/* * w1_ds2423.c * * Copyright (c) 2010 Mika Laitio * * 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. * * This program is free software; you can redistribute it and/or modify * it under the therms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include "../w1.h" #include "../w1_int.h" #include "../w1_family.h" #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 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_LICENSE("GPL"); MODULE_AUTHOR("Mika Laitio "); MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram"); MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423)); ption>space:mode:

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1 files changed, 9 insertions, 15 deletions