1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH
4 *
5 * Based on a the Linux rtc-rv3029c2.c driver written by:
6 * Gregory Hermant <gregory.hermant@calao-systems.com>
7 * Michael Buesch <m@bues.ch>
8 */
9
10 #include <common.h>
11 #include <command.h>
12 #include <dm.h>
13 #include <i2c.h>
14 #include <rtc.h>
15
16 #define RTC_RV3029_PAGE_LEN 7
17
18 /* control section */
19 #define RV3029_ONOFF_CTRL 0x00
20 #define RV3029_ONOFF_CTRL_WE BIT(0)
21 #define RV3029_ONOFF_CTRL_TE BIT(1)
22 #define RV3029_ONOFF_CTRL_TAR BIT(2)
23 #define RV3029_ONOFF_CTRL_EERE BIT(3)
24 #define RV3029_ONOFF_CTRL_SRON BIT(4)
25 #define RV3029_ONOFF_CTRL_TD0 BIT(5)
26 #define RV3029_ONOFF_CTRL_TD1 BIT(6)
27 #define RV3029_ONOFF_CTRL_CLKINT BIT(7)
28 #define RV3029_IRQ_CTRL 0x01
29 #define RV3029_IRQ_CTRL_AIE BIT(0)
30 #define RV3029_IRQ_CTRL_TIE BIT(1)
31 #define RV3029_IRQ_CTRL_V1IE BIT(2)
32 #define RV3029_IRQ_CTRL_V2IE BIT(3)
33 #define RV3029_IRQ_CTRL_SRIE BIT(4)
34 #define RV3029_IRQ_FLAGS 0x02
35 #define RV3029_IRQ_FLAGS_AF BIT(0)
36 #define RV3029_IRQ_FLAGS_TF BIT(1)
37 #define RV3029_IRQ_FLAGS_V1IF BIT(2)
38 #define RV3029_IRQ_FLAGS_V2IF BIT(3)
39 #define RV3029_IRQ_FLAGS_SRF BIT(4)
40 #define RV3029_STATUS 0x03
41 #define RV3029_STATUS_VLOW1 BIT(2)
42 #define RV3029_STATUS_VLOW2 BIT(3)
43 #define RV3029_STATUS_SR BIT(4)
44 #define RV3029_STATUS_PON BIT(5)
45 #define RV3029_STATUS_EEBUSY BIT(7)
46 #define RV3029_RST_CTRL 0x04
47 #define RV3029_RST_CTRL_SYSR BIT(4)
48 #define RV3029_CONTROL_SECTION_LEN 0x05
49
50 /* watch section */
51 #define RV3029_W_SEC 0x08
52 #define RV3029_W_MINUTES 0x09
53 #define RV3029_W_HOURS 0x0A
54 #define RV3029_REG_HR_12_24 BIT(6) /* 24h/12h mode */
55 #define RV3029_REG_HR_PM BIT(5) /* PM/AM bit in 12h mode */
56 #define RV3029_W_DATE 0x0B
57 #define RV3029_W_DAYS 0x0C
58 #define RV3029_W_MONTHS 0x0D
59 #define RV3029_W_YEARS 0x0E
60
61 /* eeprom control section */
62 #define RV3029_CONTROL_E2P_EECTRL 0x30
63 #define RV3029_TRICKLE_1K BIT(4) /* 1.5K resistance */
64 #define RV3029_TRICKLE_5K BIT(5) /* 5K resistance */
65 #define RV3029_TRICKLE_20K BIT(6) /* 20K resistance */
66 #define RV3029_TRICKLE_80K BIT(7) /* 80K resistance */
67 #define RV3029_TRICKLE_MASK (RV3029_TRICKLE_1K |\
68 RV3029_TRICKLE_5K |\
69 RV3029_TRICKLE_20K |\
70 RV3029_TRICKLE_80K)
71 #define RV3029_TRICKLE_SHIFT 4
72
73
rv3029_rtc_get(struct udevice * dev,struct rtc_time * tm)74 static int rv3029_rtc_get(struct udevice *dev, struct rtc_time *tm)
75 {
76 u8 regs[RTC_RV3029_PAGE_LEN];
77 int ret;
78
79 ret = dm_i2c_read(dev, RV3029_W_SEC, regs, sizeof(regs));
80 if (ret < 0) {
81 printf("%s: error reading RTC: %x\n", __func__, ret);
82 return -EIO;
83 }
84
85 tm->tm_sec = bcd2bin(regs[RV3029_W_SEC - RV3029_W_SEC]);
86 tm->tm_min = bcd2bin(regs[RV3029_W_MINUTES - RV3029_W_SEC]);
87
88 /* HR field has a more complex interpretation */
89 {
90 const u8 _hr = regs[RV3029_W_HOURS - RV3029_W_SEC];
91
92 if (_hr & RV3029_REG_HR_12_24) {
93 /* 12h format */
94 tm->tm_hour = bcd2bin(_hr & 0x1f);
95 if (_hr & RV3029_REG_HR_PM) /* PM flag set */
96 tm->tm_hour += 12;
97 } else {
98 /* 24h format */
99 tm->tm_hour = bcd2bin(_hr & 0x3f);
100 }
101 }
102
103 tm->tm_mday = bcd2bin(regs[RV3029_W_DATE - RV3029_W_SEC]);
104 tm->tm_mon = bcd2bin(regs[RV3029_W_MONTHS - RV3029_W_SEC]) - 1;
105 /* RTC supports only years > 1999 */
106 tm->tm_year = bcd2bin(regs[RV3029_W_YEARS - RV3029_W_SEC]) + 2000;
107 tm->tm_wday = bcd2bin(regs[RV3029_W_DAYS - RV3029_W_SEC]) - 1;
108
109 tm->tm_yday = 0;
110 tm->tm_isdst = 0;
111
112 debug("%s: %4d-%02d-%02d (wday=%d) %2d:%02d:%02d\n",
113 __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
114 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
115
116 return 0;
117 }
118
rv3029_rtc_set(struct udevice * dev,const struct rtc_time * tm)119 static int rv3029_rtc_set(struct udevice *dev, const struct rtc_time *tm)
120 {
121 u8 regs[RTC_RV3029_PAGE_LEN];
122
123 debug("%s: %4d-%02d-%02d (wday=%d( %2d:%02d:%02d\n",
124 __func__, tm->tm_year, tm->tm_mon, tm->tm_mday,
125 tm->tm_wday, tm->tm_hour, tm->tm_min, tm->tm_sec);
126
127
128 if (tm->tm_year < 2000) {
129 printf("%s: year %d (before 2000) not supported\n",
130 __func__, tm->tm_year);
131 return -EINVAL;
132 }
133
134 regs[RV3029_W_SEC - RV3029_W_SEC] = bin2bcd(tm->tm_sec);
135 regs[RV3029_W_MINUTES - RV3029_W_SEC] = bin2bcd(tm->tm_min);
136 regs[RV3029_W_HOURS - RV3029_W_SEC] = bin2bcd(tm->tm_hour);
137 regs[RV3029_W_DATE - RV3029_W_SEC] = bin2bcd(tm->tm_mday);
138 regs[RV3029_W_MONTHS - RV3029_W_SEC] = bin2bcd(tm->tm_mon + 1);
139 regs[RV3029_W_DAYS - RV3029_W_SEC] = bin2bcd(tm->tm_wday + 1) & 0x7;
140 regs[RV3029_W_YEARS - RV3029_W_SEC] = bin2bcd(tm->tm_year - 2000);
141
142 return dm_i2c_write(dev, RV3029_W_SEC, regs, sizeof(regs));
143 }
144
rv3029_rtc_reset(struct udevice * dev)145 static int rv3029_rtc_reset(struct udevice *dev)
146 {
147 u8 ctrl = RV3029_RST_CTRL_SYSR;
148 unsigned long start;
149 const unsigned long timeout_ms = 10000;
150 int ret;
151
152 /* trigger the system-reset */
153 ret = dm_i2c_write(dev, RV3029_RST_CTRL, &ctrl, 1);
154 if (ret < 0)
155 return -EIO;
156
157 /* wait for the system-reset to complete */
158 start = get_timer(0);
159 do {
160 if (get_timer(start) > timeout_ms)
161 return -ETIMEDOUT;
162
163 ret = dm_i2c_read(dev, RV3029_RST_CTRL, &ctrl, 1);
164 if (ret < 0)
165 return -EIO;
166 } while (ctrl & RV3029_RST_CTRL_SYSR);
167
168 return 0;
169 }
170
rv3029_rtc_read8(struct udevice * dev,unsigned int reg)171 static int rv3029_rtc_read8(struct udevice *dev, unsigned int reg)
172 {
173 u8 data;
174 int ret;
175
176 ret = dm_i2c_read(dev, reg, &data, sizeof(data));
177 return ret < 0 ? ret : data;
178 }
179
rv3029_rtc_write8(struct udevice * dev,unsigned int reg,int val)180 static int rv3029_rtc_write8(struct udevice *dev, unsigned int reg, int val)
181 {
182 u8 data = val;
183
184 return dm_i2c_write(dev, reg, &data, 1);
185 }
186
187 #if defined(OF_CONTROL)
rv3029_get_sr(struct udevice * dev,u8 * buf)188 static int rv3029_get_sr(struct udevice *dev, u8 *buf)
189 {
190 int ret = dm_i2c_read(dev, RV3029_STATUS, buf, 1);
191
192 if (ret < 0)
193 return -EIO;
194
195 dev_dbg(dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
196 return 0;
197 }
198
rv3029_set_sr(struct udevice * dev,u8 val)199 static int rv3029_set_sr(struct udevice *dev, u8 val)
200 {
201 int ret;
202
203 ret = dm_i2c_read(dev, RV3029_STATUS, &val, 1);
204 if (ret < 0)
205 return -EIO;
206
207 dev_dbg(dev, "status = 0x%.2x (%d)\n", val, val);
208 return 0;
209 }
210
rv3029_eeprom_busywait(struct udevice * dev)211 static int rv3029_eeprom_busywait(struct udevice *dev)
212 {
213 int i, ret;
214 u8 sr;
215
216 for (i = 100; i > 0; i--) {
217 ret = rv3029_get_sr(dev, &sr);
218 if (ret < 0)
219 break;
220 if (!(sr & RV3029_STATUS_EEBUSY))
221 break;
222 udelay(10000);
223 }
224 if (i <= 0) {
225 dev_err(dev, "EEPROM busy wait timeout.\n");
226 return -ETIMEDOUT;
227 }
228
229 return ret;
230 }
231
rv3029_update_bits(struct udevice * dev,u8 reg,u8 mask,u8 set)232 static int rv3029_update_bits(struct udevice *dev, u8 reg, u8 mask, u8 set)
233 {
234 u8 buf;
235 int ret;
236
237 ret = dm_i2c_read(dev, reg, &buf, 1);
238 if (ret < 0)
239 return ret;
240
241 if ((buf & mask) == (set && mask))
242 return 0;
243
244 buf = (buf & ~mask) | (set & mask);
245 ret = dm_i2c_read(dev, reg, &buf, 1);
246 if (ret < 0)
247 return ret;
248
249 return 0;
250 }
251
rv3029_eeprom_exit(struct udevice * dev)252 static int rv3029_eeprom_exit(struct udevice *dev)
253 {
254 /* Re-enable eeprom refresh */
255 return rv3029_update_bits(dev, RV3029_ONOFF_CTRL,
256 RV3029_ONOFF_CTRL_EERE,
257 RV3029_ONOFF_CTRL_EERE);
258 }
259
rv3029_eeprom_enter(struct udevice * dev)260 static int rv3029_eeprom_enter(struct udevice *dev)
261 {
262 int ret;
263 u8 sr;
264
265 /* Check whether we are in the allowed voltage range. */
266 ret = rv3029_get_sr(dev, &sr);
267 if (ret < 0)
268 return ret;
269 if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
270 /* We clear the bits and retry once just in case
271 * we had a brown out in early startup.
272 */
273 sr &= ~RV3029_STATUS_VLOW1;
274 sr &= ~RV3029_STATUS_VLOW2;
275 ret = rv3029_set_sr(dev, sr);
276 if (ret < 0)
277 return ret;
278 udelay(10000);
279 ret = rv3029_get_sr(dev, &sr);
280 if (ret < 0)
281 return ret;
282 if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) {
283 dev_err(dev, "Supply voltage is too low to safely access the EEPROM.\n");
284 return -ENODEV;
285 }
286 }
287
288 /* Disable eeprom refresh. */
289 ret = rv3029_update_bits(dev,
290 RV3029_ONOFF_CTRL, RV3029_ONOFF_CTRL_EERE, 0);
291 if (ret < 0)
292 return ret;
293
294 /* Wait for any previous eeprom accesses to finish. */
295 ret = rv3029_eeprom_busywait(dev);
296 if (ret < 0)
297 rv3029_eeprom_exit(dev);
298
299 return ret;
300 }
301
rv3029_eeprom_read(struct udevice * dev,u8 reg,u8 buf[],size_t len)302 static int rv3029_eeprom_read(struct udevice *dev, u8 reg,
303 u8 buf[], size_t len)
304 {
305 int ret, err;
306
307 err = rv3029_eeprom_enter(dev);
308 if (err < 0)
309 return err;
310
311 ret = dm_i2c_read(dev, reg, buf, len);
312
313 err = rv3029_eeprom_exit(dev);
314 if (err < 0)
315 return err;
316
317 return ret;
318 }
319
rv3029_eeprom_write(struct udevice * dev,u8 reg,u8 const buf[],size_t len)320 static int rv3029_eeprom_write(struct udevice *dev, u8 reg,
321 u8 const buf[], size_t len)
322 {
323 int ret;
324 size_t i;
325 u8 tmp;
326
327 ret = rv3029_eeprom_enter(dev);
328 if (ret < 0)
329 return ret;
330
331 for (i = 0; i < len; i++, reg++) {
332 ret = dm_i2c_read(dev, reg, &tmp, 1);
333 if (ret < 0)
334 break;
335 if (tmp != buf[i]) {
336 ret = dm_i2c_write(dev, reg, &buf[i], 1);
337 if (ret < 0)
338 break;
339 }
340 ret = rv3029_eeprom_busywait(dev);
341 if (ret < 0)
342 break;
343 }
344
345 ret = rv3029_eeprom_exit(dev);
346 if (ret < 0)
347 return ret;
348
349 return 0;
350 }
351
rv3029_eeprom_update_bits(struct udevice * dev,u8 reg,u8 mask,u8 set)352 static int rv3029_eeprom_update_bits(struct udevice *dev,
353 u8 reg, u8 mask, u8 set)
354 {
355 u8 buf;
356 int ret;
357
358 ret = rv3029_eeprom_read(dev, reg, &buf, 1);
359 if (ret < 0)
360 return ret;
361
362 /*
363 * If the EEPROM already reads the correct bitpattern, we don't need
364 * to update it.
365 */
366 if ((buf & mask) == (set & mask))
367 return 0;
368
369 buf = (buf & ~mask) | (set & mask);
370 ret = rv3029_eeprom_write(dev, reg, &buf, 1);
371 if (ret < 0)
372 return ret;
373
374 return 0;
375 }
376
rv3029_trickle_config(struct udevice * dev)377 static void rv3029_trickle_config(struct udevice *dev)
378 {
379 static const struct rv3029_trickle_tab_elem {
380 u32 r; /* resistance in ohms */
381 u8 conf; /* trickle config bits */
382 } rv3029_trickle_tab[] = {
383 {
384 .r = 1076,
385 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
386 RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
387 }, {
388 .r = 1091,
389 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
390 RV3029_TRICKLE_20K,
391 }, {
392 .r = 1137,
393 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K |
394 RV3029_TRICKLE_80K,
395 }, {
396 .r = 1154,
397 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_5K,
398 }, {
399 .r = 1371,
400 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K |
401 RV3029_TRICKLE_80K,
402 }, {
403 .r = 1395,
404 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_20K,
405 }, {
406 .r = 1472,
407 .conf = RV3029_TRICKLE_1K | RV3029_TRICKLE_80K,
408 }, {
409 .r = 1500,
410 .conf = RV3029_TRICKLE_1K,
411 }, {
412 .r = 3810,
413 .conf = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K |
414 RV3029_TRICKLE_80K,
415 }, {
416 .r = 4000,
417 .conf = RV3029_TRICKLE_5K | RV3029_TRICKLE_20K,
418 }, {
419 .r = 4706,
420 .conf = RV3029_TRICKLE_5K | RV3029_TRICKLE_80K,
421 }, {
422 .r = 5000,
423 .conf = RV3029_TRICKLE_5K,
424 }, {
425 .r = 16000,
426 .conf = RV3029_TRICKLE_20K | RV3029_TRICKLE_80K,
427 }, {
428 .r = 20000,
429 .conf = RV3029_TRICKLE_20K,
430 }, {
431 .r = 80000,
432 .conf = RV3029_TRICKLE_80K,
433 },
434 };
435 int err;
436 u32 ohms;
437 u8 trickle_set_bits = 0;
438
439 /* Configure the trickle charger. */
440 err = dev_read_u32(dev, "trickle-resistor-ohms", &ohms);
441
442 if (!err) {
443 /* Find trickle-charger config */
444 for (int i = 0; i < ARRAY_SIZE(rv3029_trickle_tab); i++)
445 if (rv3029_trickle_tab[i].r >= ohms) {
446 dev_dbg(dev, "trickle charger at %d ohms\n",
447 rv3029_trickle_tab[i].r);
448 trickle_set_bits = rv3029_trickle_tab[i].conf;
449 break;
450 }
451 }
452
453 dev_dbg(dev, "trickle charger config 0x%x\n", trickle_set_bits);
454 err = rv3029_eeprom_update_bits(dev, RV3029_CONTROL_E2P_EECTRL,
455 RV3029_TRICKLE_MASK,
456 trickle_set_bits);
457 if (err < 0)
458 dev_dbg(dev, "failed to update trickle charger\n");
459 }
460 #else
rv3029_trickle_config(struct udevice * dev)461 static inline void rv3029_trickle_config(struct udevice *dev)
462 {
463 }
464 #endif
465
rv3029_probe(struct udevice * dev)466 static int rv3029_probe(struct udevice *dev)
467 {
468 i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
469 DM_I2C_CHIP_WR_ADDRESS);
470
471 rv3029_trickle_config(dev);
472 return 0;
473 }
474
475 static const struct rtc_ops rv3029_rtc_ops = {
476 .get = rv3029_rtc_get,
477 .set = rv3029_rtc_set,
478 .read8 = rv3029_rtc_read8,
479 .write8 = rv3029_rtc_write8,
480 .reset = rv3029_rtc_reset,
481 };
482
483 static const struct udevice_id rv3029_rtc_ids[] = {
484 { .compatible = "mc,rv3029" },
485 { .compatible = "mc,rv3029c2" },
486 { }
487 };
488
489 U_BOOT_DRIVER(rtc_rv3029) = {
490 .name = "rtc-rv3029",
491 .id = UCLASS_RTC,
492 .probe = rv3029_probe,
493 .of_match = rv3029_rtc_ids,
494 .ops = &rv3029_rtc_ops,
495 };
496