134 lines
3.2 KiB
C
134 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* w1_ds2423.c
|
|
*
|
|
* Copyright (c) 2010 Mika Laitio <lamikr@pilppa.org>
|
|
*
|
|
* This driver will read and write the value of 4 counters to w1_slave file in
|
|
* sys filesystem.
|
|
* Inspired by the w1_therm and w1_ds2431 drivers.
|
|
*/
|
|
|
|
#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/crc16.h>
|
|
|
|
#include <linux/w1.h>
|
|
|
|
#define W1_COUNTER_DS2423 0x1D
|
|
|
|
#define CRC16_VALID 0xb001
|
|
#define CRC16_INIT 0
|
|
|
|
#define COUNTER_COUNT 4
|
|
#define READ_BYTE_COUNT 42
|
|
|
|
static ssize_t w1_slave_show(struct device *device,
|
|
struct device_attribute *attr, char *out_buf)
|
|
{
|
|
struct w1_slave *sl = dev_to_w1_slave(device);
|
|
struct w1_master *dev = sl->master;
|
|
u8 rbuf[COUNTER_COUNT * READ_BYTE_COUNT];
|
|
u8 wrbuf[3];
|
|
int rom_addr;
|
|
int read_byte_count;
|
|
int result;
|
|
ssize_t c;
|
|
int ii;
|
|
int p;
|
|
int crc;
|
|
|
|
c = PAGE_SIZE;
|
|
rom_addr = (12 << 5) + 31;
|
|
wrbuf[0] = 0xA5;
|
|
wrbuf[1] = rom_addr & 0xFF;
|
|
wrbuf[2] = rom_addr >> 8;
|
|
mutex_lock(&dev->bus_mutex);
|
|
if (!w1_reset_select_slave(sl)) {
|
|
w1_write_block(dev, wrbuf, 3);
|
|
read_byte_count = 0;
|
|
for (p = 0; p < 4; p++) {
|
|
/*
|
|
* 1 byte for first bytes in ram page read
|
|
* 4 bytes for counter
|
|
* 4 bytes for zero bits
|
|
* 2 bytes for crc
|
|
* 31 remaining bytes from the ram page
|
|
*/
|
|
read_byte_count += w1_read_block(dev,
|
|
rbuf + (p * READ_BYTE_COUNT), READ_BYTE_COUNT);
|
|
for (ii = 0; ii < READ_BYTE_COUNT; ++ii)
|
|
c -= snprintf(out_buf + PAGE_SIZE - c,
|
|
c, "%02x ",
|
|
rbuf[(p * READ_BYTE_COUNT) + ii]);
|
|
if (read_byte_count != (p + 1) * READ_BYTE_COUNT) {
|
|
dev_warn(device,
|
|
"w1_counter_read() returned %u bytes "
|
|
"instead of %d bytes wanted.\n",
|
|
read_byte_count,
|
|
READ_BYTE_COUNT);
|
|
c -= snprintf(out_buf + PAGE_SIZE - c,
|
|
c, "crc=NO\n");
|
|
} else {
|
|
if (p == 0) {
|
|
crc = crc16(CRC16_INIT, wrbuf, 3);
|
|
crc = crc16(crc, rbuf, 11);
|
|
} else {
|
|
/*
|
|
* DS2423 calculates crc from all bytes
|
|
* read after the previous crc bytes.
|
|
*/
|
|
crc = crc16(CRC16_INIT,
|
|
(rbuf + 11) +
|
|
((p - 1) * READ_BYTE_COUNT),
|
|
READ_BYTE_COUNT);
|
|
}
|
|
if (crc == CRC16_VALID) {
|
|
result = 0;
|
|
for (ii = 4; ii > 0; ii--) {
|
|
result <<= 8;
|
|
result |= rbuf[(p *
|
|
READ_BYTE_COUNT) + ii];
|
|
}
|
|
c -= snprintf(out_buf + PAGE_SIZE - c,
|
|
c, "crc=YES c=%d\n", result);
|
|
} else {
|
|
c -= snprintf(out_buf + PAGE_SIZE - c,
|
|
c, "crc=NO\n");
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
c -= snprintf(out_buf + PAGE_SIZE - c, c, "Connection error");
|
|
}
|
|
mutex_unlock(&dev->bus_mutex);
|
|
return PAGE_SIZE - c;
|
|
}
|
|
|
|
static DEVICE_ATTR_RO(w1_slave);
|
|
|
|
static struct attribute *w1_f1d_attrs[] = {
|
|
&dev_attr_w1_slave.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(w1_f1d);
|
|
|
|
static const struct w1_family_ops w1_f1d_fops = {
|
|
.groups = w1_f1d_groups,
|
|
};
|
|
|
|
static struct w1_family w1_family_1d = {
|
|
.fid = W1_COUNTER_DS2423,
|
|
.fops = &w1_f1d_fops,
|
|
};
|
|
module_w1_family(w1_family_1d);
|
|
|
|
MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>");
|
|
MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423));
|