| /*!***************************************************************************** | |
| *! | |
| *! Implements an interface for i2c compatible eeproms to run under Linux. | |
| *! Supports 2k, 8k(?) and 16k. Uses adaptive timing adjustments by | |
| *! Johan.Adolfsson@axis.com | |
| *! | |
| *! Probing results: | |
| *! 8k or not is detected (the assumes 2k or 16k) | |
| *! 2k or 16k detected using test reads and writes. | |
| *! | |
| *!------------------------------------------------------------------------ | |
| *! HISTORY | |
| *! | |
| *! DATE NAME CHANGES | |
| *! ---- ---- ------- | |
| *! Aug 28 1999 Edgar Iglesias Initial Version | |
| *! Aug 31 1999 Edgar Iglesias Allow simultaneous users. | |
| *! Sep 03 1999 Edgar Iglesias Updated probe. | |
| *! Sep 03 1999 Edgar Iglesias Added bail-out stuff if we get interrupted | |
| *! in the spin-lock. | |
| *! | |
| *! (c) 1999 Axis Communications AB, Lund, Sweden | |
| *!*****************************************************************************/ | |
| #include <linux/kernel.h> | |
| #include <linux/sched.h> | |
| #include <linux/fs.h> | |
| #include <linux/init.h> | |
| #include <linux/delay.h> | |
| #include <linux/interrupt.h> | |
| #include <linux/wait.h> | |
| #include <asm/uaccess.h> | |
| #include "i2c.h" | |
| #define D(x) | |
| /* If we should use adaptive timing or not: */ | |
| /* #define EEPROM_ADAPTIVE_TIMING */ | |
| #define EEPROM_MAJOR_NR 122 /* use a LOCAL/EXPERIMENTAL major for now */ | |
| #define EEPROM_MINOR_NR 0 | |
| /* Empirical sane initial value of the delay, the value will be adapted to | |
| * what the chip needs when using EEPROM_ADAPTIVE_TIMING. | |
| */ | |
| #define INITIAL_WRITEDELAY_US 4000 | |
| #define MAX_WRITEDELAY_US 10000 /* 10 ms according to spec for 2KB EEPROM */ | |
| /* This one defines how many times to try when eeprom fails. */ | |
| #define EEPROM_RETRIES 10 | |
| #define EEPROM_2KB (2 * 1024) | |
| /*#define EEPROM_4KB (4 * 1024)*/ /* Exists but not used in Axis products */ | |
| #define EEPROM_8KB (8 * 1024 - 1 ) /* Last byte has write protection bit */ | |
| #define EEPROM_16KB (16 * 1024) | |
| #define i2c_delay(x) udelay(x) | |
| /* | |
| * This structure describes the attached eeprom chip. | |
| * The values are probed for. | |
| */ | |
| struct eeprom_type | |
| { | |
| unsigned long size; | |
| unsigned long sequential_write_pagesize; | |
| unsigned char select_cmd; | |
| unsigned long usec_delay_writecycles; /* Min time between write cycles | |
| (up to 10ms for some models) */ | |
| unsigned long usec_delay_step; /* For adaptive algorithm */ | |
| int adapt_state; /* 1 = To high , 0 = Even, -1 = To low */ | |
| /* this one is to keep the read/write operations atomic */ | |
| struct mutex lock; | |
| int retry_cnt_addr; /* Used to keep track of number of retries for | |
| adaptive timing adjustments */ | |
| int retry_cnt_read; | |
| }; | |
| static int eeprom_open(struct inode * inode, struct file * file); | |
| static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig); | |
| static ssize_t eeprom_read(struct file * file, char * buf, size_t count, | |
| loff_t *off); | |
| static ssize_t eeprom_write(struct file * file, const char * buf, size_t count, | |
| loff_t *off); | |
| static int eeprom_close(struct inode * inode, struct file * file); | |
| static int eeprom_address(unsigned long addr); | |
| static int read_from_eeprom(char * buf, int count); | |
| static int eeprom_write_buf(loff_t addr, const char * buf, int count); | |
| static int eeprom_read_buf(loff_t addr, char * buf, int count); | |
| static void eeprom_disable_write_protect(void); | |
| static const char eeprom_name[] = "eeprom"; | |
| /* chip description */ | |
| static struct eeprom_type eeprom; | |
| /* This is the exported file-operations structure for this device. */ | |
| const struct file_operations eeprom_fops = | |
| { | |
| .llseek = eeprom_lseek, | |
| .read = eeprom_read, | |
| .write = eeprom_write, | |
| .open = eeprom_open, | |
| .release = eeprom_close | |
| }; | |
| /* eeprom init call. Probes for different eeprom models. */ | |
| int __init eeprom_init(void) | |
| { | |
| mutex_init(&eeprom.lock); | |
| #ifdef CONFIG_ETRAX_I2C_EEPROM_PROBE | |
| #define EETEXT "Found" | |
| #else | |
| #define EETEXT "Assuming" | |
| #endif | |
| if (register_chrdev(EEPROM_MAJOR_NR, eeprom_name, &eeprom_fops)) | |
| { | |
| printk(KERN_INFO "%s: unable to get major %d for eeprom device\n", | |
| eeprom_name, EEPROM_MAJOR_NR); | |
| return -1; | |
| } | |
| printk("EEPROM char device v0.3, (c) 2000 Axis Communications AB\n"); | |
| /* | |
| * Note: Most of this probing method was taken from the printserver (5470e) | |
| * codebase. It did not contain a way of finding the 16kB chips | |
| * (M24128 or variants). The method used here might not work | |
| * for all models. If you encounter problems the easiest way | |
| * is probably to define your model within #ifdef's, and hard- | |
| * code it. | |
| */ | |
| eeprom.size = 0; | |
| eeprom.usec_delay_writecycles = INITIAL_WRITEDELAY_US; | |
| eeprom.usec_delay_step = 128; | |
| eeprom.adapt_state = 0; | |
| #ifdef CONFIG_ETRAX_I2C_EEPROM_PROBE | |
| i2c_start(); | |
| i2c_outbyte(0x80); | |
| if(!i2c_getack()) | |
| { | |
| /* It's not 8k.. */ | |
| int success = 0; | |
| unsigned char buf_2k_start[16]; | |
| /* Im not sure this will work... :) */ | |
| /* assume 2kB, if failure go for 16kB */ | |
| /* Test with 16kB settings.. */ | |
| /* If it's a 2kB EEPROM and we address it outside it's range | |
| * it will mirror the address space: | |
| * 1. We read two locations (that are mirrored), | |
| * if the content differs * it's a 16kB EEPROM. | |
| * 2. if it doesn't differ - write different value to one of the locations, | |
| * check the other - if content still is the same it's a 2k EEPROM, | |
| * restore original data. | |
| */ | |
| #define LOC1 8 | |
| #define LOC2 (0x1fb) /*1fb, 3ed, 5df, 7d1 */ | |
| /* 2k settings */ | |
| i2c_stop(); | |
| eeprom.size = EEPROM_2KB; | |
| eeprom.select_cmd = 0xA0; | |
| eeprom.sequential_write_pagesize = 16; | |
| if( eeprom_read_buf( 0, buf_2k_start, 16 ) == 16 ) | |
| { | |
| D(printk("2k start: '%16.16s'\n", buf_2k_start)); | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: Failed to read in 2k mode!\n", eeprom_name); | |
| } | |
| /* 16k settings */ | |
| eeprom.size = EEPROM_16KB; | |
| eeprom.select_cmd = 0xA0; | |
| eeprom.sequential_write_pagesize = 64; | |
| { | |
| unsigned char loc1[4], loc2[4], tmp[4]; | |
| if( eeprom_read_buf(LOC2, loc2, 4) == 4) | |
| { | |
| if( eeprom_read_buf(LOC1, loc1, 4) == 4) | |
| { | |
| D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", | |
| LOC1, loc1, LOC2, loc2)); | |
| #if 0 | |
| if (memcmp(loc1, loc2, 4) != 0 ) | |
| { | |
| /* It's 16k */ | |
| printk(KERN_INFO "%s: 16k detected in step 1\n", eeprom_name); | |
| eeprom.size = EEPROM_16KB; | |
| success = 1; | |
| } | |
| else | |
| #endif | |
| { | |
| /* Do step 2 check */ | |
| /* Invert value */ | |
| loc1[0] = ~loc1[0]; | |
| if (eeprom_write_buf(LOC1, loc1, 1) == 1) | |
| { | |
| /* If 2k EEPROM this write will actually write 10 bytes | |
| * from pos 0 | |
| */ | |
| D(printk("1 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", | |
| LOC1, loc1, LOC2, loc2)); | |
| if( eeprom_read_buf(LOC1, tmp, 4) == 4) | |
| { | |
| D(printk("2 loc1: (%i) '%4.4s' tmp '%4.4s'\n", | |
| LOC1, loc1, tmp)); | |
| if (memcmp(loc1, tmp, 4) != 0 ) | |
| { | |
| printk(KERN_INFO "%s: read and write differs! Not 16kB\n", | |
| eeprom_name); | |
| loc1[0] = ~loc1[0]; | |
| if (eeprom_write_buf(LOC1, loc1, 1) == 1) | |
| { | |
| success = 1; | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: Restore 2k failed during probe," | |
| " EEPROM might be corrupt!\n", eeprom_name); | |
| } | |
| i2c_stop(); | |
| /* Go to 2k mode and write original data */ | |
| eeprom.size = EEPROM_2KB; | |
| eeprom.select_cmd = 0xA0; | |
| eeprom.sequential_write_pagesize = 16; | |
| if( eeprom_write_buf(0, buf_2k_start, 16) == 16) | |
| { | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: Failed to write back 2k start!\n", | |
| eeprom_name); | |
| } | |
| eeprom.size = EEPROM_2KB; | |
| } | |
| } | |
| if(!success) | |
| { | |
| if( eeprom_read_buf(LOC2, loc2, 1) == 1) | |
| { | |
| D(printk("0 loc1: (%i) '%4.4s' loc2 (%i) '%4.4s'\n", | |
| LOC1, loc1, LOC2, loc2)); | |
| if (memcmp(loc1, loc2, 4) == 0 ) | |
| { | |
| /* Data the same, must be mirrored -> 2k */ | |
| /* Restore data */ | |
| printk(KERN_INFO "%s: 2k detected in step 2\n", eeprom_name); | |
| loc1[0] = ~loc1[0]; | |
| if (eeprom_write_buf(LOC1, loc1, 1) == 1) | |
| { | |
| success = 1; | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: Restore 2k failed during probe," | |
| " EEPROM might be corrupt!\n", eeprom_name); | |
| } | |
| eeprom.size = EEPROM_2KB; | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: 16k detected in step 2\n", | |
| eeprom_name); | |
| loc1[0] = ~loc1[0]; | |
| /* Data differs, assume 16k */ | |
| /* Restore data */ | |
| if (eeprom_write_buf(LOC1, loc1, 1) == 1) | |
| { | |
| success = 1; | |
| } | |
| else | |
| { | |
| printk(KERN_INFO "%s: Restore 16k failed during probe," | |
| " EEPROM might be corrupt!\n", eeprom_name); | |
| } | |
| eeprom.size = EEPROM_16KB; | |
| } | |
| } | |
| } | |
| } | |
| } /* read LOC1 */ | |
| } /* address LOC1 */ | |
| if (!success) | |
| { | |
| printk(KERN_INFO "%s: Probing failed!, using 2KB!\n", eeprom_name); | |
| eeprom.size = EEPROM_2KB; | |
| } | |
| } /* read */ | |
| } | |
| } | |
| else | |
| { | |
| i2c_outbyte(0x00); | |
| if(!i2c_getack()) | |
| { | |
| /* No 8k */ | |
| eeprom.size = EEPROM_2KB; | |
| } | |
| else | |
| { | |
| i2c_start(); | |
| i2c_outbyte(0x81); | |
| if (!i2c_getack()) | |
| { | |
| eeprom.size = EEPROM_2KB; | |
| } | |
| else | |
| { | |
| /* It's a 8kB */ | |
| i2c_inbyte(); | |
| eeprom.size = EEPROM_8KB; | |
| } | |
| } | |
| } | |
| i2c_stop(); | |
| #elif defined(CONFIG_ETRAX_I2C_EEPROM_16KB) | |
| eeprom.size = EEPROM_16KB; | |
| #elif defined(CONFIG_ETRAX_I2C_EEPROM_8KB) | |
| eeprom.size = EEPROM_8KB; | |
| #elif defined(CONFIG_ETRAX_I2C_EEPROM_2KB) | |
| eeprom.size = EEPROM_2KB; | |
| #endif | |
| switch(eeprom.size) | |
| { | |
| case (EEPROM_2KB): | |
| printk("%s: " EETEXT " i2c compatible 2kB eeprom.\n", eeprom_name); | |
| eeprom.sequential_write_pagesize = 16; | |
| eeprom.select_cmd = 0xA0; | |
| break; | |
| case (EEPROM_8KB): | |
| printk("%s: " EETEXT " i2c compatible 8kB eeprom.\n", eeprom_name); | |
| eeprom.sequential_write_pagesize = 16; | |
| eeprom.select_cmd = 0x80; | |
| break; | |
| case (EEPROM_16KB): | |
| printk("%s: " EETEXT " i2c compatible 16kB eeprom.\n", eeprom_name); | |
| eeprom.sequential_write_pagesize = 64; | |
| eeprom.select_cmd = 0xA0; | |
| break; | |
| default: | |
| eeprom.size = 0; | |
| printk("%s: Did not find a supported eeprom\n", eeprom_name); | |
| break; | |
| } | |
| eeprom_disable_write_protect(); | |
| return 0; | |
| } | |
| /* Opens the device. */ | |
| static int eeprom_open(struct inode * inode, struct file * file) | |
| { | |
| if(iminor(inode) != EEPROM_MINOR_NR) | |
| return -ENXIO; | |
| if(imajor(inode) != EEPROM_MAJOR_NR) | |
| return -ENXIO; | |
| if( eeprom.size > 0 ) | |
| { | |
| /* OK */ | |
| return 0; | |
| } | |
| /* No EEprom found */ | |
| return -EFAULT; | |
| } | |
| /* Changes the current file position. */ | |
| static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig) | |
| { | |
| /* | |
| * orig 0: position from begning of eeprom | |
| * orig 1: relative from current position | |
| * orig 2: position from last eeprom address | |
| */ | |
| switch (orig) | |
| { | |
| case 0: | |
| file->f_pos = offset; | |
| break; | |
| case 1: | |
| file->f_pos += offset; | |
| break; | |
| case 2: | |
| file->f_pos = eeprom.size - offset; | |
| break; | |
| default: | |
| return -EINVAL; | |
| } | |
| /* truncate position */ | |
| if (file->f_pos < 0) | |
| { | |
| file->f_pos = 0; | |
| return(-EOVERFLOW); | |
| } | |
| if (file->f_pos >= eeprom.size) | |
| { | |
| file->f_pos = eeprom.size - 1; | |
| return(-EOVERFLOW); | |
| } | |
| return ( file->f_pos ); | |
| } | |
| /* Reads data from eeprom. */ | |
| static int eeprom_read_buf(loff_t addr, char * buf, int count) | |
| { | |
| return eeprom_read(NULL, buf, count, &addr); | |
| } | |
| /* Reads data from eeprom. */ | |
| static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t *off) | |
| { | |
| int read=0; | |
| unsigned long p = *off; | |
| unsigned char page; | |
| if(p >= eeprom.size) /* Address i 0 - (size-1) */ | |
| { | |
| return -EFAULT; | |
| } | |
| if (mutex_lock_interruptible(&eeprom.lock)) | |
| return -EINTR; | |
| page = (unsigned char) (p >> 8); | |
| if(!eeprom_address(p)) | |
| { | |
| printk(KERN_INFO "%s: Read failed to address the eeprom: " | |
| "0x%08X (%i) page: %i\n", eeprom_name, (int)p, (int)p, page); | |
| i2c_stop(); | |
| /* don't forget to wake them up */ | |
| mutex_unlock(&eeprom.lock); | |
| return -EFAULT; | |
| } | |
| if( (p + count) > eeprom.size) | |
| { | |
| /* truncate count */ | |
| count = eeprom.size - p; | |
| } | |
| /* stop dummy write op and initiate the read op */ | |
| i2c_start(); | |
| /* special case for small eeproms */ | |
| if(eeprom.size < EEPROM_16KB) | |
| { | |
| i2c_outbyte( eeprom.select_cmd | 1 | (page << 1) ); | |
| } | |
| /* go on with the actual read */ | |
| read = read_from_eeprom( buf, count); | |
| if(read > 0) | |
| { | |
| *off += read; | |
| } | |
| mutex_unlock(&eeprom.lock); | |
| return read; | |
| } | |
| /* Writes data to eeprom. */ | |
| static int eeprom_write_buf(loff_t addr, const char * buf, int count) | |
| { | |
| return eeprom_write(NULL, buf, count, &addr); | |
| } | |
| /* Writes data to eeprom. */ | |
| static ssize_t eeprom_write(struct file * file, const char * buf, size_t count, | |
| loff_t *off) | |
| { | |
| int i, written, restart=1; | |
| unsigned long p; | |
| if (!access_ok(VERIFY_READ, buf, count)) | |
| { | |
| return -EFAULT; | |
| } | |
| /* bail out if we get interrupted */ | |
| if (mutex_lock_interruptible(&eeprom.lock)) | |
| return -EINTR; | |
| for(i = 0; (i < EEPROM_RETRIES) && (restart > 0); i++) | |
| { | |
| restart = 0; | |
| written = 0; | |
| p = *off; | |
| while( (written < count) && (p < eeprom.size)) | |
| { | |
| /* address the eeprom */ | |
| if(!eeprom_address(p)) | |
| { | |
| printk(KERN_INFO "%s: Write failed to address the eeprom: " | |
| "0x%08X (%i) \n", eeprom_name, (int)p, (int)p); | |
| i2c_stop(); | |
| /* don't forget to wake them up */ | |
| mutex_unlock(&eeprom.lock); | |
| return -EFAULT; | |
| } | |
| #ifdef EEPROM_ADAPTIVE_TIMING | |
| /* Adaptive algorithm to adjust timing */ | |
| if (eeprom.retry_cnt_addr > 0) | |
| { | |
| /* To Low now */ | |
| D(printk(">D=%i d=%i\n", | |
| eeprom.usec_delay_writecycles, eeprom.usec_delay_step)); | |
| if (eeprom.usec_delay_step < 4) | |
| { | |
| eeprom.usec_delay_step++; | |
| eeprom.usec_delay_writecycles += eeprom.usec_delay_step; | |
| } | |
| else | |
| { | |
| if (eeprom.adapt_state > 0) | |
| { | |
| /* To Low before */ | |
| eeprom.usec_delay_step *= 2; | |
| if (eeprom.usec_delay_step > 2) | |
| { | |
| eeprom.usec_delay_step--; | |
| } | |
| eeprom.usec_delay_writecycles += eeprom.usec_delay_step; | |
| } | |
| else if (eeprom.adapt_state < 0) | |
| { | |
| /* To High before (toggle dir) */ | |
| eeprom.usec_delay_writecycles += eeprom.usec_delay_step; | |
| if (eeprom.usec_delay_step > 1) | |
| { | |
| eeprom.usec_delay_step /= 2; | |
| eeprom.usec_delay_step--; | |
| } | |
| } | |
| } | |
| eeprom.adapt_state = 1; | |
| } | |
| else | |
| { | |
| /* To High (or good) now */ | |
| D(printk("<D=%i d=%i\n", | |
| eeprom.usec_delay_writecycles, eeprom.usec_delay_step)); | |
| if (eeprom.adapt_state < 0) | |
| { | |
| /* To High before */ | |
| if (eeprom.usec_delay_step > 1) | |
| { | |
| eeprom.usec_delay_step *= 2; | |
| eeprom.usec_delay_step--; | |
| if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step) | |
| { | |
| eeprom.usec_delay_writecycles -= eeprom.usec_delay_step; | |
| } | |
| } | |
| } | |
| else if (eeprom.adapt_state > 0) | |
| { | |
| /* To Low before (toggle dir) */ | |
| if (eeprom.usec_delay_writecycles > eeprom.usec_delay_step) | |
| { | |
| eeprom.usec_delay_writecycles -= eeprom.usec_delay_step; | |
| } | |
| if (eeprom.usec_delay_step > 1) | |
| { | |
| eeprom.usec_delay_step /= 2; | |
| eeprom.usec_delay_step--; | |
| } | |
| eeprom.adapt_state = -1; | |
| } | |
| if (eeprom.adapt_state > -100) | |
| { | |
| eeprom.adapt_state--; | |
| } | |
| else | |
| { | |
| /* Restart adaption */ | |
| D(printk("#Restart\n")); | |
| eeprom.usec_delay_step++; | |
| } | |
| } | |
| #endif /* EEPROM_ADAPTIVE_TIMING */ | |
| /* write until we hit a page boundary or count */ | |
| do | |
| { | |
| i2c_outbyte(buf[written]); | |
| if(!i2c_getack()) | |
| { | |
| restart=1; | |
| printk(KERN_INFO "%s: write error, retrying. %d\n", eeprom_name, i); | |
| i2c_stop(); | |
| break; | |
| } | |
| written++; | |
| p++; | |
| } while( written < count && ( p % eeprom.sequential_write_pagesize )); | |
| /* end write cycle */ | |
| i2c_stop(); | |
| i2c_delay(eeprom.usec_delay_writecycles); | |
| } /* while */ | |
| } /* for */ | |
| mutex_unlock(&eeprom.lock); | |
| if (written == 0 && p >= eeprom.size){ | |
| return -ENOSPC; | |
| } | |
| *off = p; | |
| return written; | |
| } | |
| /* Closes the device. */ | |
| static int eeprom_close(struct inode * inode, struct file * file) | |
| { | |
| /* do nothing for now */ | |
| return 0; | |
| } | |
| /* Sets the current address of the eeprom. */ | |
| static int eeprom_address(unsigned long addr) | |
| { | |
| int i; | |
| unsigned char page, offset; | |
| page = (unsigned char) (addr >> 8); | |
| offset = (unsigned char) addr; | |
| for(i = 0; i < EEPROM_RETRIES; i++) | |
| { | |
| /* start a dummy write for addressing */ | |
| i2c_start(); | |
| if(eeprom.size == EEPROM_16KB) | |
| { | |
| i2c_outbyte( eeprom.select_cmd ); | |
| i2c_getack(); | |
| i2c_outbyte(page); | |
| } | |
| else | |
| { | |
| i2c_outbyte( eeprom.select_cmd | (page << 1) ); | |
| } | |
| if(!i2c_getack()) | |
| { | |
| /* retry */ | |
| i2c_stop(); | |
| /* Must have a delay here.. 500 works, >50, 100->works 5th time*/ | |
| i2c_delay(MAX_WRITEDELAY_US / EEPROM_RETRIES * i); | |
| /* The chip needs up to 10 ms from write stop to next start */ | |
| } | |
| else | |
| { | |
| i2c_outbyte(offset); | |
| if(!i2c_getack()) | |
| { | |
| /* retry */ | |
| i2c_stop(); | |
| } | |
| else | |
| break; | |
| } | |
| } | |
| eeprom.retry_cnt_addr = i; | |
| D(printk("%i\n", eeprom.retry_cnt_addr)); | |
| if(eeprom.retry_cnt_addr == EEPROM_RETRIES) | |
| { | |
| /* failed */ | |
| return 0; | |
| } | |
| return 1; | |
| } | |
| /* Reads from current address. */ | |
| static int read_from_eeprom(char * buf, int count) | |
| { | |
| int i, read=0; | |
| for(i = 0; i < EEPROM_RETRIES; i++) | |
| { | |
| if(eeprom.size == EEPROM_16KB) | |
| { | |
| i2c_outbyte( eeprom.select_cmd | 1 ); | |
| } | |
| if(i2c_getack()) | |
| { | |
| break; | |
| } | |
| } | |
| if(i == EEPROM_RETRIES) | |
| { | |
| printk(KERN_INFO "%s: failed to read from eeprom\n", eeprom_name); | |
| i2c_stop(); | |
| return -EFAULT; | |
| } | |
| while( (read < count)) | |
| { | |
| if (put_user(i2c_inbyte(), &buf[read++])) | |
| { | |
| i2c_stop(); | |
| return -EFAULT; | |
| } | |
| /* | |
| * make sure we don't ack last byte or you will get very strange | |
| * results! | |
| */ | |
| if(read < count) | |
| { | |
| i2c_sendack(); | |
| } | |
| } | |
| /* stop the operation */ | |
| i2c_stop(); | |
| return read; | |
| } | |
| /* Disables write protection if applicable. */ | |
| #define DBP_SAVE(x) | |
| #define ax_printf printk | |
| static void eeprom_disable_write_protect(void) | |
| { | |
| /* Disable write protect */ | |
| if (eeprom.size == EEPROM_8KB) | |
| { | |
| /* Step 1 Set WEL = 1 (write 00000010 to address 1FFFh */ | |
| i2c_start(); | |
| i2c_outbyte(0xbe); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false\n")); | |
| } | |
| i2c_outbyte(0xFF); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 2\n")); | |
| } | |
| i2c_outbyte(0x02); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 3\n")); | |
| } | |
| i2c_stop(); | |
| i2c_delay(1000); | |
| /* Step 2 Set RWEL = 1 (write 00000110 to address 1FFFh */ | |
| i2c_start(); | |
| i2c_outbyte(0xbe); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 55\n")); | |
| } | |
| i2c_outbyte(0xFF); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 52\n")); | |
| } | |
| i2c_outbyte(0x06); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 53\n")); | |
| } | |
| i2c_stop(); | |
| /* Step 3 Set BP1, BP0, and/or WPEN bits (write 00000110 to address 1FFFh */ | |
| i2c_start(); | |
| i2c_outbyte(0xbe); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 56\n")); | |
| } | |
| i2c_outbyte(0xFF); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 57\n")); | |
| } | |
| i2c_outbyte(0x06); | |
| if(!i2c_getack()) | |
| { | |
| DBP_SAVE(ax_printf("Get ack returns false 58\n")); | |
| } | |
| i2c_stop(); | |
| /* Write protect disabled */ | |
| } | |
| } | |
| module_init(eeprom_init); |