1/*
2 * w1_ds2413.c - w1 family 3a (DS2413) driver
3 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
4 *
5 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
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
19#include "../w1.h"
20#include "../w1_int.h"
21#include "../w1_family.h"
22
23MODULE_LICENSE("GPL");
24MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
25MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
26MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
27
28#define W1_F3A_RETRIES                     3
29#define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
30#define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
31#define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
32
33static ssize_t state_read(struct file *filp, struct kobject *kobj,
34			  struct bin_attribute *bin_attr, char *buf, loff_t off,
35			  size_t count)
36{
37	struct w1_slave *sl = kobj_to_w1_slave(kobj);
38	dev_dbg(&sl->dev,
39		"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
40		bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
41
42	if (off != 0)
43		return 0;
44	if (!buf)
45		return -EINVAL;
46
47	mutex_lock(&sl->master->bus_mutex);
48	dev_dbg(&sl->dev, "mutex locked");
49
50	if (w1_reset_select_slave(sl)) {
51		mutex_unlock(&sl->master->bus_mutex);
52		return -EIO;
53	}
54
55	w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
56	*buf = w1_read_8(sl->master);
57
58	mutex_unlock(&sl->master->bus_mutex);
59	dev_dbg(&sl->dev, "mutex unlocked");
60
61	/* check for correct complement */
62	if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
63		return -EIO;
64	else
65		return 1;
66}
67
68static BIN_ATTR_RO(state, 1);
69
70static ssize_t output_write(struct file *filp, struct kobject *kobj,
71			    struct bin_attribute *bin_attr, char *buf,
72			    loff_t off, size_t count)
73{
74	struct w1_slave *sl = kobj_to_w1_slave(kobj);
75	u8 w1_buf[3];
76	unsigned int retries = W1_F3A_RETRIES;
77
78	if (count != 1 || off != 0)
79		return -EFAULT;
80
81	dev_dbg(&sl->dev, "locking mutex for write_output");
82	mutex_lock(&sl->master->bus_mutex);
83	dev_dbg(&sl->dev, "mutex locked");
84
85	if (w1_reset_select_slave(sl))
86		goto error;
87
88	/* according to the DS2413 datasheet the most significant 6 bits
89	   should be set to "1"s, so do it now */
90	*buf = *buf | 0xFC;
91
92	while (retries--) {
93		w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
94		w1_buf[1] = *buf;
95		w1_buf[2] = ~(*buf);
96		w1_write_block(sl->master, w1_buf, 3);
97
98		if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
99			mutex_unlock(&sl->master->bus_mutex);
100			dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
101			return 1;
102		}
103		if (w1_reset_resume_command(sl->master))
104			goto error;
105	}
106
107error:
108	mutex_unlock(&sl->master->bus_mutex);
109	dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
110	return -EIO;
111}
112
113static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
114
115static struct bin_attribute *w1_f3a_bin_attrs[] = {
116	&bin_attr_state,
117	&bin_attr_output,
118	NULL,
119};
120
121static const struct attribute_group w1_f3a_group = {
122	.bin_attrs = w1_f3a_bin_attrs,
123};
124
125static const struct attribute_group *w1_f3a_groups[] = {
126	&w1_f3a_group,
127	NULL,
128};
129
130static struct w1_family_ops w1_f3a_fops = {
131	.groups		= w1_f3a_groups,
132};
133
134static struct w1_family w1_family_3a = {
135	.fid = W1_FAMILY_DS2413,
136	.fops = &w1_f3a_fops,
137};
138
139static int __init w1_f3a_init(void)
140{
141	return w1_register_family(&w1_family_3a);
142}
143
144static void __exit w1_f3a_exit(void)
145{
146	w1_unregister_family(&w1_family_3a);
147}
148
149module_init(w1_f3a_init);
150module_exit(w1_f3a_exit);
151