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