What:		/sys/class/leds/vibrator/device/autocal
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Reading it to obtain the COMP, BEMF and GAIN values
		after running the auto-calibration.

		Writing to it would restore the COMP, BEMF and GAIN registers.
		The format is "COMP BEMF GAIN" with space as delimiter.

		For example,

		$ echo "17 190 1" > autocal

		The above would restore COMP to 17, BEMF to 190 and GAIN to 1.

What:		/sys/class/leds/vibrator/device/loop
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Set the main loop for waveform playback:

		0 - No loop, play the identifier sequence only once.
		1 - Loop once.
		2 - Loop twice.
		3 - Loop 3 times.
		4 - Loop 4 times.
		5 - Loop 5 times.
		6 - Loop 6 times.
		7 - Inifinite loops. (stop with trigger or GO bit).

What:		/sys/class/leds/vibrator/device/diag_result
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Reading it to obtain the DIAG_K and DIAG_Z results
		after running the diagnostics routine.

What:		/sys/class/leds/vibrator/device/interval
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Sets the internal memory playback interval to
		either 5 ms or 1 ms.

		0 - 5 ms.
		1 - 1 ms.

What:		/sys/class/leds/vibrator/device/ctrl_loop
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Selects either closed loop or open loop mode.
		This applies to both ERM and LRA actuators.

		0 - Closed Loop.
		1 - Open Loop.

What:		/sys/class/leds/vibrator/device/mode
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Set to select the mode of operation. If the mode is
		changed during process execution, the device will
		immediately go into standby.

		rtp - RTP Mode
		waveform - Waveform Sequencer Mode
		diag - Diagnostics Routine
		autocal - Automatic Level Calibration Routine

What:		/sys/class/leds/vibrator/device/od_clamp
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Set to limit the maximum voltage defined automatic
		overdrive and automatic braking periods.

What:		/sys/class/leds/vibrator/device/rtp_input
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Set to change the playback amplitude of the haptic
		waveforms in RTP mode. The input value is interpreted
		as an 8bit signed number with a negative number indicates
		braking.

What:		/sys/class/leds/vibrator/device/scale
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		This parameter allows for proportionally scaling
		down (attenuating) the effects stored in the internal
		library to simplify the customization of haptics.
		This parameter is ignored in RTP mode.

		0 - Play effect with 100% strength.
		1 - Play effect with 75% strength.
		2 - Play effect with 50% strength.
		3 - Play effect with 25% strength.

What:		/sys/class/leds/vibrator/device/set_sequencer
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Setup the waveform sequencer by writing effect index
		and loop pairs.

		For example,
		$ echo "12 0 3 2" > set_sequencer

		The above will set up the first sequencer to play effect#12
		with no looping and the second sequencer to play effect#3 with
		two loops.

		0 - No loop, play only once.
		1 - Loop once (play twice).
		2 - Loop twice (play 3 times).
		3 - Loop 3 times (play 4 times).

What:		/sys/class/leds/vibrator/device/lra_period
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		This parameter reports the resonance frequency of the LRA
		in real time.

What:		/sys/class/leds/vibrator/device/status
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		This parameter reports the status of the driver IC.
		The following bits are set to indicate the corresponding
                error types. The status returns 0 to indicate there's no error.

		BIT 7 - DIAG_RESULT
		BIT 2 - UVLO
		BIT 1 - OVER_TEMP
		BIT 0 - OC_DETECT

What:		/sys/class/leds/vibrator/device/ol_lra_period
Date:		Mar 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		This parameter sets and gets the frequency that will be used
		to drive the LRA in open loop.

What:		/sys/class/leds/vibrator/device/lra_wave_shape
Date:		May 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		Selects which shape to use for driving the LRA when in open
		loop mode.

		0 - Square Wave
		1 - Sine Wave

What:		/sys/class/leds/vibrator/device/lp_trigger_effect
Date:		Jul 2017
KernelVersion:	4.4
Contact:	David Lin <dtwlin@google.com>
Description:
		This parameter selects the effect and enables drv2624 to be
		triggered by an external pin when the kernel is suspended.

		0 - Low-power trigger mode disabled
		1 or above - Index to the waveform sequencer to be used when
		low-power playback is triggered.
