1 /*
2 * w1_ds2413.c - w1 family 3a (DS2413) driver
3 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
4 *
5 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
6 *
7 * This source code is licensed under the GNU General Public License,
8 * Version 2. See the file COPYING for more details.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/device.h>
15 #include <linux/types.h>
16 #include <linux/delay.h>
17 #include <linux/slab.h>
18
19 #include <linux/w1.h>
20
21 #define W1_FAMILY_DS2413 0x3A
22
23 #define W1_F3A_RETRIES 3
24 #define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5
25 #define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A
26 #define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA
27
state_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)28 static ssize_t state_read(struct file *filp, struct kobject *kobj,
29 struct bin_attribute *bin_attr, char *buf, loff_t off,
30 size_t count)
31 {
32 struct w1_slave *sl = kobj_to_w1_slave(kobj);
33 dev_dbg(&sl->dev,
34 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
35 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
36
37 if (off != 0)
38 return 0;
39 if (!buf)
40 return -EINVAL;
41
42 mutex_lock(&sl->master->bus_mutex);
43 dev_dbg(&sl->dev, "mutex locked");
44
45 if (w1_reset_select_slave(sl)) {
46 mutex_unlock(&sl->master->bus_mutex);
47 return -EIO;
48 }
49
50 w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
51 *buf = w1_read_8(sl->master);
52
53 mutex_unlock(&sl->master->bus_mutex);
54 dev_dbg(&sl->dev, "mutex unlocked");
55
56 /* check for correct complement */
57 if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
58 return -EIO;
59 else
60 return 1;
61 }
62
63 static BIN_ATTR_RO(state, 1);
64
output_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)65 static ssize_t output_write(struct file *filp, struct kobject *kobj,
66 struct bin_attribute *bin_attr, char *buf,
67 loff_t off, size_t count)
68 {
69 struct w1_slave *sl = kobj_to_w1_slave(kobj);
70 u8 w1_buf[3];
71 unsigned int retries = W1_F3A_RETRIES;
72
73 if (count != 1 || off != 0)
74 return -EFAULT;
75
76 dev_dbg(&sl->dev, "locking mutex for write_output");
77 mutex_lock(&sl->master->bus_mutex);
78 dev_dbg(&sl->dev, "mutex locked");
79
80 if (w1_reset_select_slave(sl))
81 goto error;
82
83 /* according to the DS2413 datasheet the most significant 6 bits
84 should be set to "1"s, so do it now */
85 *buf = *buf | 0xFC;
86
87 while (retries--) {
88 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
89 w1_buf[1] = *buf;
90 w1_buf[2] = ~(*buf);
91 w1_write_block(sl->master, w1_buf, 3);
92
93 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
94 mutex_unlock(&sl->master->bus_mutex);
95 dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
96 return 1;
97 }
98 if (w1_reset_resume_command(sl->master))
99 goto error;
100 }
101
102 error:
103 mutex_unlock(&sl->master->bus_mutex);
104 dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
105 return -EIO;
106 }
107
108 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
109
110 static struct bin_attribute *w1_f3a_bin_attrs[] = {
111 &bin_attr_state,
112 &bin_attr_output,
113 NULL,
114 };
115
116 static const struct attribute_group w1_f3a_group = {
117 .bin_attrs = w1_f3a_bin_attrs,
118 };
119
120 static const struct attribute_group *w1_f3a_groups[] = {
121 &w1_f3a_group,
122 NULL,
123 };
124
125 static struct w1_family_ops w1_f3a_fops = {
126 .groups = w1_f3a_groups,
127 };
128
129 static struct w1_family w1_family_3a = {
130 .fid = W1_FAMILY_DS2413,
131 .fops = &w1_f3a_fops,
132 };
133 module_w1_family(w1_family_3a);
134
135 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
136 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
137 MODULE_LICENSE("GPL");
138 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
139
