1/*!***************************************************************************
2*!
3*! FILE NAME  : ds1302.c
4*!
5*! DESCRIPTION: Implements an interface for the DS1302 RTC
6*!
7*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init, get_rtc_status
8*!
9*! ---------------------------------------------------------------------------
10*!
11*! (C) Copyright 1999, 2000, 2001  Axis Communications AB, LUND, SWEDEN
12*!
13*!***************************************************************************/
14
15
16#include <linux/fs.h>
17#include <linux/init.h>
18#include <linux/mm.h>
19#include <linux/module.h>
20#include <linux/miscdevice.h>
21#include <linux/delay.h>
22#include <linux/bcd.h>
23
24#include <asm/uaccess.h>
25#include <asm/system.h>
26#include <asm/io.h>
27#include <asm/rtc.h>
28#if defined(CONFIG_M32R)
29#include <asm/m32r.h>
30#endif
31
32#define RTC_MAJOR_NR 121 /* local major, change later */
33
34static const char ds1302_name[] = "ds1302";
35
36/* Send 8 bits. */
37static void
38out_byte_rtc(unsigned int reg_addr, unsigned char x)
39{
40	//RST H
41	outw(0x0001,(unsigned long)PLD_RTCRSTODT);
42	//write data
43	outw(((x<<8)|(reg_addr&0xff)),(unsigned long)PLD_RTCWRDATA);
44	//WE
45	outw(0x0002,(unsigned long)PLD_RTCCR);
46	//wait
47	while(inw((unsigned long)PLD_RTCCR));
48
49	//RST L
50	outw(0x0000,(unsigned long)PLD_RTCRSTODT);
51
52}
53
54static unsigned char
55in_byte_rtc(unsigned int reg_addr)
56{
57	unsigned char retval;
58
59	//RST H
60	outw(0x0001,(unsigned long)PLD_RTCRSTODT);
61	//write data
62	outw((reg_addr&0xff),(unsigned long)PLD_RTCRDDATA);
63	//RE
64	outw(0x0001,(unsigned long)PLD_RTCCR);
65	//wait
66	while(inw((unsigned long)PLD_RTCCR));
67
68	//read data
69	retval=(inw((unsigned long)PLD_RTCRDDATA) & 0xff00)>>8;
70
71	//RST L
72	outw(0x0000,(unsigned long)PLD_RTCRSTODT);
73
74	return retval;
75}
76
77/* Enable writing. */
78
79static void
80ds1302_wenable(void)
81{
82	out_byte_rtc(0x8e,0x00);
83}
84
85/* Disable writing. */
86
87static void
88ds1302_wdisable(void)
89{
90	out_byte_rtc(0x8e,0x80);
91}
92
93
94
95/* Read a byte from the selected register in the DS1302. */
96
97unsigned char
98ds1302_readreg(int reg)
99{
100	unsigned char x;
101
102	x=in_byte_rtc((0x81 | (reg << 1))); /* read register */
103
104	return x;
105}
106
107/* Write a byte to the selected register. */
108
109void
110ds1302_writereg(int reg, unsigned char val)
111{
112	ds1302_wenable();
113	out_byte_rtc((0x80 | (reg << 1)),val);
114	ds1302_wdisable();
115}
116
117void
118get_rtc_time(struct rtc_time *rtc_tm)
119{
120	unsigned long flags;
121
122	local_irq_save(flags);
123
124	rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
125	rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
126	rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
127	rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
128	rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
129	rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
130
131	local_irq_restore(flags);
132
133	BCD_TO_BIN(rtc_tm->tm_sec);
134	BCD_TO_BIN(rtc_tm->tm_min);
135	BCD_TO_BIN(rtc_tm->tm_hour);
136	BCD_TO_BIN(rtc_tm->tm_mday);
137	BCD_TO_BIN(rtc_tm->tm_mon);
138	BCD_TO_BIN(rtc_tm->tm_year);
139
140	/*
141	 * Account for differences between how the RTC uses the values
142	 * and how they are defined in a struct rtc_time;
143	 */
144
145	if (rtc_tm->tm_year <= 69)
146		rtc_tm->tm_year += 100;
147
148	rtc_tm->tm_mon--;
149}
150
151static unsigned char days_in_mo[] =
152    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
153
154/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
155
156static int
157rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
158	  unsigned long arg)
159{
160	unsigned long flags;
161
162	switch(cmd) {
163		case RTC_RD_TIME:	/* read the time/date from RTC	*/
164		{
165			struct rtc_time rtc_tm;
166
167			memset(&rtc_tm, 0, sizeof (struct rtc_time));
168			get_rtc_time(&rtc_tm);
169			if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
170				return -EFAULT;
171			return 0;
172		}
173
174		case RTC_SET_TIME:	/* set the RTC */
175		{
176			struct rtc_time rtc_tm;
177			unsigned char mon, day, hrs, min, sec, leap_yr;
178			unsigned int yrs;
179
180			if (!capable(CAP_SYS_TIME))
181				return -EPERM;
182
183			if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
184				return -EFAULT;
185
186			yrs = rtc_tm.tm_year + 1900;
187			mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
188			day = rtc_tm.tm_mday;
189			hrs = rtc_tm.tm_hour;
190			min = rtc_tm.tm_min;
191			sec = rtc_tm.tm_sec;
192
193
194			if ((yrs < 1970) || (yrs > 2069))
195				return -EINVAL;
196
197			leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
198
199			if ((mon > 12) || (day == 0))
200				return -EINVAL;
201
202			if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
203				return -EINVAL;
204
205			if ((hrs >= 24) || (min >= 60) || (sec >= 60))
206				return -EINVAL;
207
208			if (yrs >= 2000)
209				yrs -= 2000;	/* RTC (0, 1, ... 69) */
210			else
211				yrs -= 1900;	/* RTC (70, 71, ... 99) */
212
213			BIN_TO_BCD(sec);
214			BIN_TO_BCD(min);
215			BIN_TO_BCD(hrs);
216			BIN_TO_BCD(day);
217			BIN_TO_BCD(mon);
218			BIN_TO_BCD(yrs);
219
220			local_irq_save(flags);
221			CMOS_WRITE(yrs, RTC_YEAR);
222			CMOS_WRITE(mon, RTC_MONTH);
223			CMOS_WRITE(day, RTC_DAY_OF_MONTH);
224			CMOS_WRITE(hrs, RTC_HOURS);
225			CMOS_WRITE(min, RTC_MINUTES);
226			CMOS_WRITE(sec, RTC_SECONDS);
227			local_irq_restore(flags);
228
229			/* Notice that at this point, the RTC is updated but
230			 * the kernel is still running with the old time.
231			 * You need to set that separately with settimeofday
232			 * or adjtimex.
233			 */
234			return 0;
235		}
236
237		case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
238		{
239			int tcs_val;
240
241			if (!capable(CAP_SYS_TIME))
242				return -EPERM;
243
244			if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
245				return -EFAULT;
246
247			tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
248			ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
249			return 0;
250		}
251		default:
252			return -EINVAL;
253	}
254}
255
256int
257get_rtc_status(char *buf)
258{
259	char *p;
260	struct rtc_time tm;
261
262	p = buf;
263
264	get_rtc_time(&tm);
265
266	/*
267	 * There is no way to tell if the luser has the RTC set for local
268	 * time or for Universal Standard Time (GMT). Probably local though.
269	 */
270
271	p += sprintf(p,
272		"rtc_time\t: %02d:%02d:%02d\n"
273		"rtc_date\t: %04d-%02d-%02d\n",
274		tm.tm_hour, tm.tm_min, tm.tm_sec,
275		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
276
277	return  p - buf;
278}
279
280
281/* The various file operations we support. */
282
283static const struct file_operations rtc_fops = {
284	.owner		= THIS_MODULE,
285	.ioctl		= rtc_ioctl,
286};
287
288/* Probe for the chip by writing something to its RAM and try reading it back. */
289
290#define MAGIC_PATTERN 0x42
291
292static int __init
293ds1302_probe(void)
294{
295	int retval, res, baur;
296
297	baur=(boot_cpu_data.bus_clock/(2*1000*1000));
298
299	printk("%s: Set PLD_RTCBAUR = %d\n", ds1302_name,baur);
300
301	outw(0x0000,(unsigned long)PLD_RTCCR);
302	outw(0x0000,(unsigned long)PLD_RTCRSTODT);
303	outw(baur,(unsigned long)PLD_RTCBAUR);
304
305	/* Try to talk to timekeeper. */
306
307	ds1302_wenable();
308	/* write RAM byte 0 */
309	/* write something magic */
310	out_byte_rtc(0xc0,MAGIC_PATTERN);
311
312	/* read RAM byte 0 */
313	if((res = in_byte_rtc(0xc1)) == MAGIC_PATTERN) {
314		char buf[100];
315		ds1302_wdisable();
316		printk("%s: RTC found.\n", ds1302_name);
317		get_rtc_status(buf);
318		printk(buf);
319		retval = 1;
320	} else {
321		printk("%s: RTC not found.\n", ds1302_name);
322		retval = 0;
323	}
324
325	return retval;
326}
327
328
329/* Just probe for the RTC and register the device to handle the ioctl needed. */
330
331int __init
332ds1302_init(void)
333{
334	if (!ds1302_probe()) {
335		return -1;
336  	}
337	return 0;
338}
339
340static int __init ds1302_register(void)
341{
342	ds1302_init();
343	if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
344		printk(KERN_INFO "%s: unable to get major %d for rtc\n",
345		       ds1302_name, RTC_MAJOR_NR);
346		return -1;
347	}
348	return 0;
349}
350
351module_init(ds1302_register);
352