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
w1_f12_read_state(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)25 static 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(&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, 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(&sl->master->bus_mutex);
58
59 return rtnval;
60 }
61
w1_f12_write_output(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)62 static 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(&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, 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(&sl->master->bus_mutex);
94 return rtnval;
95 }
96
97 #define NB_SYSFS_BIN_FILES 2
98 static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
99 {
100 .attr = {
101 .name = "state",
102 .mode = S_IRUGO,
103 },
104 .size = 1,
105 .read = w1_f12_read_state,
106 },
107 {
108 .attr = {
109 .name = "output",
110 .mode = S_IRUGO | S_IWUSR | S_IWGRP,
111 },
112 .size = 1,
113 .write = w1_f12_write_output,
114 }
115 };
116
w1_f12_add_slave(struct w1_slave * sl)117 static 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 &sl->dev.kobj,
125 &(w1_f12_sysfs_bin_files[i]));
126 if (err)
127 while (--i >= 0)
128 sysfs_remove_bin_file(&sl->dev.kobj,
129 &(w1_f12_sysfs_bin_files[i]));
130 return err;
131 }
132
w1_f12_remove_slave(struct w1_slave * sl)133 static void w1_f12_remove_slave(struct w1_slave *sl)
134 {
135 int i;
136 for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
137 sysfs_remove_bin_file(&sl->dev.kobj,
138 &(w1_f12_sysfs_bin_files[i]));
139 }
140
141 static const struct w1_family_ops w1_f12_fops = {
142 .add_slave = w1_f12_add_slave,
143 .remove_slave = w1_f12_remove_slave,
144 };
145
146 static struct w1_family w1_family_12 = {
147 .fid = W1_FAMILY_DS2406,
148 .fops = &w1_f12_fops,
149 };
150 module_w1_family(w1_family_12);
151
152 MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
153 MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
154 MODULE_LICENSE("GPL");
155