4 * Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>
5 * Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the therms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
19 #include <linux/device.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/mutex.h>
24 #include <linux/string.h>
25 #include <linux/types.h>
28 #include "../w1_family.h"
30 MODULE_LICENSE("GPL");
31 MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");
32 MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO.");
33 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2405));
35 static int w1_ds2405_select(struct w1_slave *sl, bool only_active)
37 struct w1_master *dev = sl->master;
39 u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
42 if (w1_reset_bus(dev) != 0)
46 * We cannot use a normal Match ROM command
47 * since doing so would toggle PIO state
49 w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);
51 for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {
52 int bit2send = !!(dev_addr & BIT(bit_ctr));
55 ret = w1_triplet(dev, bit2send);
57 if ((ret & (BIT(0) | BIT(1))) ==
58 (BIT(0) | BIT(1))) /* no devices found */
61 if (!!(ret & BIT(2)) != bit2send)
62 /* wrong direction taken - no such device */
69 static int w1_ds2405_read_pio(struct w1_slave *sl)
71 if (w1_ds2405_select(sl, true))
72 return 0; /* "active" means PIO is low */
74 if (w1_ds2405_select(sl, false))
80 static ssize_t state_show(struct device *device,
81 struct device_attribute *attr, char *buf)
83 struct w1_slave *sl = dev_to_w1_slave(device);
84 struct w1_master *dev = sl->master;
90 ret = mutex_lock_interruptible(&dev->bus_mutex);
94 if (!w1_ds2405_select(sl, false)) {
99 state = w1_read_8(dev);
102 dev_err(device, "non-consistent state %x\n", state);
107 *buf = state ? '1' : '0';
112 mutex_unlock(&dev->bus_mutex);
117 static ssize_t output_show(struct device *device,
118 struct device_attribute *attr, char *buf)
120 struct w1_slave *sl = dev_to_w1_slave(device);
121 struct w1_master *dev = sl->master;
126 ret = mutex_lock_interruptible(&dev->bus_mutex);
130 ret = w1_ds2405_read_pio(sl);
136 *buf = ret ? '1' : '0';
141 mutex_unlock(&dev->bus_mutex);
146 static ssize_t output_store(struct device *device,
147 struct device_attribute *attr,
148 const char *buf, size_t count)
150 struct w1_slave *sl = dev_to_w1_slave(device);
151 struct w1_master *dev = sl->master;
153 int ret, current_pio;
160 if (sscanf(buf, " %u%n", &val, &ret) < 1)
163 if (val != 0 && val != 1)
168 ret = mutex_lock_interruptible(&dev->bus_mutex);
172 current_pio = w1_ds2405_read_pio(sl);
173 if (current_pio < 0) {
174 f_retval = current_pio;
178 if (current_pio == val)
181 if (w1_reset_bus(dev) != 0) {
187 * can't use w1_reset_select_slave() here since it uses Skip ROM if
188 * there is only one device on bus
191 u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
194 cmd[0] = W1_MATCH_ROM;
195 memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));
197 w1_write_block(dev, cmd, sizeof(cmd));
202 mutex_unlock(&dev->bus_mutex);
207 static DEVICE_ATTR_RO(state);
208 static DEVICE_ATTR_RW(output);
210 static struct attribute *w1_ds2405_attrs[] = {
211 &dev_attr_state.attr,
212 &dev_attr_output.attr,
216 ATTRIBUTE_GROUPS(w1_ds2405);
218 static struct w1_family_ops w1_ds2405_fops = {
219 .groups = w1_ds2405_groups
222 static struct w1_family w1_family_ds2405 = {
223 .fid = W1_FAMILY_DS2405,
224 .fops = &w1_ds2405_fops
227 module_w1_family(w1_family_ds2405);