Commit | Line | Data |
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17fecb55 ML |
1 | /* |
2 | * w1_ds2423.c | |
3 | * | |
4 | * Copyright (c) 2010 Mika Laitio <lamikr@pilppa.org> | |
5 | * | |
6 | * This driver will read and write the value of 4 counters to w1_slave file in | |
7 | * sys filesystem. | |
8 | * Inspired by the w1_therm and w1_ds2431 drivers. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the therms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License | |
21 | * along with this program; if not, write to the Free Software | |
22 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
23 | */ | |
24 | ||
25 | #include <linux/kernel.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/moduleparam.h> | |
28 | #include <linux/device.h> | |
29 | #include <linux/types.h> | |
30 | #include <linux/delay.h> | |
31 | #include <linux/crc16.h> | |
32 | ||
33 | #include "../w1.h" | |
34 | #include "../w1_int.h" | |
35 | #include "../w1_family.h" | |
36 | ||
37 | #define CRC16_VALID 0xb001 | |
38 | #define CRC16_INIT 0 | |
39 | ||
40 | #define COUNTER_COUNT 4 | |
41 | #define READ_BYTE_COUNT 42 | |
42 | ||
94c9e6d6 GKH |
43 | static ssize_t w1_slave_show(struct device *device, |
44 | struct device_attribute *attr, char *out_buf) | |
17fecb55 ML |
45 | { |
46 | struct w1_slave *sl = dev_to_w1_slave(device); | |
47 | struct w1_master *dev = sl->master; | |
48 | u8 rbuf[COUNTER_COUNT * READ_BYTE_COUNT]; | |
49 | u8 wrbuf[3]; | |
50 | int rom_addr; | |
51 | int read_byte_count; | |
52 | int result; | |
53 | ssize_t c; | |
54 | int ii; | |
55 | int p; | |
56 | int crc; | |
57 | ||
58 | c = PAGE_SIZE; | |
59 | rom_addr = (12 << 5) + 31; | |
60 | wrbuf[0] = 0xA5; | |
61 | wrbuf[1] = rom_addr & 0xFF; | |
62 | wrbuf[2] = rom_addr >> 8; | |
b02f8bed | 63 | mutex_lock(&dev->bus_mutex); |
17fecb55 ML |
64 | if (!w1_reset_select_slave(sl)) { |
65 | w1_write_block(dev, wrbuf, 3); | |
66 | read_byte_count = 0; | |
67 | for (p = 0; p < 4; p++) { | |
68 | /* | |
69 | * 1 byte for first bytes in ram page read | |
70 | * 4 bytes for counter | |
71 | * 4 bytes for zero bits | |
72 | * 2 bytes for crc | |
73 | * 31 remaining bytes from the ram page | |
74 | */ | |
75 | read_byte_count += w1_read_block(dev, | |
76 | rbuf + (p * READ_BYTE_COUNT), READ_BYTE_COUNT); | |
77 | for (ii = 0; ii < READ_BYTE_COUNT; ++ii) | |
78 | c -= snprintf(out_buf + PAGE_SIZE - c, | |
79 | c, "%02x ", | |
80 | rbuf[(p * READ_BYTE_COUNT) + ii]); | |
81 | if (read_byte_count != (p + 1) * READ_BYTE_COUNT) { | |
82 | dev_warn(device, | |
83 | "w1_counter_read() returned %u bytes " | |
84 | "instead of %d bytes wanted.\n", | |
85 | read_byte_count, | |
86 | READ_BYTE_COUNT); | |
87 | c -= snprintf(out_buf + PAGE_SIZE - c, | |
88 | c, "crc=NO\n"); | |
89 | } else { | |
90 | if (p == 0) { | |
91 | crc = crc16(CRC16_INIT, wrbuf, 3); | |
92 | crc = crc16(crc, rbuf, 11); | |
93 | } else { | |
94 | /* | |
95 | * DS2423 calculates crc from all bytes | |
96 | * read after the previous crc bytes. | |
97 | */ | |
98 | crc = crc16(CRC16_INIT, | |
99 | (rbuf + 11) + | |
100 | ((p - 1) * READ_BYTE_COUNT), | |
101 | READ_BYTE_COUNT); | |
102 | } | |
103 | if (crc == CRC16_VALID) { | |
104 | result = 0; | |
105 | for (ii = 4; ii > 0; ii--) { | |
106 | result <<= 8; | |
107 | result |= rbuf[(p * | |
108 | READ_BYTE_COUNT) + ii]; | |
109 | } | |
110 | c -= snprintf(out_buf + PAGE_SIZE - c, | |
111 | c, "crc=YES c=%d\n", result); | |
112 | } else { | |
113 | c -= snprintf(out_buf + PAGE_SIZE - c, | |
114 | c, "crc=NO\n"); | |
115 | } | |
116 | } | |
117 | } | |
118 | } else { | |
119 | c -= snprintf(out_buf + PAGE_SIZE - c, c, "Connection error"); | |
120 | } | |
b02f8bed | 121 | mutex_unlock(&dev->bus_mutex); |
17fecb55 ML |
122 | return PAGE_SIZE - c; |
123 | } | |
124 | ||
94c9e6d6 | 125 | static DEVICE_ATTR_RO(w1_slave); |
17fecb55 | 126 | |
94c9e6d6 GKH |
127 | static struct attribute *w1_f1d_attrs[] = { |
128 | &dev_attr_w1_slave.attr, | |
129 | NULL, | |
130 | }; | |
131 | ATTRIBUTE_GROUPS(w1_f1d); | |
17fecb55 ML |
132 | |
133 | static struct w1_family_ops w1_f1d_fops = { | |
94c9e6d6 | 134 | .groups = w1_f1d_groups, |
17fecb55 ML |
135 | }; |
136 | ||
137 | static struct w1_family w1_family_1d = { | |
138 | .fid = W1_COUNTER_DS2423, | |
139 | .fops = &w1_f1d_fops, | |
140 | }; | |
939fc832 | 141 | module_w1_family(w1_family_1d); |
17fecb55 ML |
142 | |
143 | MODULE_LICENSE("GPL"); | |
144 | MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>"); | |
145 | MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram"); | |
8d7bda51 | 146 | MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423)); |