Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
[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/mutex.h>
23 #include <linux/bcd.h>
24 #include <linux/capability.h>
25
26 #include <asm/uaccess.h>
27 #include <asm/system.h>
28 #include <arch/svinto.h>
29 #include <asm/io.h>
30 #include <asm/rtc.h>
31 #include <arch/io_interface_mux.h>
32
33 #include "i2c.h"
34
35 #define RTC_MAJOR_NR 121 /* local major, change later */
36
37 static DEFINE_MUTEX(ds1302_mutex);
38 static const char ds1302_name[] = "ds1302";
39
40 /* The DS1302 might be connected to different bits on different products. 
41  * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
42  * but SDA can have a selected direction.
43  * For now, only PORT_PB is hardcoded.
44  */
45
46 /* The RST bit may be on either the Generic Port or Port PB. */
47 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
48 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
49 #define TK_RST_DIR(x)
50 #else
51 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
52 #define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
53 #endif
54
55
56 #define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
57 #define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
58
59 #define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
60 /* 1 is out, 0 is in */
61 #define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
62 #define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
63
64
65 /*
66  * The reason for tempudelay and not udelay is that loops_per_usec
67  * (used in udelay) is not set when functions here are called from time.c 
68  */
69
70 static void tempudelay(int usecs) 
71 {
72         volatile int loops;
73
74         for(loops = usecs * 12; loops > 0; loops--)
75                 /* nothing */;  
76 }
77
78
79 /* Send 8 bits. */
80 static void
81 out_byte(unsigned char x) 
82 {
83         int i;
84         TK_SDA_DIR(1);
85         for (i = 8; i--;) {
86                 /* The chip latches incoming bits on the rising edge of SCL. */
87                 TK_SCL_OUT(0);
88                 TK_SDA_OUT(x & 1);
89                 tempudelay(1);
90                 TK_SCL_OUT(1);
91                 tempudelay(1);
92                 x >>= 1;
93         }
94         TK_SDA_DIR(0);
95 }
96
97 static unsigned char
98 in_byte(void) 
99 {
100         unsigned char x = 0;
101         int i;
102
103         /* Read byte. Bits come LSB first, on the falling edge of SCL.
104          * Assume SDA is in input direction already.
105          */
106         TK_SDA_DIR(0);
107
108         for (i = 8; i--;) {
109                 TK_SCL_OUT(0);
110                 tempudelay(1);
111                 x >>= 1;
112                 x |= (TK_SDA_IN() << 7);
113                 TK_SCL_OUT(1);
114                 tempudelay(1);
115         }
116
117         return x;
118 }
119
120 /* Prepares for a transaction by de-activating RST (active-low). */
121
122 static void
123 start(void) 
124 {
125         TK_SCL_OUT(0);
126         tempudelay(1);
127         TK_RST_OUT(0);
128         tempudelay(5);
129         TK_RST_OUT(1);  
130 }
131
132 /* Ends a transaction by taking RST active again. */
133
134 static void
135 stop(void) 
136 {
137         tempudelay(2);
138         TK_RST_OUT(0);
139 }
140
141 /* Enable writing. */
142
143 static void
144 ds1302_wenable(void) 
145 {
146         start();        
147         out_byte(0x8e); /* Write control register  */
148         out_byte(0x00); /* Disable write protect bit 7 = 0 */
149         stop();
150 }
151
152 /* Disable writing. */
153
154 static void
155 ds1302_wdisable(void) 
156 {
157         start();
158         out_byte(0x8e); /* Write control register  */
159         out_byte(0x80); /* Disable write protect bit 7 = 0 */
160         stop();
161 }
162
163
164
165 /* Read a byte from the selected register in the DS1302. */
166
167 unsigned char
168 ds1302_readreg(int reg) 
169 {
170         unsigned char x;
171
172         start();
173         out_byte(0x81 | (reg << 1)); /* read register */
174         x = in_byte();
175         stop();
176
177         return x;
178 }
179
180 /* Write a byte to the selected register. */
181
182 void
183 ds1302_writereg(int reg, unsigned char val) 
184 {
185 #ifndef CONFIG_ETRAX_RTC_READONLY
186         int do_writereg = 1;
187 #else
188         int do_writereg = 0;
189
190         if (reg == RTC_TRICKLECHARGER)
191                 do_writereg = 1;
192 #endif
193
194         if (do_writereg) {
195                 ds1302_wenable();
196                 start();
197                 out_byte(0x80 | (reg << 1)); /* write register */
198                 out_byte(val);
199                 stop();
200                 ds1302_wdisable();
201         }
202 }
203
204 void
205 get_rtc_time(struct rtc_time *rtc_tm) 
206 {
207         unsigned long flags;
208
209         local_irq_save(flags);
210
211         rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
212         rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
213         rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
214         rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
215         rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
216         rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
217
218         local_irq_restore(flags);
219         
220         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
221         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
222         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
223         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
224         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
225         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
226
227         /*
228          * Account for differences between how the RTC uses the values
229          * and how they are defined in a struct rtc_time;
230          */
231
232         if (rtc_tm->tm_year <= 69)
233                 rtc_tm->tm_year += 100;
234
235         rtc_tm->tm_mon--;
236 }
237
238 static unsigned char days_in_mo[] = 
239     {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
240
241 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
242
243 static int rtc_ioctl(struct file *file, unsigned int cmd, 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 long rtc_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
358 {
359         int ret;
360
361         mutex_lock(&ds1302_mutex);
362         ret = rtc_ioctl(file, cmd, arg);
363         mutex_unlock(&ds1302_mutex);
364
365         return ret;
366 }
367
368 static void
369 print_rtc_status(void)
370 {
371         struct rtc_time tm;
372
373         get_rtc_time(&tm);
374
375         /*
376          * There is no way to tell if the luser has the RTC set for local
377          * time or for Universal Standard Time (GMT). Probably local though.
378          */
379
380         printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
381                tm.tm_hour, tm.tm_min, tm.tm_sec);
382         printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
383                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
384 }
385
386 /* The various file operations we support. */
387
388 static const struct file_operations rtc_fops = {
389         .owner          = THIS_MODULE,
390         .unlocked_ioctl = rtc_unlocked_ioctl,
391         .llseek         = noop_llseek,
392 }; 
393
394 /* Probe for the chip by writing something to its RAM and try reading it back. */
395
396 #define MAGIC_PATTERN 0x42
397
398 static int __init
399 ds1302_probe(void) 
400 {
401         int retval, res; 
402
403         TK_RST_DIR(1);
404         TK_SCL_DIR(1);
405         TK_SDA_DIR(0);
406         
407         /* Try to talk to timekeeper. */
408
409         ds1302_wenable();  
410         start();
411         out_byte(0xc0); /* write RAM byte 0 */  
412         out_byte(MAGIC_PATTERN); /* write something magic */
413         start();
414         out_byte(0xc1); /* read RAM byte 0 */
415
416         if((res = in_byte()) == MAGIC_PATTERN) {
417                 stop();
418                 ds1302_wdisable();
419                 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
420                 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
421                        ds1302_name,
422                        CONFIG_ETRAX_DS1302_SDABIT,
423                        CONFIG_ETRAX_DS1302_SCLBIT,
424 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
425                        "GENIO",
426 #else
427                        "PB",
428 #endif
429                        CONFIG_ETRAX_DS1302_RSTBIT);
430                        print_rtc_status();
431                 retval = 1;
432         } else {
433                 stop();
434                 retval = 0;
435         }
436
437         return retval;
438 }
439
440
441 /* Just probe for the RTC and register the device to handle the ioctl needed. */
442
443 int __init
444 ds1302_init(void) 
445 {
446 #ifdef CONFIG_ETRAX_I2C
447         i2c_init();
448 #endif
449
450         if (!ds1302_probe()) {
451 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
452 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
453                 /*
454                  * The only way to set g27 to output is to enable ATA.
455                  *
456                  * Make sure that R_GEN_CONFIG is setup correct.
457                  */
458                 /* Allocating the ATA interface will grab almost all
459                  * pins in I/O groups a, b, c and d.  A consequence of
460                  * allocating the ATA interface is that the fixed
461                  * interfaces shared RAM, parallel port 0, parallel
462                  * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
463                  * 1, SCSI-W, serial port 2, serial port 3,
464                  * synchronous serial port 3 and USB port 2 and almost
465                  * all GPIO pins on port g cannot be used.
466                  */
467                 if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
468                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
469                         return -1;
470                 }
471
472 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
473                 if (cris_io_interface_allocate_pins(if_gpio_grp_a,
474                                                     'g',
475                                                     CONFIG_ETRAX_DS1302_RSTBIT,
476                                                     CONFIG_ETRAX_DS1302_RSTBIT)) {
477                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
478                         return -1;
479                 }
480
481                 /* Set the direction of this bit to out. */
482                 genconfig_shadow = ((genconfig_shadow &
483                                      ~IO_MASK(R_GEN_CONFIG, g0dir)) |
484                                    (IO_STATE(R_GEN_CONFIG, g0dir, out)));
485                 *R_GEN_CONFIG = genconfig_shadow;
486 #endif
487                 if (!ds1302_probe()) {
488                         printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
489                         return -1;
490                 }
491 #else
492                 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
493                 return -1;
494 #endif
495         }
496         /* Initialise trickle charger */
497         ds1302_writereg(RTC_TRICKLECHARGER,
498                         RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
499         /* Start clock by resetting CLOCK_HALT */
500         ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
501         return 0;
502 }
503
504 static int __init ds1302_register(void)
505 {
506         ds1302_init();
507         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
508                 printk(KERN_INFO "%s: unable to get major %d for rtc\n", 
509                        ds1302_name, RTC_MAJOR_NR);
510                 return -1;
511         }
512         return 0;
513
514 }
515
516 module_init(ds1302_register);