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/*
* w1_ds2413.c - w1 family 3a (DS2413) driver
* based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
*
* Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/w1.h>
#define W1_FAMILY_DS2413 0x3A
#define W1_F3A_RETRIES 3
#define W1_F3A_FUNC_PIO_ACCESS_READ 0xF5
#define W1_F3A_FUNC_PIO_ACCESS_WRITE 0x5A
#define W1_F3A_SUCCESS_CONFIRM_BYTE 0xAA
#define W1_F3A_INVALID_PIO_STATE 0xFF
static ssize_t state_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf, loff_t off,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
unsigned int retries = W1_F3A_RETRIES;
ssize_t bytes_read = -EIO;
u8 state;
dev_dbg(&sl->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
if (off != 0)
return 0;
if (!buf)
return -EINVAL;
mutex_lock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex locked");
next:
if (w1_reset_select_slave(sl))
goto out;
while (retries--) {
w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
state = w1_read_8(sl->master);
if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
/* complement is correct */
*buf = state;
bytes_read = 1;
goto out;
} else if (state == W1_F3A_INVALID_PIO_STATE) {
/* slave didn't respond, try to select it again */
dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
"reselecting, retries left: %d\n", retries);
goto next;
}
if (w1_reset_resume_command(sl->master))
goto out; /* unrecoverable error */
dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
}
out:
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
(bytes_read > 0) ? "succeeded" : "error", retries);
return bytes_read;
}
static BIN_ATTR_RO(state, 1);
static ssize_t output_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 w1_buf[3];
unsigned int retries = W1_F3A_RETRIES;
ssize_t bytes_written = -EIO;
if (count != 1 || off != 0)
return -EFAULT;
dev_dbg(&sl->dev, "locking mutex for write_output");
mutex_lock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex locked");
if (w1_reset_select_slave(sl))
goto out;
/* according to the DS2413 datasheet the most significant 6 bits
should be set to "1"s, so do it now */
*buf = *buf | 0xFC;
while (retries--) {
w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
w1_buf[1] = *buf;
w1_buf[2] = ~(*buf);
w1_write_block(sl->master, w1_buf, 3);
if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
bytes_written = 1;
goto out;
}
if (w1_reset_resume_command(sl->master))
goto out; /* unrecoverable error */
dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
}
out:
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
(bytes_written > 0) ? "succeeded" : "error", retries);
return bytes_written;
}
static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
static struct bin_attribute *w1_f3a_bin_attrs[] = {
&bin_attr_state,
&bin_attr_output,
NULL,
};
static const struct attribute_group w1_f3a_group = {
.bin_attrs = w1_f3a_bin_attrs,
};
static const struct attribute_group *w1_f3a_groups[] = {
&w1_f3a_group,
NULL,
};
static struct w1_family_ops w1_f3a_fops = {
.groups = w1_f3a_groups,
};
static struct w1_family w1_family_3a = {
.fid = W1_FAMILY_DS2413,
.fops = &w1_f3a_fops,
};
module_w1_family(w1_family_3a);
MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
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