1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * An I2C driver for Ricoh RS5C372, R2025S/D and RV5C38[67] RTCs
4 *
5 * Copyright (C) 2005 Pavel Mironchik <pmironchik@optifacio.net>
6 * Copyright (C) 2006 Tower Technologies
7 * Copyright (C) 2008 Paul Mundt
8 */
9
10 #include <linux/i2c.h>
11 #include <linux/rtc.h>
12 #include <linux/bcd.h>
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16
17 /*
18 * Ricoh has a family of I2C based RTCs, which differ only slightly from
19 * each other. Differences center on pinout (e.g. how many interrupts,
20 * output clock, etc) and how the control registers are used. The '372
21 * is significant only because that's the one this driver first supported.
22 */
23 #define RS5C372_REG_SECS 0
24 #define RS5C372_REG_MINS 1
25 #define RS5C372_REG_HOURS 2
26 #define RS5C372_REG_WDAY 3
27 #define RS5C372_REG_DAY 4
28 #define RS5C372_REG_MONTH 5
29 #define RS5C372_REG_YEAR 6
30 #define RS5C372_REG_TRIM 7
31 # define RS5C372_TRIM_XSL 0x80 /* only if RS5C372[a|b] */
32 # define RS5C372_TRIM_MASK 0x7F
33 # define R2221TL_TRIM_DEV (1 << 7) /* only if R2221TL */
34 # define RS5C372_TRIM_DECR (1 << 6)
35
36 #define RS5C_REG_ALARM_A_MIN 8 /* or ALARM_W */
37 #define RS5C_REG_ALARM_A_HOURS 9
38 #define RS5C_REG_ALARM_A_WDAY 10
39
40 #define RS5C_REG_ALARM_B_MIN 11 /* or ALARM_D */
41 #define RS5C_REG_ALARM_B_HOURS 12
42 #define RS5C_REG_ALARM_B_WDAY 13 /* (ALARM_B only) */
43
44 #define RS5C_REG_CTRL1 14
45 # define RS5C_CTRL1_AALE (1 << 7) /* or WALE */
46 # define RS5C_CTRL1_BALE (1 << 6) /* or DALE */
47 # define RV5C387_CTRL1_24 (1 << 5)
48 # define RS5C372A_CTRL1_SL1 (1 << 5)
49 # define RS5C_CTRL1_CT_MASK (7 << 0)
50 # define RS5C_CTRL1_CT0 (0 << 0) /* no periodic irq */
51 # define RS5C_CTRL1_CT4 (4 << 0) /* 1 Hz level irq */
52 #define RS5C_REG_CTRL2 15
53 # define RS5C372_CTRL2_24 (1 << 5)
54 # define RS5C_CTRL2_XSTP (1 << 4) /* only if !R2x2x */
55 # define R2x2x_CTRL2_VDET (1 << 6) /* only if R2x2x */
56 # define R2x2x_CTRL2_XSTP (1 << 5) /* only if R2x2x */
57 # define R2x2x_CTRL2_PON (1 << 4) /* only if R2x2x */
58 # define RS5C_CTRL2_CTFG (1 << 2)
59 # define RS5C_CTRL2_AAFG (1 << 1) /* or WAFG */
60 # define RS5C_CTRL2_BAFG (1 << 0) /* or DAFG */
61
62
63 /* to read (style 1) or write registers starting at R */
64 #define RS5C_ADDR(R) (((R) << 4) | 0)
65
66
67 enum rtc_type {
68 rtc_undef = 0,
69 rtc_r2025sd,
70 rtc_r2221tl,
71 rtc_rs5c372a,
72 rtc_rs5c372b,
73 rtc_rv5c386,
74 rtc_rv5c387a,
75 };
76
77 static const struct i2c_device_id rs5c372_id[] = {
78 { "r2025sd", rtc_r2025sd },
79 { "r2221tl", rtc_r2221tl },
80 { "rs5c372a", rtc_rs5c372a },
81 { "rs5c372b", rtc_rs5c372b },
82 { "rv5c386", rtc_rv5c386 },
83 { "rv5c387a", rtc_rv5c387a },
84 { }
85 };
86 MODULE_DEVICE_TABLE(i2c, rs5c372_id);
87
88 static const __maybe_unused struct of_device_id rs5c372_of_match[] = {
89 {
90 .compatible = "ricoh,r2025sd",
91 .data = (void *)rtc_r2025sd
92 },
93 {
94 .compatible = "ricoh,r2221tl",
95 .data = (void *)rtc_r2221tl
96 },
97 {
98 .compatible = "ricoh,rs5c372a",
99 .data = (void *)rtc_rs5c372a
100 },
101 {
102 .compatible = "ricoh,rs5c372b",
103 .data = (void *)rtc_rs5c372b
104 },
105 {
106 .compatible = "ricoh,rv5c386",
107 .data = (void *)rtc_rv5c386
108 },
109 {
110 .compatible = "ricoh,rv5c387a",
111 .data = (void *)rtc_rv5c387a
112 },
113 { }
114 };
115 MODULE_DEVICE_TABLE(of, rs5c372_of_match);
116
117 /* REVISIT: this assumes that:
118 * - we're in the 21st century, so it's safe to ignore the century
119 * bit for rv5c38[67] (REG_MONTH bit 7);
120 * - we should use ALARM_A not ALARM_B (may be wrong on some boards)
121 */
122 struct rs5c372 {
123 struct i2c_client *client;
124 struct rtc_device *rtc;
125 enum rtc_type type;
126 unsigned time24:1;
127 unsigned has_irq:1;
128 unsigned smbus:1;
129 char buf[17];
130 char *regs;
131 };
132
rs5c_get_regs(struct rs5c372 * rs5c)133 static int rs5c_get_regs(struct rs5c372 *rs5c)
134 {
135 struct i2c_client *client = rs5c->client;
136 struct i2c_msg msgs[] = {
137 {
138 .addr = client->addr,
139 .flags = I2C_M_RD,
140 .len = sizeof(rs5c->buf),
141 .buf = rs5c->buf
142 },
143 };
144
145 /* This implements the third reading method from the datasheet, using
146 * an internal address that's reset after each transaction (by STOP)
147 * to 0x0f ... so we read extra registers, and skip the first one.
148 *
149 * The first method doesn't work with the iop3xx adapter driver, on at
150 * least 80219 chips; this works around that bug.
151 *
152 * The third method on the other hand doesn't work for the SMBus-only
153 * configurations, so we use the first method there, stripping off
154 * the extra register in the process.
155 */
156 if (rs5c->smbus) {
157 int addr = RS5C_ADDR(RS5C372_REG_SECS);
158 int size = sizeof(rs5c->buf) - 1;
159
160 if (i2c_smbus_read_i2c_block_data(client, addr, size,
161 rs5c->buf + 1) != size) {
162 dev_warn(&client->dev, "can't read registers\n");
163 return -EIO;
164 }
165 } else {
166 if ((i2c_transfer(client->adapter, msgs, 1)) != 1) {
167 dev_warn(&client->dev, "can't read registers\n");
168 return -EIO;
169 }
170 }
171
172 dev_dbg(&client->dev,
173 "%3ph (%02x) %3ph (%02x), %3ph, %3ph; %02x %02x\n",
174 rs5c->regs + 0, rs5c->regs[3],
175 rs5c->regs + 4, rs5c->regs[7],
176 rs5c->regs + 8, rs5c->regs + 11,
177 rs5c->regs[14], rs5c->regs[15]);
178
179 return 0;
180 }
181
rs5c_reg2hr(struct rs5c372 * rs5c,unsigned reg)182 static unsigned rs5c_reg2hr(struct rs5c372 *rs5c, unsigned reg)
183 {
184 unsigned hour;
185
186 if (rs5c->time24)
187 return bcd2bin(reg & 0x3f);
188
189 hour = bcd2bin(reg & 0x1f);
190 if (hour == 12)
191 hour = 0;
192 if (reg & 0x20)
193 hour += 12;
194 return hour;
195 }
196
rs5c_hr2reg(struct rs5c372 * rs5c,unsigned hour)197 static unsigned rs5c_hr2reg(struct rs5c372 *rs5c, unsigned hour)
198 {
199 if (rs5c->time24)
200 return bin2bcd(hour);
201
202 if (hour > 12)
203 return 0x20 | bin2bcd(hour - 12);
204 if (hour == 12)
205 return 0x20 | bin2bcd(12);
206 if (hour == 0)
207 return bin2bcd(12);
208 return bin2bcd(hour);
209 }
210
rs5c372_rtc_read_time(struct device * dev,struct rtc_time * tm)211 static int rs5c372_rtc_read_time(struct device *dev, struct rtc_time *tm)
212 {
213 struct i2c_client *client = to_i2c_client(dev);
214 struct rs5c372 *rs5c = i2c_get_clientdata(client);
215 int status = rs5c_get_regs(rs5c);
216 unsigned char ctrl2 = rs5c->regs[RS5C_REG_CTRL2];
217
218 if (status < 0)
219 return status;
220
221 switch (rs5c->type) {
222 case rtc_r2025sd:
223 case rtc_r2221tl:
224 if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
225 (rs5c->type == rtc_r2221tl && (ctrl2 & R2x2x_CTRL2_XSTP))) {
226 dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
227 return -EINVAL;
228 }
229 break;
230 default:
231 if (ctrl2 & RS5C_CTRL2_XSTP) {
232 dev_warn(&client->dev, "rtc oscillator interruption detected. Please reset the rtc clock.\n");
233 return -EINVAL;
234 }
235 }
236
237 tm->tm_sec = bcd2bin(rs5c->regs[RS5C372_REG_SECS] & 0x7f);
238 tm->tm_min = bcd2bin(rs5c->regs[RS5C372_REG_MINS] & 0x7f);
239 tm->tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C372_REG_HOURS]);
240
241 tm->tm_wday = bcd2bin(rs5c->regs[RS5C372_REG_WDAY] & 0x07);
242 tm->tm_mday = bcd2bin(rs5c->regs[RS5C372_REG_DAY] & 0x3f);
243
244 /* tm->tm_mon is zero-based */
245 tm->tm_mon = bcd2bin(rs5c->regs[RS5C372_REG_MONTH] & 0x1f) - 1;
246
247 /* year is 1900 + tm->tm_year */
248 tm->tm_year = bcd2bin(rs5c->regs[RS5C372_REG_YEAR]) + 100;
249
250 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
251 "mday=%d, mon=%d, year=%d, wday=%d\n",
252 __func__,
253 tm->tm_sec, tm->tm_min, tm->tm_hour,
254 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
255
256 return 0;
257 }
258
rs5c372_rtc_set_time(struct device * dev,struct rtc_time * tm)259 static int rs5c372_rtc_set_time(struct device *dev, struct rtc_time *tm)
260 {
261 struct i2c_client *client = to_i2c_client(dev);
262 struct rs5c372 *rs5c = i2c_get_clientdata(client);
263 unsigned char buf[7];
264 unsigned char ctrl2;
265 int addr;
266
267 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d "
268 "mday=%d, mon=%d, year=%d, wday=%d\n",
269 __func__,
270 tm->tm_sec, tm->tm_min, tm->tm_hour,
271 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
272
273 addr = RS5C_ADDR(RS5C372_REG_SECS);
274 buf[0] = bin2bcd(tm->tm_sec);
275 buf[1] = bin2bcd(tm->tm_min);
276 buf[2] = rs5c_hr2reg(rs5c, tm->tm_hour);
277 buf[3] = bin2bcd(tm->tm_wday);
278 buf[4] = bin2bcd(tm->tm_mday);
279 buf[5] = bin2bcd(tm->tm_mon + 1);
280 buf[6] = bin2bcd(tm->tm_year - 100);
281
282 if (i2c_smbus_write_i2c_block_data(client, addr, sizeof(buf), buf) < 0) {
283 dev_dbg(&client->dev, "%s: write error in line %i\n",
284 __func__, __LINE__);
285 return -EIO;
286 }
287
288 addr = RS5C_ADDR(RS5C_REG_CTRL2);
289 ctrl2 = i2c_smbus_read_byte_data(client, addr);
290
291 /* clear rtc warning bits */
292 switch (rs5c->type) {
293 case rtc_r2025sd:
294 case rtc_r2221tl:
295 ctrl2 &= ~(R2x2x_CTRL2_VDET | R2x2x_CTRL2_PON);
296 if (rs5c->type == rtc_r2025sd)
297 ctrl2 |= R2x2x_CTRL2_XSTP;
298 else
299 ctrl2 &= ~R2x2x_CTRL2_XSTP;
300 break;
301 default:
302 ctrl2 &= ~RS5C_CTRL2_XSTP;
303 break;
304 }
305
306 if (i2c_smbus_write_byte_data(client, addr, ctrl2) < 0) {
307 dev_dbg(&client->dev, "%s: write error in line %i\n",
308 __func__, __LINE__);
309 return -EIO;
310 }
311
312 return 0;
313 }
314
315 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
316 #define NEED_TRIM
317 #endif
318
319 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
320 #define NEED_TRIM
321 #endif
322
323 #ifdef NEED_TRIM
rs5c372_get_trim(struct i2c_client * client,int * osc,int * trim)324 static int rs5c372_get_trim(struct i2c_client *client, int *osc, int *trim)
325 {
326 struct rs5c372 *rs5c372 = i2c_get_clientdata(client);
327 u8 tmp = rs5c372->regs[RS5C372_REG_TRIM];
328
329 if (osc) {
330 if (rs5c372->type == rtc_rs5c372a || rs5c372->type == rtc_rs5c372b)
331 *osc = (tmp & RS5C372_TRIM_XSL) ? 32000 : 32768;
332 else
333 *osc = 32768;
334 }
335
336 if (trim) {
337 dev_dbg(&client->dev, "%s: raw trim=%x\n", __func__, tmp);
338 tmp &= RS5C372_TRIM_MASK;
339 if (tmp & 0x3e) {
340 int t = tmp & 0x3f;
341
342 if (tmp & 0x40)
343 t = (~t | (s8)0xc0) + 1;
344 else
345 t = t - 1;
346
347 tmp = t * 2;
348 } else
349 tmp = 0;
350 *trim = tmp;
351 }
352
353 return 0;
354 }
355 #endif
356
rs5c_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)357 static int rs5c_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
358 {
359 struct i2c_client *client = to_i2c_client(dev);
360 struct rs5c372 *rs5c = i2c_get_clientdata(client);
361 unsigned char buf;
362 int status, addr;
363
364 buf = rs5c->regs[RS5C_REG_CTRL1];
365
366 if (!rs5c->has_irq)
367 return -EINVAL;
368
369 status = rs5c_get_regs(rs5c);
370 if (status < 0)
371 return status;
372
373 addr = RS5C_ADDR(RS5C_REG_CTRL1);
374 if (enabled)
375 buf |= RS5C_CTRL1_AALE;
376 else
377 buf &= ~RS5C_CTRL1_AALE;
378
379 if (i2c_smbus_write_byte_data(client, addr, buf) < 0) {
380 dev_warn(dev, "can't update alarm\n");
381 status = -EIO;
382 } else
383 rs5c->regs[RS5C_REG_CTRL1] = buf;
384
385 return status;
386 }
387
388
389 /* NOTE: Since RTC_WKALM_{RD,SET} were originally defined for EFI,
390 * which only exposes a polled programming interface; and since
391 * these calls map directly to those EFI requests; we don't demand
392 * we have an IRQ for this chip when we go through this API.
393 *
394 * The older x86_pc derived RTC_ALM_{READ,SET} calls require irqs
395 * though, managed through RTC_AIE_{ON,OFF} requests.
396 */
397
rs5c_read_alarm(struct device * dev,struct rtc_wkalrm * t)398 static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
399 {
400 struct i2c_client *client = to_i2c_client(dev);
401 struct rs5c372 *rs5c = i2c_get_clientdata(client);
402 int status;
403
404 status = rs5c_get_regs(rs5c);
405 if (status < 0)
406 return status;
407
408 /* report alarm time */
409 t->time.tm_sec = 0;
410 t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
411 t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
412
413 /* ... and status */
414 t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
415 t->pending = !!(rs5c->regs[RS5C_REG_CTRL2] & RS5C_CTRL2_AAFG);
416
417 return 0;
418 }
419
rs5c_set_alarm(struct device * dev,struct rtc_wkalrm * t)420 static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
421 {
422 struct i2c_client *client = to_i2c_client(dev);
423 struct rs5c372 *rs5c = i2c_get_clientdata(client);
424 int status, addr, i;
425 unsigned char buf[3];
426
427 /* only handle up to 24 hours in the future, like RTC_ALM_SET */
428 if (t->time.tm_mday != -1
429 || t->time.tm_mon != -1
430 || t->time.tm_year != -1)
431 return -EINVAL;
432
433 /* REVISIT: round up tm_sec */
434
435 /* if needed, disable irq (clears pending status) */
436 status = rs5c_get_regs(rs5c);
437 if (status < 0)
438 return status;
439 if (rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE) {
440 addr = RS5C_ADDR(RS5C_REG_CTRL1);
441 buf[0] = rs5c->regs[RS5C_REG_CTRL1] & ~RS5C_CTRL1_AALE;
442 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0) {
443 dev_dbg(dev, "can't disable alarm\n");
444 return -EIO;
445 }
446 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
447 }
448
449 /* set alarm */
450 buf[0] = bin2bcd(t->time.tm_min);
451 buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
452 buf[2] = 0x7f; /* any/all days */
453
454 for (i = 0; i < sizeof(buf); i++) {
455 addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
456 if (i2c_smbus_write_byte_data(client, addr, buf[i]) < 0) {
457 dev_dbg(dev, "can't set alarm time\n");
458 return -EIO;
459 }
460 }
461
462 /* ... and maybe enable its irq */
463 if (t->enabled) {
464 addr = RS5C_ADDR(RS5C_REG_CTRL1);
465 buf[0] = rs5c->regs[RS5C_REG_CTRL1] | RS5C_CTRL1_AALE;
466 if (i2c_smbus_write_byte_data(client, addr, buf[0]) < 0)
467 dev_warn(dev, "can't enable alarm\n");
468 rs5c->regs[RS5C_REG_CTRL1] = buf[0];
469 }
470
471 return 0;
472 }
473
474 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
475
rs5c372_rtc_proc(struct device * dev,struct seq_file * seq)476 static int rs5c372_rtc_proc(struct device *dev, struct seq_file *seq)
477 {
478 int err, osc, trim;
479
480 err = rs5c372_get_trim(to_i2c_client(dev), &osc, &trim);
481 if (err == 0) {
482 seq_printf(seq, "crystal\t\t: %d.%03d KHz\n",
483 osc / 1000, osc % 1000);
484 seq_printf(seq, "trim\t\t: %d\n", trim);
485 }
486
487 return 0;
488 }
489
490 #else
491 #define rs5c372_rtc_proc NULL
492 #endif
493
494 #ifdef CONFIG_RTC_INTF_DEV
rs5c372_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)495 static int rs5c372_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
496 {
497 struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
498 unsigned char ctrl2;
499 int addr;
500 unsigned int flags;
501
502 dev_dbg(dev, "%s: cmd=%x\n", __func__, cmd);
503
504 addr = RS5C_ADDR(RS5C_REG_CTRL2);
505 ctrl2 = i2c_smbus_read_byte_data(rs5c->client, addr);
506
507 switch (cmd) {
508 case RTC_VL_READ:
509 flags = 0;
510
511 switch (rs5c->type) {
512 case rtc_r2025sd:
513 case rtc_r2221tl:
514 if ((rs5c->type == rtc_r2025sd && !(ctrl2 & R2x2x_CTRL2_XSTP)) ||
515 (rs5c->type == rtc_r2221tl && (ctrl2 & R2x2x_CTRL2_XSTP))) {
516 flags |= RTC_VL_DATA_INVALID;
517 }
518 if (ctrl2 & R2x2x_CTRL2_VDET)
519 flags |= RTC_VL_BACKUP_LOW;
520 break;
521 default:
522 if (ctrl2 & RS5C_CTRL2_XSTP)
523 flags |= RTC_VL_DATA_INVALID;
524 break;
525 }
526
527 return put_user(flags, (unsigned int __user *)arg);
528 case RTC_VL_CLR:
529 /* clear VDET bit */
530 if (rs5c->type == rtc_r2025sd || rs5c->type == rtc_r2221tl) {
531 ctrl2 &= ~R2x2x_CTRL2_VDET;
532 if (i2c_smbus_write_byte_data(rs5c->client, addr, ctrl2) < 0) {
533 dev_dbg(&rs5c->client->dev, "%s: write error in line %i\n",
534 __func__, __LINE__);
535 return -EIO;
536 }
537 }
538 return 0;
539 default:
540 return -ENOIOCTLCMD;
541 }
542 return 0;
543 }
544 #else
545 #define rs5c372_ioctl NULL
546 #endif
547
rs5c372_read_offset(struct device * dev,long * offset)548 static int rs5c372_read_offset(struct device *dev, long *offset)
549 {
550 struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
551 u8 val = rs5c->regs[RS5C372_REG_TRIM];
552 long ppb_per_step = 0;
553 bool decr = val & RS5C372_TRIM_DECR;
554
555 switch (rs5c->type) {
556 case rtc_r2221tl:
557 ppb_per_step = val & R2221TL_TRIM_DEV ? 1017 : 3051;
558 break;
559 case rtc_rs5c372a:
560 case rtc_rs5c372b:
561 ppb_per_step = val & RS5C372_TRIM_XSL ? 3125 : 3051;
562 break;
563 default:
564 ppb_per_step = 3051;
565 break;
566 }
567
568 /* Only bits[0:5] repsents the time counts */
569 val &= 0x3F;
570
571 /* If bits[1:5] are all 0, it means no increment or decrement */
572 if (!(val & 0x3E)) {
573 *offset = 0;
574 } else {
575 if (decr)
576 *offset = -(((~val) & 0x3F) + 1) * ppb_per_step;
577 else
578 *offset = (val - 1) * ppb_per_step;
579 }
580
581 return 0;
582 }
583
rs5c372_set_offset(struct device * dev,long offset)584 static int rs5c372_set_offset(struct device *dev, long offset)
585 {
586 struct rs5c372 *rs5c = i2c_get_clientdata(to_i2c_client(dev));
587 int addr = RS5C_ADDR(RS5C372_REG_TRIM);
588 u8 val = 0;
589 u8 tmp = 0;
590 long ppb_per_step = 3051;
591 long steps = LONG_MIN;
592
593 switch (rs5c->type) {
594 case rtc_rs5c372a:
595 case rtc_rs5c372b:
596 tmp = rs5c->regs[RS5C372_REG_TRIM];
597 if (tmp & RS5C372_TRIM_XSL) {
598 ppb_per_step = 3125;
599 val |= RS5C372_TRIM_XSL;
600 }
601 break;
602 case rtc_r2221tl:
603 /*
604 * Check if it is possible to use high resolution mode (DEV=1).
605 * In this mode, the minimum resolution is 2 / (32768 * 20 * 3),
606 * which is about 1017 ppb.
607 */
608 steps = DIV_ROUND_CLOSEST(offset, 1017);
609 if (steps >= -0x3E && steps <= 0x3E) {
610 ppb_per_step = 1017;
611 val |= R2221TL_TRIM_DEV;
612 } else {
613 /*
614 * offset is out of the range of high resolution mode.
615 * Try to use low resolution mode (DEV=0). In this mode,
616 * the minimum resolution is 2 / (32768 * 20), which is
617 * about 3051 ppb.
618 */
619 steps = LONG_MIN;
620 }
621 break;
622 default:
623 break;
624 }
625
626 if (steps == LONG_MIN) {
627 steps = DIV_ROUND_CLOSEST(offset, ppb_per_step);
628 if (steps > 0x3E || steps < -0x3E)
629 return -ERANGE;
630 }
631
632 if (steps > 0) {
633 val |= steps + 1;
634 } else {
635 val |= RS5C372_TRIM_DECR;
636 val |= (~(-steps - 1)) & 0x3F;
637 }
638
639 if (!steps || !(val & 0x3E)) {
640 /*
641 * if offset is too small, set oscillation adjustment register
642 * or time trimming register with its default value whic means
643 * no increment or decrement. But for rs5c372[a|b], the XSL bit
644 * should be kept unchanged.
645 */
646 if (rs5c->type == rtc_rs5c372a || rs5c->type == rtc_rs5c372b)
647 val &= RS5C372_TRIM_XSL;
648 else
649 val = 0;
650 }
651
652 dev_dbg(&rs5c->client->dev, "write 0x%x for offset %ld\n", val, offset);
653
654 if (i2c_smbus_write_byte_data(rs5c->client, addr, val) < 0) {
655 dev_err(&rs5c->client->dev, "failed to write 0x%x to reg %d\n", val, addr);
656 return -EIO;
657 }
658
659 rs5c->regs[RS5C372_REG_TRIM] = val;
660
661 return 0;
662 }
663
664 static const struct rtc_class_ops rs5c372_rtc_ops = {
665 .proc = rs5c372_rtc_proc,
666 .read_time = rs5c372_rtc_read_time,
667 .set_time = rs5c372_rtc_set_time,
668 .read_alarm = rs5c_read_alarm,
669 .set_alarm = rs5c_set_alarm,
670 .alarm_irq_enable = rs5c_rtc_alarm_irq_enable,
671 .ioctl = rs5c372_ioctl,
672 .read_offset = rs5c372_read_offset,
673 .set_offset = rs5c372_set_offset,
674 };
675
676 #if IS_ENABLED(CONFIG_RTC_INTF_SYSFS)
677
rs5c372_sysfs_show_trim(struct device * dev,struct device_attribute * attr,char * buf)678 static ssize_t rs5c372_sysfs_show_trim(struct device *dev,
679 struct device_attribute *attr, char *buf)
680 {
681 int err, trim;
682
683 err = rs5c372_get_trim(to_i2c_client(dev), NULL, &trim);
684 if (err)
685 return err;
686
687 return sprintf(buf, "%d\n", trim);
688 }
689 static DEVICE_ATTR(trim, S_IRUGO, rs5c372_sysfs_show_trim, NULL);
690
rs5c372_sysfs_show_osc(struct device * dev,struct device_attribute * attr,char * buf)691 static ssize_t rs5c372_sysfs_show_osc(struct device *dev,
692 struct device_attribute *attr, char *buf)
693 {
694 int err, osc;
695
696 err = rs5c372_get_trim(to_i2c_client(dev), &osc, NULL);
697 if (err)
698 return err;
699
700 return sprintf(buf, "%d.%03d KHz\n", osc / 1000, osc % 1000);
701 }
702 static DEVICE_ATTR(osc, S_IRUGO, rs5c372_sysfs_show_osc, NULL);
703
rs5c_sysfs_register(struct device * dev)704 static int rs5c_sysfs_register(struct device *dev)
705 {
706 int err;
707
708 err = device_create_file(dev, &dev_attr_trim);
709 if (err)
710 return err;
711 err = device_create_file(dev, &dev_attr_osc);
712 if (err)
713 device_remove_file(dev, &dev_attr_trim);
714
715 return err;
716 }
717
rs5c_sysfs_unregister(struct device * dev)718 static void rs5c_sysfs_unregister(struct device *dev)
719 {
720 device_remove_file(dev, &dev_attr_trim);
721 device_remove_file(dev, &dev_attr_osc);
722 }
723
724 #else
rs5c_sysfs_register(struct device * dev)725 static int rs5c_sysfs_register(struct device *dev)
726 {
727 return 0;
728 }
729
rs5c_sysfs_unregister(struct device * dev)730 static void rs5c_sysfs_unregister(struct device *dev)
731 {
732 /* nothing */
733 }
734 #endif /* SYSFS */
735
736 static struct i2c_driver rs5c372_driver;
737
rs5c_oscillator_setup(struct rs5c372 * rs5c372)738 static int rs5c_oscillator_setup(struct rs5c372 *rs5c372)
739 {
740 unsigned char buf[2];
741 int addr, i, ret = 0;
742
743 addr = RS5C_ADDR(RS5C_REG_CTRL1);
744 buf[0] = rs5c372->regs[RS5C_REG_CTRL1];
745 buf[1] = rs5c372->regs[RS5C_REG_CTRL2];
746
747 switch (rs5c372->type) {
748 case rtc_r2025sd:
749 if (buf[1] & R2x2x_CTRL2_XSTP)
750 return ret;
751 break;
752 case rtc_r2221tl:
753 if (!(buf[1] & R2x2x_CTRL2_XSTP))
754 return ret;
755 break;
756 default:
757 if (!(buf[1] & RS5C_CTRL2_XSTP))
758 return ret;
759 break;
760 }
761
762 /* use 24hr mode */
763 switch (rs5c372->type) {
764 case rtc_rs5c372a:
765 case rtc_rs5c372b:
766 buf[1] |= RS5C372_CTRL2_24;
767 rs5c372->time24 = 1;
768 break;
769 case rtc_r2025sd:
770 case rtc_r2221tl:
771 case rtc_rv5c386:
772 case rtc_rv5c387a:
773 buf[0] |= RV5C387_CTRL1_24;
774 rs5c372->time24 = 1;
775 break;
776 default:
777 /* impossible */
778 break;
779 }
780
781 for (i = 0; i < sizeof(buf); i++) {
782 addr = RS5C_ADDR(RS5C_REG_CTRL1 + i);
783 ret = i2c_smbus_write_byte_data(rs5c372->client, addr, buf[i]);
784 if (unlikely(ret < 0))
785 return ret;
786 }
787
788 rs5c372->regs[RS5C_REG_CTRL1] = buf[0];
789 rs5c372->regs[RS5C_REG_CTRL2] = buf[1];
790
791 return 0;
792 }
793
rs5c372_probe(struct i2c_client * client)794 static int rs5c372_probe(struct i2c_client *client)
795 {
796 int err = 0;
797 int smbus_mode = 0;
798 struct rs5c372 *rs5c372;
799
800 dev_dbg(&client->dev, "%s\n", __func__);
801
802 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
803 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK)) {
804 /*
805 * If we don't have any master mode adapter, try breaking
806 * it down in to the barest of capabilities.
807 */
808 if (i2c_check_functionality(client->adapter,
809 I2C_FUNC_SMBUS_BYTE_DATA |
810 I2C_FUNC_SMBUS_I2C_BLOCK))
811 smbus_mode = 1;
812 else {
813 /* Still no good, give up */
814 err = -ENODEV;
815 goto exit;
816 }
817 }
818
819 rs5c372 = devm_kzalloc(&client->dev, sizeof(struct rs5c372),
820 GFP_KERNEL);
821 if (!rs5c372) {
822 err = -ENOMEM;
823 goto exit;
824 }
825
826 rs5c372->client = client;
827 i2c_set_clientdata(client, rs5c372);
828 if (client->dev.of_node) {
829 rs5c372->type = (uintptr_t)of_device_get_match_data(&client->dev);
830 } else {
831 const struct i2c_device_id *id = i2c_match_id(rs5c372_id, client);
832 rs5c372->type = id->driver_data;
833 }
834
835 /* we read registers 0x0f then 0x00-0x0f; skip the first one */
836 rs5c372->regs = &rs5c372->buf[1];
837 rs5c372->smbus = smbus_mode;
838
839 err = rs5c_get_regs(rs5c372);
840 if (err < 0)
841 goto exit;
842
843 /* clock may be set for am/pm or 24 hr time */
844 switch (rs5c372->type) {
845 case rtc_rs5c372a:
846 case rtc_rs5c372b:
847 /* alarm uses ALARM_A; and nINTRA on 372a, nINTR on 372b.
848 * so does periodic irq, except some 327a modes.
849 */
850 if (rs5c372->regs[RS5C_REG_CTRL2] & RS5C372_CTRL2_24)
851 rs5c372->time24 = 1;
852 break;
853 case rtc_r2025sd:
854 case rtc_r2221tl:
855 case rtc_rv5c386:
856 case rtc_rv5c387a:
857 if (rs5c372->regs[RS5C_REG_CTRL1] & RV5C387_CTRL1_24)
858 rs5c372->time24 = 1;
859 /* alarm uses ALARM_W; and nINTRB for alarm and periodic
860 * irq, on both 386 and 387
861 */
862 break;
863 default:
864 dev_err(&client->dev, "unknown RTC type\n");
865 goto exit;
866 }
867
868 /* if the oscillator lost power and no other software (like
869 * the bootloader) set it up, do it here.
870 *
871 * The R2025S/D does this a little differently than the other
872 * parts, so we special case that..
873 */
874 err = rs5c_oscillator_setup(rs5c372);
875 if (unlikely(err < 0)) {
876 dev_err(&client->dev, "setup error\n");
877 goto exit;
878 }
879
880 dev_info(&client->dev, "%s found, %s\n",
881 ({ char *s; switch (rs5c372->type) {
882 case rtc_r2025sd: s = "r2025sd"; break;
883 case rtc_r2221tl: s = "r2221tl"; break;
884 case rtc_rs5c372a: s = "rs5c372a"; break;
885 case rtc_rs5c372b: s = "rs5c372b"; break;
886 case rtc_rv5c386: s = "rv5c386"; break;
887 case rtc_rv5c387a: s = "rv5c387a"; break;
888 default: s = "chip"; break;
889 }; s;}),
890 rs5c372->time24 ? "24hr" : "am/pm"
891 );
892
893 /* REVISIT use client->irq to register alarm irq ... */
894 rs5c372->rtc = devm_rtc_device_register(&client->dev,
895 rs5c372_driver.driver.name,
896 &rs5c372_rtc_ops, THIS_MODULE);
897
898 if (IS_ERR(rs5c372->rtc)) {
899 err = PTR_ERR(rs5c372->rtc);
900 goto exit;
901 }
902
903 err = rs5c_sysfs_register(&client->dev);
904 if (err)
905 goto exit;
906
907 return 0;
908
909 exit:
910 return err;
911 }
912
rs5c372_remove(struct i2c_client * client)913 static void rs5c372_remove(struct i2c_client *client)
914 {
915 rs5c_sysfs_unregister(&client->dev);
916 }
917
918 static struct i2c_driver rs5c372_driver = {
919 .driver = {
920 .name = "rtc-rs5c372",
921 .of_match_table = of_match_ptr(rs5c372_of_match),
922 },
923 .probe = rs5c372_probe,
924 .remove = rs5c372_remove,
925 .id_table = rs5c372_id,
926 };
927
928 module_i2c_driver(rs5c372_driver);
929
930 MODULE_AUTHOR(
931 "Pavel Mironchik <pmironchik@optifacio.net>, "
932 "Alessandro Zummo <a.zummo@towertech.it>, "
933 "Paul Mundt <lethal@linux-sh.org>");
934 MODULE_DESCRIPTION("Ricoh RS5C372 RTC driver");
935 MODULE_LICENSE("GPL");
936