xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision 0e8d1586)
1 /*
2  * (C) Copyright 2002 SIXNET, dge@sixnetio.com.
3  *
4  * (C) Copyright 2004, Li-Pro.Net <www.li-pro.net>
5  * Stephan Linz <linz@li-pro.net>
6  *
7  * See file CREDITS for list of people who contributed to this
8  * project.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of
13  * the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
23  * MA 02111-1307 USA
24  */
25 
26 /*
27  * Date & Time support for DS1306 RTC using SPI:
28  *
29  *    - SXNI855T:    it uses its own soft SPI here in this file
30  *    - all other:   use the external spi_xfer() function
31  *                   (see include/spi.h)
32  */
33 
34 #include <common.h>
35 #include <command.h>
36 #include <rtc.h>
37 #include <spi.h>
38 
39 #if defined(CONFIG_CMD_DATE)
40 
41 #define	RTC_SECONDS		0x00
42 #define	RTC_MINUTES		0x01
43 #define	RTC_HOURS		0x02
44 #define	RTC_DAY_OF_WEEK		0x03
45 #define	RTC_DATE_OF_MONTH	0x04
46 #define	RTC_MONTH		0x05
47 #define	RTC_YEAR		0x06
48 
49 #define	RTC_SECONDS_ALARM0	0x07
50 #define	RTC_MINUTES_ALARM0	0x08
51 #define	RTC_HOURS_ALARM0	0x09
52 #define	RTC_DAY_OF_WEEK_ALARM0	0x0a
53 
54 #define	RTC_SECONDS_ALARM1	0x0b
55 #define	RTC_MINUTES_ALARM1	0x0c
56 #define	RTC_HOURS_ALARM1	0x0d
57 #define	RTC_DAY_OF_WEEK_ALARM1	0x0e
58 
59 #define	RTC_CONTROL		0x0f
60 #define	RTC_STATUS		0x10
61 #define	RTC_TRICKLE_CHARGER	0x11
62 
63 #define	RTC_USER_RAM_BASE	0x20
64 
65 static unsigned int bin2bcd (unsigned int n);
66 static unsigned char bcd2bin (unsigned char c);
67 
68 /* ************************************************************************* */
69 #ifdef CONFIG_SXNI855T		/* !!! SHOULD BE CHANGED TO NEW CODE !!! */
70 
71 static void soft_spi_send (unsigned char n);
72 static unsigned char soft_spi_read (void);
73 static void init_spi (void);
74 
75 /*-----------------------------------------------------------------------
76  * Definitions
77  */
78 
79 #define	PB_SPISCK	0x00000002	/* PB 30 */
80 #define PB_SPIMOSI	0x00000004	/* PB 29 */
81 #define PB_SPIMISO	0x00000008	/* PB 28 */
82 #define PB_SPI_CE	0x00010000	/* PB 15 */
83 
84 /* ------------------------------------------------------------------------- */
85 
86 /* read clock time from DS1306 and return it in *tmp */
87 int rtc_get (struct rtc_time *tmp)
88 {
89 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
90 	unsigned char spi_byte;	/* Data Byte */
91 
92 	init_spi ();		/* set port B for software SPI */
93 
94 	/* Now we can enable the DS1306 RTC */
95 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
96 	udelay (10);
97 
98 	/* Shift out the address (0) of the time in the Clock Chip */
99 	soft_spi_send (0);
100 
101 	/* Put the clock readings into the rtc_time structure */
102 	tmp->tm_sec = bcd2bin (soft_spi_read ());	/* Read seconds */
103 	tmp->tm_min = bcd2bin (soft_spi_read ());	/* Read minutes */
104 
105 	/* Hours are trickier */
106 	spi_byte = soft_spi_read ();	/* Read Hours into temporary value */
107 	if (spi_byte & 0x40) {
108 		/* 12 hour mode bit is set (time is in 1-12 format) */
109 		if (spi_byte & 0x20) {
110 			/* since PM we add 11 to get 0-23 for hours */
111 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
112 		} else {
113 			/* since AM we subtract 1 to get 0-23 for hours */
114 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
115 		}
116 	} else {
117 		/* Otherwise, 0-23 hour format */
118 		tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
119 	}
120 
121 	soft_spi_read ();	/* Read and discard Day of week */
122 	tmp->tm_mday = bcd2bin (soft_spi_read ());	/* Read Day of the Month */
123 	tmp->tm_mon = bcd2bin (soft_spi_read ());	/* Read Month */
124 
125 	/* Read Year and convert to this century */
126 	tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
127 
128 	/* Now we can disable the DS1306 RTC */
129 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
130 	udelay (10);
131 
132 	GregorianDay (tmp);	/* Determine the day of week */
133 
134 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
135 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
136 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
137 
138 	return 0;
139 }
140 
141 /* ------------------------------------------------------------------------- */
142 
143 /* set clock time in DS1306 RTC and in MPC8xx RTC */
144 int rtc_set (struct rtc_time *tmp)
145 {
146 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
147 
148 	init_spi ();		/* set port B for software SPI */
149 
150 	/* Now we can enable the DS1306 RTC */
151 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
152 	udelay (10);
153 
154 	/* First disable write protect in the clock chip control register */
155 	soft_spi_send (0x8F);	/* send address of the control register */
156 	soft_spi_send (0x00);	/* send control register contents */
157 
158 	/* Now disable the DS1306 to terminate the write */
159 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
160 	udelay (10);
161 
162 	/* Now enable the DS1306 to initiate a new write */
163 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
164 	udelay (10);
165 
166 	/* Next, send the address of the clock time write registers */
167 	soft_spi_send (0x80);	/* send address of the first time register */
168 
169 	/* Use Burst Mode to send all of the time data to the clock */
170 	bin2bcd (tmp->tm_sec);
171 	soft_spi_send (bin2bcd (tmp->tm_sec));	/* Send Seconds */
172 	soft_spi_send (bin2bcd (tmp->tm_min));	/* Send Minutes */
173 	soft_spi_send (bin2bcd (tmp->tm_hour));	/* Send Hour */
174 	soft_spi_send (bin2bcd (tmp->tm_wday));	/* Send Day of the Week */
175 	soft_spi_send (bin2bcd (tmp->tm_mday));	/* Send Day of Month */
176 	soft_spi_send (bin2bcd (tmp->tm_mon));	/* Send Month */
177 	soft_spi_send (bin2bcd (tmp->tm_year - 2000));	/* Send Year */
178 
179 	/* Now we can disable the Clock chip to terminate the burst write */
180 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
181 	udelay (10);
182 
183 	/* Now we can enable the Clock chip to initiate a new write */
184 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
185 	udelay (10);
186 
187 	/* First we Enable write protect in the clock chip control register */
188 	soft_spi_send (0x8F);	/* send address of the control register */
189 	soft_spi_send (0x40);	/* send out Control Register contents */
190 
191 	/* Now disable the DS1306 */
192 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/*  Disable DS1306 Chip */
193 	udelay (10);
194 
195 	/* Set standard MPC8xx clock to the same time so Linux will
196 	 * see the time even if it doesn't have a DS1306 clock driver.
197 	 * This helps with experimenting with standard kernels.
198 	 */
199 	{
200 		ulong tim;
201 
202 		tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
203 			      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
204 
205 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
206 		immap->im_sit.sit_rtc = tim;
207 	}
208 
209 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
210 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
211 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
212 
213 	return 0;
214 }
215 
216 /* ------------------------------------------------------------------------- */
217 
218 /* Initialize Port B for software SPI */
219 static void init_spi (void)
220 {
221 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
222 
223 	/* Force output pins to begin at logic 0 */
224 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
225 
226 	/* Set these 3 signals as outputs */
227 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
228 
229 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
230 	udelay (10);
231 }
232 
233 /* ------------------------------------------------------------------------- */
234 
235 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
236 static void soft_spi_send (unsigned char n)
237 {
238 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
239 	unsigned char bitpos;	/* bit position to receive */
240 	unsigned char i;	/* Loop Control */
241 
242 	/* bit position to send, start with most significant bit */
243 	bitpos = 0x80;
244 
245 	/* Send 8 bits to software SPI */
246 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
247 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
248 
249 		if (n & bitpos)
250 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
251 		else
252 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
253 		udelay (10);
254 
255 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
256 		udelay (10);
257 
258 		bitpos >>= 1;	/* Shift for next bit position */
259 	}
260 }
261 
262 /* ------------------------------------------------------------------------- */
263 
264 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
265 static unsigned char soft_spi_read (void)
266 {
267 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
268 
269 	unsigned char spi_byte = 0;	/* Return value, assume success */
270 	unsigned char bitpos;	/* bit position to receive */
271 	unsigned char i;	/* Loop Control */
272 
273 	/* bit position to receive, start with most significant bit */
274 	bitpos = 0x80;
275 
276 	/* Read 8 bits here */
277 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
278 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
279 		udelay (10);
280 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
281 			spi_byte |= bitpos;	/* Set data accordingly */
282 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
283 		udelay (10);
284 		bitpos >>= 1;	/* Shift for next bit position */
285 	}
286 
287 	return spi_byte;	/* Return the byte read */
288 }
289 
290 /* ------------------------------------------------------------------------- */
291 
292 void rtc_reset (void)
293 {
294 	return;			/* nothing to do */
295 }
296 
297 #else  /* not CONFIG_SXNI855T */
298 /* ************************************************************************* */
299 
300 static unsigned char rtc_read (unsigned char reg);
301 static void rtc_write (unsigned char reg, unsigned char val);
302 
303 static struct spi_slave *slave;
304 
305 /* read clock time from DS1306 and return it in *tmp */
306 int rtc_get (struct rtc_time *tmp)
307 {
308 	unsigned char sec, min, hour, mday, wday, mon, year;
309 
310 	/*
311 	 * Assuming Vcc = 2.0V (lowest speed)
312 	 *
313 	 * REVISIT: If we add an rtc_init() function we can do this
314 	 * step just once.
315 	 */
316 	if (!slave) {
317 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
318 				SPI_MODE_3 | SPI_CS_HIGH);
319 		if (!slave)
320 			return;
321 	}
322 
323 	if (spi_claim_bus(slave))
324 		return;
325 
326 	sec = rtc_read (RTC_SECONDS);
327 	min = rtc_read (RTC_MINUTES);
328 	hour = rtc_read (RTC_HOURS);
329 	mday = rtc_read (RTC_DATE_OF_MONTH);
330 	wday = rtc_read (RTC_DAY_OF_WEEK);
331 	mon = rtc_read (RTC_MONTH);
332 	year = rtc_read (RTC_YEAR);
333 
334 	spi_release_bus(slave);
335 
336 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
337 	       "hr: %02x min: %02x sec: %02x\n",
338 	       year, mon, mday, wday, hour, min, sec);
339 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
340 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
341 	       rtc_read (RTC_HOURS_ALARM0),
342 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
343 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
344 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
345 	       rtc_read (RTC_HOURS_ALARM1),
346 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
347 
348 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
349 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
350 
351 	/* convert Hours */
352 	tmp->tm_hour = (hour & 0x40)
353 		? ((hour & 0x20)	/* 12 hour mode */
354 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
355 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
356 		)
357 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
358 
359 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
360 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
361 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
362 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
363 	tmp->tm_yday = 0;
364 	tmp->tm_isdst = 0;
365 
366 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
367 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
368 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
369 
370 	return 0;
371 }
372 
373 /* ------------------------------------------------------------------------- */
374 
375 /* set clock time from *tmp in DS1306 RTC */
376 int rtc_set (struct rtc_time *tmp)
377 {
378 	/* Assuming Vcc = 2.0V (lowest speed) */
379 	if (!slave) {
380 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
381 				SPI_MODE_3 | SPI_CS_HIGH);
382 		if (!slave)
383 			return;
384 	}
385 
386 	if (spi_claim_bus(slave))
387 		return;
388 
389 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
390 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
391 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
392 
393 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
394 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
395 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
396 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
397 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
398 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
399 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
400 
401 	spi_release_bus(slave);
402 }
403 
404 /* ------------------------------------------------------------------------- */
405 
406 /* reset the DS1306 */
407 void rtc_reset (void)
408 {
409 	/* Assuming Vcc = 2.0V (lowest speed) */
410 	if (!slave) {
411 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
412 				SPI_MODE_3 | SPI_CS_HIGH);
413 		if (!slave)
414 			return;
415 	}
416 
417 	if (spi_claim_bus(slave))
418 		return;
419 
420 	/* clear the control register */
421 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
422 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
423 
424 	/* reset all alarms */
425 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
426 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
427 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
428 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
429 	rtc_write (RTC_HOURS_ALARM0, 0x00);
430 	rtc_write (RTC_HOURS_ALARM1, 0x00);
431 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
432 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
433 
434 	spi_release_bus(slave);
435 }
436 
437 /* ------------------------------------------------------------------------- */
438 
439 static unsigned char rtc_read (unsigned char reg)
440 {
441 	int ret;
442 
443 	ret = spi_w8r8(slave, reg);
444 	return ret < 0 ? 0 : ret;
445 }
446 
447 /* ------------------------------------------------------------------------- */
448 
449 static void rtc_write (unsigned char reg, unsigned char val)
450 {
451 	unsigned char dout[2];	/* SPI Output Data Bytes */
452 	unsigned char din[2];	/* SPI Input Data Bytes */
453 
454 	dout[0] = 0x80 | reg;
455 	dout[1] = val;
456 
457 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
458 }
459 
460 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
461 
462 /* ------------------------------------------------------------------------- */
463 
464 static unsigned char bcd2bin (unsigned char n)
465 {
466 	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
467 }
468 
469 /* ------------------------------------------------------------------------- */
470 
471 static unsigned int bin2bcd (unsigned int n)
472 {
473 	return (((n / 10) << 4) | (n % 10));
474 }
475 /* ------------------------------------------------------------------------- */
476 
477 #endif
478