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 | |
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(lock: &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 | |
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 | /* |
103 | * according to the DS2413 datasheet the most significant 6 bits |
104 | * should be set to "1"s, so do it now |
105 | */ |
106 | *buf = *buf | 0xFC; |
107 | |
108 | while (retries--) { |
109 | w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE; |
110 | w1_buf[1] = *buf; |
111 | w1_buf[2] = ~(*buf); |
112 | w1_write_block(sl->master, w1_buf, 3); |
113 | |
114 | if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) { |
115 | bytes_written = 1; |
116 | goto out; |
117 | } |
118 | if (w1_reset_resume_command(sl->master)) |
119 | goto out; /* unrecoverable error */ |
120 | |
121 | dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n" , retries); |
122 | } |
123 | |
124 | out: |
125 | mutex_unlock(lock: &sl->master->bus_mutex); |
126 | dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n" , |
127 | (bytes_written > 0) ? "succeeded" : "error" , retries); |
128 | return bytes_written; |
129 | } |
130 | |
131 | static BIN_ATTR(output, 0664, NULL, output_write, 1); |
132 | |
133 | static struct bin_attribute *w1_f3a_bin_attrs[] = { |
134 | &bin_attr_state, |
135 | &bin_attr_output, |
136 | NULL, |
137 | }; |
138 | |
139 | static const struct attribute_group w1_f3a_group = { |
140 | .bin_attrs = w1_f3a_bin_attrs, |
141 | }; |
142 | |
143 | static const struct attribute_group *w1_f3a_groups[] = { |
144 | &w1_f3a_group, |
145 | NULL, |
146 | }; |
147 | |
148 | static const struct w1_family_ops w1_f3a_fops = { |
149 | .groups = w1_f3a_groups, |
150 | }; |
151 | |
152 | static struct w1_family w1_family_3a = { |
153 | .fid = W1_FAMILY_DS2413, |
154 | .fops = &w1_f3a_fops, |
155 | }; |
156 | module_w1_family(w1_family_3a); |
157 | |
158 | MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>" ); |
159 | MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO" ); |
160 | MODULE_LICENSE("GPL" ); |
161 | MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413)); |
162 | |