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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 | /* * 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. * * 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 <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 "../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_counter_read(struct device *device, struct device_attribute *attr, char *buf); static struct device_attribute w1_counter_attr = __ATTR(w1_slave, S_IRUGO, w1_counter_read, NULL); static ssize_t w1_counter_read(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->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->mutex); return PAGE_SIZE - c; } static int w1_f1d_add_slave(struct w1_slave *sl) { return device_create_file(&sl->dev, &w1_counter_attr); } static void w1_f1d_remove_slave(struct w1_slave *sl) { device_remove_file(&sl->dev, &w1_counter_attr); } static struct w1_family_ops w1_f1d_fops = { .add_slave = w1_f1d_add_slave, .remove_slave = w1_f1d_remove_slave, }; static struct w1_family w1_family_1d = { .fid = W1_COUNTER_DS2423, .fops = &w1_f1d_fops, }; static int __init w1_f1d_init(void) { return w1_register_family(&w1_family_1d); } static void __exit w1_f1d_exit(void) { w1_unregister_family(&w1_family_1d); } module_init(w1_f1d_init); module_exit(w1_f1d_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>"); MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram"); |