w1: new w1_ds2406 driver

Some preliminary work at making use of this driver led me to implement
CRC-16 checks on read and write to deal with the occasional glitchiness of
the 1-Wire bus.  The revised driver (attached) returns an I/O error if the
CRC check fails.  When reading the chip's state, either you get a valid
indication or you get an I/O error.  When changing its state, either the
change is successful or an I/O error is returned.

Signed-off-by: Scott Alfter <scott@alfter.us>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Scott Alfter 2014-06-17 20:42:05 +00:00 committed by Greg Kroah-Hartman
parent 7242d42ace
commit 94859308a2
5 changed files with 202 additions and 0 deletions

View File

@ -0,0 +1,25 @@
w1_ds2406 kernel driver
=======================
Supported chips:
* Maxim DS2406 (and other family 0x12) addressable switches
Author: Scott Alfter <scott@alfter.us>
Description
-----------
The w1_ds2406 driver allows connected devices to be switched on and off.
These chips also provide 128 bytes of OTP EPROM, but reading/writing it is
not supported. In TSOC-6 form, the DS2406 provides two switch outputs and
can be provided with power on a dedicated input. In TO-92 form, it provides
one output and uses parasitic power only.
The driver provides two sysfs files. state is readable; it gives the
current state of each switch, with PIO A in bit 0 and PIO B in bit 1. The
driver ORs this state with 0x30, so shell scripts get an ASCII 0/1/2/3 to
work with. output is writable; bits 0 and 1 control PIO A and B,
respectively. Bits 2-7 are ignored, so it's safe to write ASCII data.
CRCs are checked on read and write. Failed checks cause an I/O error to be
returned. On a failed write, the switch status is not changed.

View File

@ -38,6 +38,13 @@ config W1_SLAVE_DS2413
Say Y here if you want to use a 1-wire
DS2413 Dual Channel Addressable Switch device support
config W1_SLAVE_DS2406
tristate "Dual Channel Addressable Switch 0x12 family support (DS2406)"
help
Say Y or M here if you want to use a 1-wire
DS2406 Dual Channel Addressable Switch. EPROM read/write
support for these devices is not implemented.
config W1_SLAVE_DS2423
tristate "Counter 1-wire device (DS2423)"
select CRC16

View File

@ -6,6 +6,7 @@ obj-$(CONFIG_W1_SLAVE_THERM) += w1_therm.o
obj-$(CONFIG_W1_SLAVE_SMEM) += w1_smem.o
obj-$(CONFIG_W1_SLAVE_DS2408) += w1_ds2408.o
obj-$(CONFIG_W1_SLAVE_DS2413) += w1_ds2413.o
obj-$(CONFIG_W1_SLAVE_DS2406) += w1_ds2406.o
obj-$(CONFIG_W1_SLAVE_DS2423) += w1_ds2423.o
obj-$(CONFIG_W1_SLAVE_DS2431) += w1_ds2431.o
obj-$(CONFIG_W1_SLAVE_DS2433) += w1_ds2433.o

View File

@ -0,0 +1,168 @@
/*
* w1_ds2406.c - w1 family 12 (DS2406) driver
* based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
*
* Copyright (c) 2014 Scott Alfter <scott@alfter.us>
*
* 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/crc16.h>
#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
#define W1_F12_FUNC_READ_STATUS 0xAA
#define W1_F12_FUNC_WRITE_STATUS 0x55
static ssize_t w1_f12_read_state(
struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u16 crc=0;
int i;
ssize_t rtnval=1;
if (off != 0)
return 0;
if (!buf)
return -EINVAL;
mutex_lock(&sl->master->bus_mutex);
if (w1_reset_select_slave(sl)) {
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
w1_write_block(sl->master, w1_buf, 3);
w1_read_block(sl->master, w1_buf+3, 3);
for (i=0; i<6; i++)
crc=crc16_byte(crc, w1_buf[i]);
if (crc==0xb001) /* good read? */
*buf=((w1_buf[3]>>5)&3)|0x30;
else
rtnval=-EIO;
mutex_unlock(&sl->master->bus_mutex);
return rtnval;
}
static ssize_t w1_f12_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[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
u16 crc=0;
int i;
ssize_t rtnval=1;
if (count != 1 || off != 0)
return -EFAULT;
mutex_lock(&sl->master->bus_mutex);
if (w1_reset_select_slave(sl)) {
mutex_unlock(&sl->master->bus_mutex);
return -EIO;
}
w1_buf[3] = (((*buf)&3)<<5)|0x1F;
w1_write_block(sl->master, w1_buf, 4);
w1_read_block(sl->master, w1_buf+4, 2);
for (i=0; i<6; i++)
crc=crc16_byte(crc, w1_buf[i]);
if (crc==0xb001) /* good read? */
w1_write_8(sl->master, 0xFF);
else
rtnval=-EIO;
mutex_unlock(&sl->master->bus_mutex);
return rtnval;
}
#define NB_SYSFS_BIN_FILES 2
static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
{
.attr = {
.name = "state",
.mode = S_IRUGO,
},
.size = 1,
.read = w1_f12_read_state,
},
{
.attr = {
.name = "output",
.mode = S_IRUGO | S_IWUSR | S_IWGRP,
},
.size = 1,
.write = w1_f12_write_output,
}
};
static int w1_f12_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_f12_sysfs_bin_files[i]));
if (err)
while (--i >= 0)
sysfs_remove_bin_file(&sl->dev.kobj,
&(w1_f12_sysfs_bin_files[i]));
return err;
}
static void w1_f12_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_f12_sysfs_bin_files[i]));
}
static struct w1_family_ops w1_f12_fops = {
.add_slave = w1_f12_add_slave,
.remove_slave = w1_f12_remove_slave,
};
static struct w1_family w1_family_12 = {
.fid = W1_FAMILY_DS2406,
.fops = &w1_f12_fops,
};
static int __init w1_f12_init(void)
{
return w1_register_family(&w1_family_12);
}
static void __exit w1_f12_exit(void)
{
w1_unregister_family(&w1_family_12);
}
module_init(w1_f12_init);
module_exit(w1_f12_exit);

View File

@ -40,6 +40,7 @@
#define W1_FAMILY_DS2760 0x30
#define W1_FAMILY_DS2780 0x32
#define W1_FAMILY_DS2413 0x3A
#define W1_FAMILY_DS2406 0x12
#define W1_THERM_DS1825 0x3B
#define W1_FAMILY_DS2781 0x3D
#define W1_THERM_DS28EA00 0x42