Re: [PATCH 112/114] clk: scmi: remove round_rate() in favor of determine_rate()

On Wed, Aug 27, 2025 at 09:13:17AM -0400, Brian Masney wrote:
> On Wed, Aug 27, 2025 at 03:09:33PM +0800, Peng Fan wrote:
> > Hi Brian, Sudeep, Cristian
> > 
> > On Mon, Aug 11, 2025 at 11:19:44AM -0400, Brian Masney via B4 Relay wrote:
> > >From: Brian Masney <[email protected]>
> > >
> > >This driver implements both the determine_rate() and round_rate() clk
> > >ops, and the round_rate() clk ops is deprecated. When both are defined,
> > >clk_core_determine_round_nolock() from the clk core will only use the
> > >determine_rate() clk ops, so let's remove the round_rate() clk ops since
> > >it's unused.
> > >
> > >Signed-off-by: Brian Masney <[email protected]>
> > >---
> > > drivers/clk/clk-scmi.c | 30 ------------------------------
> > > 1 file changed, 30 deletions(-)
> > >
> > >diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> > >index d2408403283fc72f0cf902e65f4c08bcbc7b4b0b..6c6ddb92e7cf6a0cfac2c7e19c0f15f777bb8c51 100644
> > >--- a/drivers/clk/clk-scmi.c
> > >+++ b/drivers/clk/clk-scmi.c
> > >@@ -54,35 +54,6 @@ static unsigned long scmi_clk_recalc_rate(struct clk_hw *hw,
> > > 	return rate;
> > > }
> > > 
> > >-static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> > >-				unsigned long *parent_rate)
> > >-{
> > 
> > I see the point of round_rate is not used if determine_rate is there.
> > But reading the code of round_rate, It might be better to rename
> > scmi_clk_round_rate to scmi_clk_determine_rate.
> > 
> > Anyway, need Sudeep and Cristian to comment.
> 
> In this case, yes the round_rate implementation is filled out, whereas
> the determine_rate lets the firmware handle it, and
> scmi_clk_recalc_rate() will later populate the rate the clock is running
> at.
> 
> I can convert round_rate over to determine_rate in this case, however it
> would be a change to what's there now, and risks a regression. Here's
> the relevant code from drivers/clk/clk.c where the determine_rate and
> round_rate ops are called:

I am inclined towards this. Determine rate was added recently when the
clock parent support was added IIUC, so I don't think it should regress
anything.

> 
>     static int clk_core_determine_round_nolock(struct clk_core *core,
>                                                struct clk_rate_request *req)
>     {
>     	...
>             if (clk_core_rate_is_protected(core)) {
>                     req->rate = core->rate;
>             } else if (core->ops->determine_rate) {
>                     return core->ops->determine_rate(core->hw, req);
>             } else if (core->ops->round_rate) {
>                     rate = core->ops->round_rate(core->hw, req->rate,
>                                                  &req->best_parent_rate);
>     	...
> 
> If Sudeep / Cristian want the round rate converted to determine rate in
> this driver, then I can do that in a v2.
> 

Yes please. Also please post it independent if it doesn't have to be in
the series. To many in cc and lots of patches to respin all.

-- 
Regards,
Sudeep