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
25static 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
62static 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
98static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
99	{
100		.attr = {
101			.name = "state",
102			.mode = 0444,
103		},
104		.size = 1,
105		.read = w1_f12_read_state,
106	},
107	{
108		.attr = {
109			.name = "output",
110			.mode = 0664,
111		},
112		.size = 1,
113		.write = w1_f12_write_output,
114	}
115};
116
117static 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
133static void w1_f12_remove_slave(struct w1_slave *sl)
134{
135	int i;
136
137	for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
138		sysfs_remove_bin_file(&sl->dev.kobj,
139			&(w1_f12_sysfs_bin_files[i]));
140}
141
142static const struct w1_family_ops w1_f12_fops = {
143	.add_slave      = w1_f12_add_slave,
144	.remove_slave   = w1_f12_remove_slave,
145};
146
147static struct w1_family w1_family_12 = {
148	.fid = W1_FAMILY_DS2406,
149	.fops = &w1_f12_fops,
150};
151module_w1_family(w1_family_12);
152
153MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
154MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
155MODULE_LICENSE("GPL");
156