linux/drivers/w1/slaves/w1_ds2413.c

179 lines
4.1 KiB
C

/*
* 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 "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
#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
static ssize_t w1_f3a_read_state(
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);
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");
if (w1_reset_select_slave(sl)) {
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
*buf = w1_read_8(sl->master);
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex unlocked");
/* check for correct complement */
if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
return -EIO;
else
return 1;
}
static ssize_t w1_f3a_write_output(
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;
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 error;
/* 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) {
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
return 1;
}
if (w1_reset_resume_command(sl->master))
goto error;
}
error:
mutex_unlock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
return -EIO;
}
#define NB_SYSFS_BIN_FILES 2
static struct bin_attribute w1_f3a_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
{
.attr = {
.name = "state",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f3a_read_state,
},
{
.attr = {
.name = "output",
.mode = S_IRUGO | S_IWUSR | S_IWGRP,
},
.size = 1,
.write = w1_f3a_write_output,
}
};
static int w1_f3a_add_slave(struct w1_slave *sl)
{
int err = 0;
int i;
for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
err = sysfs_create_bin_file(
&sl->dev.kobj,
&(w1_f3a_sysfs_bin_files[i]));
if (err)
while (--i >= 0)
sysfs_remove_bin_file(&sl->dev.kobj,
&(w1_f3a_sysfs_bin_files[i]));
return err;
}
static void w1_f3a_remove_slave(struct w1_slave *sl)
{
int i;
for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
sysfs_remove_bin_file(&sl->dev.kobj,
&(w1_f3a_sysfs_bin_files[i]));
}
static struct w1_family_ops w1_f3a_fops = {
.add_slave = w1_f3a_add_slave,
.remove_slave = w1_f3a_remove_slave,
};
static struct w1_family w1_family_3a = {
.fid = W1_FAMILY_DS2413,
.fops = &w1_f3a_fops,
};
static int __init w1_f3a_init(void)
{
return w1_register_family(&w1_family_3a);
}
static void __exit w1_f3a_exit(void)
{
w1_unregister_family(&w1_family_3a);
}
module_init(w1_f3a_init);
module_exit(w1_f3a_exit);