
112 int ret;
113
114 ret = isl12022_read_regs(client, ISL12022_REG_SC, buf, sizeof(buf));
115 if (ret)
116 return ret;
117
118 if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) {
119 dev_warn(&client->dev,
120 "voltage dropped below %u%%, "
121 "date and time is not reliable.\n",
122 buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75);
123 }
124
125 dev_dbg(&client->dev,
126 "%s: raw data is sec=%02x, min=%02x, hr=%02x, "
127 "mday=%02x, mon=%02x, year=%02x, wday=%02x, "
128 "sr=%02x, int=%02x",
129 __func__,
130 buf[ISL12022_REG_SC],
131 buf[ISL12022_REG_MN],
132 buf[ISL12022_REG_HR],
133 buf[ISL12022_REG_DT],
134 buf[ISL12022_REG_MO],
135 buf[ISL12022_REG_YR],
136 buf[ISL12022_REG_DW],
137 buf[ISL12022_REG_SR],
138 buf[ISL12022_REG_INT]);
139
140 tm->tm_sec = bcd2bin(buf[ISL12022_REG_SC] & 0x7F);
141 tm->tm_min = bcd2bin(buf[ISL12022_REG_MN] & 0x7F);
142 tm->tm_hour = bcd2bin(buf[ISL12022_REG_HR] & 0x3F);
143 tm->tm_mday = bcd2bin(buf[ISL12022_REG_DT] & 0x3F);
144 tm->tm_wday = buf[ISL12022_REG_DW] & 0x07;
145 tm->tm_mon = bcd2bin(buf[ISL12022_REG_MO] & 0x1F) - 1;
146 tm->tm_year = bcd2bin(buf[ISL12022_REG_YR]) + 100;
147
148 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
149 "mday=%d, mon=%d, year=%d, wday=%d\n",
150 __func__,
151 tm->tm_sec, tm->tm_min, tm->tm_hour,
152 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
153
154 return rtc_valid_tm(tm);
155}
156
157static int isl12022_set_datetime(struct i2c_client *client, struct rtc_time *tm)
158{
159 struct isl12022 *isl12022 = i2c_get_clientdata(client);
160 size_t i;
161 int ret;
162 uint8_t buf[ISL12022_REG_DW + 1];
163
164 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
165 "mday=%d, mon=%d, year=%d, wday=%d\n",
166 __func__,
167 tm->tm_sec, tm->tm_min, tm->tm_hour,
168 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
169
170 if (!isl12022->write_enabled) {
171
172 ret = isl12022_read_regs(client, ISL12022_REG_INT, buf, 1);
173 if (ret)
174 return ret;
175
176
177
178 if (!(buf[0] & ISL12022_INT_WRTC)) {
179 dev_info(&client->dev,
180 "init write enable and 24 hour format\n");
181
182
183 ret = isl12022_write_reg(client,
184 ISL12022_REG_INT,
185 buf[0] | ISL12022_INT_WRTC);
186 if (ret)
187 return ret;
188
189
190
191
192 ret = isl12022_read_regs(client, ISL12022_REG_HR,
193 buf, 1);
194 if (ret)
195 return ret;
196
197 ret = isl12022_write_reg(client,
198 ISL12022_REG_HR,
199 buf[0] | ISL12022_HR_MIL);
200 if (ret)
201 return ret;
202 }
203
204 isl12022->write_enabled = 1;
205 }
206
207
208 buf[ISL12022_REG_SC] = bin2bcd(tm->tm_sec);
209 buf[ISL12022_REG_MN] = bin2bcd(tm->tm_min);
210 buf[ISL12022_REG_HR] = bin2bcd(tm->tm_hour) | ISL12022_HR_MIL;
211
212 buf[ISL12022_REG_DT] = bin2bcd(tm->tm_mday);
213
214
215 buf[ISL12022_REG_MO] = bin2bcd(tm->tm_mon + 1);
216
217
218 buf[ISL12022_REG_YR] = bin2bcd(tm->tm_year % 100);
219
220 buf[ISL12022_REG_DW] = tm->tm_wday & 0x07;
221
222
223 for (i = 0; i < ARRAY_SIZE(buf); i++) {
224 ret = isl12022_write_reg(client, ISL12022_REG_SC + i,
225 buf[ISL12022_REG_SC + i]);
226 if (ret)
227 return -EIO;
228 }
229
230 return 0;
231}
232
233static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm)
234{
235 return isl12022_get_datetime(to_i2c_client(dev), tm);
236}
237
238static int isl12022_rtc_set_time(struct device *dev, struct rtc_time *tm)
239{
240 return isl12022_set_datetime(to_i2c_client(dev), tm);
241}
242
243static const struct rtc_class_ops isl12022_rtc_ops = {
244 .read_time = isl12022_rtc_read_time,
245 .set_time = isl12022_rtc_set_time,
246};
247
248static int isl12022_probe(struct i2c_client *client,
249 const struct i2c_device_id *id)
250{
251 struct isl12022 *isl12022;
252
253 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
254 return -ENODEV;
255
256 isl12022 = devm_kzalloc(&client->dev, sizeof(struct isl12022),
257 GFP_KERNEL);
258 if (!isl12022)
259 return -ENOMEM;
260
261 dev_dbg(&client->dev, "chip found, driver version " DRV_VERSION "\n");
262
263 i2c_set_clientdata(client, isl12022);
264
265 isl12022->rtc = devm_rtc_device_register(&client->dev,
266 isl12022_driver.driver.name,
267 &isl12022_rtc_ops, THIS_MODULE);
268 return PTR_ERR_OR_ZERO(isl12022->rtc);
269}
270
271#ifdef CONFIG_OF
272static const struct of_device_id isl12022_dt_match[] = {
273 { .compatible = "isl,isl12022" },
274 { .compatible = "isil,isl12022" },
275 { },
276};
277MODULE_DEVICE_TABLE(of, isl12022_dt_match);
278#endif
279
280static const struct i2c_device_id isl12022_id[] = {
281 { "isl12022", 0 },
282 { }
283};
284MODULE_DEVICE_TABLE(i2c, isl12022_id);
285
286static struct i2c_driver isl12022_driver = {
287 .driver = {
288 .name = "rtc-isl12022",
289#ifdef CONFIG_OF
290 .of_match_table = of_match_ptr(isl12022_dt_match),
291#endif
292 },
293 .probe = isl12022_probe,
294 .id_table = isl12022_id,
295};
296
297module_i2c_driver(isl12022_driver);
298
299MODULE_AUTHOR("roman.fietze@telemotive.de");
300MODULE_DESCRIPTION("ISL 12022 RTC driver");
301MODULE_LICENSE("GPL");
302MODULE_VERSION(DRV_VERSION);
303
