[PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[Brian Masney]

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.

The existing scmi_clk_determine_rate() is a noop implementation that
lets the firmware round the rate as appropriate. Drop the existing
determine_rate implementation and convert the existing round_rate()
implementation over to determine_rate().

scmi_clk_determine_rate() was added recently when the clock parent
support was added, so it's not expected that this change will regress
anything.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
Changes since v1:
- Split out individual patch from larger v1 114 patch series
- Drop noop determine_rate implementation; convert round_rate
---
 drivers/clk/clk-scmi.c | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index d2408403283fc72f0cf902e65f4c08bcbc7b4b0b..78dd2d9c7cabd18f2a05cffd0408cfefaf34fce0 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -54,8 +54,8 @@ 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)
+static int scmi_clk_determine_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
 {
 	u64 fmin, fmax, ftmp;
 	struct scmi_clk *clk = to_scmi_clk(hw);
@@ -67,20 +67,27 @@ static long scmi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 	 * running at then.
 	 */
 	if (clk->info->rate_discrete)
-		return rate;
+		return 0;
 
 	fmin = clk->info->range.min_rate;
 	fmax = clk->info->range.max_rate;
-	if (rate <= fmin)
-		return fmin;
-	else if (rate >= fmax)
-		return fmax;
+	if (req->rate <= fmin) {
+		req->rate = fmin;
+
+		return 0;
+	} else if (req->rate >= fmax) {
+		req->rate = fmax;
 
-	ftmp = rate - fmin;
+		return 0;
+	}
+
+	ftmp = req->rate - fmin;
 	ftmp += clk->info->range.step_size - 1; /* to round up */
 	do_div(ftmp, clk->info->range.step_size);
 
-	return ftmp * clk->info->range.step_size + fmin;
+	req->rate = ftmp * clk->info->range.step_size + fmin;
+
+	return 0;
 }
 
 static int scmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -119,15 +126,6 @@ static u8 scmi_clk_get_parent(struct clk_hw *hw)
 	return p_idx;
 }
 
-static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
-{
-	/*
-	 * Suppose all the requested rates are supported, and let firmware
-	 * to handle the left work.
-	 */
-	return 0;
-}
-
 static int scmi_clk_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
@@ -300,7 +298,6 @@ scmi_clk_ops_alloc(struct device *dev, unsigned long feats_key)
 
 	/* Rate ops */
 	ops->recalc_rate = scmi_clk_recalc_rate;
-	ops->round_rate = scmi_clk_round_rate;
 	ops->determine_rate = scmi_clk_determine_rate;
 	if (feats_key & BIT(SCMI_CLK_RATE_CTRL_SUPPORTED))
 		ops->set_rate = scmi_clk_set_rate;

---
base-commit: 3c642997252eef4449cb6b6e02af3dc22515d817
change-id: 20250827-clk-scmi-round-rate-7e3d4099134a

Best regards,
-- 
Brian Masney <bmasney@redhat.com>

Re: [PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[Sudeep Holla]

On Fri, Aug 29, 2025 at 06:09:03PM +0800, Peng Fan wrote:
> On Wed, Aug 27, 2025 at 01:12:07PM -0400, Brian Masney wrote:
> >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.
> >
> >The existing scmi_clk_determine_rate() is a noop implementation that
> >lets the firmware round the rate as appropriate. Drop the existing
> >determine_rate implementation and convert the existing round_rate()
> >implementation over to determine_rate().
> >
> >scmi_clk_determine_rate() was added recently when the clock parent
> >support was added, so it's not expected that this change will regress
> >anything.
> >
> >Signed-off-by: Brian Masney <bmasney@redhat.com>
> 
> Reviewed-by: Peng Fan <peng.fan@nxp.com>

Peng,

It would be great if you can test it with parent clock support on i.MX
platforms just to be sure this doesn't regress anything.

-- 
Regards,
Sudeep

Re: [PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[Sudeep Holla]

On Wed, Aug 27, 2025 at 01:12:07PM -0400, Brian Masney wrote:
> 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.
> 
> The existing scmi_clk_determine_rate() is a noop implementation that
> lets the firmware round the rate as appropriate. Drop the existing
> determine_rate implementation and convert the existing round_rate()
> implementation over to determine_rate().
> 
> scmi_clk_determine_rate() was added recently when the clock parent
> support was added, so it's not expected that this change will regress
> anything.
> 

Changes LGTM,

Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

I assume it can go via clk tree.

-- 
Regards,
Sudeep

Re: [PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[Peng Fan]

On Wed, Aug 27, 2025 at 01:12:07PM -0400, Brian Masney wrote:
>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.
>
>The existing scmi_clk_determine_rate() is a noop implementation that
>lets the firmware round the rate as appropriate. Drop the existing
>determine_rate implementation and convert the existing round_rate()
>implementation over to determine_rate().
>
>scmi_clk_determine_rate() was added recently when the clock parent
>support was added, so it's not expected that this change will regress
>anything.
>
>Signed-off-by: Brian Masney <bmasney@redhat.com>

Reviewed-by: Peng Fan <peng.fan@nxp.com>

Re: [PATCH v2] clk: scmi: migrate round_rate() to determine_rate()

[Peng Fan]

On Fri, Aug 29, 2025 at 10:59:15AM +0100, Sudeep Holla wrote:
>On Fri, Aug 29, 2025 at 06:09:03PM +0800, Peng Fan wrote:
>> On Wed, Aug 27, 2025 at 01:12:07PM -0400, Brian Masney wrote:
>> >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.
>> >
>> >The existing scmi_clk_determine_rate() is a noop implementation that
>> >lets the firmware round the rate as appropriate. Drop the existing
>> >determine_rate implementation and convert the existing round_rate()
>> >implementation over to determine_rate().
>> >
>> >scmi_clk_determine_rate() was added recently when the clock parent
>> >support was added, so it's not expected that this change will regress
>> >anything.
>> >
>> >Signed-off-by: Brian Masney <bmasney@redhat.com>
>> 
>> Reviewed-by: Peng Fan <peng.fan@nxp.com>
>
>Peng,
>
>It would be great if you can test it with parent clock support on i.MX
>platforms just to be sure this doesn't regress anything.

Just gave a test on i.MX95-EVK, it boots well and eth0 works, 
the results in /sys/kernel/debug/clk/clk_summary also looks correct.

Tested-by: Peng Fan <peng.fan@nxp.com> #i.MX95-19x19-EVK

Regards
Peng

>
>-- 
>Regards,
>Sudeep