xref: /kernel/linux/linux-5.10/Documentation/ABI/testing/sysfs-bus-iio-timer-stm32

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.

		Additional modes (on TRGO2 only):

		- "OC5REF"
				OC5REF signal is used as trigger output.
		- "OC6REF"
				OC6REF signal is used as trigger output.
		- "compare_pulse_OC4REF":
				OC4REF rising or falling edges generate pulses.
		- "compare_pulse_OC6REF":
				OC6REF rising or falling edges generate pulses.
		- "compare_pulse_OC4REF_r_or_OC6REF_r":
				OC4REF or OC6REF rising edges generate pulses.
		- "compare_pulse_OC4REF_r_or_OC6REF_f":
				OC4REF rising or OC6REF falling edges generate
				pulses.
		- "compare_pulse_OC5REF_r_or_OC6REF_r":
				OC5REF or OC6REF rising edges generate pulses.
		- "compare_pulse_OC5REF_r_or_OC6REF_f":
				OC5REF rising or OC6REF falling edges generate
				pulses.

		::

		  +-----------+   +-------------+            +---------+
		  | Prescaler +-> | Counter     |        +-> | Master  | TRGO(2)
		  +-----------+   +--+--------+-+        |-> | Control +-->
		                     |        |          ||  +---------+
		                  +--v--------+-+ OCxREF ||  +---------+
		                  | Chx compare +----------> | Output  | ChX
		                  +-----------+-+         |  | Control +-->
		                        .     |           |  +---------+
		                        .     |           |    .
		                  +-----------v-+ OC6REF  |    .
		                  | Ch6 compare +---------+>
		                  +-------------+

		Example with: "compare_pulse_OC4REF_r_or_OC6REF_r"::

		                  X
		                X   X
		              X .   . X
		            X   .   .   X
		          X     .   .     X
		  count X .     .   .     . X
		          .     .   .     .
		          .     .   .     .
		          +---------------+
		  OC4REF  |     .   .     |
		        +-+     .   .     +-+
		          .     +---+     .
		  OC6REF  .     |   |     .
		        +-------+   +-------+
		          +-+   +-+
		  TRGO2   | |   | |
		        +-+ +---+ +---------+

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.

What:		/sys/bus/iio/devices/iio:deviceX/in_count0_preset
KernelVersion:	4.12
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the current preset value.
		Writing sets the preset value.
		When counting up the counter starts from 0 and fires an
		event when reach preset value.
		When counting down the counter start from preset value
		and fire event when reach 0.

What:		/sys/bus/iio/devices/iio:deviceX/in_count_enable_mode_available
KernelVersion:	4.12
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the list possible enable modes.

What:		/sys/bus/iio/devices/iio:deviceX/in_count0_enable_mode
KernelVersion:	4.12
Contact:	benjamin.gaignard@st.com
Description:
		Configure the device counter enable modes, in all case
		counting direction is set by in_count0_count_direction
		attribute and the counter is clocked by the internal clock.

		always:
			Counter is always ON.

		gated:
			Counting is enabled when connected trigger signal
			level is high else counting is disabled.

		triggered:
			Counting is enabled on rising edge of the connected
			trigger, and remains enabled for the duration of this
			selected mode.

What:		/sys/bus/iio/devices/iio:deviceX/in_count_trigger_mode_available
KernelVersion:	4.13
Contact:	benjamin.gaignard@st.com
Description:
		Reading returns the list possible trigger modes.

What:		/sys/bus/iio/devices/iio:deviceX/in_count0_trigger_mode
KernelVersion:	4.13
Contact:	benjamin.gaignard@st.com
Description:
		Configure the device counter trigger mode
		counting direction is set by in_count0_count_direction
		attribute and the counter is clocked by the connected trigger
		rising edges.