1 /*!*****************************************************************************
3 *! Implements an interface for i2c compatible eeproms to run under linux.
4 *! Supports 2k, 8k(?) and 16k. Uses adaptive timing adjustents by
5 *! Johan.Adolfsson@axis.com
8 *! 8k or not is detected (the assumes 2k or 16k)
9 *! 2k or 16k detected using test reads and writes.
11 *!------------------------------------------------------------------------
16 *! Aug 28 1999 Edgar Iglesias Initial Version
17 *! Aug 31 1999 Edgar Iglesias Allow simultaneous users.
18 *! Sep 03 1999 Edgar Iglesias Updated probe.
19 *! Sep 03 1999 Edgar Iglesias Added bail-out stuff if we get interrupted
23 *! Revision 1.10 2003/09/11 07:29:48 starvik
24 *! Merge of Linux 2.6.0-test5
26 *! Revision 1.9 2003/07/04 08:27:37 starvik
27 *! Merge of Linux 2.5.74
29 *! Revision 1.8 2003/04/09 05:20:47 starvik
30 *! Merge of Linux 2.5.67
32 *! Revision 1.6 2003/02/10 07:19:28 starvik
33 *! Removed misplaced ;
35 *! Revision 1.5 2002/12/11 13:13:57 starvik
36 *! Added arch/ to v10 specific includes
37 *! Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
39 *! Revision 1.4 2002/11/20 11:56:10 starvik
40 *! Merge of Linux 2.5.48
42 *! Revision 1.3 2002/11/18 13:16:06 starvik
43 *! Linux 2.5 port of latest 2.4 drivers
45 *! Revision 1.8 2001/06/15 13:24:29 jonashg
46 *! * Added verification of pointers from userspace in read and write.
47 *! * Made busy counter volatile.
48 *! * Added define for inital write delay.
49 *! * Removed warnings by using loff_t instead of unsigned long.
51 *! Revision 1.7 2001/06/14 15:26:54 jonashg
52 *! Removed test because condition is always true.
54 *! Revision 1.6 2001/06/14 15:18:20 jonashg
55 *! Kb -> kB (makes quite a difference if you don't know if you have 2k or 16k).
57 *! Revision 1.5 2001/06/14 14:39:51 jonashg
58 *! Forgot to use name when registering the driver.
60 *! Revision 1.4 2001/06/14 14:35:47 jonashg
61 *! * Gave driver a name and used it in printk's.
64 *! Revision 1.3 2001/03/19 16:04:46 markusl
65 *! Fixed init of fops struct
67 *! Revision 1.2 2001/03/19 10:35:07 markusl
68 *! 2.4 port of eeprom driver
70 *! Revision 1.8 2000/05/18 10:42:25 edgar
71 *! Make sure to end write cycle on _every_ write
73 *! Revision 1.7 2000/01/17 17:41:01 johana
74 *! Adjusted probing and return -ENOSPC when writing outside EEPROM
76 *! Revision 1.6 2000/01/17 15:50:36 johana
77 *! Added adaptive timing adjustments and fixed autoprobing for 2k and 16k(?)
80 *! Revision 1.5 1999/09/03 15:07:37 edgar
81 *! Added bail-out check to the spinlock
83 *! Revision 1.4 1999/09/03 12:11:17 bjornw
84 *! Proper atomicity (need to use spinlocks, not if's). users -> busy.
87 *! (c) 1999 Axis Communications AB, Lund, Sweden
88 *!*****************************************************************************/
90 #include <linux/config.h>
91 #include <linux/kernel.h>
92 #include <linux/sched.h>
94 #include <linux/init.h>
95 #include <linux/delay.h>
96 #include <linux/interrupt.h>
97 #include <asm/uaccess.h>
102 /* If we should use adaptive timing or not: */
103 //#define EEPROM_ADAPTIVE_TIMING
105 #define EEPROM_MAJOR_NR 122 /* use a LOCAL/EXPERIMENTAL major for now */
106 #define EEPROM_MINOR_NR 0
108 /* Empirical sane initial value of the delay, the value will be adapted to
109 * what the chip needs when using EEPROM_ADAPTIVE_TIMING.
111 #define INITIAL_WRITEDELAY_US 4000
112 #define MAX_WRITEDELAY_US 10000 /* 10 ms according to spec for 2KB EEPROM */
114 /* This one defines how many times to try when eeprom fails. */
115 #define EEPROM_RETRIES 10
117 #define EEPROM_2KB (2 * 1024)
118 /*#define EEPROM_4KB (4 * 1024)*/ /* Exists but not used in Axis products */
119 #define EEPROM_8KB (8 * 1024 - 1 ) /* Last byte has write protection bit */
120 #define EEPROM_16KB (16 * 1024)
122 #define i2c_delay(x) udelay(x)
125 * This structure describes the attached eeprom chip.
126 * The values are probed for.
132 unsigned long sequential_write_pagesize;
133 unsigned char select_cmd;
134 unsigned long usec_delay_writecycles; /* Min time between write cycles
135 (up to 10ms for some models) */
136 unsigned long usec_delay_step; /* For adaptive algorithm */
137 int adapt_state; /* 1 = To high , 0 = Even, -1 = To low */
139 /* this one is to keep the read/write operations atomic */
140 wait_queue_head_t wait_q;
142 int retry_cnt_addr; /* Used to keep track of number of retries for
143 adaptive timing adjustments */
147 static int eeprom_open(struct inode * inode, struct file * file);
148 static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig);
149 static ssize_t eeprom_read(struct file * file, char * buf, size_t count,
151 static ssize_t eeprom_write(struct file * file, const char * buf, size_t count,
153 static int eeprom_close(struct inode * inode, struct file * file);
155 static int eeprom_address(unsigned long addr);
156 static int read_from_eeprom(char * buf, int count);
157 static int eeprom_write_buf(loff_t addr, const char * buf, int count);
158 static int eeprom_read_buf(loff_t addr, char * buf, int count);
160 static void eeprom_disable_write_protect(void);
163 static const char eeprom_name[] = "eeprom";
165 /* chip description */
166 static struct eeprom_type eeprom;
168 /* This is the exported file-operations structure for this device. */
169 struct file_operations eeprom_fops =
171 .llseek = eeprom_lseek,
173 .write = eeprom_write,
175 .release = eeprom_close
178 /* eeprom init call. Probes for different eeprom models. */
180 int __init eeprom_init(void)
182 init_waitqueue_head(&eeprom.wait_q);
185 #ifdef CONFIG_ETRAX_I2C_EEPROM_PROBE
186 #define EETEXT "Found"
188 #define EETEXT "Assuming"
190 if (register_chrdev(EEPROM_MAJOR_NR, eeprom_name, &eeprom_fops))
192 printk(KERN_INFO "%s: unable to get major %d for eeprom device\n",
193 eeprom_name, EEPROM_MAJOR_NR);
197 printk("EEPROM char device v0.3, (c) 2000 Axis Communications AB\n");
200 * Note: Most of this probing method was taken from the printserver (5470e)
201 * codebase. It did not contain a way of finding the 16kB chips
202 * (M24128 or variants). The method used here might not work
203 * for all models. If you encounter problems the easiest way
204 * is probably to define your model within #ifdef's, and hard-
209 eeprom.usec_delay_writecycles = INITIAL_WRITEDELAY_US;
210 eeprom.usec_delay_step = 128;
211 eeprom.adapt_state = 0;
213 #ifdef CONFIG_ETRAX_I2C_EEPROM_PROBE
220 unsigned char buf_2k_start[16];
222 /* Im not sure this will work... :) */
223 /* assume 2kB, if failure go for 16kB */
224 /* Test with 16kB settings.. */
225 /* If it's a 2kB EEPROM and we address it outside it's range
226 * it will mirror the address space:
227 * 1. We read two locations (that are mirrored),
228 * if the content differs * it's a 16kB EEPROM.
229 * 2. if it doesn't differ - write different value to one of the locations,
230 * check the other - if content still is the same it's a 2k EEPROM,
231 * restore original data.
234 #define LOC2 (0x1fb) /*1fb, 3ed, 5df, 7d1 */
238 eeprom.size = EEPROM_2KB;
239 eeprom.select_cmd = 0xA0;
240 eeprom.sequential_write_pagesize = 16;
241 if( eeprom_read_buf( 0, buf_2k_start, 16 ) == 16 )
243 D(printk("2k start: '%16.16s'\n", buf_2k_start));
247 printk(KERN_INFO "%s: Failed to read in 2k mode!\n", eeprom_name);
251 eeprom.size = EEPROM_16KB;
252 eeprom.select_cmd = 0xA0;
253 eeprom.sequential_write_pagesize = 64;
256 unsigned char loc1[4], loc2[4], tmp[4];
257 if( eeprom_read_buf(LOC2, loc2, 4) == 4)
259 if( eeprom_read_buf(LOC1, loc1, 4) == 4)
261 D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n",
262 LOC1, loc1, LOC2, loc2));
264 if (memcmp(loc1, loc2, 4) != 0 )
267 printk(KERN_INFO "%s: 16k detected in step 1\n", eeprom_name);
268 eeprom.size = EEPROM_16KB;
274 /* Do step 2 check */
277 if (eeprom_write_buf(LOC1, loc1, 1) == 1)
279 /* If 2k EEPROM this write will actually write 10 bytes
282 D(printk("1 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n",
283 LOC1, loc1, LOC2, loc2));
284 if( eeprom_read_buf(LOC1, tmp, 4) == 4)
286 D(printk("2 loc1: (%i) '%4.4s' tmp '%4.4s'\n",
288 if (memcmp(loc1, tmp, 4) != 0 )
290 printk(KERN_INFO "%s: read and write differs! Not 16kB\n",
294 if (eeprom_write_buf(LOC1, loc1, 1) == 1)
300 printk(KERN_INFO "%s: Restore 2k failed during probe,"
301 " EEPROM might be corrupt!\n", eeprom_name);
305 /* Go to 2k mode and write original data */
306 eeprom.size = EEPROM_2KB;
307 eeprom.select_cmd = 0xA0;
308 eeprom.sequential_write_pagesize = 16;
309 if( eeprom_write_buf(0, buf_2k_start, 16) == 16)
314 printk(KERN_INFO "%s: Failed to write back 2k start!\n",
318 eeprom.size = EEPROM_2KB;
324 if( eeprom_read_buf(LOC2, loc2, 1) == 1)
326 D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n",
327 LOC1, loc1, LOC2, loc2));
328 if (memcmp(loc1, loc2, 4) == 0 )
330 /* Data the same, must be mirrored -> 2k */
332 printk(KERN_INFO "%s: 2k detected in step 2\n", eeprom_name);
334 if (eeprom_write_buf(LOC1, loc1, 1) == 1)
340 printk(KERN_INFO "%s: Restore 2k failed during probe,"
341 " EEPROM might be corrupt!\n", eeprom_name);
345 eeprom.size = EEPROM_2KB;
349 printk(KERN_INFO "%s: 16k detected in step 2\n",
352 /* Data differs, assume 16k */
354 if (eeprom_write_buf(LOC1, loc1, 1) == 1)
360 printk(KERN_INFO "%s: Restore 16k failed during probe,"
361 " EEPROM might be corrupt!\n", eeprom_name);
364 eeprom.size = EEPROM_16KB;
373 printk(KERN_INFO "%s: Probing failed!, using 2KB!\n", eeprom_name);
374 eeprom.size = EEPROM_2KB;
385 eeprom.size = EEPROM_2KB;
393 eeprom.size = EEPROM_2KB;
399 eeprom.size = EEPROM_8KB;
404 #elif defined(CONFIG_ETRAX_I2C_EEPROM_16KB)
405 eeprom.size = EEPROM_16KB;
406 #elif defined(CONFIG_ETRAX_I2C_EEPROM_8KB)
407 eeprom.size = EEPROM_8KB;
408 #elif defined(CONFIG_ETRAX_I2C_EEPROM_2KB)
409 eeprom.size = EEPROM_2KB;
415 printk("%s: " EETEXT " i2c compatible 2kB eeprom.\n", eeprom_name);
416 eeprom.sequential_write_pagesize = 16;
417 eeprom.select_cmd = 0xA0;
420 printk("%s: " EETEXT " i2c compatible 8kB eeprom.\n", eeprom_name);
421 eeprom.sequential_write_pagesize = 16;
422 eeprom.select_cmd = 0x80;
425 printk("%s: " EETEXT " i2c compatible 16kB eeprom.\n", eeprom_name);
426 eeprom.sequential_write_pagesize = 64;
427 eeprom.select_cmd = 0xA0;
431 printk("%s: Did not find a supported eeprom\n", eeprom_name);
437 eeprom_disable_write_protect();
442 /* Opens the device. */
444 static int eeprom_open(struct inode * inode, struct file * file)
447 if(MINOR(inode->i_rdev) != EEPROM_MINOR_NR)
449 if(MAJOR(inode->i_rdev) != EEPROM_MAJOR_NR)
452 if( eeprom.size > 0 )
458 /* No EEprom found */
462 /* Changes the current file position. */
464 static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig)
467 * orig 0: position from begning of eeprom
468 * orig 1: relative from current position
469 * orig 2: position from last eeprom address
475 file->f_pos = offset;
478 file->f_pos += offset;
481 file->f_pos = eeprom.size - offset;
487 /* truncate position */
494 if (file->f_pos >= eeprom.size)
496 file->f_pos = eeprom.size - 1;
500 return ( file->f_pos );
503 /* Reads data from eeprom. */
505 static int eeprom_read_buf(loff_t addr, char * buf, int count)
510 return eeprom_read(&f, buf, count, &addr);
515 /* Reads data from eeprom. */
517 static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t *off)
520 unsigned long p = file->f_pos;
524 if(p >= eeprom.size) /* Address i 0 - (size-1) */
531 interruptible_sleep_on(&eeprom.wait_q);
533 /* bail out if we get interrupted */
534 if (signal_pending(current))
540 page = (unsigned char) (p >> 8);
542 if(!eeprom_address(p))
544 printk(KERN_INFO "%s: Read failed to address the eeprom: "
545 "0x%08X (%i) page: %i\n", eeprom_name, (int)p, (int)p, page);
548 /* don't forget to wake them up */
550 wake_up_interruptible(&eeprom.wait_q);
554 if( (p + count) > eeprom.size)
557 count = eeprom.size - p;
560 /* stop dummy write op and initiate the read op */
563 /* special case for small eeproms */
564 if(eeprom.size < EEPROM_16KB)
566 i2c_outbyte( eeprom.select_cmd | 1 | (page << 1) );
569 /* go on with the actual read */
570 read = read_from_eeprom( buf, count);
578 wake_up_interruptible(&eeprom.wait_q);
582 /* Writes data to eeprom. */
584 static int eeprom_write_buf(loff_t addr, const char * buf, int count)
590 return eeprom_write(&f, buf, count, &addr);
594 /* Writes data to eeprom. */
596 static ssize_t eeprom_write(struct file * file, const char * buf, size_t count,
599 int i, written, restart=1;
602 if (!access_ok(VERIFY_READ, buf, count))
609 interruptible_sleep_on(&eeprom.wait_q);
610 /* bail out if we get interrupted */
611 if (signal_pending(current))
615 for(i = 0; (i < EEPROM_RETRIES) && (restart > 0); i++)
622 while( (written < count) && (p < eeprom.size))
624 /* address the eeprom */
625 if(!eeprom_address(p))
627 printk(KERN_INFO "%s: Write failed to address the eeprom: "
628 "0x%08X (%i) \n", eeprom_name, (int)p, (int)p);
631 /* don't forget to wake them up */
633 wake_up_interruptible(&eeprom.wait_q);
636 #ifdef EEPROM_ADAPTIVE_TIMING
637 /* Adaptive algorithm to adjust timing */
638 if (eeprom.retry_cnt_addr > 0)
641 D(printk(">D=%i d=%i\n",
642 eeprom.usec_delay_writecycles, eeprom.usec_delay_step));
644 if (eeprom.usec_delay_step < 4)
646 eeprom.usec_delay_step++;
647 eeprom.usec_delay_writecycles += eeprom.usec_delay_step;
652 if (eeprom.adapt_state > 0)
655 eeprom.usec_delay_step *= 2;
656 if (eeprom.usec_delay_step > 2)
658 eeprom.usec_delay_step--;
660 eeprom.usec_delay_writecycles += eeprom.usec_delay_step;
662 else if (eeprom.adapt_state < 0)
664 /* To High before (toggle dir) */
665 eeprom.usec_delay_writecycles += eeprom.usec_delay_step;
666 if (eeprom.usec_delay_step > 1)
668 eeprom.usec_delay_step /= 2;
669 eeprom.usec_delay_step--;
674 eeprom.adapt_state = 1;
678 /* To High (or good) now */
679 D(printk("<D=%i d=%i\n",
680 eeprom.usec_delay_writecycles, eeprom.usec_delay_step));
682 if (eeprom.adapt_state < 0)
685 if (eeprom.usec_delay_step > 1)
687 eeprom.usec_delay_step *= 2;
688 eeprom.usec_delay_step--;
690 if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step)
692 eeprom.usec_delay_writecycles -= eeprom.usec_delay_step;
696 else if (eeprom.adapt_state > 0)
698 /* To Low before (toggle dir) */
699 if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step)
701 eeprom.usec_delay_writecycles -= eeprom.usec_delay_step;
703 if (eeprom.usec_delay_step > 1)
705 eeprom.usec_delay_step /= 2;
706 eeprom.usec_delay_step--;
709 eeprom.adapt_state = -1;
712 if (eeprom.adapt_state > -100)
714 eeprom.adapt_state--;
718 /* Restart adaption */
719 D(printk("#Restart\n"));
720 eeprom.usec_delay_step++;
723 #endif /* EEPROM_ADAPTIVE_TIMING */
724 /* write until we hit a page boundary or count */
727 i2c_outbyte(buf[written]);
731 printk(KERN_INFO "%s: write error, retrying. %d\n", eeprom_name, i);
737 } while( written < count && ( p % eeprom.sequential_write_pagesize ));
739 /* end write cycle */
741 i2c_delay(eeprom.usec_delay_writecycles);
746 wake_up_interruptible(&eeprom.wait_q);
747 if (written == 0 && file->f_pos >= eeprom.size){
750 file->f_pos += written;
754 /* Closes the device. */
756 static int eeprom_close(struct inode * inode, struct file * file)
758 /* do nothing for now */
762 /* Sets the current address of the eeprom. */
764 static int eeprom_address(unsigned long addr)
767 unsigned char page, offset;
769 page = (unsigned char) (addr >> 8);
770 offset = (unsigned char) addr;
772 for(i = 0; i < EEPROM_RETRIES; i++)
774 /* start a dummy write for addressing */
777 if(eeprom.size == EEPROM_16KB)
779 i2c_outbyte( eeprom.select_cmd );
785 i2c_outbyte( eeprom.select_cmd | (page << 1) );
791 /* Must have a delay here.. 500 works, >50, 100->works 5th time*/
792 i2c_delay(MAX_WRITEDELAY_US / EEPROM_RETRIES * i);
793 /* The chip needs up to 10 ms from write stop to next start */
811 eeprom.retry_cnt_addr = i;
812 D(printk("%i\n", eeprom.retry_cnt_addr));
813 if(eeprom.retry_cnt_addr == EEPROM_RETRIES)
821 /* Reads from current address. */
823 static int read_from_eeprom(char * buf, int count)
827 for(i = 0; i < EEPROM_RETRIES; i++)
829 if(eeprom.size == EEPROM_16KB)
831 i2c_outbyte( eeprom.select_cmd | 1 );
840 if(i == EEPROM_RETRIES)
842 printk(KERN_INFO "%s: failed to read from eeprom\n", eeprom_name);
848 while( (read < count))
850 if (put_user(i2c_inbyte(), &buf[read++]))
858 * make sure we don't ack last byte or you will get very strange
867 /* stop the operation */
873 /* Disables write protection if applicable. */
876 #define ax_printf printk
877 static void eeprom_disable_write_protect(void)
879 /* Disable write protect */
880 if (eeprom.size == EEPROM_8KB)
882 /* Step 1 Set WEL = 1 (write 00000010 to address 1FFFh */
887 DBP_SAVE(ax_printf("Get ack returns false\n"));
892 DBP_SAVE(ax_printf("Get ack returns false 2\n"));
897 DBP_SAVE(ax_printf("Get ack returns false 3\n"));
903 /* Step 2 Set RWEL = 1 (write 00000110 to address 1FFFh */
908 DBP_SAVE(ax_printf("Get ack returns false 55\n"));
913 DBP_SAVE(ax_printf("Get ack returns false 52\n"));
918 DBP_SAVE(ax_printf("Get ack returns false 53\n"));
922 /* Step 3 Set BP1, BP0, and/or WPEN bits (write 00000110 to address 1FFFh */
927 DBP_SAVE(ax_printf("Get ack returns false 56\n"));
932 DBP_SAVE(ax_printf("Get ack returns false 57\n"));
937 DBP_SAVE(ax_printf("Get ack returns false 58\n"));
941 /* Write protect disabled */
945 module_init(eeprom_init);