Commit bbecb07f authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Greg Kroah-Hartman

siox: new driver framework for eckelmann SIOX

SIOX is a bus system invented at Eckelmann AG to control their building
management and refrigeration systems. Traditionally the bus was
implemented on custom microcontrollers, today Linux based machines are
in use, too.

The topology on a SIOX bus looks as follows:

      ,------->--DCLK-->---------------+----------------------.
      ^                                v                      v
 ,--------.                ,----------------------.       ,------
 |        |                |   ,--------------.   |       |
 |        |--->--DOUT-->---|->-|shift register|->-|--->---|
 |        |                |   `--------------'   |       |
 | master |                |        device        |       |  device
 |        |                |   ,--------------.   |       |
 |        |---<--DIN---<---|-<-|shift register|-<-|---<---|
 |        |                |   `--------------'   |       |
 `--------'                `----------------------'       `------
      v                                ^                      ^
      `----------DLD-------------------+----------------------'

There are two control lines (DCLK and DLD) driven from the bus master to
all devices in parallel and two daisy chained data lines, one for input
and one for output. DCLK is the clock to shift both chains by a single
bit. On an edge of DLD the devices latch both their input and output
shift registers.

This patch adds a framework for this bus type.
Acked-by: default avatarGavin Schenk <g.schenk@eckelmann.de>
Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0ba002bc
What: /sys/bus/siox/devices/siox-X/active
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
On reading represents the current state of the bus. If it
contains a "0" the bus is stopped and connected devices are
expected to not do anything because their watchdog triggered.
When the file contains a "1" the bus is operated and periodically
does a push-pull cycle to write and read data from the
connected devices.
When writing a "0" or "1" the bus moves to the described state.
What: /sys/bus/siox/devices/siox-X/device_add
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Write-only file. Write
<type> <inbytes> <outbytes> <statustype>
to add a new device dynamically. <type> is the name that is used to match
to a driver (similar to the platform bus). <inbytes> and <outbytes> define
the length of the input and output shift register in bytes respectively.
<statustype> defines the 4 bit device type that is check to identify connection
problems.
The new device is added to the end of the existing chain.
What: /sys/bus/siox/devices/siox-X/device_remove
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Write-only file. A single write removes the last device in the siox chain.
What: /sys/bus/siox/devices/siox-X/poll_interval_ns
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Defines the interval between two poll cycles in nano seconds.
Note this is rounded to jiffies on writing. On reading the current value
is returned.
What: /sys/bus/siox/devices/siox-X-Y/connected
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value. "0" means the Yth device on siox bus X isn't "connected" i.e.
communication with it is not ensured. "1" signals a working connection.
What: /sys/bus/siox/devices/siox-X-Y/inbytes
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value reporting the inbytes value provided to siox-X/device_add
What: /sys/bus/siox/devices/siox-X-Y/status_errors
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Counts the number of time intervals when the read status byte doesn't yield the
expected value.
What: /sys/bus/siox/devices/siox-X-Y/type
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value reporting the type value provided to siox-X/device_add.
What: /sys/bus/siox/devices/siox-X-Y/watchdog
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value reporting if the watchdog of the siox device is
active. "0" means the watchdog is not active and the device is expected to
be operational. "1" means the watchdog keeps the device in reset.
What: /sys/bus/siox/devices/siox-X-Y/watchdog_errors
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value reporting the number to time intervals when the
watchdog was active.
What: /sys/bus/siox/devices/siox-X-Y/outbytes
KernelVersion: 4.16
Contact: Gavin Schenk <g.schenk@eckelmann.de>, Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Description:
Read-only value reporting the outbytes value provided to siox-X/device_add.
......@@ -211,4 +211,6 @@ source "drivers/mux/Kconfig"
source "drivers/opp/Kconfig"
source "drivers/siox/Kconfig"
endmenu
......@@ -184,3 +184,4 @@ obj-$(CONFIG_FPGA) += fpga/
obj-$(CONFIG_FSI) += fsi/
obj-$(CONFIG_TEE) += tee/
obj-$(CONFIG_MULTIPLEXER) += mux/
obj-$(CONFIG_SIOX) += siox/
menuconfig SIOX
tristate "Eckelmann SIOX Support"
help
SIOX stands for Serial Input Output eXtension and is a synchronous
bus system invented by Eckelmann AG. It is used in their control and
remote monitoring systems for commercial and industrial refrigeration
to drive additional I/O units.
Unless you know better, it is probably safe to say "no" here.
obj-$(CONFIG_SIOX) += siox-core.o
This diff is collapsed.
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2017 Pengutronix, Uwe Kleine-König <kernel@pengutronix.de>
*/
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/siox.h>
#define to_siox_master(_dev) container_of((_dev), struct siox_master, dev)
struct siox_master {
/* these fields should be initialized by the driver */
int busno;
int (*pushpull)(struct siox_master *smaster,
size_t setbuf_len, const u8 setbuf[],
size_t getbuf_len, u8 getbuf[]);
/* might be initialized by the driver, if 0 it is set to HZ / 40 */
unsigned long poll_interval; /* in jiffies */
/* framework private stuff */
struct mutex lock;
bool active;
struct module *owner;
struct device dev;
unsigned int num_devices;
struct list_head devices;
size_t setbuf_len, getbuf_len;
size_t buf_len;
u8 *buf;
u8 status;
unsigned long last_poll;
struct task_struct *poll_thread;
};
static inline void *siox_master_get_devdata(struct siox_master *smaster)
{
return dev_get_drvdata(&smaster->dev);
}
struct siox_master *siox_master_alloc(struct device *dev, size_t size);
static inline void siox_master_put(struct siox_master *smaster)
{
put_device(&smaster->dev);
}
int siox_master_register(struct siox_master *smaster);
void siox_master_unregister(struct siox_master *smaster);
/*
* Copyright (C) 2015 Pengutronix, Uwe Kleine-König <kernel@pengutronix.de>
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*/
#include <linux/device.h>
#define to_siox_device(_dev) container_of((_dev), struct siox_device, dev)
struct siox_device {
struct list_head node; /* node in smaster->devices */
struct siox_master *smaster;
struct device dev;
const char *type;
size_t inbytes;
size_t outbytes;
u8 statustype;
u8 status_read_clean;
u8 status_written;
u8 status_written_lastcycle;
bool connected;
/* statistics */
unsigned int watchdog_errors;
unsigned int status_errors;
struct kernfs_node *status_errors_kn;
struct kernfs_node *watchdog_kn;
struct kernfs_node *watchdog_errors_kn;
struct kernfs_node *connected_kn;
};
bool siox_device_synced(struct siox_device *sdevice);
bool siox_device_connected(struct siox_device *sdevice);
struct siox_driver {
int (*probe)(struct siox_device *sdevice);
int (*remove)(struct siox_device *sdevice);
void (*shutdown)(struct siox_device *sdevice);
/*
* buf is big enough to hold sdev->inbytes - 1 bytes, the status byte
* is in the scope of the framework.
*/
int (*set_data)(struct siox_device *sdevice, u8 status, u8 buf[]);
/*
* buf is big enough to hold sdev->outbytes - 1 bytes, the status byte
* is in the scope of the framework
*/
int (*get_data)(struct siox_device *sdevice, const u8 buf[]);
struct device_driver driver;
};
static inline struct siox_driver *to_siox_driver(struct device_driver *driver)
{
if (driver)
return container_of(driver, struct siox_driver, driver);
else
return NULL;
}
int __siox_driver_register(struct siox_driver *sdriver, struct module *owner);
static inline int siox_driver_register(struct siox_driver *sdriver)
{
return __siox_driver_register(sdriver, THIS_MODULE);
}
static inline void siox_driver_unregister(struct siox_driver *sdriver)
{
return driver_unregister(&sdriver->driver);
}
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