xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision 6d8962e8)
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 /* ************************************************************************* */
66 #ifdef CONFIG_SXNI855T		/* !!! SHOULD BE CHANGED TO NEW CODE !!! */
67 
68 static void soft_spi_send (unsigned char n);
69 static unsigned char soft_spi_read (void);
70 static void init_spi (void);
71 
72 /*-----------------------------------------------------------------------
73  * Definitions
74  */
75 
76 #define	PB_SPISCK	0x00000002	/* PB 30 */
77 #define PB_SPIMOSI	0x00000004	/* PB 29 */
78 #define PB_SPIMISO	0x00000008	/* PB 28 */
79 #define PB_SPI_CE	0x00010000	/* PB 15 */
80 
81 /* ------------------------------------------------------------------------- */
82 
83 /* read clock time from DS1306 and return it in *tmp */
84 int rtc_get (struct rtc_time *tmp)
85 {
86 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
87 	unsigned char spi_byte;	/* Data Byte */
88 
89 	init_spi ();		/* set port B for software SPI */
90 
91 	/* Now we can enable the DS1306 RTC */
92 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
93 	udelay (10);
94 
95 	/* Shift out the address (0) of the time in the Clock Chip */
96 	soft_spi_send (0);
97 
98 	/* Put the clock readings into the rtc_time structure */
99 	tmp->tm_sec = bcd2bin (soft_spi_read ());	/* Read seconds */
100 	tmp->tm_min = bcd2bin (soft_spi_read ());	/* Read minutes */
101 
102 	/* Hours are trickier */
103 	spi_byte = soft_spi_read ();	/* Read Hours into temporary value */
104 	if (spi_byte & 0x40) {
105 		/* 12 hour mode bit is set (time is in 1-12 format) */
106 		if (spi_byte & 0x20) {
107 			/* since PM we add 11 to get 0-23 for hours */
108 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
109 		} else {
110 			/* since AM we subtract 1 to get 0-23 for hours */
111 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
112 		}
113 	} else {
114 		/* Otherwise, 0-23 hour format */
115 		tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
116 	}
117 
118 	soft_spi_read ();	/* Read and discard Day of week */
119 	tmp->tm_mday = bcd2bin (soft_spi_read ());	/* Read Day of the Month */
120 	tmp->tm_mon = bcd2bin (soft_spi_read ());	/* Read Month */
121 
122 	/* Read Year and convert to this century */
123 	tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
124 
125 	/* Now we can disable the DS1306 RTC */
126 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
127 	udelay (10);
128 
129 	GregorianDay (tmp);	/* Determine the day of week */
130 
131 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
132 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
133 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
134 
135 	return 0;
136 }
137 
138 /* ------------------------------------------------------------------------- */
139 
140 /* set clock time in DS1306 RTC and in MPC8xx RTC */
141 int rtc_set (struct rtc_time *tmp)
142 {
143 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
144 
145 	init_spi ();		/* set port B for software SPI */
146 
147 	/* Now we can enable the DS1306 RTC */
148 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
149 	udelay (10);
150 
151 	/* First disable write protect in the clock chip control register */
152 	soft_spi_send (0x8F);	/* send address of the control register */
153 	soft_spi_send (0x00);	/* send control register contents */
154 
155 	/* Now disable the DS1306 to terminate the write */
156 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
157 	udelay (10);
158 
159 	/* Now enable the DS1306 to initiate a new write */
160 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
161 	udelay (10);
162 
163 	/* Next, send the address of the clock time write registers */
164 	soft_spi_send (0x80);	/* send address of the first time register */
165 
166 	/* Use Burst Mode to send all of the time data to the clock */
167 	bin2bcd (tmp->tm_sec);
168 	soft_spi_send (bin2bcd (tmp->tm_sec));	/* Send Seconds */
169 	soft_spi_send (bin2bcd (tmp->tm_min));	/* Send Minutes */
170 	soft_spi_send (bin2bcd (tmp->tm_hour));	/* Send Hour */
171 	soft_spi_send (bin2bcd (tmp->tm_wday));	/* Send Day of the Week */
172 	soft_spi_send (bin2bcd (tmp->tm_mday));	/* Send Day of Month */
173 	soft_spi_send (bin2bcd (tmp->tm_mon));	/* Send Month */
174 	soft_spi_send (bin2bcd (tmp->tm_year - 2000));	/* Send Year */
175 
176 	/* Now we can disable the Clock chip to terminate the burst write */
177 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
178 	udelay (10);
179 
180 	/* Now we can enable the Clock chip to initiate a new write */
181 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
182 	udelay (10);
183 
184 	/* First we Enable write protect in the clock chip control register */
185 	soft_spi_send (0x8F);	/* send address of the control register */
186 	soft_spi_send (0x40);	/* send out Control Register contents */
187 
188 	/* Now disable the DS1306 */
189 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/*  Disable DS1306 Chip */
190 	udelay (10);
191 
192 	/* Set standard MPC8xx clock to the same time so Linux will
193 	 * see the time even if it doesn't have a DS1306 clock driver.
194 	 * This helps with experimenting with standard kernels.
195 	 */
196 	{
197 		ulong tim;
198 
199 		tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
200 			      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
201 
202 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
203 		immap->im_sit.sit_rtc = tim;
204 	}
205 
206 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
207 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
208 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
209 
210 	return 0;
211 }
212 
213 /* ------------------------------------------------------------------------- */
214 
215 /* Initialize Port B for software SPI */
216 static void init_spi (void)
217 {
218 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
219 
220 	/* Force output pins to begin at logic 0 */
221 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
222 
223 	/* Set these 3 signals as outputs */
224 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
225 
226 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
227 	udelay (10);
228 }
229 
230 /* ------------------------------------------------------------------------- */
231 
232 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
233 static void soft_spi_send (unsigned char n)
234 {
235 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
236 	unsigned char bitpos;	/* bit position to receive */
237 	unsigned char i;	/* Loop Control */
238 
239 	/* bit position to send, start with most significant bit */
240 	bitpos = 0x80;
241 
242 	/* Send 8 bits to software SPI */
243 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
244 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
245 
246 		if (n & bitpos)
247 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
248 		else
249 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
250 		udelay (10);
251 
252 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
253 		udelay (10);
254 
255 		bitpos >>= 1;	/* Shift for next bit position */
256 	}
257 }
258 
259 /* ------------------------------------------------------------------------- */
260 
261 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
262 static unsigned char soft_spi_read (void)
263 {
264 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
265 
266 	unsigned char spi_byte = 0;	/* Return value, assume success */
267 	unsigned char bitpos;	/* bit position to receive */
268 	unsigned char i;	/* Loop Control */
269 
270 	/* bit position to receive, start with most significant bit */
271 	bitpos = 0x80;
272 
273 	/* Read 8 bits here */
274 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
275 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
276 		udelay (10);
277 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
278 			spi_byte |= bitpos;	/* Set data accordingly */
279 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
280 		udelay (10);
281 		bitpos >>= 1;	/* Shift for next bit position */
282 	}
283 
284 	return spi_byte;	/* Return the byte read */
285 }
286 
287 /* ------------------------------------------------------------------------- */
288 
289 void rtc_reset (void)
290 {
291 	return;			/* nothing to do */
292 }
293 
294 #else  /* not CONFIG_SXNI855T */
295 /* ************************************************************************* */
296 
297 static unsigned char rtc_read (unsigned char reg);
298 static void rtc_write (unsigned char reg, unsigned char val);
299 
300 static struct spi_slave *slave;
301 
302 /* read clock time from DS1306 and return it in *tmp */
303 int rtc_get (struct rtc_time *tmp)
304 {
305 	unsigned char sec, min, hour, mday, wday, mon, year;
306 
307 	/*
308 	 * Assuming Vcc = 2.0V (lowest speed)
309 	 *
310 	 * REVISIT: If we add an rtc_init() function we can do this
311 	 * step just once.
312 	 */
313 	if (!slave) {
314 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
315 				SPI_MODE_3 | SPI_CS_HIGH);
316 		if (!slave)
317 			return;
318 	}
319 
320 	if (spi_claim_bus(slave))
321 		return;
322 
323 	sec = rtc_read (RTC_SECONDS);
324 	min = rtc_read (RTC_MINUTES);
325 	hour = rtc_read (RTC_HOURS);
326 	mday = rtc_read (RTC_DATE_OF_MONTH);
327 	wday = rtc_read (RTC_DAY_OF_WEEK);
328 	mon = rtc_read (RTC_MONTH);
329 	year = rtc_read (RTC_YEAR);
330 
331 	spi_release_bus(slave);
332 
333 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
334 	       "hr: %02x min: %02x sec: %02x\n",
335 	       year, mon, mday, wday, hour, min, sec);
336 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
337 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
338 	       rtc_read (RTC_HOURS_ALARM0),
339 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
340 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
341 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
342 	       rtc_read (RTC_HOURS_ALARM1),
343 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
344 
345 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
346 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
347 
348 	/* convert Hours */
349 	tmp->tm_hour = (hour & 0x40)
350 		? ((hour & 0x20)	/* 12 hour mode */
351 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
352 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
353 		)
354 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
355 
356 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
357 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
358 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
359 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
360 	tmp->tm_yday = 0;
361 	tmp->tm_isdst = 0;
362 
363 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
364 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
365 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
366 
367 	return 0;
368 }
369 
370 /* ------------------------------------------------------------------------- */
371 
372 /* set clock time from *tmp in DS1306 RTC */
373 int rtc_set (struct rtc_time *tmp)
374 {
375 	/* Assuming Vcc = 2.0V (lowest speed) */
376 	if (!slave) {
377 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
378 				SPI_MODE_3 | SPI_CS_HIGH);
379 		if (!slave)
380 			return;
381 	}
382 
383 	if (spi_claim_bus(slave))
384 		return;
385 
386 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
387 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
388 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
389 
390 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
391 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
392 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
393 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
394 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
395 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
396 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
397 
398 	spi_release_bus(slave);
399 }
400 
401 /* ------------------------------------------------------------------------- */
402 
403 /* reset the DS1306 */
404 void rtc_reset (void)
405 {
406 	/* Assuming Vcc = 2.0V (lowest speed) */
407 	if (!slave) {
408 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
409 				SPI_MODE_3 | SPI_CS_HIGH);
410 		if (!slave)
411 			return;
412 	}
413 
414 	if (spi_claim_bus(slave))
415 		return;
416 
417 	/* clear the control register */
418 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
419 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
420 
421 	/* reset all alarms */
422 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
423 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
424 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
425 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
426 	rtc_write (RTC_HOURS_ALARM0, 0x00);
427 	rtc_write (RTC_HOURS_ALARM1, 0x00);
428 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
429 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
430 
431 	spi_release_bus(slave);
432 }
433 
434 /* ------------------------------------------------------------------------- */
435 
436 static unsigned char rtc_read (unsigned char reg)
437 {
438 	int ret;
439 
440 	ret = spi_w8r8(slave, reg);
441 	return ret < 0 ? 0 : ret;
442 }
443 
444 /* ------------------------------------------------------------------------- */
445 
446 static void rtc_write (unsigned char reg, unsigned char val)
447 {
448 	unsigned char dout[2];	/* SPI Output Data Bytes */
449 	unsigned char din[2];	/* SPI Input Data Bytes */
450 
451 	dout[0] = 0x80 | reg;
452 	dout[1] = val;
453 
454 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
455 }
456 
457 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
458 
459 #endif
460