forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
133 lines
3.2 KiB
133 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* w1_ds2423.c |
|
* |
|
* Copyright (c) 2010 Mika Laitio <[email protected]> |
|
* |
|
* 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 <[email protected]>"); |
|
MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram"); |
|
MODULE_LICENSE("GPL"); |
|
MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423));
|
|
|