1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * w1_ds2413.c - w1 family 3a (DS2413) driver
4 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
5 *
6 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/device.h>
13 #include <linux/types.h>
14 #include <linux/delay.h>
15 #include <linux/slab.h>
16
17 #include <linux/w1.h>
18
19 #define W1_FAMILY_DS2413 0x3A
20
21 #define W1_F3A_RETRIES 3
22 #define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5
23 #define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A
24 #define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA
25 #define W1_F3A_INVALID_PIO_STATE 0xFF
26
state_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)27 static ssize_t state_read(struct file *filp, struct kobject *kobj,
28 struct bin_attribute *bin_attr, char *buf, loff_t off,
29 size_t count)
30 {
31 struct w1_slave *sl = kobj_to_w1_slave(kobj);
32 unsigned int retries = W1_F3A_RETRIES;
33 ssize_t bytes_read = -EIO;
34 u8 state;
35
36 dev_dbg(&sl->dev,
37 "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
38 bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
39
40 if (off != 0)
41 return 0;
42 if (!buf)
43 return -EINVAL;
44
45 mutex_lock(&sl->master->bus_mutex);
46 dev_dbg(&sl->dev, "mutex locked");
47
48 next:
49 if (w1_reset_select_slave(sl))
50 goto out;
51
52 while (retries--) {
53 w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
54
55 state = w1_read_8(sl->master);
56 if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
57 /* complement is correct */
58 *buf = state;
59 bytes_read = 1;
60 goto out;
61 } else if (state == W1_F3A_INVALID_PIO_STATE) {
62 /* slave didn't respond, try to select it again */
63 dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
64 "reselecting, retries left: %d\n", retries);
65 goto next;
66 }
67
68 if (w1_reset_resume_command(sl->master))
69 goto out; /* unrecoverable error */
70
71 dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
72 }
73
74 out:
75 mutex_unlock(&sl->master->bus_mutex);
76 dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
77 (bytes_read > 0) ? "succeeded" : "error", retries);
78 return bytes_read;
79 }
80
81 static BIN_ATTR_RO(state, 1);
82
output_write(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)83 static ssize_t output_write(struct file *filp, struct kobject *kobj,
84 struct bin_attribute *bin_attr, char *buf,
85 loff_t off, size_t count)
86 {
87 struct w1_slave *sl = kobj_to_w1_slave(kobj);
88 u8 w1_buf[3];
89 unsigned int retries = W1_F3A_RETRIES;
90 ssize_t bytes_written = -EIO;
91
92 if (count != 1 || off != 0)
93 return -EFAULT;
94
95 dev_dbg(&sl->dev, "locking mutex for write_output");
96 mutex_lock(&sl->master->bus_mutex);
97 dev_dbg(&sl->dev, "mutex locked");
98
99 if (w1_reset_select_slave(sl))
100 goto out;
101
102 /* according to the DS2413 datasheet the most significant 6 bits
103 should be set to "1"s, so do it now */
104 *buf = *buf | 0xFC;
105
106 while (retries--) {
107 w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
108 w1_buf[1] = *buf;
109 w1_buf[2] = ~(*buf);
110 w1_write_block(sl->master, w1_buf, 3);
111
112 if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
113 bytes_written = 1;
114 goto out;
115 }
116 if (w1_reset_resume_command(sl->master))
117 goto out; /* unrecoverable error */
118
119 dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
120 }
121
122 out:
123 mutex_unlock(&sl->master->bus_mutex);
124 dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
125 (bytes_written > 0) ? "succeeded" : "error", retries);
126 return bytes_written;
127 }
128
129 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
130
131 static struct bin_attribute *w1_f3a_bin_attrs[] = {
132 &bin_attr_state,
133 &bin_attr_output,
134 NULL,
135 };
136
137 static const struct attribute_group w1_f3a_group = {
138 .bin_attrs = w1_f3a_bin_attrs,
139 };
140
141 static const struct attribute_group *w1_f3a_groups[] = {
142 &w1_f3a_group,
143 NULL,
144 };
145
146 static const struct w1_family_ops w1_f3a_fops = {
147 .groups = w1_f3a_groups,
148 };
149
150 static struct w1_family w1_family_3a = {
151 .fid = W1_FAMILY_DS2413,
152 .fops = &w1_f3a_fops,
153 };
154 module_w1_family(w1_family_3a);
155
156 MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
157 MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
158 MODULE_LICENSE("GPL");
159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
160