docs: sysfs: coresight: Add sysfs ABI documentation for CTI

Add API usage document for sysfs API in CTI driver.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200320165303.13681-12-mathieu.poirier@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-coresight-devices-cti

+What:		/sys/bus/coresight/devices/<cti-name>/enable
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Enable/Disable the CTI hardware.
+
+What:		/sys/bus/coresight/devices/<cti-name>/powered
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Indicate if the CTI hardware is powered.
+
+What:		/sys/bus/coresight/devices/<cti-name>/ctmid
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Display the associated CTM ID
+
+What:		/sys/bus/coresight/devices/<cti-name>/nr_trigger_cons
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Number of devices connected to triggers on this CTI
+
+What:		/sys/bus/coresight/devices/<cti-name>/triggers<N>/name
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Name of connected device <N>
+
+What:		/sys/bus/coresight/devices/<cti-name>/triggers<N>/in_signals
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Input trigger signals from connected device <N>
+
+What:		/sys/bus/coresight/devices/<cti-name>/triggers<N>/in_types
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Functional types for the input trigger signals
+		from connected device <N>
+
+What:		/sys/bus/coresight/devices/<cti-name>/triggers<N>/out_signals
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Output trigger signals to connected device <N>
+
+What:		/sys/bus/coresight/devices/<cti-name>/triggers<N>/out_types
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Functional types for the output trigger signals
+		to connected device <N>
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/inout_sel
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Select the index for inen and outen registers.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/inen
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Read or write the CTIINEN register selected by inout_sel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/outen
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Read or write the CTIOUTEN register selected by inout_sel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/gate
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Read or write CTIGATE register.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/asicctl
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Read or write ASICCTL register.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/intack
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Write the INTACK register.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/appset
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Set CTIAPPSET register to activate channel. Read back to
+		determine current value of register.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/appclear
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Write APPCLEAR register to deactivate channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/apppulse
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Write APPPULSE to pulse a channel active for one clock
+		cycle.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/chinstatus
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Read current status of channel inputs.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/choutstatus
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) read current status of channel outputs.
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/triginstatus
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) read current status of input trigger signals
+
+What:		/sys/bus/coresight/devices/<cti-name>/regs/trigoutstatus
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) read current status of output trigger signals.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trigin_attach
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Attach a CTI input trigger to a CTM channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trigin_detach
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Detach a CTI input trigger from a CTM channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trigout_attach
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Attach a CTI output trigger to a CTM channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trigout_detach
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Detach a CTI output trigger from a CTM channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_gate_enable
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Enable CTIGATE for single channel (W) or list enabled
+		channels through the gate (R).
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_gate_disable
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Disable CTIGATE for single channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_set
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Activate a single channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_clear
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Deactivate a single channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_pulse
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Pulse a single channel - activate for a single clock cycle.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trigout_filtered
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) List of output triggers filtered across all connections.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/trig_filter_enable
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Enable or disable trigger output signal filtering.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_inuse
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) show channels with at least one attached trigger signal.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_free
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) show channels with no attached trigger signals.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_xtrigs_sel
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(RW) Write channel number to select a channel to view, read to
+		see selected channel number.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_xtrigs_in
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Read to see input triggers connected to selected view
+		channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_xtrigs_out
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(R) Read to see output triggers connected to selected view
+		channel.
+
+What:		/sys/bus/coresight/devices/<cti-name>/channels/chan_xtrigs_reset
+Date:		March 2020
+KernelVersion	5.7
+Contact:	Mike Leach or Mathieu Poirier
+Description:	(W) Clear all channel / trigger programming.