- 根目录:
- drivers
- w1
- slaves
- w1_ds28e04.c
/*
* w1_ds28e04.c - w1 family 1C (DS28E04) driver
*
* Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#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 <linux/slab.h>
#include <linux/crc16.h>
#include <linux/uaccess.h>
#define CRC16_INIT 0
#define CRC16_VALID 0xb001
#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));
/* Allow the strong pullup to be disabled, but default to enabled.
* If it was disabled a parasite powered device might not get the required
* current to copy the data from the scratchpad to EEPROM. If it is enabled
* parasite powered devices have a better chance of getting the current
* required.
*/
static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
/* enable/disable CRC checking on DS28E04-100 memory accesses */
static char w1_enable_crccheck = 1;
#define W1_EEPROM_SIZE 512
#define W1_PAGE_COUNT 16
#define W1_PAGE_SIZE 32
#define W1_PAGE_BITS 5
#define W1_PAGE_MASK 0x1F
#define W1_F1C_READ_EEPROM 0xF0
#define W1_F1C_WRITE_SCRATCH 0x0F
#define W1_F1C_READ_SCRATCH 0xAA
#define W1_F1C_COPY_SCRATCH 0x55
#define W1_F1C_ACCESS_WRITE 0x5A
#define W1_1C_REG_LOGIC_STATE 0x220
struct w1_f1C_data {
u8 memory[W1_EEPROM_SIZE];
u32 validcrc;
};
/**
* Check the file size bounds and adjusts count as needed.
* This would not be needed if the file size didn't reset to 0 after a write.
*/
static inline size_t w1_f1C_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 int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data,
int block)
{
u8 wrbuf[3];
int off = block * W1_PAGE_SIZE;
if (data->validcrc & (1 << block))
return 0;
if (w1_reset_select_slave(sl)) {
data->validcrc = 0;
return -EIO;
}
wrbuf[0] = W1_F1C_READ_EEPROM;
wrbuf[1] = off & 0xff;
wrbuf[2] = off >> 8;
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
/* cache the block if the CRC is valid */
if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
data->validcrc |= (1 << block);
return 0;
}
static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
{
u8 wrbuf[3];
/* read directly from the EEPROM */
if (w1_reset_select_slave(sl))
return -EIO;
wrbuf[0] = W1_F1C_READ_EEPROM;
wrbuf[1] = addr & 0xff;
wrbuf[2] = addr >> 8;
w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
return w1_read_block(sl->master, data, len);
}
static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
struct w1_f1C_data *data = sl->family_data;
int i, min_page, max_page;
count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
if (count == 0)
return 0;
mutex_lock(&sl->master->mutex);
if (w1_enable_crccheck) {
min_page = (off >> W1_PAGE_BITS);
max_page = (off + count - 1) >> W1_PAGE_BITS;
for (i = min_page; i <= max_page; i++) {
if (w1_f1C_refresh_block(sl, data, i)) {
count = -EIO;
goto out_up;
}
}
memcpy(buf, &data->memory[off], count);
} else {
count = w1_f1C_read(sl, off, count, buf);
}
out_up:
mutex_unlock(&sl->master->mutex);
return count;
}
/**
* Writes to the scratchpad and reads it back for verification.
* Then copies the scratchpad to EEPROM.
* The data must be on one page.
* 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_f1C_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;
unsigned int tm = 10;
int i;
struct w1_f1C_data *f1C = sl->family_data;
/* Write the data to the scratchpad */
if (w1_reset_select_slave(sl))
return -1;
wrbuf[0] = W1_F1C_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_F1C_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_F1C_COPY_SCRATCH;
wrbuf[3] = es;
for (i = 0; i < sizeof(wrbuf); ++i) {
/* issue 10ms strong pullup (or delay) on the last byte
for writing the data from the scratchpad to EEPROM */
if (w1_strong_pullup && i == sizeof(wrbuf)-1)
w1_next_pullup(sl->master, tm);
w1_write_8(sl->master, wrbuf[i]);
}
if (!w1_strong_pullup)
msleep(tm);
if (w1_enable_crccheck) {
/* invalidate cached data */
f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
}
/* Reset the bus to wake up the EEPROM (this may not be needed) */
w1_reset_bus(sl->master);
return 0;
}
static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int addr, len, idx;
count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
if (count == 0)
return 0;
if (w1_enable_crccheck) {
/* can only write full blocks in cached mode */
if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
(int)off, count);
return -EINVAL;
}
/* make sure the block CRCs are valid */
for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE)
!= CRC16_VALID) {
dev_err(&sl->dev, "bad CRC at offset %d\n",
(int)off);
return -EINVAL;
}
}
}
mutex_lock(&sl->master->mutex);
/* 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_f1C_write(sl, addr, len, &buf[idx]) < 0) {
count = -EIO;
goto out_up;
}
idx += len;
}
out_up:
mutex_unlock(&sl->master->mutex);
return count;
}
static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
static ssize_t pio_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf, loff_t off,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
int ret;
/* check arguments */
if (off != 0 || count != 1 || buf == NULL)
return -EINVAL;
mutex_lock(&sl->master->mutex);
ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
mutex_unlock(&sl->master->mutex);
return ret;
}
static ssize_t pio_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf, loff_t off,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 wrbuf[3];
u8 ack;
/* check arguments */
if (off != 0 || count != 1 || buf == NULL)
return -EINVAL;
mutex_lock(&sl->master->mutex);
/* Write the PIO data */
if (w1_reset_select_slave(sl)) {
mutex_unlock(&sl->master->mutex);
return -1;
}
/* set bit 7..2 to value '1' */
*buf = *buf | 0xFC;
wrbuf[0] = W1_F1C_ACCESS_WRITE;
wrbuf[1] = *buf;
wrbuf[2] = ~(*buf);
w1_write_block(sl->master, wrbuf, 3);
w1_read_block(sl->master, &ack, sizeof(ack));
mutex_unlock(&sl->master->mutex);
/* check for acknowledgement */
if (ack != 0xAA)
return -EIO;
return count;
}
static BIN_ATTR_RW(pio, 1);
static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
if (put_user(w1_enable_crccheck + 0x30, buf))
return -EFAULT;
return sizeof(w1_enable_crccheck);
}
static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
char val;
if (count != 1 || !buf)
return -EINVAL;
if (get_user(val, buf))
return -EFAULT;
/* convert to decimal */
val = val - 0x30;
if (val != 0 && val != 1)
return -EINVAL;
/* set the new value */
w1_enable_crccheck = val;
return sizeof(w1_enable_crccheck);
}
static DEVICE_ATTR_RW(crccheck);
static struct attribute *w1_f1C_attrs[] = {
&dev_attr_crccheck.attr,
NULL,
};
static struct bin_attribute *w1_f1C_bin_attrs[] = {
&bin_attr_eeprom,
&bin_attr_pio,
NULL,
};
static const struct attribute_group w1_f1C_group = {
.attrs = w1_f1C_attrs,
.bin_attrs = w1_f1C_bin_attrs,
};
static const struct attribute_group *w1_f1C_groups[] = {
&w1_f1C_group,
NULL,
};
static int w1_f1C_add_slave(struct w1_slave *sl)
{
struct w1_f1C_data *data = NULL;
if (w1_enable_crccheck) {
data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
sl->family_data = data;
}
return 0;
}
static void w1_f1C_remove_slave(struct w1_slave *sl)
{
kfree(sl->family_data);
sl->family_data = NULL;
}
static struct w1_family_ops w1_f1C_fops = {
.add_slave = w1_f1C_add_slave,
.remove_slave = w1_f1C_remove_slave,
.groups = w1_f1C_groups,
};
static struct w1_family w1_family_1C = {
.fid = W1_FAMILY_DS28E04,
.fops = &w1_f1C_fops,
};
static int __init w1_f1C_init(void)
{
return w1_register_family(&w1_family_1C);
}
static void __exit w1_f1C_fini(void)
{
w1_unregister_family(&w1_family_1C);
}
module_init(w1_f1C_init);
module_exit(w1_f1C_fini);