Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / arch / cris / arch-v10 / drivers / ds1302.c
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 *! ---------------------------------------------------------------------------
10 *!
11 *! (C) Copyright 1999-2007 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 #include <linux/capability.h>
24
25 #include <asm/uaccess.h>
26 #include <asm/system.h>
27 #include <arch/svinto.h>
28 #include <asm/io.h>
29 #include <asm/rtc.h>
30 #include <arch/io_interface_mux.h>
31
32 #include "i2c.h"
33
34 #define RTC_MAJOR_NR 121 /* local major, change later */
35
36 static const char ds1302_name[] = "ds1302";
37
38 /* The DS1302 might be connected to different bits on different products. 
39  * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
40  * but SDA can have a selected direction.
41  * For now, only PORT_PB is hardcoded.
42  */
43
44 /* The RST bit may be on either the Generic Port or Port PB. */
45 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
46 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
47 #define TK_RST_DIR(x)
48 #else
49 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
50 #define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
51 #endif
52
53
54 #define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
55 #define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
56
57 #define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
58 /* 1 is out, 0 is in */
59 #define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
60 #define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
61
62
63 /*
64  * The reason for tempudelay and not udelay is that loops_per_usec
65  * (used in udelay) is not set when functions here are called from time.c 
66  */
67
68 static void tempudelay(int usecs) 
69 {
70         volatile int loops;
71
72         for(loops = usecs * 12; loops > 0; loops--)
73                 /* nothing */;  
74 }
75
76
77 /* Send 8 bits. */
78 static void
79 out_byte(unsigned char x) 
80 {
81         int i;
82         TK_SDA_DIR(1);
83         for (i = 8; i--;) {
84                 /* The chip latches incoming bits on the rising edge of SCL. */
85                 TK_SCL_OUT(0);
86                 TK_SDA_OUT(x & 1);
87                 tempudelay(1);
88                 TK_SCL_OUT(1);
89                 tempudelay(1);
90                 x >>= 1;
91         }
92         TK_SDA_DIR(0);
93 }
94
95 static unsigned char
96 in_byte(void) 
97 {
98         unsigned char x = 0;
99         int i;
100
101         /* Read byte. Bits come LSB first, on the falling edge of SCL.
102          * Assume SDA is in input direction already.
103          */
104         TK_SDA_DIR(0);
105
106         for (i = 8; i--;) {
107                 TK_SCL_OUT(0);
108                 tempudelay(1);
109                 x >>= 1;
110                 x |= (TK_SDA_IN() << 7);
111                 TK_SCL_OUT(1);
112                 tempudelay(1);
113         }
114
115         return x;
116 }
117
118 /* Prepares for a transaction by de-activating RST (active-low). */
119
120 static void
121 start(void) 
122 {
123         TK_SCL_OUT(0);
124         tempudelay(1);
125         TK_RST_OUT(0);
126         tempudelay(5);
127         TK_RST_OUT(1);  
128 }
129
130 /* Ends a transaction by taking RST active again. */
131
132 static void
133 stop(void) 
134 {
135         tempudelay(2);
136         TK_RST_OUT(0);
137 }
138
139 /* Enable writing. */
140
141 static void
142 ds1302_wenable(void) 
143 {
144         start();        
145         out_byte(0x8e); /* Write control register  */
146         out_byte(0x00); /* Disable write protect bit 7 = 0 */
147         stop();
148 }
149
150 /* Disable writing. */
151
152 static void
153 ds1302_wdisable(void) 
154 {
155         start();
156         out_byte(0x8e); /* Write control register  */
157         out_byte(0x80); /* Disable write protect bit 7 = 0 */
158         stop();
159 }
160
161
162
163 /* Read a byte from the selected register in the DS1302. */
164
165 unsigned char
166 ds1302_readreg(int reg) 
167 {
168         unsigned char x;
169
170         start();
171         out_byte(0x81 | (reg << 1)); /* read register */
172         x = in_byte();
173         stop();
174
175         return x;
176 }
177
178 /* Write a byte to the selected register. */
179
180 void
181 ds1302_writereg(int reg, unsigned char val) 
182 {
183 #ifndef CONFIG_ETRAX_RTC_READONLY
184         int do_writereg = 1;
185 #else
186         int do_writereg = 0;
187
188         if (reg == RTC_TRICKLECHARGER)
189                 do_writereg = 1;
190 #endif
191
192         if (do_writereg) {
193                 ds1302_wenable();
194                 start();
195                 out_byte(0x80 | (reg << 1)); /* write register */
196                 out_byte(val);
197                 stop();
198                 ds1302_wdisable();
199         }
200 }
201
202 void
203 get_rtc_time(struct rtc_time *rtc_tm) 
204 {
205         unsigned long flags;
206
207         local_irq_save(flags);
208
209         rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
210         rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
211         rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
212         rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
213         rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
214         rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
215
216         local_irq_restore(flags);
217         
218         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
219         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
220         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
221         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
222         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
223         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
224
225         /*
226          * Account for differences between how the RTC uses the values
227          * and how they are defined in a struct rtc_time;
228          */
229
230         if (rtc_tm->tm_year <= 69)
231                 rtc_tm->tm_year += 100;
232
233         rtc_tm->tm_mon--;
234 }
235
236 static unsigned char days_in_mo[] = 
237     {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
238
239 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
240
241 static int
242 rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
243           unsigned long arg) 
244 {
245         unsigned long flags;
246
247         switch(cmd) {
248                 case RTC_RD_TIME:       /* read the time/date from RTC  */
249                 {
250                         struct rtc_time rtc_tm;
251                                                 
252                         memset(&rtc_tm, 0, sizeof (struct rtc_time));
253                         get_rtc_time(&rtc_tm);                                          
254                         if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
255                                 return -EFAULT; 
256                         return 0;
257                 }
258
259                 case RTC_SET_TIME:      /* set the RTC */
260                 {
261                         struct rtc_time rtc_tm;
262                         unsigned char mon, day, hrs, min, sec, leap_yr;
263                         unsigned int yrs;
264
265                         if (!capable(CAP_SYS_TIME))
266                                 return -EPERM;
267
268                         if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
269                                 return -EFAULT;
270
271                         yrs = rtc_tm.tm_year + 1900;
272                         mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
273                         day = rtc_tm.tm_mday;
274                         hrs = rtc_tm.tm_hour;
275                         min = rtc_tm.tm_min;
276                         sec = rtc_tm.tm_sec;
277                         
278                         
279                         if ((yrs < 1970) || (yrs > 2069))
280                                 return -EINVAL;
281
282                         leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
283
284                         if ((mon > 12) || (day == 0))
285                                 return -EINVAL;
286
287                         if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
288                                 return -EINVAL;
289                         
290                         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
291                                 return -EINVAL;
292
293                         if (yrs >= 2000)
294                                 yrs -= 2000;    /* RTC (0, 1, ... 69) */
295                         else
296                                 yrs -= 1900;    /* RTC (70, 71, ... 99) */
297
298                         sec = bin2bcd(sec);
299                         min = bin2bcd(min);
300                         hrs = bin2bcd(hrs);
301                         day = bin2bcd(day);
302                         mon = bin2bcd(mon);
303                         yrs = bin2bcd(yrs);
304
305                         local_irq_save(flags);
306                         CMOS_WRITE(yrs, RTC_YEAR);
307                         CMOS_WRITE(mon, RTC_MONTH);
308                         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
309                         CMOS_WRITE(hrs, RTC_HOURS);
310                         CMOS_WRITE(min, RTC_MINUTES);
311                         CMOS_WRITE(sec, RTC_SECONDS);
312                         local_irq_restore(flags);
313
314                         /* Notice that at this point, the RTC is updated but
315                          * the kernel is still running with the old time.
316                          * You need to set that separately with settimeofday
317                          * or adjtimex.
318                          */
319                         return 0;
320                 }
321
322                 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
323                 {
324                         int tcs_val;
325
326                         if (!capable(CAP_SYS_TIME))
327                                 return -EPERM;
328                         
329                         if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
330                                 return -EFAULT;
331
332                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
333                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
334                         return 0;
335                 }
336                 case RTC_VL_READ:
337                 {
338                         /* TODO:
339                          * Implement voltage low detection support
340                          */
341                         printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
342                                " is not supported\n");
343                         return 0;
344                 }
345                 case RTC_VL_CLR:
346                 {
347                         /* TODO:
348                          * Nothing to do since Voltage Low detection is not supported
349                          */
350                         return 0;
351                 }
352                 default:
353                         return -ENOIOCTLCMD;
354         }
355 }
356
357 static void
358 print_rtc_status(void)
359 {
360         struct rtc_time tm;
361
362         get_rtc_time(&tm);
363
364         /*
365          * There is no way to tell if the luser has the RTC set for local
366          * time or for Universal Standard Time (GMT). Probably local though.
367          */
368
369         printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
370                tm.tm_hour, tm.tm_min, tm.tm_sec);
371         printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
372                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
373 }
374
375 /* The various file operations we support. */
376
377 static const struct file_operations rtc_fops = {
378         .owner =        THIS_MODULE,
379         .ioctl =        rtc_ioctl,
380 }; 
381
382 /* Probe for the chip by writing something to its RAM and try reading it back. */
383
384 #define MAGIC_PATTERN 0x42
385
386 static int __init
387 ds1302_probe(void) 
388 {
389         int retval, res; 
390
391         TK_RST_DIR(1);
392         TK_SCL_DIR(1);
393         TK_SDA_DIR(0);
394         
395         /* Try to talk to timekeeper. */
396
397         ds1302_wenable();  
398         start();
399         out_byte(0xc0); /* write RAM byte 0 */  
400         out_byte(MAGIC_PATTERN); /* write something magic */
401         start();
402         out_byte(0xc1); /* read RAM byte 0 */
403
404         if((res = in_byte()) == MAGIC_PATTERN) {
405                 stop();
406                 ds1302_wdisable();
407                 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
408                 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
409                        ds1302_name,
410                        CONFIG_ETRAX_DS1302_SDABIT,
411                        CONFIG_ETRAX_DS1302_SCLBIT,
412 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
413                        "GENIO",
414 #else
415                        "PB",
416 #endif
417                        CONFIG_ETRAX_DS1302_RSTBIT);
418                        print_rtc_status();
419                 retval = 1;
420         } else {
421                 stop();
422                 retval = 0;
423         }
424
425         return retval;
426 }
427
428
429 /* Just probe for the RTC and register the device to handle the ioctl needed. */
430
431 int __init
432 ds1302_init(void) 
433 {
434 #ifdef CONFIG_ETRAX_I2C
435         i2c_init();
436 #endif
437
438         if (!ds1302_probe()) {
439 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
440 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
441                 /*
442                  * The only way to set g27 to output is to enable ATA.
443                  *
444                  * Make sure that R_GEN_CONFIG is setup correct.
445                  */
446                 /* Allocating the ATA interface will grab almost all
447                  * pins in I/O groups a, b, c and d.  A consequence of
448                  * allocating the ATA interface is that the fixed
449                  * interfaces shared RAM, parallel port 0, parallel
450                  * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
451                  * 1, SCSI-W, serial port 2, serial port 3,
452                  * synchronous serial port 3 and USB port 2 and almost
453                  * all GPIO pins on port g cannot be used.
454                  */
455                 if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
456                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
457                         return -1;
458                 }
459
460 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
461                 if (cris_io_interface_allocate_pins(if_gpio_grp_a,
462                                                     'g',
463                                                     CONFIG_ETRAX_DS1302_RSTBIT,
464                                                     CONFIG_ETRAX_DS1302_RSTBIT)) {
465                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
466                         return -1;
467                 }
468
469                 /* Set the direction of this bit to out. */
470                 genconfig_shadow = ((genconfig_shadow &
471                                      ~IO_MASK(R_GEN_CONFIG, g0dir)) |
472                                    (IO_STATE(R_GEN_CONFIG, g0dir, out)));
473                 *R_GEN_CONFIG = genconfig_shadow;
474 #endif
475                 if (!ds1302_probe()) {
476                         printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
477                         return -1;
478                 }
479 #else
480                 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
481                 return -1;
482 #endif
483         }
484         /* Initialise trickle charger */
485         ds1302_writereg(RTC_TRICKLECHARGER,
486                         RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
487         /* Start clock by resetting CLOCK_HALT */
488         ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
489         return 0;
490 }
491
492 static int __init ds1302_register(void)
493 {
494         ds1302_init();
495         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
496                 printk(KERN_INFO "%s: unable to get major %d for rtc\n", 
497                        ds1302_name, RTC_MAJOR_NR);
498                 return -1;
499         }
500         return 0;
501
502 }
503
504 module_init(ds1302_register);