[go: nahoru, domu]
1/*
2 * w1_ds2406.c - w1 family 12 (DS2406) driver
3 * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
4 *
5 * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
6 *
7 * This source code is licensed under the GNU General Public License,
8 * Version 2. See the file COPYING for more details.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/moduleparam.h>
14#include <linux/device.h>
15#include <linux/types.h>
16#include <linux/delay.h>
17#include <linux/slab.h>
18#include <linux/crc16.h>
19
20#include "../w1.h"
21#include "../w1_int.h"
22#include "../w1_family.h"
23
24MODULE_LICENSE("GPL");
25MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
26MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
27
28#define W1_F12_FUNC_READ_STATUS		   0xAA
29#define W1_F12_FUNC_WRITE_STATUS	   0x55
30
31static ssize_t w1_f12_read_state(
32	struct file *filp, struct kobject *kobj,
33	struct bin_attribute *bin_attr,
34	char *buf, loff_t off, size_t count)
35{
36	u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
37	struct w1_slave *sl = kobj_to_w1_slave(kobj);
38	u16 crc=0;
39	int i;
40	ssize_t rtnval=1;
41
42	if (off != 0)
43		return 0;
44	if (!buf)
45		return -EINVAL;
46
47	mutex_lock(&sl->master->bus_mutex);
48
49	if (w1_reset_select_slave(sl)) {
50		mutex_unlock(&sl->master->bus_mutex);
51		return -EIO;
52	}
53
54	w1_write_block(sl->master, w1_buf, 3);
55	w1_read_block(sl->master, w1_buf+3, 3);
56	for (i=0; i<6; i++)
57		crc=crc16_byte(crc, w1_buf[i]);
58	if (crc==0xb001) /* good read? */
59		*buf=((w1_buf[3]>>5)&3)|0x30;
60	else
61		rtnval=-EIO;
62
63	mutex_unlock(&sl->master->bus_mutex);
64
65	return rtnval;
66}
67
68static ssize_t w1_f12_write_output(
69	struct file *filp, struct kobject *kobj,
70	struct bin_attribute *bin_attr,
71	char *buf, loff_t off, size_t count)
72{
73	struct w1_slave *sl = kobj_to_w1_slave(kobj);
74	u8 w1_buf[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
75	u16 crc=0;
76	int i;
77	ssize_t rtnval=1;
78
79	if (count != 1 || off != 0)
80		return -EFAULT;
81
82	mutex_lock(&sl->master->bus_mutex);
83
84	if (w1_reset_select_slave(sl)) {
85		mutex_unlock(&sl->master->bus_mutex);
86		return -EIO;
87	}
88
89	w1_buf[3] = (((*buf)&3)<<5)|0x1F;
90	w1_write_block(sl->master, w1_buf, 4);
91	w1_read_block(sl->master, w1_buf+4, 2);
92	for (i=0; i<6; i++)
93		crc=crc16_byte(crc, w1_buf[i]);
94	if (crc==0xb001) /* good read? */
95		w1_write_8(sl->master, 0xFF);
96	else
97		rtnval=-EIO;
98
99	mutex_unlock(&sl->master->bus_mutex);
100	return rtnval;
101}
102
103#define NB_SYSFS_BIN_FILES 2
104static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
105	{
106		.attr = {
107			.name = "state",
108			.mode = S_IRUGO,
109		},
110		.size = 1,
111		.read = w1_f12_read_state,
112	},
113	{
114		.attr = {
115			.name = "output",
116			.mode = S_IRUGO | S_IWUSR | S_IWGRP,
117		},
118		.size = 1,
119		.write = w1_f12_write_output,
120	}
121};
122
123static int w1_f12_add_slave(struct w1_slave *sl)
124{
125	int err = 0;
126	int i;
127
128	for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
129		err = sysfs_create_bin_file(
130			&sl->dev.kobj,
131			&(w1_f12_sysfs_bin_files[i]));
132	if (err)
133		while (--i >= 0)
134			sysfs_remove_bin_file(&sl->dev.kobj,
135				&(w1_f12_sysfs_bin_files[i]));
136	return err;
137}
138
139static void w1_f12_remove_slave(struct w1_slave *sl)
140{
141	int i;
142	for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
143		sysfs_remove_bin_file(&sl->dev.kobj,
144			&(w1_f12_sysfs_bin_files[i]));
145}
146
147static struct w1_family_ops w1_f12_fops = {
148	.add_slave      = w1_f12_add_slave,
149	.remove_slave   = w1_f12_remove_slave,
150};
151
152static struct w1_family w1_family_12 = {
153	.fid = W1_FAMILY_DS2406,
154	.fops = &w1_f12_fops,
155};
156
157static int __init w1_f12_init(void)
158{
159	return w1_register_family(&w1_family_12);
160}
161
162static void __exit w1_f12_exit(void)
163{
164	w1_unregister_family(&w1_family_12);
165}
166
167module_init(w1_f12_init);
168module_exit(w1_f12_exit);
169