1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * w1_ds2413.c - w1 family 3a (DS2413) driver
4 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
5 *
6 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
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
17#include <linux/w1.h>
18
19#define W1_FAMILY_DS2413	0x3A
20
21#define W1_F3A_RETRIES                     3
22#define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
23#define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
24#define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
25#define W1_F3A_INVALID_PIO_STATE           0xFF
26
27static ssize_t state_read(struct file *filp, struct kobject *kobj,
28			  struct bin_attribute *bin_attr, char *buf, loff_t off,
29			  size_t count)
30{
31	struct w1_slave *sl = kobj_to_w1_slave(kobj);
32	unsigned int retries = W1_F3A_RETRIES;
33	ssize_t bytes_read = -EIO;
34	u8 state;
35
36	dev_dbg(&sl->dev,
37		"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
38		bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
39
40	if (off != 0)
41		return 0;
42	if (!buf)
43		return -EINVAL;
44
45	mutex_lock(&sl->master->bus_mutex);
46	dev_dbg(&sl->dev, "mutex locked");
47
48next:
49	if (w1_reset_select_slave(sl))
50		goto out;
51
52	while (retries--) {
53		w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
54
55		state = w1_read_8(sl->master);
56		if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
57			/* complement is correct */
58			*buf = state;
59			bytes_read = 1;
60			goto out;
61		} else if (state == W1_F3A_INVALID_PIO_STATE) {
62			/* slave didn't respond, try to select it again */
63			dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
64					    "reselecting, retries left: %d\n", retries);
65			goto next;
66		}
67
68		if (w1_reset_resume_command(sl->master))
69			goto out; /* unrecoverable error */
70
71		dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
72	}
73
74out:
75	mutex_unlock(&sl->master->bus_mutex);
76	dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
77		(bytes_read > 0) ? "succeeded" : "error", retries);
78	return bytes_read;
79}
80
81static BIN_ATTR_RO(state, 1);
82
83static ssize_t output_write(struct file *filp, struct kobject *kobj,
84			    struct bin_attribute *bin_attr, char *buf,
85			    loff_t off, size_t count)
86{
87	struct w1_slave *sl = kobj_to_w1_slave(kobj);
88	u8 w1_buf[3];
89	unsigned int retries = W1_F3A_RETRIES;
90	ssize_t bytes_written = -EIO;
91
92	if (count != 1 || off != 0)
93		return -EFAULT;
94
95	dev_dbg(&sl->dev, "locking mutex for write_output");
96	mutex_lock(&sl->master->bus_mutex);
97	dev_dbg(&sl->dev, "mutex locked");
98
99	if (w1_reset_select_slave(sl))
100		goto out;
101
102	/* according to the DS2413 datasheet the most significant 6 bits
103	   should be set to "1"s, so do it now */
104	*buf = *buf | 0xFC;
105
106	while (retries--) {
107		w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
108		w1_buf[1] = *buf;
109		w1_buf[2] = ~(*buf);
110		w1_write_block(sl->master, w1_buf, 3);
111
112		if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
113			bytes_written = 1;
114			goto out;
115		}
116		if (w1_reset_resume_command(sl->master))
117			goto out; /* unrecoverable error */
118
119		dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
120	}
121
122out:
123	mutex_unlock(&sl->master->bus_mutex);
124	dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
125		(bytes_written > 0) ? "succeeded" : "error", retries);
126	return bytes_written;
127}
128
129static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
130
131static struct bin_attribute *w1_f3a_bin_attrs[] = {
132	&bin_attr_state,
133	&bin_attr_output,
134	NULL,
135};
136
137static const struct attribute_group w1_f3a_group = {
138	.bin_attrs = w1_f3a_bin_attrs,
139};
140
141static const struct attribute_group *w1_f3a_groups[] = {
142	&w1_f3a_group,
143	NULL,
144};
145
146static const struct w1_family_ops w1_f3a_fops = {
147	.groups		= w1_f3a_groups,
148};
149
150static struct w1_family w1_family_3a = {
151	.fid = W1_FAMILY_DS2413,
152	.fops = &w1_f3a_fops,
153};
154module_w1_family(w1_family_3a);
155
156MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
157MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
158MODULE_LICENSE("GPL");
159MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
160