1/*!***************************************************************************
2*!
3*! FILE NAME  : ds1302.c
4*!
5*! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O
6*!
7*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init
8*!
9*! $Log: ds1302.c,v $
10*! Revision 1.1.1.1  2007/08/03 18:51:41  rnuti
11*! Importing Linux MIPS Kernel 2.6.22
12*!
13*! Revision 1.18  2005/01/24 09:11:26  mikaelam
14*! Minor changes to get DS1302 RTC chip driver to work
15*!
16*! Revision 1.17  2005/01/05 06:11:22  starvik
17*! No need to do local_irq_disable after local_irq_save.
18*!
19*! Revision 1.16  2004/12/13 12:21:52  starvik
20*! Added I/O and DMA allocators from Linux 2.4
21*!
22*! Revision 1.14  2004/08/24 06:48:43  starvik
23*! Whitespace cleanup
24*!
25*! Revision 1.13  2004/05/28 09:26:59  starvik
26*! Modified I2C initialization to work in 2.6.
27*!
28*! Revision 1.12  2004/05/14 07:58:03  starvik
29*! Merge of changes from 2.4
30*!
31*! Revision 1.10  2004/02/04 09:25:12  starvik
32*! Merge of Linux 2.6.2
33*!
34*! Revision 1.9  2003/07/04 08:27:37  starvik
35*! Merge of Linux 2.5.74
36*!
37*! Revision 1.8  2003/04/09 05:20:47  starvik
38*! Merge of Linux 2.5.67
39*!
40*! Revision 1.6  2003/01/09 14:42:51  starvik
41*! Merge of Linux 2.5.55
42*!
43*! Revision 1.4  2002/12/11 13:13:57  starvik
44*! Added arch/ to v10 specific includes
45*! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
46*!
47*! Revision 1.3  2002/11/20 11:56:10  starvik
48*! Merge of Linux 2.5.48
49*!
50*! Revision 1.2  2002/11/18 13:16:06  starvik
51*! Linux 2.5 port of latest 2.4 drivers
52*!
53*! Revision 1.15  2002/10/11 16:14:33  johana
54*! Added CONFIG_ETRAX_DS1302_TRICKLE_CHARGE and initial setting of the
55*! trcklecharge register.
56*!
57*! Revision 1.14  2002/10/10 12:15:38  magnusmn
58*! Added support for having the RST signal on bit g0
59*!
60*! Revision 1.13  2002/05/29 15:16:08  johana
61*! Removed unused variables.
62*!
63*! Revision 1.12  2002/04/10 15:35:25  johana
64*! Moved probe function closer to init function and marked it __init.
65*!
66*! Revision 1.11  2001/06/14 12:35:52  jonashg
67*! The ATA hack is back. It is unfortunately the only way to set g27 to output.
68*!
69*! Revision 1.9  2001/06/14 10:00:14  jonashg
70*! No need for tempudelay to be inline anymore (had to adjust the usec to
71*! loops conversion because of this to make it slow enough to be a udelay).
72*!
73*! Revision 1.8  2001/06/14 08:06:32  jonashg
74*! Made tempudelay delay usecs (well, just a tad more).
75*!
76*! Revision 1.7  2001/06/13 14:18:11  jonashg
77*! Only allow processes with SYS_TIME capability to set time and charge.
78*!
79*! Revision 1.6  2001/06/12 15:22:07  jonashg
80*! * Made init function __init.
81*! * Parameter to out_byte() is unsigned char.
82*! * The magic number 42 has got a name.
83*! * Removed comment about /proc (nothing is exported there).
84*!
85*! Revision 1.5  2001/06/12 14:35:13  jonashg
86*! Gave the module a name and added it to printk's.
87*!
88*! Revision 1.4  2001/05/31 14:53:40  jonashg
89*! Made tempudelay() inline so that the watchdog doesn't reset (see
90*! function comment).
91*!
92*! Revision 1.3  2001/03/26 16:03:06  bjornw
93*! Needs linux/config.h
94*!
95*! Revision 1.2  2001/03/20 19:42:00  bjornw
96*! Use the ETRAX prefix on the DS1302 options
97*!
98*! Revision 1.1  2001/03/20 09:13:50  magnusmn
99*! Linux 2.4 port
100*!
101*! Revision 1.10  2000/07/05 15:38:23  bjornw
102*! Dont update kernel time when a RTC_SET_TIME is done
103*!
104*! Revision 1.9  2000/03/02 15:42:59  macce
105*! * Hack to make RTC work on all 2100/2400
106*!
107*! Revision 1.8  2000/02/23 16:59:18  torbjore
108*! added setup of R_GEN_CONFIG when RTC is connected to the generic port.
109*!
110*! Revision 1.7  2000/01/17 15:51:43  johana
111*! Added RTC_SET_CHARGE ioctl to enable trickle charger.
112*!
113*! Revision 1.6  1999/10/27 13:19:47  bjornw
114*! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.
115*! /dev/rtc calls it now.
116*!
117*! Revision 1.5  1999/10/27 12:39:37  bjornw
118*! Disabled superuser check. Anyone can now set the time.
119*!
120*! Revision 1.4  1999/09/02 13:27:46  pkj
121*! Added shadow for R_PORT_PB_CONFIG.
122*! Renamed port_g_shadow to port_g_data_shadow.
123*!
124*! Revision 1.3  1999/09/02 08:28:06  pkj
125*! Made it possible to select either port PB or the generic port for the RST
126*! signal line to the DS1302 RTC.
127*! Also make sure the RST bit is configured as output on Port PB (if used).
128*!
129*! Revision 1.2  1999/09/01 14:47:20  bjornw
130*! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read
131*! and set the date. Register as major 121.
132*!
133*! Revision 1.1  1999/09/01 09:45:29  bjornw
134*! Implemented a DS1302 RTC driver.
135*!
136*!
137*! ---------------------------------------------------------------------------
138*!
139*! (C) Copyright 1999, 2000, 2001, 2002, 2003, 2004  Axis Communications AB, LUND, SWEDEN
140*!
141*! $Id: ds1302.c,v 1.1.1.1 2007/08/03 18:51:41 Exp $
142*!
143*!***************************************************************************/
144
145
146#include <linux/fs.h>
147#include <linux/init.h>
148#include <linux/mm.h>
149#include <linux/module.h>
150#include <linux/miscdevice.h>
151#include <linux/delay.h>
152#include <linux/bcd.h>
153#include <linux/capability.h>
154
155#include <asm/uaccess.h>
156#include <asm/system.h>
157#include <asm/arch/svinto.h>
158#include <asm/io.h>
159#include <asm/rtc.h>
160#include <asm/arch/io_interface_mux.h>
161
162#define RTC_MAJOR_NR 121 /* local major, change later */
163
164static const char ds1302_name[] = "ds1302";
165
166/* The DS1302 might be connected to different bits on different products.
167 * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
168 * but SDA can have a selected direction.
169 * For now, only PORT_PB is hardcoded.
170 */
171
172/* The RST bit may be on either the Generic Port or Port PB. */
173#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
174#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
175#define TK_RST_DIR(x)
176#else
177#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
178#define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
179#endif
180
181
182#define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
183#define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
184
185#define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
186/* 1 is out, 0 is in */
187#define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
188#define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
189
190
191/*
192 * The reason for tempudelay and not udelay is that loops_per_usec
193 * (used in udelay) is not set when functions here are called from time.c
194 */
195
196static void tempudelay(int usecs)
197{
198	volatile int loops;
199
200	for(loops = usecs * 12; loops > 0; loops--)
201		/* nothing */;
202}
203
204
205/* Send 8 bits. */
206static void
207out_byte(unsigned char x)
208{
209	int i;
210	TK_SDA_DIR(1);
211	for (i = 8; i--;) {
212		/* The chip latches incoming bits on the rising edge of SCL. */
213		TK_SCL_OUT(0);
214		TK_SDA_OUT(x & 1);
215		tempudelay(1);
216		TK_SCL_OUT(1);
217		tempudelay(1);
218		x >>= 1;
219	}
220	TK_SDA_DIR(0);
221}
222
223static unsigned char
224in_byte(void)
225{
226	unsigned char x = 0;
227	int i;
228
229	/* Read byte. Bits come LSB first, on the falling edge of SCL.
230	 * Assume SDA is in input direction already.
231	 */
232	TK_SDA_DIR(0);
233
234	for (i = 8; i--;) {
235		TK_SCL_OUT(0);
236		tempudelay(1);
237		x >>= 1;
238		x |= (TK_SDA_IN() << 7);
239		TK_SCL_OUT(1);
240		tempudelay(1);
241	}
242
243	return x;
244}
245
246/* Prepares for a transaction by de-activating RST (active-low). */
247
248static void
249start(void)
250{
251	TK_SCL_OUT(0);
252	tempudelay(1);
253	TK_RST_OUT(0);
254	tempudelay(5);
255	TK_RST_OUT(1);
256}
257
258/* Ends a transaction by taking RST active again. */
259
260static void
261stop(void)
262{
263	tempudelay(2);
264	TK_RST_OUT(0);
265}
266
267/* Enable writing. */
268
269static void
270ds1302_wenable(void)
271{
272	start();
273	out_byte(0x8e); /* Write control register  */
274	out_byte(0x00); /* Disable write protect bit 7 = 0 */
275	stop();
276}
277
278/* Disable writing. */
279
280static void
281ds1302_wdisable(void)
282{
283	start();
284	out_byte(0x8e); /* Write control register  */
285	out_byte(0x80); /* Disable write protect bit 7 = 0 */
286	stop();
287}
288
289
290
291/* Read a byte from the selected register in the DS1302. */
292
293unsigned char
294ds1302_readreg(int reg)
295{
296	unsigned char x;
297
298	start();
299	out_byte(0x81 | (reg << 1)); /* read register */
300	x = in_byte();
301	stop();
302
303	return x;
304}
305
306/* Write a byte to the selected register. */
307
308void
309ds1302_writereg(int reg, unsigned char val)
310{
311#ifndef CONFIG_ETRAX_RTC_READONLY
312	int do_writereg = 1;
313#else
314	int do_writereg = 0;
315
316	if (reg == RTC_TRICKLECHARGER)
317		do_writereg = 1;
318#endif
319
320	if (do_writereg) {
321		ds1302_wenable();
322		start();
323		out_byte(0x80 | (reg << 1)); /* write register */
324		out_byte(val);
325		stop();
326		ds1302_wdisable();
327	}
328}
329
330void
331get_rtc_time(struct rtc_time *rtc_tm)
332{
333	unsigned long flags;
334
335	local_irq_save(flags);
336
337	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
338	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
339	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
340	rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
341	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
342	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
343
344	local_irq_restore(flags);
345
346	BCD_TO_BIN(rtc_tm->tm_sec);
347	BCD_TO_BIN(rtc_tm->tm_min);
348	BCD_TO_BIN(rtc_tm->tm_hour);
349	BCD_TO_BIN(rtc_tm->tm_mday);
350	BCD_TO_BIN(rtc_tm->tm_mon);
351	BCD_TO_BIN(rtc_tm->tm_year);
352
353	/*
354	 * Account for differences between how the RTC uses the values
355	 * and how they are defined in a struct rtc_time;
356	 */
357
358	if (rtc_tm->tm_year <= 69)
359		rtc_tm->tm_year += 100;
360
361	rtc_tm->tm_mon--;
362}
363
364static unsigned char days_in_mo[] =
365    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
366
367/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
368
369static int
370rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
371	  unsigned long arg)
372{
373	unsigned long flags;
374
375	switch(cmd) {
376		case RTC_RD_TIME:	/* read the time/date from RTC	*/
377		{
378			struct rtc_time rtc_tm;
379
380			memset(&rtc_tm, 0, sizeof (struct rtc_time));
381			get_rtc_time(&rtc_tm);
382			if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
383				return -EFAULT;
384			return 0;
385		}
386
387		case RTC_SET_TIME:	/* set the RTC */
388		{
389			struct rtc_time rtc_tm;
390			unsigned char mon, day, hrs, min, sec, leap_yr;
391			unsigned int yrs;
392
393			if (!capable(CAP_SYS_TIME))
394				return -EPERM;
395
396			if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
397				return -EFAULT;
398
399			yrs = rtc_tm.tm_year + 1900;
400			mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
401			day = rtc_tm.tm_mday;
402			hrs = rtc_tm.tm_hour;
403			min = rtc_tm.tm_min;
404			sec = rtc_tm.tm_sec;
405
406
407			if ((yrs < 1970) || (yrs > 2069))
408				return -EINVAL;
409
410			leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
411
412			if ((mon > 12) || (day == 0))
413				return -EINVAL;
414
415			if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
416				return -EINVAL;
417
418			if ((hrs >= 24) || (min >= 60) || (sec >= 60))
419				return -EINVAL;
420
421			if (yrs >= 2000)
422				yrs -= 2000;	/* RTC (0, 1, ... 69) */
423			else
424				yrs -= 1900;	/* RTC (70, 71, ... 99) */
425
426			BIN_TO_BCD(sec);
427			BIN_TO_BCD(min);
428			BIN_TO_BCD(hrs);
429			BIN_TO_BCD(day);
430			BIN_TO_BCD(mon);
431			BIN_TO_BCD(yrs);
432
433			local_irq_save(flags);
434			CMOS_WRITE(yrs, RTC_YEAR);
435			CMOS_WRITE(mon, RTC_MONTH);
436			CMOS_WRITE(day, RTC_DAY_OF_MONTH);
437			CMOS_WRITE(hrs, RTC_HOURS);
438			CMOS_WRITE(min, RTC_MINUTES);
439			CMOS_WRITE(sec, RTC_SECONDS);
440			local_irq_restore(flags);
441
442			/* Notice that at this point, the RTC is updated but
443			 * the kernel is still running with the old time.
444			 * You need to set that separately with settimeofday
445			 * or adjtimex.
446			 */
447			return 0;
448		}
449
450		case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
451		{
452			int tcs_val;
453
454			if (!capable(CAP_SYS_TIME))
455				return -EPERM;
456
457			if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
458				return -EFAULT;
459
460			tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
461			ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
462			return 0;
463		}
464		case RTC_VLOW_RD:
465		{
466			/* TODO:
467			 * Implement voltage low detection support
468			 */
469			printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
470			       " is not supported\n");
471			return 0;
472		}
473		case RTC_VLOW_SET:
474		{
475			/* TODO:
476			 * Nothing to do since Voltage Low detection is not supported
477			 */
478			return 0;
479		}
480		default:
481			return -ENOIOCTLCMD;
482	}
483}
484
485static void
486print_rtc_status(void)
487{
488	struct rtc_time tm;
489
490	get_rtc_time(&tm);
491
492	/*
493	 * There is no way to tell if the luser has the RTC set for local
494	 * time or for Universal Standard Time (GMT). Probably local though.
495	 */
496
497	printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
498	       tm.tm_hour, tm.tm_min, tm.tm_sec);
499	printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
500	       tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
501}
502
503/* The various file operations we support. */
504
505static const struct file_operations rtc_fops = {
506	.owner =	THIS_MODULE,
507	.ioctl =	rtc_ioctl,
508};
509
510/* Probe for the chip by writing something to its RAM and try reading it back. */
511
512#define MAGIC_PATTERN 0x42
513
514static int __init
515ds1302_probe(void)
516{
517	int retval, res;
518
519	TK_RST_DIR(1);
520	TK_SCL_DIR(1);
521	TK_SDA_DIR(0);
522
523	/* Try to talk to timekeeper. */
524
525	ds1302_wenable();
526	start();
527	out_byte(0xc0); /* write RAM byte 0 */
528	out_byte(MAGIC_PATTERN); /* write something magic */
529	start();
530	out_byte(0xc1); /* read RAM byte 0 */
531
532	if((res = in_byte()) == MAGIC_PATTERN) {
533		stop();
534		ds1302_wdisable();
535		printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
536		printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
537		       ds1302_name,
538		       CONFIG_ETRAX_DS1302_SDABIT,
539		       CONFIG_ETRAX_DS1302_SCLBIT,
540#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
541		       "GENIO",
542#else
543		       "PB",
544#endif
545		       CONFIG_ETRAX_DS1302_RSTBIT);
546		       print_rtc_status();
547		retval = 1;
548	} else {
549		stop();
550		retval = 0;
551	}
552
553	return retval;
554}
555
556
557/* Just probe for the RTC and register the device to handle the ioctl needed. */
558
559int __init
560ds1302_init(void)
561{
562#ifdef CONFIG_ETRAX_I2C
563	i2c_init();
564#endif
565
566	if (!ds1302_probe()) {
567#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
568#if CONFIG_ETRAX_DS1302_RSTBIT == 27
569		/*
570		 * The only way to set g27 to output is to enable ATA.
571		 *
572		 * Make sure that R_GEN_CONFIG is setup correct.
573		 */
574		/* Allocating the ATA interface will grab almost all
575		 * pins in I/O groups a, b, c and d.  A consequence of
576		 * allocating the ATA interface is that the fixed
577		 * interfaces shared RAM, parallel port 0, parallel
578		 * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
579		 * 1, SCSI-W, serial port 2, serial port 3,
580		 * synchronous serial port 3 and USB port 2 and almost
581		 * all GPIO pins on port g cannot be used.
582		 */
583		if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
584			printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
585			return -1;
586		}
587
588#elif CONFIG_ETRAX_DS1302_RSTBIT == 0
589		if (cris_io_interface_allocate_pins(if_gpio_grp_a,
590						    'g',
591						    CONFIG_ETRAX_DS1302_RSTBIT,
592						    CONFIG_ETRAX_DS1302_RSTBIT)) {
593			printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
594			return -1;
595		}
596
597		/* Set the direction of this bit to out. */
598		genconfig_shadow = ((genconfig_shadow &
599 				     ~IO_MASK(R_GEN_CONFIG, g0dir)) |
600 				   (IO_STATE(R_GEN_CONFIG, g0dir, out)));
601		*R_GEN_CONFIG = genconfig_shadow;
602#endif
603		if (!ds1302_probe()) {
604			printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
605			return -1;
606		}
607#else
608		printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
609		return -1;
610#endif
611  	}
612	/* Initialise trickle charger */
613	ds1302_writereg(RTC_TRICKLECHARGER,
614			RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
615        /* Start clock by resetting CLOCK_HALT */
616	ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
617	return 0;
618}
619
620static int __init ds1302_register(void)
621{
622	ds1302_init();
623	if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
624		printk(KERN_INFO "%s: unable to get major %d for rtc\n",
625		       ds1302_name, RTC_MAJOR_NR);
626		return -1;
627	}
628        return 0;
629
630}
631
632module_init(ds1302_register);
633