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

Documentation/ABI/testing/sysfs-bus-siox

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+87 −0
Original line number Diff line number Diff line 
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.

drivers/Kconfig

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Original line number Diff line number Diff line
@@ -211,4 +211,6 @@ source "drivers/mux/Kconfig" 


source "drivers/opp/Kconfig"



source "drivers/siox/Kconfig"



endmenu

drivers/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -184,3 +184,4 @@ obj-$(CONFIG_FPGA) += fpga/ 
obj-$(CONFIG_FSI)		+= fsi/

obj-$(CONFIG_TEE)		+= tee/

obj-$(CONFIG_MULTIPLEXER)	+= mux/

obj-$(CONFIG_SIOX)		+= siox/

drivers/siox/Kconfig

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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.

drivers/siox/Makefile

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obj-$(CONFIG_SIOX) += siox-core.o