1What:		/sys/bus/css/devices/.../type
2Date:		March 2008
3Contact:	linux-s390@vger.kernel.org
4Description:	Contains the subchannel type, as reported by the hardware.
5		This attribute is present for all subchannel types.
6
7What:		/sys/bus/css/devices/.../modalias
8Date:		March 2008
9Contact:	linux-s390@vger.kernel.org
10Description:	Contains the module alias as reported with uevents.
11		It is of the format css:t<type> and present for all
12		subchannel types.
13
14What:		/sys/bus/css/drivers/io_subchannel/.../chpids
15Date:		December 2002
16Contact:	linux-s390@vger.kernel.org
17Description:	Contains the ids of the channel paths used by this
18		subchannel, as reported by the channel subsystem
19		during subchannel recognition.
20
21		Note: This is an I/O-subchannel specific attribute.
22Users:		s390-tools, HAL
23
24What:		/sys/bus/css/drivers/io_subchannel/.../pimpampom
25Date:		December 2002
26Contact:	linux-s390@vger.kernel.org
27Description:	Contains the PIM/PAM/POM values, as reported by the
28		channel subsystem when last queried by the common I/O
29		layer (this implies that this attribute is not necessarily
30		in sync with the values current in the channel subsystem).
31
32		Note: This is an I/O-subchannel specific attribute.
33Users:		s390-tools, HAL
34
35What:		/sys/bus/css/devices/.../driver_override
36Date:		June 2019
37Contact:	linux-s390@vger.kernel.org
38Description:	This file allows the driver for a device to be specified. When
39		specified, only a driver with a name matching the value written
40		to driver_override will have an opportunity to bind to the
41		device. The override is specified by writing a string to the
42		driver_override file (echo vfio-ccw > driver_override) and
43		may be cleared with an empty string (echo > driver_override).
44		This returns the device to standard matching rules binding.
45		Writing to driver_override does not automatically unbind the
46		device from its current driver or make any attempt to
47		automatically load the specified driver.  If no driver with a
48		matching name is currently loaded in the kernel, the device
49		will not bind to any driver.  This also allows devices to
50		opt-out of driver binding using a driver_override name such as
51		"none".  Only a single driver may be specified in the override,
52		there is no support for parsing delimiters.
53
54		Note that unlike the mechanism of the same name for pci, this
55		file does not allow to override basic matching rules. I.e.,
56		the driver must still match the subchannel type of the device.
57