1 /*!***************************************************************************
3 *! FILE NAME : ds1302.c
5 *! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O
7 *! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init
10 *! Revision 1.18 2005/01/24 09:11:26 mikaelam
11 *! Minor changes to get DS1302 RTC chip driver to work
13 *! Revision 1.17 2005/01/05 06:11:22 starvik
14 *! No need to do local_irq_disable after local_irq_save.
16 *! Revision 1.16 2004/12/13 12:21:52 starvik
17 *! Added I/O and DMA allocators from Linux 2.4
19 *! Revision 1.14 2004/08/24 06:48:43 starvik
22 *! Revision 1.13 2004/05/28 09:26:59 starvik
23 *! Modified I2C initialization to work in 2.6.
25 *! Revision 1.12 2004/05/14 07:58:03 starvik
26 *! Merge of changes from 2.4
28 *! Revision 1.10 2004/02/04 09:25:12 starvik
29 *! Merge of Linux 2.6.2
31 *! Revision 1.9 2003/07/04 08:27:37 starvik
32 *! Merge of Linux 2.5.74
34 *! Revision 1.8 2003/04/09 05:20:47 starvik
35 *! Merge of Linux 2.5.67
37 *! Revision 1.6 2003/01/09 14:42:51 starvik
38 *! Merge of Linux 2.5.55
40 *! Revision 1.4 2002/12/11 13:13:57 starvik
41 *! Added arch/ to v10 specific includes
42 *! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
44 *! Revision 1.3 2002/11/20 11:56:10 starvik
45 *! Merge of Linux 2.5.48
47 *! Revision 1.2 2002/11/18 13:16:06 starvik
48 *! Linux 2.5 port of latest 2.4 drivers
50 *! Revision 1.15 2002/10/11 16:14:33 johana
51 *! Added CONFIG_ETRAX_DS1302_TRICKLE_CHARGE and initial setting of the
52 *! trcklecharge register.
54 *! Revision 1.14 2002/10/10 12:15:38 magnusmn
55 *! Added support for having the RST signal on bit g0
57 *! Revision 1.13 2002/05/29 15:16:08 johana
58 *! Removed unused variables.
60 *! Revision 1.12 2002/04/10 15:35:25 johana
61 *! Moved probe function closer to init function and marked it __init.
63 *! Revision 1.11 2001/06/14 12:35:52 jonashg
64 *! The ATA hack is back. It is unfortunately the only way to set g27 to output.
66 *! Revision 1.9 2001/06/14 10:00:14 jonashg
67 *! No need for tempudelay to be inline anymore (had to adjust the usec to
68 *! loops conversion because of this to make it slow enough to be a udelay).
70 *! Revision 1.8 2001/06/14 08:06:32 jonashg
71 *! Made tempudelay delay usecs (well, just a tad more).
73 *! Revision 1.7 2001/06/13 14:18:11 jonashg
74 *! Only allow processes with SYS_TIME capability to set time and charge.
76 *! Revision 1.6 2001/06/12 15:22:07 jonashg
77 *! * Made init function __init.
78 *! * Parameter to out_byte() is unsigned char.
79 *! * The magic number 42 has got a name.
80 *! * Removed comment about /proc (nothing is exported there).
82 *! Revision 1.5 2001/06/12 14:35:13 jonashg
83 *! Gave the module a name and added it to printk's.
85 *! Revision 1.4 2001/05/31 14:53:40 jonashg
86 *! Made tempudelay() inline so that the watchdog doesn't reset (see
89 *! Revision 1.3 2001/03/26 16:03:06 bjornw
90 *! Needs linux/config.h
92 *! Revision 1.2 2001/03/20 19:42:00 bjornw
93 *! Use the ETRAX prefix on the DS1302 options
95 *! Revision 1.1 2001/03/20 09:13:50 magnusmn
98 *! Revision 1.10 2000/07/05 15:38:23 bjornw
99 *! Dont update kernel time when a RTC_SET_TIME is done
101 *! Revision 1.9 2000/03/02 15:42:59 macce
102 *! * Hack to make RTC work on all 2100/2400
104 *! Revision 1.8 2000/02/23 16:59:18 torbjore
105 *! added setup of R_GEN_CONFIG when RTC is connected to the generic port.
107 *! Revision 1.7 2000/01/17 15:51:43 johana
108 *! Added RTC_SET_CHARGE ioctl to enable trickle charger.
110 *! Revision 1.6 1999/10/27 13:19:47 bjornw
111 *! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.
112 *! /dev/rtc calls it now.
114 *! Revision 1.5 1999/10/27 12:39:37 bjornw
115 *! Disabled superuser check. Anyone can now set the time.
117 *! Revision 1.4 1999/09/02 13:27:46 pkj
118 *! Added shadow for R_PORT_PB_CONFIG.
119 *! Renamed port_g_shadow to port_g_data_shadow.
121 *! Revision 1.3 1999/09/02 08:28:06 pkj
122 *! Made it possible to select either port PB or the generic port for the RST
123 *! signal line to the DS1302 RTC.
124 *! Also make sure the RST bit is configured as output on Port PB (if used).
126 *! Revision 1.2 1999/09/01 14:47:20 bjornw
127 *! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read
128 *! and set the date. Register as major 121.
130 *! Revision 1.1 1999/09/01 09:45:29 bjornw
131 *! Implemented a DS1302 RTC driver.
134 *! ---------------------------------------------------------------------------
136 *! (C) Copyright 1999, 2000, 2001, 2002, 2003, 2004 Axis Communications AB, LUND, SWEDEN
138 *! $Id: ds1302.c,v 1.18 2005/01/24 09:11:26 mikaelam Exp $
140 *!***************************************************************************/
142 #include <linux/config.h>
144 #include <linux/fs.h>
145 #include <linux/init.h>
146 #include <linux/mm.h>
147 #include <linux/module.h>
148 #include <linux/miscdevice.h>
149 #include <linux/delay.h>
150 #include <linux/bcd.h>
151 #include <linux/capability.h>
153 #include <asm/uaccess.h>
154 #include <asm/system.h>
155 #include <asm/arch/svinto.h>
158 #include <asm/arch/io_interface_mux.h>
160 #define RTC_MAJOR_NR 121 /* local major, change later */
162 static const char ds1302_name[] = "ds1302";
164 /* The DS1302 might be connected to different bits on different products.
165 * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
166 * but SDA can have a selected direction.
167 * For now, only PORT_PB is hardcoded.
170 /* The RST bit may be on either the Generic Port or Port PB. */
171 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
172 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA, port_g_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
173 #define TK_RST_DIR(x)
175 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
176 #define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
180 #define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
181 #define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
183 #define TK_SDA_IN() ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
184 /* 1 is out, 0 is in */
185 #define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
186 #define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
190 * The reason for tempudelay and not udelay is that loops_per_usec
191 * (used in udelay) is not set when functions here are called from time.c
194 static void tempudelay(int usecs)
198 for(loops = usecs * 12; loops > 0; loops--)
205 out_byte(unsigned char x)
210 /* The chip latches incoming bits on the rising edge of SCL. */
227 /* Read byte. Bits come LSB first, on the falling edge of SCL.
228 * Assume SDA is in input direction already.
236 x |= (TK_SDA_IN() << 7);
244 /* Prepares for a transaction by de-activating RST (active-low). */
256 /* Ends a transaction by taking RST active again. */
265 /* Enable writing. */
271 out_byte(0x8e); /* Write control register */
272 out_byte(0x00); /* Disable write protect bit 7 = 0 */
276 /* Disable writing. */
279 ds1302_wdisable(void)
282 out_byte(0x8e); /* Write control register */
283 out_byte(0x80); /* Disable write protect bit 7 = 0 */
289 /* Read a byte from the selected register in the DS1302. */
292 ds1302_readreg(int reg)
297 out_byte(0x81 | (reg << 1)); /* read register */
304 /* Write a byte to the selected register. */
307 ds1302_writereg(int reg, unsigned char val)
309 #ifndef CONFIG_ETRAX_RTC_READONLY
314 if (reg == RTC_TRICKLECHARGER)
321 out_byte(0x80 | (reg << 1)); /* write register */
329 get_rtc_time(struct rtc_time *rtc_tm)
333 local_irq_save(flags);
335 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
336 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
337 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
338 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
339 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
340 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
342 local_irq_restore(flags);
344 BCD_TO_BIN(rtc_tm->tm_sec);
345 BCD_TO_BIN(rtc_tm->tm_min);
346 BCD_TO_BIN(rtc_tm->tm_hour);
347 BCD_TO_BIN(rtc_tm->tm_mday);
348 BCD_TO_BIN(rtc_tm->tm_mon);
349 BCD_TO_BIN(rtc_tm->tm_year);
352 * Account for differences between how the RTC uses the values
353 * and how they are defined in a struct rtc_time;
356 if (rtc_tm->tm_year <= 69)
357 rtc_tm->tm_year += 100;
362 static unsigned char days_in_mo[] =
363 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
365 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
368 rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
374 case RTC_RD_TIME: /* read the time/date from RTC */
376 struct rtc_time rtc_tm;
378 memset(&rtc_tm, 0, sizeof (struct rtc_time));
379 get_rtc_time(&rtc_tm);
380 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
385 case RTC_SET_TIME: /* set the RTC */
387 struct rtc_time rtc_tm;
388 unsigned char mon, day, hrs, min, sec, leap_yr;
391 if (!capable(CAP_SYS_TIME))
394 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
397 yrs = rtc_tm.tm_year + 1900;
398 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
399 day = rtc_tm.tm_mday;
400 hrs = rtc_tm.tm_hour;
405 if ((yrs < 1970) || (yrs > 2069))
408 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
410 if ((mon > 12) || (day == 0))
413 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
416 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
420 yrs -= 2000; /* RTC (0, 1, ... 69) */
422 yrs -= 1900; /* RTC (70, 71, ... 99) */
431 local_irq_save(flags);
432 CMOS_WRITE(yrs, RTC_YEAR);
433 CMOS_WRITE(mon, RTC_MONTH);
434 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
435 CMOS_WRITE(hrs, RTC_HOURS);
436 CMOS_WRITE(min, RTC_MINUTES);
437 CMOS_WRITE(sec, RTC_SECONDS);
438 local_irq_restore(flags);
440 /* Notice that at this point, the RTC is updated but
441 * the kernel is still running with the old time.
442 * You need to set that separately with settimeofday
448 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
452 if (!capable(CAP_SYS_TIME))
455 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
458 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
459 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
465 * Implement voltage low detection support
467 printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
468 " is not supported\n");
474 * Nothing to do since Voltage Low detection is not supported
484 print_rtc_status(void)
491 * There is no way to tell if the luser has the RTC set for local
492 * time or for Universal Standard Time (GMT). Probably local though.
495 printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
496 tm.tm_hour, tm.tm_min, tm.tm_sec);
497 printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
498 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
501 /* The various file operations we support. */
503 static struct file_operations rtc_fops = {
504 .owner = THIS_MODULE,
508 /* Probe for the chip by writing something to its RAM and try reading it back. */
510 #define MAGIC_PATTERN 0x42
521 /* Try to talk to timekeeper. */
525 out_byte(0xc0); /* write RAM byte 0 */
526 out_byte(MAGIC_PATTERN); /* write something magic */
528 out_byte(0xc1); /* read RAM byte 0 */
530 if((res = in_byte()) == MAGIC_PATTERN) {
533 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
534 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
536 CONFIG_ETRAX_DS1302_SDABIT,
537 CONFIG_ETRAX_DS1302_SCLBIT,
538 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
543 CONFIG_ETRAX_DS1302_RSTBIT);
555 /* Just probe for the RTC and register the device to handle the ioctl needed. */
560 #ifdef CONFIG_ETRAX_I2C
564 if (!ds1302_probe()) {
565 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
566 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
568 * The only way to set g27 to output is to enable ATA.
570 * Make sure that R_GEN_CONFIG is setup correct.
572 /* Allocating the ATA interface will grab almost all
573 * pins in I/O groups a, b, c and d. A consequence of
574 * allocating the ATA interface is that the fixed
575 * interfaces shared RAM, parallel port 0, parallel
576 * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
577 * 1, SCSI-W, serial port 2, serial port 3,
578 * synchronous serial port 3 and USB port 2 and almost
579 * all GPIO pins on port g cannot be used.
581 if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
582 printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
586 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
587 if (cris_io_interface_allocate_pins(if_gpio_grp_a,
589 CONFIG_ETRAX_DS1302_RSTBIT,
590 CONFIG_ETRAX_DS1302_RSTBIT)) {
591 printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
595 /* Set the direction of this bit to out. */
596 genconfig_shadow = ((genconfig_shadow &
597 ~IO_MASK(R_GEN_CONFIG, g0dir)) |
598 (IO_STATE(R_GEN_CONFIG, g0dir, out)));
599 *R_GEN_CONFIG = genconfig_shadow;
601 if (!ds1302_probe()) {
602 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
606 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
610 /* Initialise trickle charger */
611 ds1302_writereg(RTC_TRICKLECHARGER,
612 RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
613 /* Start clock by resetting CLOCK_HALT */
614 ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
618 static int __init ds1302_register(void)
621 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
622 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
623 ds1302_name, RTC_MAJOR_NR);
630 module_init(ds1302_register);