Re: [PATCH 1/2] clk: add kernel docs for struct clk_core

[Stephen Boyd]

Quoting Brian Masney (2026-03-04 14:51:03)
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 47093cda9df32223c1120c3710261296027c4cd3..18b7a14e3f2c595d82401be9382a062fbca8a5c6 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -63,6 +63,65 @@ struct clk_parent_map {
>         int                     index;
>  };
>  
> +/**
> + * struct clk_core - This structure represents the internal state of a clk
> + * within the kernel's clock tree. Drivers do not interact with this structure
> + * directly. The clk_core is manipulated by the framework to manage clock
> + * operations, parent/child relationships, rate, and other properties.

Trim this down and use active voice please.

 /**
  * struct clk_core - The internal state of a clk in the clk tree.
  *
  * Managed by the clk framework. Clk providers and consumers do not
  * interact with this structure directly. Instead, clk operations flow
  * through the framework and the framework manipulates this structure
  * to keep track of parent/child relationships, rate, enable state,
  * etc.
  *

Does the longer paragraph description follow directly after the one line
short description? Or does it come after all the members?

> + *
> + * @name:              Unique name of the clk for identification.
> + * @ops:               Pointer to hardware-specific operations for this clk.
> + * @hw:                Pointer for traversing from a struct clk to its
> + *                     corresponding hardware-specific structure.
> + * @owner:             Kernel module owning this clk (for reference counting).
> + * @dev:               Device associated with this clk (optional)
> + * @rpm_node:          Node for runtime power management list management.
> + * @of_node:           Device tree node associated with this clk (if applicable)
> + * @parent:            Pointer to the current parent in the clock tree.
> + * @parents:           Array of possible parents (for muxes/selectable parents).
> + * @num_parents:       Number of possible parents

Add a period.

> + * @new_parent_index:  Index of the new parent during parent change. This is
> + *                     also used when a clk's rate is changed.

Not sure we need to get into the details here. Maybe 'Index of the new
parent during parent change operations'

> + * @rate:              Current clock rate (Hz). This is effectively a cached

Sorta same comment. Not sure we should do anything besides say this is
the cached clk rate in Hz. Maybe we need a better top-level comment
indicating how rates are cached instead and how the framework uses flags
to change the behavior.

> + *                     value of what the hardware has been programmed with. It's
> + *                     initialized by reading the value at boot time, and will
> + *                     be updated every time an operation affects the rate.
> + *                     Clocks with the CLK_GET_RATE_NOCACHE flag should not use
> + *                     this value, as its rate is expected to change behind the
> + *                     kernel's back (because the firmware might change it, for
> + *                     example). Also, if the clock is orphan, it's set to 0

is an orphan

> + *                     and updated when (and if) its parent is later loaded, so

later registered

> + *                     its content is only ever valid if clk_core->orphan is
> + *                     false.
> + * @req_rate:          The last rate requested by a call to clk_set_rate. It's

Use clk_set_rate() to indicate a function.

> + *                     initialized to clk_core->rate. It's also updated to
> + *                     clk_core->rate every time the clock is reparented, and
> + *                     when we're doing the orphan -> !orphan transition.
> + * @new_rate:          New rate to be set during a rate change operation.
> + * @new_parent:        Pointer to new parent during parent change. This is also
> + *                     used when a clk's rate is changed.
> + * @new_child:         Pointer to new child during reparenting. This is also
> + *                     used when a clk's rate is changed.
> + * @flags:             Clock property and capability flags.

Can we somehow link this to the CLK_* defines in clk-provider.h?

> + * @orphan:            True if this clk is currently orphaned.
> + * @rpm_enabled:       True if runtime power management is enabled for this clk.
> + * @enable_count:      Reference count of enables.
> + * @prepare_count:     Reference count of prepares.
> + * @protect_count:     Protection reference count against disable.
> + * @min_rate:          Minimum supported clock rate (Hz).
> + * @max_rate:          Maximum supported clock rate (Hz).
> + * @accuracy:          Accuracy of the clock rate (parts per billion).
> + * @phase:             Current phase (degrees).
> + * @duty:              Current duty cycle configuration (as ratio: num/den).
> + * @children:          All of the children of this clk.
> + * @child_node:        Node for linking as a child in the parent's list.
> + * @hashtable_node:    Node for hash table that allows fast clock lookup by name.

fast clk lookup

> + * @clks:              All of the clk consumers registered.
> + * @notifier_count:    Number of notifiers registered for this clk.
> + * @dentry:            DebugFS entry for this clk.
> + * @debug_node:        DebugFS node for this clk.
> + * @ref:               Reference count for structure lifetime management.