xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision aa11d85c)
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 void 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 
214 /* ------------------------------------------------------------------------- */
215 
216 /* Initialize Port B for software SPI */
217 static void init_spi (void)
218 {
219 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
220 
221 	/* Force output pins to begin at logic 0 */
222 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
223 
224 	/* Set these 3 signals as outputs */
225 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
226 
227 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
228 	udelay (10);
229 }
230 
231 /* ------------------------------------------------------------------------- */
232 
233 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
234 static void soft_spi_send (unsigned char n)
235 {
236 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
237 	unsigned char bitpos;	/* bit position to receive */
238 	unsigned char i;	/* Loop Control */
239 
240 	/* bit position to send, start with most significant bit */
241 	bitpos = 0x80;
242 
243 	/* Send 8 bits to software SPI */
244 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
245 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
246 
247 		if (n & bitpos)
248 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
249 		else
250 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
251 		udelay (10);
252 
253 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
254 		udelay (10);
255 
256 		bitpos >>= 1;	/* Shift for next bit position */
257 	}
258 }
259 
260 /* ------------------------------------------------------------------------- */
261 
262 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
263 static unsigned char soft_spi_read (void)
264 {
265 	volatile immap_t *immap = (immap_t *) CFG_IMMR;
266 
267 	unsigned char spi_byte = 0;	/* Return value, assume success */
268 	unsigned char bitpos;	/* bit position to receive */
269 	unsigned char i;	/* Loop Control */
270 
271 	/* bit position to receive, start with most significant bit */
272 	bitpos = 0x80;
273 
274 	/* Read 8 bits here */
275 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
276 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
277 		udelay (10);
278 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
279 			spi_byte |= bitpos;	/* Set data accordingly */
280 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
281 		udelay (10);
282 		bitpos >>= 1;	/* Shift for next bit position */
283 	}
284 
285 	return spi_byte;	/* Return the byte read */
286 }
287 
288 /* ------------------------------------------------------------------------- */
289 
290 void rtc_reset (void)
291 {
292 	return;			/* nothing to do */
293 }
294 
295 #else  /* not CONFIG_SXNI855T */
296 /* ************************************************************************* */
297 
298 static unsigned char rtc_read (unsigned char reg);
299 static void rtc_write (unsigned char reg, unsigned char val);
300 
301 static struct spi_slave *slave;
302 
303 /* read clock time from DS1306 and return it in *tmp */
304 int rtc_get (struct rtc_time *tmp)
305 {
306 	unsigned char sec, min, hour, mday, wday, mon, year;
307 
308 	/*
309 	 * Assuming Vcc = 2.0V (lowest speed)
310 	 *
311 	 * REVISIT: If we add an rtc_init() function we can do this
312 	 * step just once.
313 	 */
314 	if (!slave) {
315 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
316 				SPI_MODE_3 | SPI_CS_HIGH);
317 		if (!slave)
318 			return;
319 	}
320 
321 	if (spi_claim_bus(slave))
322 		return;
323 
324 	sec = rtc_read (RTC_SECONDS);
325 	min = rtc_read (RTC_MINUTES);
326 	hour = rtc_read (RTC_HOURS);
327 	mday = rtc_read (RTC_DATE_OF_MONTH);
328 	wday = rtc_read (RTC_DAY_OF_WEEK);
329 	mon = rtc_read (RTC_MONTH);
330 	year = rtc_read (RTC_YEAR);
331 
332 	spi_release_bus(slave);
333 
334 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
335 	       "hr: %02x min: %02x sec: %02x\n",
336 	       year, mon, mday, wday, hour, min, sec);
337 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
338 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
339 	       rtc_read (RTC_HOURS_ALARM0),
340 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
341 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
342 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
343 	       rtc_read (RTC_HOURS_ALARM1),
344 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
345 
346 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
347 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
348 
349 	/* convert Hours */
350 	tmp->tm_hour = (hour & 0x40)
351 		? ((hour & 0x20)	/* 12 hour mode */
352 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
353 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
354 		)
355 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
356 
357 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
358 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
359 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
360 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
361 	tmp->tm_yday = 0;
362 	tmp->tm_isdst = 0;
363 
364 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
365 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
366 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
367 
368 	return 0;
369 }
370 
371 /* ------------------------------------------------------------------------- */
372 
373 /* set clock time from *tmp in DS1306 RTC */
374 void rtc_set (struct rtc_time *tmp)
375 {
376 	/* Assuming Vcc = 2.0V (lowest speed) */
377 	if (!slave) {
378 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
379 				SPI_MODE_3 | SPI_CS_HIGH);
380 		if (!slave)
381 			return;
382 	}
383 
384 	if (spi_claim_bus(slave))
385 		return;
386 
387 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
388 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
389 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
390 
391 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
392 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
393 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
394 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
395 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
396 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
397 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
398 
399 	spi_release_bus(slave);
400 }
401 
402 /* ------------------------------------------------------------------------- */
403 
404 /* reset the DS1306 */
405 void rtc_reset (void)
406 {
407 	/* Assuming Vcc = 2.0V (lowest speed) */
408 	if (!slave) {
409 		slave = spi_setup_slave(0, CFG_SPI_RTC_DEVID, 600000,
410 				SPI_MODE_3 | SPI_CS_HIGH);
411 		if (!slave)
412 			return;
413 	}
414 
415 	if (spi_claim_bus(slave))
416 		return;
417 
418 	/* clear the control register */
419 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
420 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
421 
422 	/* reset all alarms */
423 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
424 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
425 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
426 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
427 	rtc_write (RTC_HOURS_ALARM0, 0x00);
428 	rtc_write (RTC_HOURS_ALARM1, 0x00);
429 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
430 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
431 
432 	spi_release_bus(slave);
433 }
434 
435 /* ------------------------------------------------------------------------- */
436 
437 static unsigned char rtc_read (unsigned char reg)
438 {
439 	int ret;
440 
441 	ret = spi_w8r8(slave, reg);
442 	return ret < 0 ? 0 : ret;
443 }
444 
445 /* ------------------------------------------------------------------------- */
446 
447 static void rtc_write (unsigned char reg, unsigned char val)
448 {
449 	unsigned char dout[2];	/* SPI Output Data Bytes */
450 	unsigned char din[2];	/* SPI Input Data Bytes */
451 
452 	dout[0] = 0x80 | reg;
453 	dout[1] = val;
454 
455 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
456 }
457 
458 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
459 
460 /* ------------------------------------------------------------------------- */
461 
462 static unsigned char bcd2bin (unsigned char n)
463 {
464 	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
465 }
466 
467 /* ------------------------------------------------------------------------- */
468 
469 static unsigned int bin2bcd (unsigned int n)
470 {
471 	return (((n / 10) << 4) | (n % 10));
472 }
473 /* ------------------------------------------------------------------------- */
474 
475 #endif
476