What:		/sys/bus/iio/devices/triggerX/master_mode_available
KernelVersion:	4.11
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the list possible master modes which are:
		- "reset"     :	The UG bit from the TIMx_EGR register is used as trigger output (TRGO).
		- "enable"    : The Counter Enable signal CNT_EN is used as trigger output.
		- "update"    : The update event is selected as trigger output.
				For instance a master timer can then be used as a prescaler for a slave timer.
		- "compare_pulse" : The trigger output send a positive pulse when the CC1IF flag is to be set.
		- "OC1REF"    : OC1REF signal is used as trigger output.
		- "OC2REF"    : OC2REF signal is used as trigger output.
		- "OC3REF"    : OC3REF signal is used as trigger output.
		- "OC4REF"    : OC4REF signal is used as trigger output.

What:		/sys/bus/iio/devices/triggerX/master_mode
KernelVersion:	4.11
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the current master modes.
		Writing set the master mode

What:		/sys/bus/iio/devices/triggerX/sampling_frequency
KernelVersion:	4.11
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the current sampling frequency.
		Writing an value different of 0 set and start sampling.
		Writing 0 stop sampling.