Add documentation on:
- measurement of phase of signal between pin and dpll
- adjustment of pin signal phase
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
---
Documentation/driver-api/dpll.rst | 53 ++++++++++++++++++++++++++++++-
1 file changed, 52 insertions(+), 1 deletion(-)
diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst
index 69670deb8c4e..e3d593841aa7 100644
--- a/Documentation/driver-api/dpll.rst
+++ b/Documentation/driver-api/dpll.rst
@@ -173,6 +173,47 @@ in order to configure active input of a MUX-type pin, the user needs to
request desired pin state of the child pin on the parent pin,
as described in the ``MUX-type pins`` chapter.
+Phase offset measurement and adjustment
+========================================
+
+Device may provide ability to measure a phase difference between signals
+on a pin and its parent dpll device. If pin-dpll phase offset measurement
+is supported, it shall be provided with ``DPLL_A_PIN_PHASE_OFFSET``
+attribute for each parent dpll device.
+
+Device may also provide ability to adjust a signal phase on a pin.
+If pin phase adjustment is supported, minimal and maximal values that pin
+handle shall be provide to the user on ``DPLL_CMD_PIN_GET`` respond
+with ``DPLL_A_PIN_PHASE_ADJUST_MIN`` and ``DPLL_A_PIN_PHASE_ADJUST_MAX``
+attributes. Configured phase adjust value is provided with
+``DPLL_A_PIN_PHASE_ADJUST`` attribute of a pin, and value change can be
+requested with the same attribute with ``DPLL_CMD_PIN_SET`` command.
+
+ =============================== ======================================
+ ``DPLL_A_PIN_ID`` configured pin id
+ ``DPLL_A_PIN_PHASE_ADJUST_MIN`` attr minimum value of phase adjustment
+ ``DPLL_A_PIN_PHASE_ADJUST_MAX`` attr maximum value of phase adjustment
+ ``DPLL_A_PIN_PHASE_ADJUST`` attr configured value of phase
+ adjustment on parent dpll device
+ ``DPLL_A_PIN_PARENT_DEVICE`` nested attribute for requesting
+ configuration on given parent dpll
+ device
+ ``DPLL_A_PIN_PARENT_ID`` parent dpll device id
+ ``DPLL_A_PIN_PHASE_OFFSET`` attr measured phase difference
+ between a pin and parent dpll device
+ =============================== ======================================
+
+All phase related values are provided in pico seconds, which represents
+time difference between signals phase. The negative value means that
+phase of signal on pin is earlier in time than dpll's signal. Positive
+value means that phase of signal on pin is later in time than signal of
+a dpll.
+
+Phase adjust (also min and max) values are integers, but measured phase
+offset values are fractional with 3-digit decimal places and shell be
+divided with ``DPLL_PIN_PHASE_OFFSET_DIVIDER`` to get integer part and
+modulo divided to get fractional part.
+
Configuration commands group
============================
@@ -263,6 +304,12 @@ according to attribute purpose.
frequencies
``DPLL_A_PIN_ANY_FREQUENCY_MIN`` attr minimum value of frequency
``DPLL_A_PIN_ANY_FREQUENCY_MAX`` attr maximum value of frequency
+ ``DPLL_A_PIN_PHASE_ADJUST_MIN`` attr minimum value of phase
+ adjustment
+ ``DPLL_A_PIN_PHASE_ADJUST_MAX`` attr maximum value of phase
+ adjustment
+ ``DPLL_A_PIN_PHASE_ADJUST`` attr configured value of phase
+ adjustment on parent device
``DPLL_A_PIN_PARENT_DEVICE`` nested attr for each parent device
the pin is connected with
``DPLL_A_PIN_PARENT_ID`` attr parent dpll device id
@@ -270,8 +317,10 @@ according to attribute purpose.
dpll device
``DPLL_A_PIN_STATE`` attr state of pin on the parent
dpll device
- ``DPLL_A_PIN_DIRECTION`` attr direction of a pin on the
+ ``DPLL_A_PIN_DIRECTION`` attr direction of a pin on the
parent dpll device
+ ``DPLL_A_PIN_PHASE_OFFSET`` attr measured phase difference
+ between a pin and parent dpll
``DPLL_A_PIN_PARENT_PIN`` nested attr for each parent pin
the pin is connected with
``DPLL_A_PIN_PARENT_ID`` attr parent pin id
@@ -284,6 +333,8 @@ according to attribute purpose.
``DPLL_CMD_PIN_SET`` command to set pins configuration
``DPLL_A_PIN_ID`` attr unique a pin ID
``DPLL_A_PIN_FREQUENCY`` attr requested frequency of a pin
+ ``DPLL_A_PIN_PHASE_ADJUST`` attr requested value of phase
+ adjustment on parent device
``DPLL_A_PIN_PARENT_DEVICE`` nested attr for each parent dpll
device configuration request
``DPLL_A_PIN_PARENT_ID`` attr parent dpll device id
--
2.38.1
