xref: /openbmc/u-boot/drivers/rtc/rv3029.c (revision 9450ab2b)
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