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12#include <linux/module.h>
13#include <linux/rtc.h>
14#include <linux/i2c.h>
15#include <linux/bitrev.h>
16#include <linux/bcd.h>
17#include <linux/slab.h>
18
19#define S35390A_CMD_STATUS1 0
20#define S35390A_CMD_STATUS2 1
21#define S35390A_CMD_TIME1 2
22#define S35390A_CMD_TIME2 3
23#define S35390A_CMD_INT2_REG1 5
24
25#define S35390A_BYTE_YEAR 0
26#define S35390A_BYTE_MONTH 1
27#define S35390A_BYTE_DAY 2
28#define S35390A_BYTE_WDAY 3
29#define S35390A_BYTE_HOURS 4
30#define S35390A_BYTE_MINS 5
31#define S35390A_BYTE_SECS 6
32
33#define S35390A_ALRM_BYTE_WDAY 0
34#define S35390A_ALRM_BYTE_HOURS 1
35#define S35390A_ALRM_BYTE_MINS 2
36
37#define S35390A_FLAG_POC 0x01
38#define S35390A_FLAG_BLD 0x02
39#define S35390A_FLAG_24H 0x40
40#define S35390A_FLAG_RESET 0x80
41#define S35390A_FLAG_TEST 0x01
42
43#define S35390A_INT2_MODE_MASK 0xF0
44
45#define S35390A_INT2_MODE_NOINTR 0x00
46#define S35390A_INT2_MODE_FREQ 0x10
47#define S35390A_INT2_MODE_ALARM 0x40
48#define S35390A_INT2_MODE_PMIN_EDG 0x20
49
50static const struct i2c_device_id s35390a_id[] = {
51 { "s35390a", 0 },
52 { }
53};
54MODULE_DEVICE_TABLE(i2c, s35390a_id);
55
56struct s35390a {
57 struct i2c_client *client[8];
58 struct rtc_device *rtc;
59 int twentyfourhour;
60};
61
62static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
63{
64 struct i2c_client *client = s35390a->client[reg];
65 struct i2c_msg msg[] = {
66 {
67 .addr = client->addr,
68 .len = len,
69 .buf = buf
70 },
71 };
72
73 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
74 return -EIO;
75
76 return 0;
77}
78
79static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
80{
81 struct i2c_client *client = s35390a->client[reg];
82 struct i2c_msg msg[] = {
83 {
84 .addr = client->addr,
85 .flags = I2C_M_RD,
86 .len = len,
87 .buf = buf
88 },
89 };
90
91 if ((i2c_transfer(client->adapter, msg, 1)) != 1)
92 return -EIO;
93
94 return 0;
95}
96
97static int s35390a_reset(struct s35390a *s35390a)
98{
99 char buf[1];
100
101 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)
102 return -EIO;
103
104 if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))
105 return 0;
106
107 buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);
108 buf[0] &= 0xf0;
109 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
110}
111
112static int s35390a_disable_test_mode(struct s35390a *s35390a)
113{
114 char buf[1];
115
116 if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
117 return -EIO;
118
119 if (!(buf[0] & S35390A_FLAG_TEST))
120 return 0;
121
122 buf[0] &= ~S35390A_FLAG_TEST;
123 return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
124}
125
126static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
127{
128 if (s35390a->twentyfourhour)
129 return bin2bcd(hour);
130
131 if (hour < 12)
132 return bin2bcd(hour);
133
134 return 0x40 | bin2bcd(hour - 12);
135}
136
137static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
138{
139 unsigned hour;
140
141 if (s35390a->twentyfourhour)
142 return bcd2bin(reg & 0x3f);
143
144 hour = bcd2bin(reg & 0x3f);
145 if (reg & 0x40)
146 hour += 12;
147
148 return hour;
149}
150
151static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
152{
153 struct s35390a *s35390a = i2c_get_clientdata(client);
154 int i, err;
155 char buf[7];
156
157 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
158 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
159 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
160 tm->tm_wday);
161
162 buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
163 buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
164 buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
165 buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
166 buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
167 buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
168 buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
169
170
171 for (i = 0; i < 7; ++i)
172 buf[i] = bitrev8(buf[i]);
173
174 err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
175
176 return err;
177}
178
179static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
180{
181 struct s35390a *s35390a = i2c_get_clientdata(client);
182 char buf[7];
183 int i, err;
184
185 err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
186 if (err < 0)
187 return err;
188
189
190 for (i = 0; i < 7; ++i)
191 buf[i] = bitrev8(buf[i]);
192
193 tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
194 tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
195 tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
196 tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
197 tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
198 tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
199 tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
200
201 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
202 "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
203 tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
204 tm->tm_wday);
205
206 return rtc_valid_tm(tm);
207}
208
209static int s35390a_set_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
210{
211 struct s35390a *s35390a = i2c_get_clientdata(client);
212 char buf[3], sts = 0;
213 int err, i;
214
215 dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
216 "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
217 alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
218 alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
219
220
221 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
222 if (err < 0)
223 return err;
224
225
226 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
227 if (err < 0)
228 return err;
229
230 if (alm->enabled)
231 sts = S35390A_INT2_MODE_ALARM;
232 else
233 sts = S35390A_INT2_MODE_NOINTR;
234
235
236 sts = bitrev8(sts);
237
238
239 err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
240 if (err < 0)
241 return err;
242
243 if (alm->time.tm_wday != -1)
244 buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
245
246 buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
247 alm->time.tm_hour) | 0x80;
248 buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
249
250 if (alm->time.tm_hour >= 12)
251 buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
252
253 for (i = 0; i < 3; ++i)
254 buf[i] = bitrev8(buf[i]);
255
256 err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
257 sizeof(buf));
258
259 return err;
260}
261
262static int s35390a_read_alarm(struct i2c_client *client, struct rtc_wkalrm *alm)
263{
264 struct s35390a *s35390a = i2c_get_clientdata(client);
265 char buf[3], sts;
266 int i, err;
267
268 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
269 if (err < 0)
270 return err;
271
272 if (bitrev8(sts) != S35390A_INT2_MODE_ALARM)
273 return -EINVAL;
274
275 err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
276 if (err < 0)
277 return err;
278
279
280 for (i = 0; i < 3; ++i) {
281 buf[i] = bitrev8(buf[i]);
282 buf[i] &= ~0x80;
283 }
284
285 alm->time.tm_wday = bcd2bin(buf[S35390A_ALRM_BYTE_WDAY]);
286 alm->time.tm_hour = s35390a_reg2hr(s35390a,
287 buf[S35390A_ALRM_BYTE_HOURS]);
288 alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS]);
289
290 dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
291 __func__, alm->time.tm_min, alm->time.tm_hour,
292 alm->time.tm_wday);
293
294 return 0;
295}
296
297static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
298{
299 return s35390a_read_alarm(to_i2c_client(dev), alm);
300}
301
302static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
303{
304 return s35390a_set_alarm(to_i2c_client(dev), alm);
305}
306
307static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
308{
309 return s35390a_get_datetime(to_i2c_client(dev), tm);
310}
311
312static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
313{
314 return s35390a_set_datetime(to_i2c_client(dev), tm);
315}
316
317static const struct rtc_class_ops s35390a_rtc_ops = {
318 .read_time = s35390a_rtc_read_time,
319 .set_time = s35390a_rtc_set_time,
320 .set_alarm = s35390a_rtc_set_alarm,
321 .read_alarm = s35390a_rtc_read_alarm,
322
323};
324
325static struct i2c_driver s35390a_driver;
326
327static int s35390a_probe(struct i2c_client *client,
328 const struct i2c_device_id *id)
329{
330 int err;
331 unsigned int i;
332 struct s35390a *s35390a;
333 struct rtc_time tm;
334 char buf[1];
335
336 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
337 err = -ENODEV;
338 goto exit;
339 }
340
341 s35390a = devm_kzalloc(&client->dev, sizeof(struct s35390a),
342 GFP_KERNEL);
343 if (!s35390a) {
344 err = -ENOMEM;
345 goto exit;
346 }
347
348 s35390a->client[0] = client;
349 i2c_set_clientdata(client, s35390a);
350
351
352 for (i = 1; i < 8; ++i) {
353 s35390a->client[i] = i2c_new_dummy(client->adapter,
354 client->addr + i);
355 if (!s35390a->client[i]) {
356 dev_err(&client->dev, "Address %02x unavailable\n",
357 client->addr + i);
358 err = -EBUSY;
359 goto exit_dummy;
360 }
361 }
362
363 err = s35390a_reset(s35390a);
364 if (err < 0) {
365 dev_err(&client->dev, "error resetting chip\n");
366 goto exit_dummy;
367 }
368
369 err = s35390a_disable_test_mode(s35390a);
370 if (err < 0) {
371 dev_err(&client->dev, "error disabling test mode\n");
372 goto exit_dummy;
373 }
374
375 err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));
376 if (err < 0) {
377 dev_err(&client->dev, "error checking 12/24 hour mode\n");
378 goto exit_dummy;
379 }
380 if (buf[0] & S35390A_FLAG_24H)
381 s35390a->twentyfourhour = 1;
382 else
383 s35390a->twentyfourhour = 0;
384
385 if (s35390a_get_datetime(client, &tm) < 0)
386 dev_warn(&client->dev, "clock needs to be set\n");
387
388 device_set_wakeup_capable(&client->dev, 1);
389
390 s35390a->rtc = devm_rtc_device_register(&client->dev,
391 s35390a_driver.driver.name,
392 &s35390a_rtc_ops, THIS_MODULE);
393
394 if (IS_ERR(s35390a->rtc)) {
395 err = PTR_ERR(s35390a->rtc);
396 goto exit_dummy;
397 }
398 return 0;
399
400exit_dummy:
401 for (i = 1; i < 8; ++i)
402 if (s35390a->client[i])
403 i2c_unregister_device(s35390a->client[i]);
404
405exit:
406 return err;
407}
408
409static int s35390a_remove(struct i2c_client *client)
410{
411 unsigned int i;
412 struct s35390a *s35390a = i2c_get_clientdata(client);
413
414 for (i = 1; i < 8; ++i)
415 if (s35390a->client[i])
416 i2c_unregister_device(s35390a->client[i]);
417
418 return 0;
419}
420
421static struct i2c_driver s35390a_driver = {
422 .driver = {
423 .name = "rtc-s35390a",
424 },
425 .probe = s35390a_probe,
426 .remove = s35390a_remove,
427 .id_table = s35390a_id,
428};
429
430module_i2c_driver(s35390a_driver);
431
432MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
433MODULE_DESCRIPTION("S35390A RTC driver");
434MODULE_LICENSE("GPL");
435
