[v2,0/5] Rework SCMI Clock driver clk_ops setup procedure

Message

Cristian Marussi March 25, 2024, 9 p.m. UTC

Hi,

a small series to review how the SCMI Clock driver chooses and sets up the
CLK operations to associate to a clock when registering with CLK framework.

SCMI clocks exposed by the platform sports a growing number of clock
properties since SCMI v3.2: discovered SCMI clocks could be restricted in
terms of capability to set state/rate/parent/duty_cycle and the platform
itself can have a varying support in terms of atomic support.

Knowing upfront which operations are NOT allowed on some clocks helps
avoiding needless message exchanges.

As a result, the SCMI Clock driver, when registering resources with the
CLK framework, aims to provide only the specific clk_ops as known to be
certainly supported by the specific SCMI clock resource.

Using static pre-compiled clk_ops structures to fulfill all the possible
(and possibly growing) combinations of clock features is cumbersome and
error-prone (there are 32 possible combinations as of now to account for
the above mentioned clock features variation).

This rework introduces a dynamic allocation mechanism to be able to
configure the required clk_ops at run-time when the SCMI clocks are
enumerated.

Only one single clk_ops is generated for each of the features combinations
effectively found in the set of returned SCMI resources.

Once this preliminary rework is done in 1/5, the following patches use this
new clk_ops schema to introduce a number of restricted clk_ops depending on
the specific retrieved SCMI clocks characteristics.

Based on v6.9-rc1

Thanks,
Cristian

V2
- rebased on v6.9-rc1

Cristian Marussi (5):
  clk: scmi: Allocate CLK operations dynamically
  clk: scmi: Add support for state control restricted clocks
  clk: scmi: Add support for rate change restricted clocks
  clk: scmi: Add support for re-parenting restricted clocks
  clk: scmi: Add support for get/set duty_cycle operations

 drivers/clk/clk-scmi.c | 226 ++++++++++++++++++++++++++++++++---------
 1 file changed, 179 insertions(+), 47 deletions(-)

Comments

Sudeep Holla April 4, 2024, 2:25 p.m. UTC | #1

Hi Stephen,

On Mon, Mar 25, 2024 at 09:00:20PM +0000, Cristian Marussi wrote:
> Hi,
>

[...]

>
> This rework introduces a dynamic allocation mechanism to be able to
> configure the required clk_ops at run-time when the SCMI clocks are
> enumerated.
>
> Only one single clk_ops is generated for each of the features combinations
> effectively found in the set of returned SCMI resources.
>
> Once this preliminary rework is done in 1/5, the following patches use this
> new clk_ops schema to introduce a number of restricted clk_ops depending on
> the specific retrieved SCMI clocks characteristics.
>

Let me know if you are happy with this changes. There is no strict
dependency on the changes in SCMI tree ATM, so I can provide reviewed-by
if you would like to take it via clk tree. If you prefer me to take it
via SCMI tree, please provide Ack if you are OK with the changes.

--
Regards,
Sudeep