xref: /openbmc/u-boot/drivers/rtc/ds1306.c (revision dd1033e4)
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 #define	RTC_SECONDS		0x00
23 #define	RTC_MINUTES		0x01
24 #define	RTC_HOURS		0x02
25 #define	RTC_DAY_OF_WEEK		0x03
26 #define	RTC_DATE_OF_MONTH	0x04
27 #define	RTC_MONTH		0x05
28 #define	RTC_YEAR		0x06
29 
30 #define	RTC_SECONDS_ALARM0	0x07
31 #define	RTC_MINUTES_ALARM0	0x08
32 #define	RTC_HOURS_ALARM0	0x09
33 #define	RTC_DAY_OF_WEEK_ALARM0	0x0a
34 
35 #define	RTC_SECONDS_ALARM1	0x0b
36 #define	RTC_MINUTES_ALARM1	0x0c
37 #define	RTC_HOURS_ALARM1	0x0d
38 #define	RTC_DAY_OF_WEEK_ALARM1	0x0e
39 
40 #define	RTC_CONTROL		0x0f
41 #define	RTC_STATUS		0x10
42 #define	RTC_TRICKLE_CHARGER	0x11
43 
44 #define	RTC_USER_RAM_BASE	0x20
45 
46 /* ************************************************************************* */
47 #ifdef CONFIG_SXNI855T		/* !!! SHOULD BE CHANGED TO NEW CODE !!! */
48 
49 static void soft_spi_send (unsigned char n);
50 static unsigned char soft_spi_read (void);
51 static void init_spi (void);
52 
53 /*-----------------------------------------------------------------------
54  * Definitions
55  */
56 
57 #define	PB_SPISCK	0x00000002	/* PB 30 */
58 #define PB_SPIMOSI	0x00000004	/* PB 29 */
59 #define PB_SPIMISO	0x00000008	/* PB 28 */
60 #define PB_SPI_CE	0x00010000	/* PB 15 */
61 
62 /* ------------------------------------------------------------------------- */
63 
64 /* read clock time from DS1306 and return it in *tmp */
65 int rtc_get (struct rtc_time *tmp)
66 {
67 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
68 	unsigned char spi_byte;	/* Data Byte */
69 
70 	init_spi ();		/* set port B for software SPI */
71 
72 	/* Now we can enable the DS1306 RTC */
73 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
74 	udelay (10);
75 
76 	/* Shift out the address (0) of the time in the Clock Chip */
77 	soft_spi_send (0);
78 
79 	/* Put the clock readings into the rtc_time structure */
80 	tmp->tm_sec = bcd2bin (soft_spi_read ());	/* Read seconds */
81 	tmp->tm_min = bcd2bin (soft_spi_read ());	/* Read minutes */
82 
83 	/* Hours are trickier */
84 	spi_byte = soft_spi_read ();	/* Read Hours into temporary value */
85 	if (spi_byte & 0x40) {
86 		/* 12 hour mode bit is set (time is in 1-12 format) */
87 		if (spi_byte & 0x20) {
88 			/* since PM we add 11 to get 0-23 for hours */
89 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) + 11;
90 		} else {
91 			/* since AM we subtract 1 to get 0-23 for hours */
92 			tmp->tm_hour = (bcd2bin (spi_byte & 0x1F)) - 1;
93 		}
94 	} else {
95 		/* Otherwise, 0-23 hour format */
96 		tmp->tm_hour = (bcd2bin (spi_byte & 0x3F));
97 	}
98 
99 	soft_spi_read ();	/* Read and discard Day of week */
100 	tmp->tm_mday = bcd2bin (soft_spi_read ());	/* Read Day of the Month */
101 	tmp->tm_mon = bcd2bin (soft_spi_read ());	/* Read Month */
102 
103 	/* Read Year and convert to this century */
104 	tmp->tm_year = bcd2bin (soft_spi_read ()) + 2000;
105 
106 	/* Now we can disable the DS1306 RTC */
107 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
108 	udelay (10);
109 
110 	rtc_calc_weekday(tmp);	/* Determine the day of week */
111 
112 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
113 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
114 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
115 
116 	return 0;
117 }
118 
119 /* ------------------------------------------------------------------------- */
120 
121 /* set clock time in DS1306 RTC and in MPC8xx RTC */
122 int rtc_set (struct rtc_time *tmp)
123 {
124 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
125 
126 	init_spi ();		/* set port B for software SPI */
127 
128 	/* Now we can enable the DS1306 RTC */
129 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
130 	udelay (10);
131 
132 	/* First disable write protect in the clock chip control register */
133 	soft_spi_send (0x8F);	/* send address of the control register */
134 	soft_spi_send (0x00);	/* send control register contents */
135 
136 	/* Now disable the DS1306 to terminate the write */
137 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;
138 	udelay (10);
139 
140 	/* Now enable the DS1306 to initiate a new write */
141 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;
142 	udelay (10);
143 
144 	/* Next, send the address of the clock time write registers */
145 	soft_spi_send (0x80);	/* send address of the first time register */
146 
147 	/* Use Burst Mode to send all of the time data to the clock */
148 	bin2bcd (tmp->tm_sec);
149 	soft_spi_send (bin2bcd (tmp->tm_sec));	/* Send Seconds */
150 	soft_spi_send (bin2bcd (tmp->tm_min));	/* Send Minutes */
151 	soft_spi_send (bin2bcd (tmp->tm_hour));	/* Send Hour */
152 	soft_spi_send (bin2bcd (tmp->tm_wday));	/* Send Day of the Week */
153 	soft_spi_send (bin2bcd (tmp->tm_mday));	/* Send Day of Month */
154 	soft_spi_send (bin2bcd (tmp->tm_mon));	/* Send Month */
155 	soft_spi_send (bin2bcd (tmp->tm_year - 2000));	/* Send Year */
156 
157 	/* Now we can disable the Clock chip to terminate the burst write */
158 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/* Disable DS1306 Chip */
159 	udelay (10);
160 
161 	/* Now we can enable the Clock chip to initiate a new write */
162 	immap->im_cpm.cp_pbdat |= PB_SPI_CE;	/* Enable DS1306 Chip */
163 	udelay (10);
164 
165 	/* First we Enable write protect in the clock chip control register */
166 	soft_spi_send (0x8F);	/* send address of the control register */
167 	soft_spi_send (0x40);	/* send out Control Register contents */
168 
169 	/* Now disable the DS1306 */
170 	immap->im_cpm.cp_pbdat &= ~PB_SPI_CE;	/*  Disable DS1306 Chip */
171 	udelay (10);
172 
173 	/* Set standard MPC8xx clock to the same time so Linux will
174 	 * see the time even if it doesn't have a DS1306 clock driver.
175 	 * This helps with experimenting with standard kernels.
176 	 */
177 	{
178 		ulong tim;
179 
180 		tim = rtc_mktime(tmp);
181 
182 		immap->im_sitk.sitk_rtck = KAPWR_KEY;
183 		immap->im_sit.sit_rtc = tim;
184 	}
185 
186 	debug ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
187 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
188 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
189 
190 	return 0;
191 }
192 
193 /* ------------------------------------------------------------------------- */
194 
195 /* Initialize Port B for software SPI */
196 static void init_spi (void)
197 {
198 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
199 
200 	/* Force output pins to begin at logic 0 */
201 	immap->im_cpm.cp_pbdat &= ~(PB_SPI_CE | PB_SPIMOSI | PB_SPISCK);
202 
203 	/* Set these 3 signals as outputs */
204 	immap->im_cpm.cp_pbdir |= (PB_SPIMOSI | PB_SPI_CE | PB_SPISCK);
205 
206 	immap->im_cpm.cp_pbdir &= ~PB_SPIMISO;	/* Make MISO pin an input */
207 	udelay (10);
208 }
209 
210 /* ------------------------------------------------------------------------- */
211 
212 /* NOTE: soft_spi_send() assumes that the I/O lines are configured already */
213 static void soft_spi_send (unsigned char n)
214 {
215 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
216 	unsigned char bitpos;	/* bit position to receive */
217 	unsigned char i;	/* Loop Control */
218 
219 	/* bit position to send, start with most significant bit */
220 	bitpos = 0x80;
221 
222 	/* Send 8 bits to software SPI */
223 	for (i = 0; i < 8; i++) {	/* Loop for 8 bits */
224 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
225 
226 		if (n & bitpos)
227 			immap->im_cpm.cp_pbdat |= PB_SPIMOSI;	/* Set MOSI to 1 */
228 		else
229 			immap->im_cpm.cp_pbdat &= ~PB_SPIMOSI;	/* Set MOSI to 0 */
230 		udelay (10);
231 
232 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
233 		udelay (10);
234 
235 		bitpos >>= 1;	/* Shift for next bit position */
236 	}
237 }
238 
239 /* ------------------------------------------------------------------------- */
240 
241 /* NOTE: soft_spi_read() assumes that the I/O lines are configured already */
242 static unsigned char soft_spi_read (void)
243 {
244 	volatile immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
245 
246 	unsigned char spi_byte = 0;	/* Return value, assume success */
247 	unsigned char bitpos;	/* bit position to receive */
248 	unsigned char i;	/* Loop Control */
249 
250 	/* bit position to receive, start with most significant bit */
251 	bitpos = 0x80;
252 
253 	/* Read 8 bits here */
254 	for (i = 0; i < 8; i++) {	/* Do 8 bits in loop */
255 		immap->im_cpm.cp_pbdat |= PB_SPISCK;	/* Raise SCK */
256 		udelay (10);
257 		if (immap->im_cpm.cp_pbdat & PB_SPIMISO)	/* Get a bit of data */
258 			spi_byte |= bitpos;	/* Set data accordingly */
259 		immap->im_cpm.cp_pbdat &= ~PB_SPISCK;	/* Lower SCK */
260 		udelay (10);
261 		bitpos >>= 1;	/* Shift for next bit position */
262 	}
263 
264 	return spi_byte;	/* Return the byte read */
265 }
266 
267 /* ------------------------------------------------------------------------- */
268 
269 void rtc_reset (void)
270 {
271 	return;			/* nothing to do */
272 }
273 
274 #else  /* not CONFIG_SXNI855T */
275 /* ************************************************************************* */
276 
277 static unsigned char rtc_read (unsigned char reg);
278 static void rtc_write (unsigned char reg, unsigned char val);
279 
280 static struct spi_slave *slave;
281 
282 /* read clock time from DS1306 and return it in *tmp */
283 int rtc_get (struct rtc_time *tmp)
284 {
285 	unsigned char sec, min, hour, mday, wday, mon, year;
286 
287 	/*
288 	 * Assuming Vcc = 2.0V (lowest speed)
289 	 *
290 	 * REVISIT: If we add an rtc_init() function we can do this
291 	 * step just once.
292 	 */
293 	if (!slave) {
294 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
295 				SPI_MODE_3 | SPI_CS_HIGH);
296 		if (!slave)
297 			return;
298 	}
299 
300 	if (spi_claim_bus(slave))
301 		return;
302 
303 	sec = rtc_read (RTC_SECONDS);
304 	min = rtc_read (RTC_MINUTES);
305 	hour = rtc_read (RTC_HOURS);
306 	mday = rtc_read (RTC_DATE_OF_MONTH);
307 	wday = rtc_read (RTC_DAY_OF_WEEK);
308 	mon = rtc_read (RTC_MONTH);
309 	year = rtc_read (RTC_YEAR);
310 
311 	spi_release_bus(slave);
312 
313 	debug ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
314 	       "hr: %02x min: %02x sec: %02x\n",
315 	       year, mon, mday, wday, hour, min, sec);
316 	debug ("Alarms[0]: wday: %02x hour: %02x min: %02x sec: %02x\n",
317 	       rtc_read (RTC_DAY_OF_WEEK_ALARM0),
318 	       rtc_read (RTC_HOURS_ALARM0),
319 	       rtc_read (RTC_MINUTES_ALARM0), rtc_read (RTC_SECONDS_ALARM0));
320 	debug ("Alarms[1]: wday: %02x hour: %02x min: %02x sec: %02x\n",
321 	       rtc_read (RTC_DAY_OF_WEEK_ALARM1),
322 	       rtc_read (RTC_HOURS_ALARM1),
323 	       rtc_read (RTC_MINUTES_ALARM1), rtc_read (RTC_SECONDS_ALARM1));
324 
325 	tmp->tm_sec = bcd2bin (sec & 0x7F);	/* convert Seconds */
326 	tmp->tm_min = bcd2bin (min & 0x7F);	/* convert Minutes */
327 
328 	/* convert Hours */
329 	tmp->tm_hour = (hour & 0x40)
330 		? ((hour & 0x20)	/* 12 hour mode */
331 		   ? bcd2bin (hour & 0x1F) + 11	/* PM */
332 		   : bcd2bin (hour & 0x1F) - 1	/* AM */
333 		)
334 		: bcd2bin (hour & 0x3F);	/* 24 hour mode */
335 
336 	tmp->tm_mday = bcd2bin (mday & 0x3F);	/* convert Day of the Month */
337 	tmp->tm_mon = bcd2bin (mon & 0x1F);	/* convert Month */
338 	tmp->tm_year = bcd2bin (year) + 2000;	/* convert Year */
339 	tmp->tm_wday = bcd2bin (wday & 0x07) - 1;	/* convert Day of the Week */
340 	tmp->tm_yday = 0;
341 	tmp->tm_isdst = 0;
342 
343 	debug ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
344 	       tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
345 	       tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
346 
347 	return 0;
348 }
349 
350 /* ------------------------------------------------------------------------- */
351 
352 /* set clock time from *tmp in DS1306 RTC */
353 int rtc_set (struct rtc_time *tmp)
354 {
355 	/* Assuming Vcc = 2.0V (lowest speed) */
356 	if (!slave) {
357 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
358 				SPI_MODE_3 | SPI_CS_HIGH);
359 		if (!slave)
360 			return;
361 	}
362 
363 	if (spi_claim_bus(slave))
364 		return;
365 
366 	debug ("Set 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 	rtc_write (RTC_SECONDS, bin2bcd (tmp->tm_sec));
371 	rtc_write (RTC_MINUTES, bin2bcd (tmp->tm_min));
372 	rtc_write (RTC_HOURS, bin2bcd (tmp->tm_hour));
373 	rtc_write (RTC_DAY_OF_WEEK, bin2bcd (tmp->tm_wday + 1));
374 	rtc_write (RTC_DATE_OF_MONTH, bin2bcd (tmp->tm_mday));
375 	rtc_write (RTC_MONTH, bin2bcd (tmp->tm_mon));
376 	rtc_write (RTC_YEAR, bin2bcd (tmp->tm_year - 2000));
377 
378 	spi_release_bus(slave);
379 }
380 
381 /* ------------------------------------------------------------------------- */
382 
383 /* reset the DS1306 */
384 void rtc_reset (void)
385 {
386 	/* Assuming Vcc = 2.0V (lowest speed) */
387 	if (!slave) {
388 		slave = spi_setup_slave(0, CONFIG_SYS_SPI_RTC_DEVID, 600000,
389 				SPI_MODE_3 | SPI_CS_HIGH);
390 		if (!slave)
391 			return;
392 	}
393 
394 	if (spi_claim_bus(slave))
395 		return;
396 
397 	/* clear the control register */
398 	rtc_write (RTC_CONTROL, 0x00);	/* 1st step: reset WP */
399 	rtc_write (RTC_CONTROL, 0x00);	/* 2nd step: reset 1Hz, AIE1, AIE0 */
400 
401 	/* reset all alarms */
402 	rtc_write (RTC_SECONDS_ALARM0, 0x00);
403 	rtc_write (RTC_SECONDS_ALARM1, 0x00);
404 	rtc_write (RTC_MINUTES_ALARM0, 0x00);
405 	rtc_write (RTC_MINUTES_ALARM1, 0x00);
406 	rtc_write (RTC_HOURS_ALARM0, 0x00);
407 	rtc_write (RTC_HOURS_ALARM1, 0x00);
408 	rtc_write (RTC_DAY_OF_WEEK_ALARM0, 0x00);
409 	rtc_write (RTC_DAY_OF_WEEK_ALARM1, 0x00);
410 
411 	spi_release_bus(slave);
412 }
413 
414 /* ------------------------------------------------------------------------- */
415 
416 static unsigned char rtc_read (unsigned char reg)
417 {
418 	int ret;
419 
420 	ret = spi_w8r8(slave, reg);
421 	return ret < 0 ? 0 : ret;
422 }
423 
424 /* ------------------------------------------------------------------------- */
425 
426 static void rtc_write (unsigned char reg, unsigned char val)
427 {
428 	unsigned char dout[2];	/* SPI Output Data Bytes */
429 	unsigned char din[2];	/* SPI Input Data Bytes */
430 
431 	dout[0] = 0x80 | reg;
432 	dout[1] = val;
433 
434 	spi_xfer (slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
435 }
436 
437 #endif /* end of code exclusion (see #ifdef CONFIG_SXNI855T above) */
438