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-rw-r--r-- | Documentation/driver-api/dpll.rst | 53 |
1 files changed, 52 insertions, 1 deletions
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 |