xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision 90c08fa0)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2002 SIXNET, dge@sixnetio.com.
4  *
5  * (C) Copyright 2004, Li-Pro.Net <www.li-pro.net>
6  * Stephan Linz <linz@li-pro.net>
7  */
8 
9 /*
10  * Date & Time support for DS1306 RTC using SPI:
11  *
12  *    - SXNI855T:    it uses its own soft SPI here in this file
13  *    - all other:   use the external spi_xfer() function
14  *                   (see include/spi.h)
15  */
16 
17 #include <common.h>
18 #include <command.h>
19 #include <rtc.h>
20 #include <spi.h>
21 
22 #if defined(CONFIG_CMD_DATE)
23 
24 #define	RTC_SECONDS		0x00
25 #define	RTC_MINUTES		0x01
26 #define	RTC_HOURS		0x02
27 #define	RTC_DAY_OF_WEEK		0x03
28 #define	RTC_DATE_OF_MONTH	0x04
29 #define	RTC_MONTH		0x05
30 #define	RTC_YEAR		0x06
31 
32 #define	RTC_SECONDS_ALARM0	0x07
33 #define	RTC_MINUTES_ALARM0	0x08
34 #define	RTC_HOURS_ALARM0	0x09
35 #define	RTC_DAY_OF_WEEK_ALARM0	0x0a
36 
37 #define	RTC_SECONDS_ALARM1	0x0b
38 #define	RTC_MINUTES_ALARM1	0x0c
39 #define	RTC_HOURS_ALARM1	0x0d
40 #define	RTC_DAY_OF_WEEK_ALARM1	0x0e
41 
42 #define	RTC_CONTROL		0x0f
43 #define	RTC_STATUS		0x10
44 #define	RTC_TRICKLE_CHARGER	0x11
45 
46 #define	RTC_USER_RAM_BASE	0x20
47 
48 /* ************************************************************************* */
49 #ifdef CONFIG_SXNI855T		/* !!! SHOULD BE CHANGED TO NEW CODE !!! */
50 
51 static void soft_spi_send (unsigned char n);
52 static unsigned char soft_spi_read (void);
53 static void init_spi (void);
54 
55 /*-----------------------------------------------------------------------
56  * Definitions
57  */
58 
59 #define	PB_SPISCK	0x00000002	/* PB 30 */
60 #define PB_SPIMOSI	0x00000004	/* PB 29 */
61 #define PB_SPIMISO	0x00000008	/* PB 28 */
62 #define PB_SPI_CE	0x00010000	/* PB 15 */
63 
64 /* ------------------------------------------------------------------------- */
65 
66 /* read clock time from DS1306 and return it in *tmp */
67 int rtc_get (struct rtc_time *tmp)
68 {
69 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
70 	unsigned char spi_byte;	/* Data Byte */
71 
72 	init_spi ();		/* set port B for software SPI */
73 
74 	/* Now we can enable the DS1306 RTC */
75 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
76 	udelay (10);
77 
78 	/* Shift out the address (0) of the time in the Clock Chip */
79 	soft_spi_send (0);
80 
81 	/* Put the clock readings into the rtc_time structure */
82 	tmp->tm_sec = bcd2bin (soft_spi_read ());	/* Read seconds */
83 	tmp->tm_min = bcd2bin (soft_spi_read ());	/* Read minutes */
84 
85 	/* Hours are trickier */
86 	spi_byte = soft_spi_read ();	/* Read Hours into temporary value */
87 	if (spi_byte & 0x40) {
88 		/* 12 hour mode bit is set (time is in 1-12 format) */
89 		if (spi_byte & 0x20) {
90 			/* since PM we add 11 to get 0-23 for hours */
91 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
92 		} else {
93 			/* since AM we subtract 1 to get 0-23 for hours */
94 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
95 		}
96 	} else {
97 		/* Otherwise, 0-23 hour format */
98 		tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
99 	}
100 
101 	soft_spi_read ();	/* Read and discard Day of week */
102 	tmp->tm_mday = bcd2bin (soft_spi_read ());	/* Read Day of the Month */
103 	tmp->tm_mon = bcd2bin (soft_spi_read ());	/* Read Month */
104 
105 	/* Read Year and convert to this century */
106 	tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
107 
108 	/* Now we can disable the DS1306 RTC */
109 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
110 	udelay (10);
111 
112 	rtc_calc_weekday(tmp);	/* Determine the day of week */
113 
114 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
115 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
116 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
117 
118 	return 0;
119 }
120 
121 /* ------------------------------------------------------------------------- */
122 
123 /* set clock time in DS1306 RTC and in MPC8xx RTC */
124 int rtc_set (struct rtc_time *tmp)
125 {
126 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
127 
128 	init_spi ();		/* set port B for software SPI */
129 
130 	/* Now we can enable the DS1306 RTC */
131 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
132 	udelay (10);
133 
134 	/* First disable write protect in the clock chip control register */
135 	soft_spi_send (0x8F);	/* send address of the control register */
136 	soft_spi_send (0x00);	/* send control register contents */
137 
138 	/* Now disable the DS1306 to terminate the write */
139 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
140 	udelay (10);
141 
142 	/* Now enable the DS1306 to initiate a new write */
143 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
144 	udelay (10);
145 
146 	/* Next, send the address of the clock time write registers */
147 	soft_spi_send (0x80);	/* send address of the first time register */
148 
149 	/* Use Burst Mode to send all of the time data to the clock */
150 	bin2bcd (tmp->tm_sec);
151 	soft_spi_send (bin2bcd (tmp->tm_sec));	/* Send Seconds */
152 	soft_spi_send (bin2bcd (tmp->tm_min));	/* Send Minutes */
153 	soft_spi_send (bin2bcd (tmp->tm_hour));	/* Send Hour */
154 	soft_spi_send (bin2bcd (tmp->tm_wday));	/* Send Day of the Week */
155 	soft_spi_send (bin2bcd (tmp->tm_mday));	/* Send Day of Month */
156 	soft_spi_send (bin2bcd (tmp->tm_mon));	/* Send Month */
157 	soft_spi_send (bin2bcd (tmp->tm_year - 2000));	/* Send Year */
158 
159 	/* Now we can disable the Clock chip to terminate the burst write */
160 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
161 	udelay (10);
162 
163 	/* Now we can enable the Clock chip to initiate a new write */
164 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
165 	udelay (10);
166 
167 	/* First we Enable write protect in the clock chip control register */
168 	soft_spi_send (0x8F);	/* send address of the control register */
169 	soft_spi_send (0x40);	/* send out Control Register contents */
170 
171 	/* Now disable the DS1306 */
172 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/*  Disable DS1306 Chip */
173 	udelay (10);
174 
175 	/* Set standard MPC8xx clock to the same time so Linux will
176 	 * see the time even if it doesn't have a DS1306 clock driver.
177 	 * This helps with experimenting with standard kernels.
178 	 */
179 	{
180 		ulong tim;
181 
182 		tim = rtc_mktime(tmp);
183 
184 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
185 		immap->im_sit.sit_rtc = tim;
186 	}
187 
188 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
189 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
190 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
191 
192 	return 0;
193 }
194 
195 /* ------------------------------------------------------------------------- */
196 
197 /* Initialize Port B for software SPI */
198 static void init_spi (void)
199 {
200 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
201 
202 	/* Force output pins to begin at logic 0 */
203 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
204 
205 	/* Set these 3 signals as outputs */
206 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
207 
208 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
209 	udelay (10);
210 }
211 
212 /* ------------------------------------------------------------------------- */
213 
214 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
215 static void soft_spi_send (unsigned char n)
216 {
217 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
218 	unsigned char bitpos;	/* bit position to receive */
219 	unsigned char i;	/* Loop Control */
220 
221 	/* bit position to send, start with most significant bit */
222 	bitpos = 0x80;
223 
224 	/* Send 8 bits to software SPI */
225 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
226 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
227 
228 		if (n & bitpos)
229 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
230 		else
231 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
232 		udelay (10);
233 
234 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
235 		udelay (10);
236 
237 		bitpos >>= 1;	/* Shift for next bit position */
238 	}
239 }
240 
241 /* ------------------------------------------------------------------------- */
242 
243 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
244 static unsigned char soft_spi_read (void)
245 {
246 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
247 
248 	unsigned char spi_byte = 0;	/* Return value, assume success */
249 	unsigned char bitpos;	/* bit position to receive */
250 	unsigned char i;	/* Loop Control */
251 
252 	/* bit position to receive, start with most significant bit */
253 	bitpos = 0x80;
254 
255 	/* Read 8 bits here */
256 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
257 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
258 		udelay (10);
259 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
260 			spi_byte |= bitpos;	/* Set data accordingly */
261 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
262 		udelay (10);
263 		bitpos >>= 1;	/* Shift for next bit position */
264 	}
265 
266 	return spi_byte;	/* Return the byte read */
267 }
268 
269 /* ------------------------------------------------------------------------- */
270 
271 void rtc_reset (void)
272 {
273 	return;			/* nothing to do */
274 }
275 
276 #else  /* not CONFIG_SXNI855T */
277 /* ************************************************************************* */
278 
279 static unsigned char rtc_read (unsigned char reg);
280 static void rtc_write (unsigned char reg, unsigned char val);
281 
282 static struct spi_slave *slave;
283 
284 /* read clock time from DS1306 and return it in *tmp */
285 int rtc_get (struct rtc_time *tmp)
286 {
287 	unsigned char sec, min, hour, mday, wday, mon, year;
288 
289 	/*
290 	 * Assuming Vcc = 2.0V (lowest speed)
291 	 *
292 	 * REVISIT: If we add an rtc_init() function we can do this
293 	 * step just once.
294 	 */
295 	if (!slave) {
296 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
297 				SPI_MODE_3 | SPI_CS_HIGH);
298 		if (!slave)
299 			return;
300 	}
301 
302 	if (spi_claim_bus(slave))
303 		return;
304 
305 	sec = rtc_read (RTC_SECONDS);
306 	min = rtc_read (RTC_MINUTES);
307 	hour = rtc_read (RTC_HOURS);
308 	mday = rtc_read (RTC_DATE_OF_MONTH);
309 	wday = rtc_read (RTC_DAY_OF_WEEK);
310 	mon = rtc_read (RTC_MONTH);
311 	year = rtc_read (RTC_YEAR);
312 
313 	spi_release_bus(slave);
314 
315 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
316 	       "hr: %02x min: %02x sec: %02x\n",
317 	       year, mon, mday, wday, hour, min, sec);
318 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
319 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
320 	       rtc_read (RTC_HOURS_ALARM0),
321 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
322 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
323 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
324 	       rtc_read (RTC_HOURS_ALARM1),
325 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
326 
327 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
328 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
329 
330 	/* convert Hours */
331 	tmp->tm_hour = (hour & 0x40)
332 		? ((hour & 0x20)	/* 12 hour mode */
333 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
334 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
335 		)
336 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
337 
338 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
339 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
340 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
341 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
342 	tmp->tm_yday = 0;
343 	tmp->tm_isdst = 0;
344 
345 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
346 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
347 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
348 
349 	return 0;
350 }
351 
352 /* ------------------------------------------------------------------------- */
353 
354 /* set clock time from *tmp in DS1306 RTC */
355 int rtc_set (struct rtc_time *tmp)
356 {
357 	/* Assuming Vcc = 2.0V (lowest speed) */
358 	if (!slave) {
359 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
360 				SPI_MODE_3 | SPI_CS_HIGH);
361 		if (!slave)
362 			return;
363 	}
364 
365 	if (spi_claim_bus(slave))
366 		return;
367 
368 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
369 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
370 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
371 
372 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
373 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
374 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
375 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
376 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
377 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
378 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
379 
380 	spi_release_bus(slave);
381 }
382 
383 /* ------------------------------------------------------------------------- */
384 
385 /* reset the DS1306 */
386 void rtc_reset (void)
387 {
388 	/* Assuming Vcc = 2.0V (lowest speed) */
389 	if (!slave) {
390 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
391 				SPI_MODE_3 | SPI_CS_HIGH);
392 		if (!slave)
393 			return;
394 	}
395 
396 	if (spi_claim_bus(slave))
397 		return;
398 
399 	/* clear the control register */
400 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
401 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
402 
403 	/* reset all alarms */
404 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
405 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
406 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
407 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
408 	rtc_write (RTC_HOURS_ALARM0, 0x00);
409 	rtc_write (RTC_HOURS_ALARM1, 0x00);
410 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
411 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
412 
413 	spi_release_bus(slave);
414 }
415 
416 /* ------------------------------------------------------------------------- */
417 
418 static unsigned char rtc_read (unsigned char reg)
419 {
420 	int ret;
421 
422 	ret = spi_w8r8(slave, reg);
423 	return ret < 0 ? 0 : ret;
424 }
425 
426 /* ------------------------------------------------------------------------- */
427 
428 static void rtc_write (unsigned char reg, unsigned char val)
429 {
430 	unsigned char dout[2];	/* SPI Output Data Bytes */
431 	unsigned char din[2];	/* SPI Input Data Bytes */
432 
433 	dout[0] = 0x80 | reg;
434 	dout[1] = val;
435 
436 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
437 }
438 
439 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
440 
441 #endif
442