/*
* w1_ds2433.c - w1 family 23 (DS2433) driver
*
* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the smems of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include "w1.h"
#include "w1_io.h"
#include "w1_int.h"
#include "w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
#define W1_EEPROM_SIZE 512
#define W1_PAGE_SIZE 32
#define W1_PAGE_BITS 5
#define W1_PAGE_MASK 0x1F
#define W1_F23_READ_EEPROM 0xF0
#define W1_F23_WRITE_SCRATCH 0x0F
#define W1_F23_READ_SCRATCH 0xAA
#define W1_F23_COPY_SCRATCH 0x55
/**
* Check the file size bounds and adjusts count as needed.
* This may not be needed if the sysfs layer checks bounds.
*/
static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
{
if (off > size)
return 0;
if ((off + count) > size)
return (size - off);
return count;
}
static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 wrbuf[3];
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
atomic_inc(&sl->refcnt);
if (down_interruptible(&sl->master->mutex)) {
count = 0;
goto out_dec;
}
/* read directly from the EEPROM */
if (w1_reset_select_slave(sl)) {
count = -EIO;
goto out_up;
}
wrbuf[0] = W1_F23_READ_EEPROM;
wrbuf[1] = off & 0xff;
wrbuf[2] = off >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, buf, count);
out_up:
up(&sl->master->mutex);
out_dec:
atomic_dec(&sl->refcnt);
return count;
}
/**
* Writes to the scratchpad and reads it back for verification.
* The master must be locked.
*
* @param sl The slave structure
* @param addr Address for the write
* @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
* @param data The data to write
* @return 0=Success -1=failure
*/
static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
{
u8 wrbuf[4];
u8 rdbuf[W1_PAGE_SIZE + 3];
u8 es = (addr + len - 1) & 0x1f;
/* Write the data to the scratchpad */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F23_WRITE_SCRATCH;
wrbuf[1] = addr & 0xff;
wrbuf[2] = addr >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_write_block(sl->master, data, len);
/* Read the scratchpad and verify */
if (w1_reset_select_slave(sl))
return -1;
w1_write_8(sl->master, W1_F23_READ_SCRATCH);
w1_read_block(sl->master, rdbuf, len + 3);
/* Compare what was read against the data written */
if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
(rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
return -1;
/* Copy the scratchpad to EEPROM */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F23_COPY_SCRATCH;
wrbuf[3] = es;
w1_write_block(sl->master, wrbuf, 4);
/* Sleep for 5 ms to wait for the write to complete */
msleep(5);
/* Reset the bus to wake up the EEPROM (this may not be needed) */
w1_reset_bus(sl->master);
return 0;
}
static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int addr, len, idx;
if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
return 0;
atomic_inc(&sl->refcnt);
if (down_interruptible(&sl->master->mutex)) {
count = 0;
goto out_dec;
}
/* Can only write data to one page at a time */
idx = 0;
while (idx < count) {
addr = off + idx;
len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
if (len > (count - idx))
len = count - idx;
if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
count = -EIO;
goto out_up;
}
idx += len;
}
out_up:
up(&sl->master->mutex);
out_dec:
atomic_dec(&sl->refcnt);
return count;
}
static struct bin_attribute w1_f23_bin_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO | S_IWUSR,
.owner = THIS_MODULE,
},
.size = W1_EEPROM_SIZE,
.read = w1_f23_read_bin,
.write = w1_f23_write_bin,
};
static int w1_f23_add_slave(struct w1_slave *sl)
{
return sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}
static void w1_f23_remove_slave(struct w1_slave *sl)
{
sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
}
static struct w1_family_ops w1_f23_fops = {
.add_slave = w1_f23_add_slave,
.remove_slave = w1_f23_remove_slave,
};
static struct w1_family w1_family_23 = {
.fid = W1_EEPROM_DS2433,
.fops = &w1_f23_fops,
};
static int __init w1_f23_init(void)
{
return w1_register_family(&w1_family_23);
}
static void __exit w1_f23_fini(void)
{
w1_unregister_family(&w1_family_23);
}
module_init(w1_f23_init);
module_exit(w1_f23_fini);
