Re: [RFC PATCH v8 01/10] dpll: documentation on DPLL subsystem interface

From: Bagas Sanjaya
Date: Fri Jun 09 2023 - 23:23:03 EST

On Fri, Jun 09, 2023 at 02:18:44PM +0200, Arkadiusz Kubalewski wrote:
> diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst
> new file mode 100644
> index 000000000000..8caa4af022ad
> --- /dev/null
> +++ b/Documentation/driver-api/dpll.rst
> @@ -0,0 +1,458 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===============================
> +The Linux kernel dpll subsystem
> +===============================
> +
> +The main purpose of dpll subsystem is to provide general interface
> +to configure devices that use any kind of Digital PLL and could use
> +different sources of signal to synchronize to as well as different
> +types of outputs.
> +The main interface is NETLINK_GENERIC based protocol with an event
> +monitoring multicast group defined.
> +
> +Device object
> +=============
> +
> +Single dpll device object means single Digital PLL circuit and bunch of
> +connected pins.
> +It reports the supported modes of operation and current status to the
> +user in response to the `do` request of netlink command
> +``DPLL_CMD_DEVICE_GET`` and list of dplls registered in the subsystem
> +with `dump` netlink request of the same command.
> +Changing the configuration of dpll device is done with `do` request of
> +netlink ``DPLL_CMD_DEVICE_SET`` command.
> +A device handle is ``DPLL_A_ID``, it shall be provided to get or set
> +configuration of particular device in the system. It can be obtained
> +with a ``DPLL_CMD_DEVICE_GET`` `dump` request or
> +a ``DPLL_CMD_DEVICE_ID_GET`` `do` request, where the one must provide
> +attributes that result in single device match.
> +
> +Pin object
> +==========
> +
> +A pin is amorphic object which represents either input or output, it
> +could be internal component of the device, as well as externally
> +connected.
> +The number of pins per dpll vary, but usually multiple pins shall be
> +provided for a single dpll device.
> +Pin's properties, capabilities and status is provided to the user in
> +response to `do` request of netlink ``DPLL_CMD_PIN_GET`` command.
> +It is also possible to list all the pins that were registered in the
> +system with `dump` request of ``DPLL_CMD_PIN_GET`` command.
> +Configuration of a pin can be changed by `do` request of netlink
> +``DPLL_CMD_PIN_SET`` command.
> +Pin handle is a ``DPLL_A_PIN_ID``, it shall be provided to get or set
> +configuration of particular pin in the system. It can be obtained with
> +``DPLL_CMD_PIN_GET`` `dump` request or ``DPLL_CMD_PIN_ID_GET`` `do`
> +request, where user provides attributes that result in single pin match.
> +
> +Pin selection
> +=============
> +
> +In general, selected pin (the one which signal is driving the dpll
> +device) can be obtained from ``DPLL_A_PIN_STATE`` attribute, and only
> +one pin shall be in ``DPLL_PIN_STATE_CONNECTED`` state for any dpll
> +device.
> +
> +Pin selection can be done either manually or automatically, depending
> +on hardware capabilities and active dpll device work mode
> +(``DPLL_A_MODE`` attribute). The consequence is that there are
> +differences for each mode in terms of available pin states, as well as
> +for the states the user can request for a dpll device.
> +
> +In manual mode (``DPLL_MODE_MANUAL``) the user can request or receive
> +one of following pin states:
> +- ``DPLL_PIN_STATE_CONNECTED`` - the pin is used to drive dpll device
> +- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin is not used to drive dpll
> + device
> +
> +In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can request or
> +receive one of following pin states:
> +- ``DPLL_PIN_STATE_SELECTABLE`` - the pin shall be considered as valid
> + input for automatic selection algorithm
> +- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin shall be not considered as
> + a valid input for automatic selection algorithm
> +In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can only receive
> +pin state ``DPLL_PIN_STATE_CONNECTED`` once automatic selection
> +algorithm locks a dpll device with one of the inputs.
> +
> +For other dpll device operating modes there is no pin selection
> +mechanics.
> +
> +Shared pins
> +===========
> +
> +A single pin object can be attached to multiple dpll devices.
> +Then there are two groups of configuration knobs:
> +1) Set on a pin - the configuration affects all dpll devices pin is
> + registered to (i.e. ``DPLL_A_PIN_FREQUENCY``),
> +2) Set on a pin-dpll tuple - the configuration affects only selected
> + dpll device (i.e. ``DPLL_A_PIN_PRIO``, ``DPLL_A_PIN_STATE``,
> + ``DPLL_A_PIN_DIRECTION``).
> +
> +MUX-type pins
> +=============
> +
> +A pin can be MUX-type, it aggregates child pins and serves as a pin
> +multiplexer. One or more pins are registered with MUX-type instead of
> +being directly registered to a dpll device.
> +Pins registered with a MUX-type provide user with additional nested
> +attribute ``DPLL_A_PIN_PARENT`` for each parent they were registered
> +with.
> +If a pin was registered with multiple parent pins, they behave like a
> +multiple output multiplexer. In this case output of a
> +``DPLL_CMD_PIN_GET`` would contain multiple pin-parent nested
> +attributes with current state related to each parent, like:
> +
> +``'pin': [{
> + {'clock-id': 282574471561216,
> + 'module-name': 'ice',
> + 'pin-dpll-caps': 4,
> + 'pin-id': 13,
> + 'pin-parent': [{'pin-id': 2, 'pin-state': 'connected'},
> + {'pin-id': 3, 'pin-state': 'disconnected'},
> + {'id': 0, 'pin-direction': 'input'},
> + {'id': 1, 'pin-direction': 'input'}],
> + 'pin-type': 'synce-eth-port'}
> +}]``
> +
> +Only one child pin can provide its signal to the parent MUX-type pin at
> +a time, the selection is done by requesting change of a child pin state
> +on desired parent, with the use of ``DPLL_A_PIN_PARENT`` nested
> +attribute. Example of netlink `set state on parent pin` message format:
> +
> + ===================== =============================================
> + ``DPLL_A_PIN_ID`` child pin id
> + ``DPLL_A_PIN_PARENT`` nested attribute for requesting configuration
> + related to parent pin
> + ``DPLL_A_PIN_ID`` parent pin id
> + ``DPLL_A_PIN_STATE`` requested pin state on parent
> +
> +Pin priority
> +============
> +
> +Some devices might offer a capability of automatic pin selection mode
> +(enum value ``DPLL_MODE_AUTOMATIC`` of ``DPLL_A_MODE`` attribute).
> +Usually, automatic selection is performed on the hardware level, which
> +means only pins directly connected to the dpll can be used for automatic
> +input pin selection.
> +In automatic selection mode, the user cannot manually select a input
> +pin for the device, instead the user shall provide all directly
> +connected pins with a priority ``DPLL_A_PIN_PRIO``, the device would
> +pick a highest priority valid signal and use it to control the DPLL
> +device. Example of netlink `set priority on parent pin` message format:
> +
> + ===================== =============================================
> + ``DPLL_A_PIN_ID`` child pin id
> + ``DPLL_A_PIN_PARENT`` nested attribute for requesting configuration
> + related to parent pin
> + ``DPLL_A_ID`` parent dpll id
> + ``DPLL_A_PIN_PRIO`` requested pin prio on parent dpll
> +
> +Child pin of MUX-type is not capable of automatic input pin selection,
> +in order to configure a 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.
> +
> +Configuration commands group
> +============================
> +
> +Configuration commands are used to get information about registered
> +dpll devices (and pins), as well as set configuration of device or pins.
> +As dpll devices must be abstracted and reflect real hardware,
> +there is no way to add new dpll device via netlink from user space and
> +each device should be registered by its driver.
> +
> +All netlink commands require ``GENL_ADMIN_PERM``. This is to prevent
> +any spamming/DoS from unauthorized userspace applications.
> +
> +List of netlink commands with possible attributes
> +=================================================
> +
> +All constants identifying command types use a ``DPLL_CMD_`` prefix and
> +suffix according to command purpose. All attributes use a ``DPLL_A_``
> +prefix and suffix according to attribute purpose:
> +
> + ==================================== =================================
> + ``DPLL_CMD_DEVICE_ID_GET`` command to get device ID
> + ``DPLL_A_MODULE_NAME`` attr module name of registerer
> + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier
> + (EUI-64), as defined by the
> + IEEE 1588 standard
> + ``DPLL_A_TYPE`` attr type of dpll device
> + ``DPLL_CMD_DEVICE_GET`` command to get device info or
> + dump list of available devices
> + ``DPLL_A_ID`` attr unique dpll device ID
> + ``DPLL_A_MODULE_NAME`` attr module name of registerer
> + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier
> + (EUI-64), as defined by the
> + IEEE 1588 standard
> + ``DPLL_A_MODE`` attr selection mode
> + ``DPLL_A_MODE_SUPPORTED`` attr available selection modes
> + ``DPLL_A_LOCK_STATUS`` attr dpll device lock status
> + ``DPLL_A_TEMP`` attr device temperature info
> + ``DPLL_A_TYPE`` attr type of dpll device
> + ``DPLL_CMD_DEVICE_SET`` command to set dpll device config
> + ``DPLL_A_ID`` attr internal dpll device index
> + ``DPLL_A_MODE`` attr selection mode to configure
> + ``DPLL_CMD_PIN_GET`` command to get pin ID
> + ``DPLL_A_MODULE_NAME`` attr module name of registerer
> + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier
> + (EUI-64), as defined by the
> + IEEE 1588 standard
> + ``DPLL_A_PIN_BOARD_LABEL`` attr pin board label provided
> + by registerer
> + ``DPLL_A_PIN_PANEL_LABEL`` attr pin panel label provided
> + by registerer
> + ``DPLL_A_PIN_PACKAGE_LABEL`` attr pin package label provided
> + by registerer
> + ``DPLL_A_PIN_TYPE`` attr type of a pin
> + ``DPLL_CMD_PIN_GET`` command to get pin info or dump
> + list of available pins
> + ``DPLL_A_PIN_ID`` attr unique a pin ID
> + ``DPLL_A_MODULE_NAME`` attr module name of registerer
> + ``DPLL_A_CLOCK_ID`` attr Unique Clock Identifier
> + (EUI-64), as defined by the
> + IEEE 1588 standard
> + ``DPLL_A_PIN_BOARD_LABEL`` attr pin board label provided
> + by registerer
> + ``DPLL_A_PIN_PANEL_LABEL`` attr pin panel label provided
> + by registerer
> + ``DPLL_A_PIN_PACKAGE_LABEL`` attr pin package label provided
> + by registerer
> + ``DPLL_A_PIN_TYPE`` attr type of a pin
> + ``DPLL_A_PIN_DIRECTION`` attr direction of a pin
> + ``DPLL_A_PIN_FREQUENCY`` attr current frequency of a pin
> + ``DPLL_A_PIN_FREQUENCY_SUPPORTED`` nested attr provides supported
> + 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_PARENT`` nested attr for each parent the
> + pin is connected with
> + ``DPLL_A_ID`` attr provided if parent is dpll
> + device
> + ``DPLL_A_PIN_ID`` attr provided if parent is a pin
> + ``DPLL_A_PIN_PRIO`` attr priority of pin on the
> + dpll device
> + ``DPLL_A_PIN_STATE`` attr state of pin on the dpll
> + device or on the parent pin
> + ``DPLL_A_PIN_DPLL_CAPS`` attr bitmask of pin-dpll
> + capabilities
> + ``DPLL_CMD_PIN_SET`` command to set pins configuration
> + ``DPLL_A_PIN_ID`` attr unique a pin ID
> + ``DPLL_A_PIN_DIRECTION`` attr requested direction of a pin
> + ``DPLL_A_PIN_FREQUENCY`` attr requested frequency of a pin
> + ``DPLL_A_PIN_PARENT`` nested attr for each parent
> + related configuration of a pin
> + requested
> + ``DPLL_A_ID`` attr provided if parent is dpll
> + device
> + ``DPLL_A_PIN_ID`` attr provided if parent is a pin
> + ``DPLL_A_PIN_PRIO`` attr requested priority of pin on
> + the dpll device
> + ``DPLL_A_PIN_STATE`` attr requested state of pin on
> + the dpll device or on the parent
> + pin
> +
> +Netlink dump requests
> +=====================
> +
> +The ``DPLL_CMD_DEVICE_GET`` and ``DPLL_CMD_PIN_GET`` commands are
> +capable of dump type netlink requests, in which case the response is in
> +the same format as for their ``do`` request, but every device or pin
> +registered in the system is returned.
> +
> +SET commands format
> +===================
> +
> +``DPLL_CMD_DEVICE_SET`` - to target a dpll device, the user provides
> +``DPLL_A_ID``, which is unique identifier of dpll device in the system,
> +as well as parameter being configured (``DPLL_A_MODE``).
> +
> +``DPLL_CMD_PIN_SET`` - to target a pin user has to provide a
> +``DPLL_A_PIN_ID``, which is unique identifier of a pin in the system.
> +Also configured pin parameters must be added.
> +If ``DPLL_A_PIN_DIRECTION`` or ``DPLL_A_PIN_FREQUENCY`` are configured,
> +this affects all the dpll device they are connected, that is why those
> +attributes shall not be enclosed in ``DPLL_A_PIN_PARENT``.
> +Other attributes:
> +``DPLL_A_PIN_PRIO`` or ``DPLL_A_PIN_STATE`` must be enclosed in
> +``DPLL_A_PIN_PARENT`` as their configuration relates to only one
> +parent dpll or parent pin.
> +Nested attribute of either ``DPLL_A_ID`` or ``DPLL_A_PIN_ID`` determines
> +if configuration was requested on a dpll device or on a pin
> +respectively.
> +In general, it is possible to configure multiple parameters at once, but
> +internally each parameter change will be invoked separately, where order
> +of configuration is not guaranteed by any means.
> +
> +Device level configuration pre-defined enums
> +=================================================
> +
> +Values for ``DPLL_A_LOCK_STATUS`` attribute:
> +
> + ================================== ===================================
> + ``DPLL_LOCK_STATUS_UNLOCKED`` dpll device is in freerun, not
> + locked to any input pin
> + ``DPLL_LOCK_STATUS_LOCKED`` dpll device is locked to the input
> + but no holdover capability yet
> + acquired
> + ``DPLL_LOCK_STATUS_LOCKED_HO_ACQ`` dpll device is locked to the input
> + pin with holdover capability
> + acquired
> + ``DPLL_LOCK_STATUS_HOLDOVER`` dpll device lost a lock, using its
> + frequency holdover capabilities
> +
> +Values for ``DPLL_A_MODE`` attribute:
> +
> + ======================= ==============================================
> + ``DPLL_MODE_MANUAL`` input pin is manually selected by setting pin
> + state to ``DPLL_PIN_STATE_CONNECTED`` on a
> + dpll device
> + ``DPLL_MODE_AUTOMATIC`` input pin is auto selected according to
> + configured pin priorities and input signal
> + validity
> + ``DPLL_MODE_HOLDOVER`` force holdover mode of dpll
> + ``DPLL_MODE_FREERUN`` dpll device is driven by supplied system clock
> + without holdover capabilities
> +
> +Values for ``DPLL_A_TYPE`` attribute:
> +
> + ================= ===================================================
> + ``DPLL_TYPE_PPS`` dpll device used to provide pulse-per-second output
> + ``DPLL_TYPE_EEC`` dpll device used to drive ethernet equipment clock
> +
> +Pin level configuration pre-defined enums
> +=========================================
> +
> +Values for ``DPLL_A_PIN_STATE`` attribute:
> +
> + =============================== ======================================
> + ``DPLL_PIN_STATE_CONNECTED`` Pin used as active input for a dpll
> + device or for a parent pin
> + ``DPLL_PIN_STATE_DISCONNECTED`` Pin disconnected from a dpll device or
> + from a parent pin
> + ``DPLL_PIN_STATE_SELECTABLE`` Pin enabled for automatic selection
> +
> +Values for ``DPLL_A_PIN_DIRECTION`` attribute:
> +
> + ============================= ====================================
> + ``DPLL_PIN_DIRECTION_INPUT`` used to provide its signal to a dpll
> + device
> + ``DPLL_PIN_DIRECTION_OUTPUT`` used to output the signal from a dpll
> + device
> +
> +Values for ``DPLL_A_PIN_TYPE`` attributes:
> +
> + ================================ =====================================
> + ``DPLL_PIN_TYPE_MUX`` MUX type pin, connected pins shall
> + have their own types
> + ``DPLL_PIN_TYPE_EXT`` External pin
> + ``DPLL_PIN_TYPE_SYNCE_ETH_PORT`` SyncE on Ethernet port
> + ``DPLL_PIN_TYPE_INT_OSCILLATOR`` Internal Oscillator (i.e. Holdover
> + with Atomic Clock as an input)
> + ``DPLL_PIN_TYPE_GNSS`` GNSS 1PPS input
> +
> +Values for ``DPLL_A_PIN_DPLL_CAPS`` attributes:
> +
> + ====================================== ===============================
> + ``DPLL_PIN_CAPS_DIRECTION_CAN_CHANGE`` Bit present if direction of
> + pin can change
> + ``DPLL_PIN_CAPS_PRIORITY_CAN_CHANGE`` Bit present if priority of pin
> + can change
> + ``DPLL_PIN_CAPS_STATE_CAN_CHANGE`` Bit present if state of pin can
> + change
> +
> +Notifications
> +=============
> +
> +dpll device can provide notifications regarding status changes of the
> +device, i.e. lock status changes, input/output changes or other alarms.
> +There is one multicast group that is used to notify user-space apps via
> +netlink socket: ``DPLL_MCGRP_MONITOR``
> +
> +Notifications messages:
> +
> + ============================== =====================================
> + ``DPLL_CMD_DEVICE_CREATE_NTF`` dpll device was created
> + ``DPLL_CMD_DEVICE_DELETE_NTF`` dpll device was deleted
> + ``DPLL_CMD_DEVICE_CHANGE_NTF`` dpll device has changed
> + ``DPLL_CMD_PIN_CREATE_NTF`` dpll pin was created
> + ``DPLL_CMD_PIN_DELETE_NTF`` dpll pin was deleted
> + ``DPLL_CMD_PIN_CHANGE_NTF`` dpll pin has changed
> +
> +Events format is the same as for the corresponding get command.
> +Format of ``DPLL_CMD_DEVICE_`` events is the same as response of
> +``DPLL_CMD_DEVICE_GET``.
> +Format of ``DPLL_CMD_PIN_`` events is same as response of
> +``DPLL_CMD_PIN_GET``.
> +
> +Device driver implementation
> +============================
> +
> +Device is allocated by dpll_device_get() call. Second call with the
> +same arguments will not create new object but provides pointer to
> +previously created device for given arguments, it also increases
> +refcount of that object.
> +Device is deallocated by dpll_device_put() call, which first
> +decreases the refcount, once refcount is cleared the object is
> +destroyed.
> +
> +Device should implement set of operations and register device via
> +dpll_device_register() at which point it becomes available to the
> +users. Multiple driver instances can obtain reference to it with
> +dpll_device_get(), as well as register dpll device with their own
> +ops and priv.
> +
> +The pins are allocated separately with dpll_pin_get(), it works
> +similarly to dpll_device_get(). Function first creates object and then
> +for each call with the same arguments only the object refcount
> +increases. Also dpll_pin_put() works similarly to dpll_device_put().
> +
> +A pin can be registered with parent dpll device or parent pin, depending
> +on hardware needs. Each registration requires registerer to provide set
> +of pin callbacks, and private data pointer for calling them:
> +- dpll_pin_register() - register pin with a dpll device,
> +- dpll_pin_on_pin_register() - register pin with another MUX type pin.
> +
> +Notifications of adding or removing dpll devices are created within
> +subsystem itself.
> +Notifications about registering/deregistering pins are also invoked by
> +the subsystem.
> +Notifications about status changes either of dpll device or a pin are
> +invoked in two ways:
> +- after successful change was requested on dpll subsystem, the subsystem
> + calls corresponding notification,
> +- requested by device driver with dpll_device_change_ntf() or
> + dpll_pin_change_ntf() when driver informs about the status change.
> +
> +The device driver using dpll interface is not required to implement all
> +the callback operation. Neverthelessi, there are few required to be
> +implemented.
> +Required dpll device level callback operations:
> +- ``.mode_get``,
> +- ``.lock_status_get``.
> +
> +Required pin level callback operations:
> +- ``.state_get`` (pins registered with dpll device),
> +- ``.state_on_pin_get`` (pins registered with parent pin),
> +- ``.direction_get``.
> +
> +Every other operation handler is checked for existence and
> +``-ENOTSUPP`` is returned in case of absence of specific handler.
> +
> +SyncE enablement
> +================
> +For SyncE enablement it is required to allow control over dpll device
> +for a software application which monitors and configures the inputs of
> +dpll device in response to current state of a dpll device and its
> +inputs.
> +In such scenario, dpll device input signal shall be also configurable
> +to drive dpll with signal recovered from the PHY netdevice.
> +This is done by exposing a pin to the netdevice - attaching pin to the
> +netdevice itself with:
> +netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin);
> +Exposed pin id handle ``DPLL_A_PIN_ID`` is then identifiable by the user
> +as it is attached to rtnetlink respond to get ``RTM_NEWLINK`` command in
> +nested attribute ``IFLA_DPLL_PIN``.

There are countless htmldocs warnings, so I have to fix them up:

---- >8 ----
diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst
index 8caa4af022ad82..5b2d3e3b9f8893 100644
--- a/Documentation/driver-api/dpll.rst
+++ b/Documentation/driver-api/dpll.rst
@@ -63,16 +63,19 @@ for the states the user can request for a dpll device.

In manual mode (``DPLL_MODE_MANUAL``) the user can request or receive
one of following pin states:
+
- ``DPLL_PIN_STATE_CONNECTED`` - the pin is used to drive dpll device
- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin is not used to drive dpll
device

In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can request or
receive one of following pin states:
+
- ``DPLL_PIN_STATE_SELECTABLE`` - the pin shall be considered as valid
input for automatic selection algorithm
- ``DPLL_PIN_STATE_DISCONNECTED`` - the pin shall be not considered as
a valid input for automatic selection algorithm
+
In automatic mode (``DPLL_MODE_AUTOMATIC``) the user can only receive
pin state ``DPLL_PIN_STATE_CONNECTED`` once automatic selection
algorithm locks a dpll device with one of the inputs.
@@ -85,6 +88,7 @@ Shared pins

A single pin object can be attached to multiple dpll devices.
Then there are two groups of configuration knobs:
+
1) Set on a pin - the configuration affects all dpll devices pin is
registered to (i.e. ``DPLL_A_PIN_FREQUENCY``),
2) Set on a pin-dpll tuple - the configuration affects only selected
@@ -103,31 +107,32 @@ with.
If a pin was registered with multiple parent pins, they behave like a
multiple output multiplexer. In this case output of a
``DPLL_CMD_PIN_GET`` would contain multiple pin-parent nested
-attributes with current state related to each parent, like:
+attributes with current state related to each parent, like::

-``'pin': [{
- {'clock-id': 282574471561216,
- 'module-name': 'ice',
- 'pin-dpll-caps': 4,
- 'pin-id': 13,
- 'pin-parent': [{'pin-id': 2, 'pin-state': 'connected'},
- {'pin-id': 3, 'pin-state': 'disconnected'},
- {'id': 0, 'pin-direction': 'input'},
- {'id': 1, 'pin-direction': 'input'}],
- 'pin-type': 'synce-eth-port'}
-}]``
+ 'pin': [{
+ {'clock-id': 282574471561216,
+ 'module-name': 'ice',
+ 'pin-dpll-caps': 4,
+ 'pin-id': 13,
+ 'pin-parent': [{'pin-id': 2, 'pin-state': 'connected'},
+ {'pin-id': 3, 'pin-state': 'disconnected'},
+ {'id': 0, 'pin-direction': 'input'},
+ {'id': 1, 'pin-direction': 'input'}],
+ 'pin-type': 'synce-eth-port'}
+ }]

Only one child pin can provide its signal to the parent MUX-type pin at
a time, the selection is done by requesting change of a child pin state
on desired parent, with the use of ``DPLL_A_PIN_PARENT`` nested
attribute. Example of netlink `set state on parent pin` message format:

- ===================== =============================================
+ ====================== =============================================
``DPLL_A_PIN_ID`` child pin id
``DPLL_A_PIN_PARENT`` nested attribute for requesting configuration
related to parent pin
``DPLL_A_PIN_ID`` parent pin id
``DPLL_A_PIN_STATE`` requested pin state on parent
+ ====================== =============================================

Pin priority
============
@@ -149,6 +154,7 @@ device. Example of netlink `set priority on parent pin` message format:
related to parent pin
``DPLL_A_ID`` parent dpll id
``DPLL_A_PIN_PRIO`` requested pin prio on parent dpll
+ ===================== =============================================

Child pin of MUX-type is not capable of automatic input pin selection,
in order to configure a input of a MUX-type pin, the user needs to
@@ -254,6 +260,7 @@ prefix and suffix according to attribute purpose:
``DPLL_A_PIN_STATE`` attr requested state of pin on
the dpll device or on the parent
pin
+ ==================================== =================================

Netlink dump requests
=====================
@@ -303,6 +310,7 @@ Values for ``DPLL_A_LOCK_STATUS`` attribute:
acquired
``DPLL_LOCK_STATUS_HOLDOVER`` dpll device lost a lock, using its
frequency holdover capabilities
+ ================================== ===================================

Values for ``DPLL_A_MODE`` attribute:

@@ -316,12 +324,14 @@ Values for ``DPLL_A_MODE`` attribute:
``DPLL_MODE_HOLDOVER`` force holdover mode of dpll
``DPLL_MODE_FREERUN`` dpll device is driven by supplied system clock
without holdover capabilities
+ ======================= ==============================================

Values for ``DPLL_A_TYPE`` attribute:

================= ===================================================
``DPLL_TYPE_PPS`` dpll device used to provide pulse-per-second output
``DPLL_TYPE_EEC`` dpll device used to drive ethernet equipment clock
+ ================= ===================================================

Pin level configuration pre-defined enums
=========================================
@@ -334,6 +344,7 @@ Values for ``DPLL_A_PIN_STATE`` attribute:
``DPLL_PIN_STATE_DISCONNECTED`` Pin disconnected from a dpll device or
from a parent pin
``DPLL_PIN_STATE_SELECTABLE`` Pin enabled for automatic selection
+ =============================== ======================================

Values for ``DPLL_A_PIN_DIRECTION`` attribute:

@@ -342,6 +353,7 @@ Values for ``DPLL_A_PIN_DIRECTION`` attribute:
device
``DPLL_PIN_DIRECTION_OUTPUT`` used to output the signal from a dpll
device
+ ============================= ====================================

Values for ``DPLL_A_PIN_TYPE`` attributes:

@@ -353,6 +365,7 @@ Values for ``DPLL_A_PIN_TYPE`` attributes:
``DPLL_PIN_TYPE_INT_OSCILLATOR`` Internal Oscillator (i.e. Holdover
with Atomic Clock as an input)
``DPLL_PIN_TYPE_GNSS`` GNSS 1PPS input
+ ================================ =====================================

Values for ``DPLL_A_PIN_DPLL_CAPS`` attributes:

@@ -363,6 +376,7 @@ Values for ``DPLL_A_PIN_DPLL_CAPS`` attributes:
can change
``DPLL_PIN_CAPS_STATE_CAN_CHANGE`` Bit present if state of pin can
change
+ ====================================== ===============================

Notifications
=============
@@ -381,6 +395,7 @@ Notifications messages:
``DPLL_CMD_PIN_CREATE_NTF`` dpll pin was created
``DPLL_CMD_PIN_DELETE_NTF`` dpll pin was deleted
``DPLL_CMD_PIN_CHANGE_NTF`` dpll pin has changed
+ ============================== =====================================

Events format is the same as for the corresponding get command.
Format of ``DPLL_CMD_DEVICE_`` events is the same as response of
@@ -413,6 +428,7 @@ increases. Also dpll_pin_put() works similarly to dpll_device_put().
A pin can be registered with parent dpll device or parent pin, depending
on hardware needs. Each registration requires registerer to provide set
of pin callbacks, and private data pointer for calling them:
+
- dpll_pin_register() - register pin with a dpll device,
- dpll_pin_on_pin_register() - register pin with another MUX type pin.

@@ -422,6 +438,7 @@ Notifications about registering/deregistering pins are also invoked by
the subsystem.
Notifications about status changes either of dpll device or a pin are
invoked in two ways:
+
- after successful change was requested on dpll subsystem, the subsystem
calls corresponding notification,
- requested by device driver with dpll_device_change_ntf() or
@@ -431,10 +448,11 @@ The device driver using dpll interface is not required to implement all
the callback operation. Neverthelessi, there are few required to be
implemented.
Required dpll device level callback operations:
+
- ``.mode_get``,
- ``.lock_status_get``.

-Required pin level callback operations:
+oRequired pin level callback operations:
- ``.state_get`` (pins registered with dpll device),
- ``.state_on_pin_get`` (pins registered with parent pin),
- ``.direction_get``.
@@ -451,8 +469,8 @@ inputs.
In such scenario, dpll device input signal shall be also configurable
to drive dpll with signal recovered from the PHY netdevice.
This is done by exposing a pin to the netdevice - attaching pin to the
-netdevice itself with:
-netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin);
+netdevice itself with
+``netdev_dpll_pin_set(struct net_device *dev, struct dpll_pin *dpll_pin)``.
Exposed pin id handle ``DPLL_A_PIN_ID`` is then identifiable by the user
as it is attached to rtnetlink respond to get ``RTM_NEWLINK`` command in
nested attribute ``IFLA_DPLL_PIN``.

(but because the fix diff above is quite large, Co-developed-by: from
me may qualify).

Thanks.

--
An old man doll... just what I always wanted! - Clara

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