1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * w1_ds2406.c - w1 family 12 (DS2406) driver
4 * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
5 *
6 * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
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#include <linux/crc16.h>
17
18#include <linux/w1.h>
19
20#define W1_FAMILY_DS2406 0x12
21
22#define W1_F12_FUNC_READ_STATUS 0xAA
23#define W1_F12_FUNC_WRITE_STATUS 0x55
24
25static ssize_t w1_f12_read_state(
26 struct file *filp, struct kobject *kobj,
27 struct bin_attribute *bin_attr,
28 char *buf, loff_t off, size_t count)
29{
30 u8 w1_buf[6] = {W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
31 struct w1_slave *sl = kobj_to_w1_slave(kobj);
32 u16 crc = 0;
33 int i;
34 ssize_t rtnval = 1;
35
36 if (off != 0)
37 return 0;
38 if (!buf)
39 return -EINVAL;
40
41 mutex_lock(&sl->master->bus_mutex);
42
43 if (w1_reset_select_slave(sl)) {
44 mutex_unlock(lock: &sl->master->bus_mutex);
45 return -EIO;
46 }
47
48 w1_write_block(sl->master, w1_buf, 3);
49 w1_read_block(sl->master, w1_buf+3, 3);
50 for (i = 0; i < 6; i++)
51 crc = crc16_byte(crc, data: w1_buf[i]);
52 if (crc == 0xb001) /* good read? */
53 *buf = ((w1_buf[3]>>5)&3)|0x30;
54 else
55 rtnval = -EIO;
56
57 mutex_unlock(lock: &sl->master->bus_mutex);
58
59 return rtnval;
60}
61
62static ssize_t w1_f12_write_output(
63 struct file *filp, struct kobject *kobj,
64 struct bin_attribute *bin_attr,
65 char *buf, loff_t off, size_t count)
66{
67 struct w1_slave *sl = kobj_to_w1_slave(kobj);
68 u8 w1_buf[6] = {W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
69 u16 crc = 0;
70 int i;
71 ssize_t rtnval = 1;
72
73 if (count != 1 || off != 0)
74 return -EFAULT;
75
76 mutex_lock(&sl->master->bus_mutex);
77
78 if (w1_reset_select_slave(sl)) {
79 mutex_unlock(lock: &sl->master->bus_mutex);
80 return -EIO;
81 }
82
83 w1_buf[3] = (((*buf)&3)<<5)|0x1F;
84 w1_write_block(sl->master, w1_buf, 4);
85 w1_read_block(sl->master, w1_buf+4, 2);
86 for (i = 0; i < 6; i++)
87 crc = crc16_byte(crc, data: w1_buf[i]);
88 if (crc == 0xb001) /* good read? */
89 w1_write_8(sl->master, 0xFF);
90 else
91 rtnval = -EIO;
92
93 mutex_unlock(lock: &sl->master->bus_mutex);
94 return rtnval;
95}
96
97#define NB_SYSFS_BIN_FILES 2
98static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
99 {
100 .attr = {
101 .name = "state",
102 .mode = 0444,
103 },
104 .size = 1,
105 .read = w1_f12_read_state,
106 },
107 {
108 .attr = {
109 .name = "output",
110 .mode = 0664,
111 },
112 .size = 1,
113 .write = w1_f12_write_output,
114 }
115};
116
117static int w1_f12_add_slave(struct w1_slave *sl)
118{
119 int err = 0;
120 int i;
121
122 for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
123 err = sysfs_create_bin_file(
124 kobj: &sl->dev.kobj,
125 attr: &(w1_f12_sysfs_bin_files[i]));
126 if (err)
127 while (--i >= 0)
128 sysfs_remove_bin_file(kobj: &sl->dev.kobj,
129 attr: &(w1_f12_sysfs_bin_files[i]));
130 return err;
131}
132
133static void w1_f12_remove_slave(struct w1_slave *sl)
134{
135 int i;
136
137 for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
138 sysfs_remove_bin_file(kobj: &sl->dev.kobj,
139 attr: &(w1_f12_sysfs_bin_files[i]));
140}
141
142static const struct w1_family_ops w1_f12_fops = {
143 .add_slave = w1_f12_add_slave,
144 .remove_slave = w1_f12_remove_slave,
145};
146
147static struct w1_family w1_family_12 = {
148 .fid = W1_FAMILY_DS2406,
149 .fops = &w1_f12_fops,
150};
151module_w1_family(w1_family_12);
152
153MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
154MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
155MODULE_LICENSE("GPL");
156

source code of linux/drivers/w1/slaves/w1_ds2406.c