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 1.13 2004/05/28 09:26:59 starvik
11 *! Modified I2C initialization to work in 2.6.
13 *! Revision 1.12 2004/05/14 07:58:03 starvik
14 *! Merge of changes from 2.4
16 *! Revision 1.10 2004/02/04 09:25:12 starvik
17 *! Merge of Linux 2.6.2
19 *! Revision 1.9 2003/07/04 08:27:37 starvik
20 *! Merge of Linux 2.5.74
22 *! Revision 1.8 2003/04/09 05:20:47 starvik
23 *! Merge of Linux 2.5.67
25 *! Revision 1.6 2003/01/09 14:42:51 starvik
26 *! Merge of Linux 2.5.55
28 *! Revision 1.4 2002/12/11 13:13:57 starvik
29 *! Added arch/ to v10 specific includes
30 *! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
32 *! Revision 1.3 2002/11/20 11:56:10 starvik
33 *! Merge of Linux 2.5.48
35 *! Revision 1.2 2002/11/18 13:16:06 starvik
36 *! Linux 2.5 port of latest 2.4 drivers
38 *! Revision 1.15 2002/10/11 16:14:33 johana
39 *! Added CONFIG_ETRAX_DS1302_TRICKLE_CHARGE and initial setting of the
40 *! trcklecharge register.
42 *! Revision 1.14 2002/10/10 12:15:38 magnusmn
43 *! Added support for having the RST signal on bit g0
45 *! Revision 1.13 2002/05/29 15:16:08 johana
46 *! Removed unused variables.
48 *! Revision 1.12 2002/04/10 15:35:25 johana
49 *! Moved probe function closer to init function and marked it __init.
51 *! Revision 1.11 2001/06/14 12:35:52 jonashg
52 *! The ATA hack is back. It is unfortunately the only way to set g27 to output.
54 *! Revision 1.9 2001/06/14 10:00:14 jonashg
55 *! No need for tempudelay to be inline anymore (had to adjust the usec to
56 *! loops conversion because of this to make it slow enough to be a udelay).
58 *! Revision 1.8 2001/06/14 08:06:32 jonashg
59 *! Made tempudelay delay usecs (well, just a tad more).
61 *! Revision 1.7 2001/06/13 14:18:11 jonashg
62 *! Only allow processes with SYS_TIME capability to set time and charge.
64 *! Revision 1.6 2001/06/12 15:22:07 jonashg
65 *! * Made init function __init.
66 *! * Parameter to out_byte() is unsigned char.
67 *! * The magic number 42 has got a name.
68 *! * Removed comment about /proc (nothing is exported there).
70 *! Revision 1.5 2001/06/12 14:35:13 jonashg
71 *! Gave the module a name and added it to printk's.
73 *! Revision 1.4 2001/05/31 14:53:40 jonashg
74 *! Made tempudelay() inline so that the watchdog doesn't reset (see
77 *! Revision 1.3 2001/03/26 16:03:06 bjornw
78 *! Needs linux/config.h
80 *! Revision 1.2 2001/03/20 19:42:00 bjornw
81 *! Use the ETRAX prefix on the DS1302 options
83 *! Revision 1.1 2001/03/20 09:13:50 magnusmn
86 *! Revision 1.10 2000/07/05 15:38:23 bjornw
87 *! Dont update kernel time when a RTC_SET_TIME is done
89 *! Revision 1.9 2000/03/02 15:42:59 macce
90 *! * Hack to make RTC work on all 2100/2400
92 *! Revision 1.8 2000/02/23 16:59:18 torbjore
93 *! added setup of R_GEN_CONFIG when RTC is connected to the generic port.
95 *! Revision 1.7 2000/01/17 15:51:43 johana
96 *! Added RTC_SET_CHARGE ioctl to enable trickle charger.
98 *! Revision 1.6 1999/10/27 13:19:47 bjornw
99 *! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.
100 *! /dev/rtc calls it now.
102 *! Revision 1.5 1999/10/27 12:39:37 bjornw
103 *! Disabled superuser check. Anyone can now set the time.
105 *! Revision 1.4 1999/09/02 13:27:46 pkj
106 *! Added shadow for R_PORT_PB_CONFIG.
107 *! Renamed port_g_shadow to port_g_data_shadow.
109 *! Revision 1.3 1999/09/02 08:28:06 pkj
110 *! Made it possible to select either port PB or the generic port for the RST
111 *! signal line to the DS1302 RTC.
112 *! Also make sure the RST bit is configured as output on Port PB (if used).
114 *! Revision 1.2 1999/09/01 14:47:20 bjornw
115 *! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read
116 *! and set the date. Register as major 121.
118 *! Revision 1.1 1999/09/01 09:45:29 bjornw
119 *! Implemented a DS1302 RTC driver.
122 *! ---------------------------------------------------------------------------
124 *! (C) Copyright 1999, 2000, 2001 Axis Communications AB, LUND, SWEDEN
126 *! $Id: ds1302.c,v 1.13 2004/05/28 09:26:59 starvik Exp $
128 *!***************************************************************************/
130 #include <linux/config.h>
132 #include <linux/fs.h>
133 #include <linux/init.h>
134 #include <linux/mm.h>
135 #include <linux/module.h>
136 #include <linux/miscdevice.h>
137 #include <linux/delay.h>
138 #include <linux/bcd.h>
140 #include <asm/uaccess.h>
141 #include <asm/system.h>
142 #include <asm/arch/svinto.h>
146 #define RTC_MAJOR_NR 121 /* local major, change later */
148 static const char ds1302_name[] = "ds1302";
150 /* The DS1302 might be connected to different bits on different products.
151 * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
152 * but SDA can have a selected direction.
153 * For now, only PORT_PB is hardcoded.
156 /* The RST bit may be on either the Generic Port or Port PB. */
157 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
158 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA, port_g_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
159 #define TK_RST_DIR(x)
161 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
162 #define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
166 #define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
167 #define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
169 #define TK_SDA_IN() ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
170 /* 1 is out, 0 is in */
171 #define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
172 #define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR, port_pb_dir_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
176 * The reason for tempudelay and not udelay is that loops_per_usec
177 * (used in udelay) is not set when functions here are called from time.c
180 static void tempudelay(int usecs)
184 for(loops = usecs * 12; loops > 0; loops--)
191 out_byte(unsigned char x)
196 /* The chip latches incoming bits on the rising edge of SCL. */
213 /* Read byte. Bits come LSB first, on the falling edge of SCL.
214 * Assume SDA is in input direction already.
222 x |= (TK_SDA_IN() << 7);
230 /* Prepares for a transaction by de-activating RST (active-low). */
242 /* Ends a transaction by taking RST active again. */
251 /* Enable writing. */
257 out_byte(0x8e); /* Write control register */
258 out_byte(0x00); /* Disable write protect bit 7 = 0 */
262 /* Disable writing. */
265 ds1302_wdisable(void)
268 out_byte(0x8e); /* Write control register */
269 out_byte(0x80); /* Disable write protect bit 7 = 0 */
275 /* Read a byte from the selected register in the DS1302. */
278 ds1302_readreg(int reg)
283 out_byte(0x81 | (reg << 1)); /* read register */
290 /* Write a byte to the selected register. */
293 ds1302_writereg(int reg, unsigned char val)
295 #ifndef CONFIG_ETRAX_RTC_READONLY
300 if (reg == RTC_TRICKLECHARGER)
307 out_byte(0x80 | (reg << 1)); /* write register */
315 get_rtc_time(struct rtc_time *rtc_tm)
319 local_irq_save(flags);
322 rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
323 rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
324 rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
325 rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
326 rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
327 rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
329 local_irq_restore(flags);
331 BCD_TO_BIN(rtc_tm->tm_sec);
332 BCD_TO_BIN(rtc_tm->tm_min);
333 BCD_TO_BIN(rtc_tm->tm_hour);
334 BCD_TO_BIN(rtc_tm->tm_mday);
335 BCD_TO_BIN(rtc_tm->tm_mon);
336 BCD_TO_BIN(rtc_tm->tm_year);
339 * Account for differences between how the RTC uses the values
340 * and how they are defined in a struct rtc_time;
343 if (rtc_tm->tm_year <= 69)
344 rtc_tm->tm_year += 100;
349 static unsigned char days_in_mo[] =
350 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
352 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
355 rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
361 case RTC_RD_TIME: /* read the time/date from RTC */
363 struct rtc_time rtc_tm;
365 memset(&rtc_tm, 0, sizeof (struct rtc_time));
366 get_rtc_time(&rtc_tm);
367 if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
372 case RTC_SET_TIME: /* set the RTC */
374 struct rtc_time rtc_tm;
375 unsigned char mon, day, hrs, min, sec, leap_yr;
378 if (!capable(CAP_SYS_TIME))
381 if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
384 yrs = rtc_tm.tm_year + 1900;
385 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
386 day = rtc_tm.tm_mday;
387 hrs = rtc_tm.tm_hour;
392 if ((yrs < 1970) || (yrs > 2069))
395 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
397 if ((mon > 12) || (day == 0))
400 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
403 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
407 yrs -= 2000; /* RTC (0, 1, ... 69) */
409 yrs -= 1900; /* RTC (70, 71, ... 99) */
418 local_irq_save(flags);
420 CMOS_WRITE(yrs, RTC_YEAR);
421 CMOS_WRITE(mon, RTC_MONTH);
422 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
423 CMOS_WRITE(hrs, RTC_HOURS);
424 CMOS_WRITE(min, RTC_MINUTES);
425 CMOS_WRITE(sec, RTC_SECONDS);
426 local_irq_restore(flags);
428 /* Notice that at this point, the RTC is updated but
429 * the kernel is still running with the old time.
430 * You need to set that separately with settimeofday
436 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
440 if (!capable(CAP_SYS_TIME))
443 if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
446 tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
447 ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
453 * Implement voltage low detection support
455 printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
456 " is not supported\n");
462 * Nothing to do since Voltage Low detection is not supported
472 print_rtc_status(void)
479 * There is no way to tell if the luser has the RTC set for local
480 * time or for Universal Standard Time (GMT). Probably local though.
483 printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
484 tm.tm_hour, tm.tm_min, tm.tm_sec);
485 printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
486 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
489 /* The various file operations we support. */
491 static struct file_operations rtc_fops = {
492 .owner = THIS_MODULE,
496 /* Probe for the chip by writing something to its RAM and try reading it back. */
498 #define MAGIC_PATTERN 0x42
509 /* Try to talk to timekeeper. */
513 out_byte(0xc0); /* write RAM byte 0 */
514 out_byte(MAGIC_PATTERN); /* write something magic */
516 out_byte(0xc1); /* read RAM byte 0 */
518 if((res = in_byte()) == MAGIC_PATTERN) {
521 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
522 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
524 CONFIG_ETRAX_DS1302_SDABIT,
525 CONFIG_ETRAX_DS1302_SCLBIT,
526 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
531 CONFIG_ETRAX_DS1302_RSTBIT);
543 /* Just probe for the RTC and register the device to handle the ioctl needed. */
550 if (!ds1302_probe()) {
551 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
552 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
554 * The only way to set g27 to output is to enable ATA.
556 * Make sure that R_GEN_CONFIG is setup correct.
558 genconfig_shadow = ((genconfig_shadow &
559 ~IO_MASK(R_GEN_CONFIG, ata)) |
560 (IO_STATE(R_GEN_CONFIG, ata, select)));
561 *R_GEN_CONFIG = genconfig_shadow;
562 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
564 /* Set the direction of this bit to out. */
565 genconfig_shadow = ((genconfig_shadow &
566 ~IO_MASK(R_GEN_CONFIG, g0dir)) |
567 (IO_STATE(R_GEN_CONFIG, g0dir, out)));
568 *R_GEN_CONFIG = genconfig_shadow;
570 if (!ds1302_probe()) {
571 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
575 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
579 /* Initialise trickle charger */
580 ds1302_writereg(RTC_TRICKLECHARGER,
581 RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
582 /* Start clock by resetting CLOCK_HALT */
583 ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
587 static int __init ds1302_register(void)
590 if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
591 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
592 ds1302_name, RTC_MAJOR_NR);
599 module_init(ds1302_register);