xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision 743d7592)
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  * SPDX-License-Identifier:	GPL-2.0+
8  */
9 
10 /*
11  * Date & Time support for DS1306 RTC using SPI:
12  *
13  *    - SXNI855T:    it uses its own soft SPI here in this file
14  *    - all other:   use the external spi_xfer() function
15  *                   (see include/spi.h)
16  */
17 
18 #include <common.h>
19 #include <command.h>
20 #include <rtc.h>
21 #include <spi.h>
22 
23 #if defined(CONFIG_CMD_DATE)
24 
25 #define	RTC_SECONDS		0x00
26 #define	RTC_MINUTES		0x01
27 #define	RTC_HOURS		0x02
28 #define	RTC_DAY_OF_WEEK		0x03
29 #define	RTC_DATE_OF_MONTH	0x04
30 #define	RTC_MONTH		0x05
31 #define	RTC_YEAR		0x06
32 
33 #define	RTC_SECONDS_ALARM0	0x07
34 #define	RTC_MINUTES_ALARM0	0x08
35 #define	RTC_HOURS_ALARM0	0x09
36 #define	RTC_DAY_OF_WEEK_ALARM0	0x0a
37 
38 #define	RTC_SECONDS_ALARM1	0x0b
39 #define	RTC_MINUTES_ALARM1	0x0c
40 #define	RTC_HOURS_ALARM1	0x0d
41 #define	RTC_DAY_OF_WEEK_ALARM1	0x0e
42 
43 #define	RTC_CONTROL		0x0f
44 #define	RTC_STATUS		0x10
45 #define	RTC_TRICKLE_CHARGER	0x11
46 
47 #define	RTC_USER_RAM_BASE	0x20
48 
49 /* ************************************************************************* */
50 #ifdef CONFIG_SXNI855T		/* !!! SHOULD BE CHANGED TO NEW CODE !!! */
51 
52 static void soft_spi_send (unsigned char n);
53 static unsigned char soft_spi_read (void);
54 static void init_spi (void);
55 
56 /*-----------------------------------------------------------------------
57  * Definitions
58  */
59 
60 #define	PB_SPISCK	0x00000002	/* PB 30 */
61 #define PB_SPIMOSI	0x00000004	/* PB 29 */
62 #define PB_SPIMISO	0x00000008	/* PB 28 */
63 #define PB_SPI_CE	0x00010000	/* PB 15 */
64 
65 /* ------------------------------------------------------------------------- */
66 
67 /* read clock time from DS1306 and return it in *tmp */
68 int rtc_get (struct rtc_time *tmp)
69 {
70 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
71 	unsigned char spi_byte;	/* Data Byte */
72 
73 	init_spi ();		/* set port B for software SPI */
74 
75 	/* Now we can enable the DS1306 RTC */
76 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
77 	udelay (10);
78 
79 	/* Shift out the address (0) of the time in the Clock Chip */
80 	soft_spi_send (0);
81 
82 	/* Put the clock readings into the rtc_time structure */
83 	tmp->tm_sec = bcd2bin (soft_spi_read ());	/* Read seconds */
84 	tmp->tm_min = bcd2bin (soft_spi_read ());	/* Read minutes */
85 
86 	/* Hours are trickier */
87 	spi_byte = soft_spi_read ();	/* Read Hours into temporary value */
88 	if (spi_byte & 0x40) {
89 		/* 12 hour mode bit is set (time is in 1-12 format) */
90 		if (spi_byte & 0x20) {
91 			/* since PM we add 11 to get 0-23 for hours */
92 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
93 		} else {
94 			/* since AM we subtract 1 to get 0-23 for hours */
95 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
96 		}
97 	} else {
98 		/* Otherwise, 0-23 hour format */
99 		tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
100 	}
101 
102 	soft_spi_read ();	/* Read and discard Day of week */
103 	tmp->tm_mday = bcd2bin (soft_spi_read ());	/* Read Day of the Month */
104 	tmp->tm_mon = bcd2bin (soft_spi_read ());	/* Read Month */
105 
106 	/* Read Year and convert to this century */
107 	tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
108 
109 	/* Now we can disable the DS1306 RTC */
110 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
111 	udelay (10);
112 
113 	rtc_calc_weekday(tmp);	/* Determine the day of week */
114 
115 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
116 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
117 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
118 
119 	return 0;
120 }
121 
122 /* ------------------------------------------------------------------------- */
123 
124 /* set clock time in DS1306 RTC and in MPC8xx RTC */
125 int rtc_set (struct rtc_time *tmp)
126 {
127 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
128 
129 	init_spi ();		/* set port B for software SPI */
130 
131 	/* Now we can enable the DS1306 RTC */
132 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
133 	udelay (10);
134 
135 	/* First disable write protect in the clock chip control register */
136 	soft_spi_send (0x8F);	/* send address of the control register */
137 	soft_spi_send (0x00);	/* send control register contents */
138 
139 	/* Now disable the DS1306 to terminate the write */
140 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
141 	udelay (10);
142 
143 	/* Now enable the DS1306 to initiate a new write */
144 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
145 	udelay (10);
146 
147 	/* Next, send the address of the clock time write registers */
148 	soft_spi_send (0x80);	/* send address of the first time register */
149 
150 	/* Use Burst Mode to send all of the time data to the clock */
151 	bin2bcd (tmp->tm_sec);
152 	soft_spi_send (bin2bcd (tmp->tm_sec));	/* Send Seconds */
153 	soft_spi_send (bin2bcd (tmp->tm_min));	/* Send Minutes */
154 	soft_spi_send (bin2bcd (tmp->tm_hour));	/* Send Hour */
155 	soft_spi_send (bin2bcd (tmp->tm_wday));	/* Send Day of the Week */
156 	soft_spi_send (bin2bcd (tmp->tm_mday));	/* Send Day of Month */
157 	soft_spi_send (bin2bcd (tmp->tm_mon));	/* Send Month */
158 	soft_spi_send (bin2bcd (tmp->tm_year - 2000));	/* Send Year */
159 
160 	/* Now we can disable the Clock chip to terminate the burst write */
161 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
162 	udelay (10);
163 
164 	/* Now we can enable the Clock chip to initiate a new write */
165 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
166 	udelay (10);
167 
168 	/* First we Enable write protect in the clock chip control register */
169 	soft_spi_send (0x8F);	/* send address of the control register */
170 	soft_spi_send (0x40);	/* send out Control Register contents */
171 
172 	/* Now disable the DS1306 */
173 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/*  Disable DS1306 Chip */
174 	udelay (10);
175 
176 	/* Set standard MPC8xx clock to the same time so Linux will
177 	 * see the time even if it doesn't have a DS1306 clock driver.
178 	 * This helps with experimenting with standard kernels.
179 	 */
180 	{
181 		ulong tim;
182 
183 		tim = rtc_mktime(tmp);
184 
185 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
186 		immap->im_sit.sit_rtc = tim;
187 	}
188 
189 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
190 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
191 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
192 
193 	return 0;
194 }
195 
196 /* ------------------------------------------------------------------------- */
197 
198 /* Initialize Port B for software SPI */
199 static void init_spi (void)
200 {
201 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
202 
203 	/* Force output pins to begin at logic 0 */
204 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
205 
206 	/* Set these 3 signals as outputs */
207 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
208 
209 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
210 	udelay (10);
211 }
212 
213 /* ------------------------------------------------------------------------- */
214 
215 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
216 static void soft_spi_send (unsigned char n)
217 {
218 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
219 	unsigned char bitpos;	/* bit position to receive */
220 	unsigned char i;	/* Loop Control */
221 
222 	/* bit position to send, start with most significant bit */
223 	bitpos = 0x80;
224 
225 	/* Send 8 bits to software SPI */
226 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
227 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
228 
229 		if (n & bitpos)
230 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
231 		else
232 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
233 		udelay (10);
234 
235 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
236 		udelay (10);
237 
238 		bitpos >>= 1;	/* Shift for next bit position */
239 	}
240 }
241 
242 /* ------------------------------------------------------------------------- */
243 
244 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
245 static unsigned char soft_spi_read (void)
246 {
247 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
248 
249 	unsigned char spi_byte = 0;	/* Return value, assume success */
250 	unsigned char bitpos;	/* bit position to receive */
251 	unsigned char i;	/* Loop Control */
252 
253 	/* bit position to receive, start with most significant bit */
254 	bitpos = 0x80;
255 
256 	/* Read 8 bits here */
257 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
258 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
259 		udelay (10);
260 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
261 			spi_byte |= bitpos;	/* Set data accordingly */
262 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
263 		udelay (10);
264 		bitpos >>= 1;	/* Shift for next bit position */
265 	}
266 
267 	return spi_byte;	/* Return the byte read */
268 }
269 
270 /* ------------------------------------------------------------------------- */
271 
272 void rtc_reset (void)
273 {
274 	return;			/* nothing to do */
275 }
276 
277 #else  /* not CONFIG_SXNI855T */
278 /* ************************************************************************* */
279 
280 static unsigned char rtc_read (unsigned char reg);
281 static void rtc_write (unsigned char reg, unsigned char val);
282 
283 static struct spi_slave *slave;
284 
285 /* read clock time from DS1306 and return it in *tmp */
286 int rtc_get (struct rtc_time *tmp)
287 {
288 	unsigned char sec, min, hour, mday, wday, mon, year;
289 
290 	/*
291 	 * Assuming Vcc = 2.0V (lowest speed)
292 	 *
293 	 * REVISIT: If we add an rtc_init() function we can do this
294 	 * step just once.
295 	 */
296 	if (!slave) {
297 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
298 				SPI_MODE_3 | SPI_CS_HIGH);
299 		if (!slave)
300 			return;
301 	}
302 
303 	if (spi_claim_bus(slave))
304 		return;
305 
306 	sec = rtc_read (RTC_SECONDS);
307 	min = rtc_read (RTC_MINUTES);
308 	hour = rtc_read (RTC_HOURS);
309 	mday = rtc_read (RTC_DATE_OF_MONTH);
310 	wday = rtc_read (RTC_DAY_OF_WEEK);
311 	mon = rtc_read (RTC_MONTH);
312 	year = rtc_read (RTC_YEAR);
313 
314 	spi_release_bus(slave);
315 
316 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
317 	       "hr: %02x min: %02x sec: %02x\n",
318 	       year, mon, mday, wday, hour, min, sec);
319 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
320 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
321 	       rtc_read (RTC_HOURS_ALARM0),
322 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
323 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
324 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
325 	       rtc_read (RTC_HOURS_ALARM1),
326 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
327 
328 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
329 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
330 
331 	/* convert Hours */
332 	tmp->tm_hour = (hour & 0x40)
333 		? ((hour & 0x20)	/* 12 hour mode */
334 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
335 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
336 		)
337 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
338 
339 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
340 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
341 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
342 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
343 	tmp->tm_yday = 0;
344 	tmp->tm_isdst = 0;
345 
346 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
347 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
348 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
349 
350 	return 0;
351 }
352 
353 /* ------------------------------------------------------------------------- */
354 
355 /* set clock time from *tmp in DS1306 RTC */
356 int rtc_set (struct rtc_time *tmp)
357 {
358 	/* Assuming Vcc = 2.0V (lowest speed) */
359 	if (!slave) {
360 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
361 				SPI_MODE_3 | SPI_CS_HIGH);
362 		if (!slave)
363 			return;
364 	}
365 
366 	if (spi_claim_bus(slave))
367 		return;
368 
369 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
370 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
371 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
372 
373 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
374 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
375 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
376 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
377 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
378 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
379 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
380 
381 	spi_release_bus(slave);
382 }
383 
384 /* ------------------------------------------------------------------------- */
385 
386 /* reset the DS1306 */
387 void rtc_reset (void)
388 {
389 	/* Assuming Vcc = 2.0V (lowest speed) */
390 	if (!slave) {
391 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
392 				SPI_MODE_3 | SPI_CS_HIGH);
393 		if (!slave)
394 			return;
395 	}
396 
397 	if (spi_claim_bus(slave))
398 		return;
399 
400 	/* clear the control register */
401 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
402 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
403 
404 	/* reset all alarms */
405 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
406 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
407 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
408 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
409 	rtc_write (RTC_HOURS_ALARM0, 0x00);
410 	rtc_write (RTC_HOURS_ALARM1, 0x00);
411 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
412 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
413 
414 	spi_release_bus(slave);
415 }
416 
417 /* ------------------------------------------------------------------------- */
418 
419 static unsigned char rtc_read (unsigned char reg)
420 {
421 	int ret;
422 
423 	ret = spi_w8r8(slave, reg);
424 	return ret < 0 ? 0 : ret;
425 }
426 
427 /* ------------------------------------------------------------------------- */
428 
429 static void rtc_write (unsigned char reg, unsigned char val)
430 {
431 	unsigned char dout[2];	/* SPI Output Data Bytes */
432 	unsigned char din[2];	/* SPI Input Data Bytes */
433 
434 	dout[0] = 0x80 | reg;
435 	dout[1] = val;
436 
437 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
438 }
439 
440 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
441 
442 #endif
443