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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* w1_ds2405.c
*
* Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>
* Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/w1.h>
#define W1_FAMILY_DS2405 0x05
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO.");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2405));
static int w1_ds2405_select(struct w1_slave *sl, bool only_active)
{
struct w1_master *dev = sl->master;
u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
unsigned int bit_ctr;
if (w1_reset_bus(dev) != 0)
return 0;
/*
* We cannot use a normal Match ROM command
* since doing so would toggle PIO state
*/
w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);
for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {
int bit2send = !!(dev_addr & BIT(bit_ctr));
u8 ret;
ret = w1_triplet(dev, bit2send);
if ((ret & (BIT(0) | BIT(1))) ==
(BIT(0) | BIT(1))) /* no devices found */
return 0;
if (!!(ret & BIT(2)) != bit2send)
/* wrong direction taken - no such device */
return 0;
}
return 1;
}
static int w1_ds2405_read_pio(struct w1_slave *sl)
{
if (w1_ds2405_select(sl, true))
return 0; /* "active" means PIO is low */
if (w1_ds2405_select(sl, false))
return 1;
return -ENODEV;
}
static ssize_t state_show(struct device *device,
struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret;
ssize_t f_retval;
u8 state;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
if (!w1_ds2405_select(sl, false)) {
f_retval = -ENODEV;
goto out_unlock;
}
state = w1_read_8(dev);
if (state != 0 &&
state != 0xff) {
dev_err(device, "non-consistent state %x\n", state);
f_retval = -EIO;
goto out_unlock;
}
*buf = state ? '1' : '0';
f_retval = 1;
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static ssize_t output_show(struct device *device,
struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret;
ssize_t f_retval;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
ret = w1_ds2405_read_pio(sl);
if (ret < 0) {
f_retval = ret;
goto out_unlock;
}
*buf = ret ? '1' : '0';
f_retval = 1;
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static ssize_t output_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret, current_pio;
unsigned int val;
ssize_t f_retval;
if (count < 1)
return -EINVAL;
if (sscanf(buf, " %u%n", &val, &ret) < 1)
return -EINVAL;
if (val != 0 && val != 1)
return -EINVAL;
f_retval = ret;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
current_pio = w1_ds2405_read_pio(sl);
if (current_pio < 0) {
f_retval = current_pio;
goto out_unlock;
}
if (current_pio == val)
goto out_unlock;
if (w1_reset_bus(dev) != 0) {
f_retval = -ENODEV;
goto out_unlock;
}
/*
* can't use w1_reset_select_slave() here since it uses Skip ROM if
* there is only one device on bus
*/
do {
u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
u8 cmd[9];
cmd[0] = W1_MATCH_ROM;
memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));
w1_write_block(dev, cmd, sizeof(cmd));
} while (0);
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static DEVICE_ATTR_RO(state);
static DEVICE_ATTR_RW(output);
static struct attribute *w1_ds2405_attrs[] = {
&dev_attr_state.attr,
&dev_attr_output.attr,
NULL
};
ATTRIBUTE_GROUPS(w1_ds2405);
static const struct w1_family_ops w1_ds2405_fops = {
.groups = w1_ds2405_groups
};
static struct w1_family w1_family_ds2405 = {
.fid = W1_FAMILY_DS2405,
.fops = &w1_ds2405_fops
};
module_w1_family(w1_family_ds2405);
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