[PATCH v3 00/15] clk: introduce clk_determine_rate_noop() and update drivers to use it

[PATCH v3 00/15] clk: introduce clk_determine_rate_noop() and update drivers to use it

[Brian Masney]

There are some clocks where the determine_rate clk op is just an empty
function that returns 0. This can be either because the rounding is
managed by the firmware/hardware, or the clock is capable of any rate.
Let's add a new new shared function to clk.c named
clk_determine_rate_noop(), and update all of the drivers that have an
empty determine_rate() ops to use this new shared function.

The first patch in this series also includes a minor cleanup to
drivers/clk/imx/clk-scu.c. I included it as the first patch so it
doesn't get buried in the middle of this series. I change this same
driver later in the series to use clk_determine_rate_noop().

Changes since v2:
https://lore.kernel.org/all/20260309-clk-det-rate-fw-managed-v2-0-c48ef5a3100a@redhat.com/
- Dropped the NOOP flag and just use a dedicated noop function.

Merge Strategy
--------------
All of this needs to be directly merged by Stephen as one series into
his tree. Subsystem maintainers: please leave a Reviewed-by or Acked-by
for Stephen. To reduce the noise, I am only CCing people on their
respective drivers.

Since there's only 3 drivers outside of drivers/clk that need to be
updated, I included them in this same series for completeness. These
should go through Stephen's tree as well.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
Brian Masney (15):
      clk: imx: scu: drop redundant init.ops variable assignment
      clk: add clk_determine_rate_noop()
      clk: hisilicon: hi3660-stub: use clk_determine_rate_noop()
      clk: imx: scu: use clk_determine_rate_noop()
      clk: qcom: rpm: use clk_determine_rate_noop()
      clk: qcom: rpmh: use clk_determine_rate_noop()
      clk: qcom: smd-rpm: use clk_determine_rate_noop()
      clk: renesas: rzg2l-cpg: use clk_determine_rate_noop()
      clk: rp1: use clk_determine_rate_noop()
      clk: samsung: acpm: use clk_determine_rate_noop()
      clk: scpi: use clk_determine_rate_noop()
      clk: sprd: use clk_determine_rate_noop()
      phy: mediatek: phy-mtk-hdmi-mt2701: use clk_determine_rate_noop()
      pmdomain: mediatek: airoha: use clk_determine_rate_noop()
      pmdomain: mediatek: mtk-mfg: use clk_determine_rate_noop()

 drivers/clk/clk-rp1.c                           |  8 +-------
 drivers/clk/clk-scpi.c                          | 14 +-------------
 drivers/clk/clk.c                               | 18 ++++++++++++++++++
 drivers/clk/hisilicon/clk-hi3660-stub.c         | 12 +-----------
 drivers/clk/imx/clk-scu.c                       | 24 +++---------------------
 drivers/clk/qcom/clk-rpm.c                      | 15 ++-------------
 drivers/clk/qcom/clk-rpmh.c                     |  8 +-------
 drivers/clk/qcom/clk-smd-rpm.c                  | 13 +------------
 drivers/clk/renesas/rzg2l-cpg.c                 |  8 +-------
 drivers/clk/samsung/clk-acpm.c                  | 14 +-------------
 drivers/clk/sprd/pll.c                          |  8 +-------
 drivers/phy/mediatek/phy-mtk-hdmi-mt2701.c      |  8 +-------
 drivers/pmdomain/mediatek/airoha-cpu-pmdomain.c |  8 +-------
 drivers/pmdomain/mediatek/mtk-mfg-pmdomain.c    | 23 ++---------------------
 include/linux/clk-provider.h                    |  1 +
 15 files changed, 36 insertions(+), 146 deletions(-)
---
base-commit: 4cd074ae20bbcc293bbbce9163abe99d68ae6ae0
change-id: 20260505-clk-determine-rate-noop-17a544f78018

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

[PATCH v3 02/15] clk: add clk_determine_rate_noop()

[Brian Masney]

Add a new helper clk_determine_rate_noop() that's for clocks where the
rate rounding is handled by the firmware/hardware, or the clock is
capable of any rate. The requested rate is passed through unchanged,
and the actual rate will be learned via recalc_rate() after the rate
is set.

This shared helper will be used to get rid of the driver-specific empty
determine rate implementations that are present in the tree.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Brian Masney <bmasney@redhat.com>
To: Abel Vesa <abelvesa@kernel.org>
To: Peng Fan <peng.fan@nxp.com>
To: Frank Li <Frank.Li@nxp.com>
To: Sascha Hauer <s.hauer@pengutronix.de>
To: Pengutronix Kernel Team <kernel@pengutronix.de>
To: Fabio Estevam <festevam@gmail.com>
To: Anson Huang <anson.huang@nxp.com>
To: Bjorn Andersson <andersson@kernel.org>
To: Geert Uytterhoeven <geert+renesas@glider.be>
To: Andrea della Porta <andrea.porta@suse.com>
To: Tudor Ambarus <tudor.ambarus@linaro.org>
To: Krzysztof Kozlowski <krzk@kernel.org>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>
To: Chanwoo Choi <cw00.choi@samsung.com>
To: Alim Akhtar <alim.akhtar@samsung.com>
To: Sudeep Holla <sudeep.holla@kernel.org>
To: Cristian Marussi <cristian.marussi@arm.com>
To: Orson Zhai <orsonzhai@gmail.com>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
To: Chunyan Zhang <zhang.lyra@gmail.com>
To: Chun-Kuang Hu <chunkuang.hu@kernel.org>
To: Philipp Zabel <p.zabel@pengutronix.de>
To: Chunfeng Yun <chunfeng.yun@mediatek.com>
To: Vinod Koul <vkoul@kernel.org>
To: Neil Armstrong <neil.armstrong@linaro.org>
To: Matthias Brugger <matthias.bgg@gmail.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: Ulf Hansson <ulfh@kernel.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: imx@lists.linux.dev
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: arm-scmi@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-phy@lists.infradead.org
Cc: linux-pm@vger.kernel.org
---
 drivers/clk/clk.c            | 18 ++++++++++++++++++
 include/linux/clk-provider.h |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 048adfa86a5d..956e147f4d4e 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -882,6 +882,24 @@ int clk_hw_determine_rate_no_reparent(struct clk_hw *hw,
 }
 EXPORT_SYMBOL_GPL(clk_hw_determine_rate_no_reparent);
 
+/**
+ * clk_determine_rate_noop - clk_ops::determine_rate noop implementation
+ * @hw: clk to determine rate on
+ * @req: rate request
+ *
+ * Noop determine rate for clocks where the rate rounding is handled by the
+ * firmware/hardware, or the clock is capable of any rate. The requested rate is
+ * passed through unchanged, and the actual rate will be learned via
+ * recalc_rate() after the rate is set.
+ *
+ * Returns: 0 always
+ */
+int clk_determine_rate_noop(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(clk_determine_rate_noop);
+
 /***        clk api        ***/
 
 static void clk_core_rate_unprotect(struct clk_core *core)
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index b01a38fef8cf..334b9211a157 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1431,6 +1431,7 @@ int clk_mux_determine_rate_flags(struct clk_hw *hw,
 				 unsigned long flags);
 int clk_hw_determine_rate_no_reparent(struct clk_hw *hw,
 				      struct clk_rate_request *req);
+int clk_determine_rate_noop(struct clk_hw *hw, struct clk_rate_request *req);
 void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent);
 void clk_hw_get_rate_range(struct clk_hw *hw, unsigned long *min_rate,
 			   unsigned long *max_rate);

-- 
2.54.0

[PATCH v3 10/15] clk: samsung: acpm: use clk_determine_rate_noop()

[Brian Masney]

Drop the driver-specific empty determine_rate() function and use the new
shared clk_determine_rate_noop() helper.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
To: Tudor Ambarus <tudor.ambarus@linaro.org>
To: Krzysztof Kozlowski <krzk@kernel.org>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>
To: Chanwoo Choi <cw00.choi@samsung.com>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Brian Masney <bmasney@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
---
 drivers/clk/samsung/clk-acpm.c | 14 +-------------
 1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/drivers/clk/samsung/clk-acpm.c b/drivers/clk/samsung/clk-acpm.c
index d8944160793a..7a07bfd4948b 100644
--- a/drivers/clk/samsung/clk-acpm.c
+++ b/drivers/clk/samsung/clk-acpm.c
@@ -72,18 +72,6 @@ static unsigned long acpm_clk_recalc_rate(struct clk_hw *hw,
 					clk->mbox_chan_id, clk->id);
 }
 
-static int acpm_clk_determine_rate(struct clk_hw *hw,
-				   struct clk_rate_request *req)
-{
-	/*
-	 * We can't figure out what rate it will be, so just return the
-	 * rate back to the caller. acpm_clk_recalc_rate() will be called
-	 * after the rate is set and we'll know what rate the clock is
-	 * running at then.
-	 */
-	return 0;
-}
-
 static int acpm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 			     unsigned long parent_rate)
 {
@@ -95,7 +83,7 @@ static int acpm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 
 static const struct clk_ops acpm_clk_ops = {
 	.recalc_rate = acpm_clk_recalc_rate,
-	.determine_rate = acpm_clk_determine_rate,
+	.determine_rate = clk_determine_rate_noop,
 	.set_rate = acpm_clk_set_rate,
 };
 

-- 
2.54.0

Re: [PATCH v3 10/15] clk: samsung: acpm: use clk_determine_rate_noop()

[Tudor Ambarus]

Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>

Re: [PATCH v3 10/15] clk: samsung: acpm: use clk_determine_rate_noop()

[Krzysztof Kozlowski]

On 06/05/2026 02:49, Brian Masney wrote:
> Drop the driver-specific empty determine_rate() function and use the new
> shared clk_determine_rate_noop() helper.

<form letter>
This is a friendly reminder during the review process.

It looks like you received a tag and forgot to add it.

...

If a tag was not added on purpose, please state in the patch changelog
or cover letter why and what changed.
</form letter>

Last part is important.

Best regards,
Krzysztof

Re: [PATCH v3 10/15] clk: samsung: acpm: use clk_determine_rate_noop()

[Brian Masney]

Hi Krzysztof,

On Wed, May 06, 2026 at 03:47:33PM +0200, Krzysztof Kozlowski wrote:
> On 06/05/2026 02:49, Brian Masney wrote:
> > Drop the driver-specific empty determine_rate() function and use the new
> > shared clk_determine_rate_noop() helper.
> 
> <form letter>
> This is a friendly reminder during the review process.
> 
> It looks like you received a tag and forgot to add it.
> 
> ...
> 
> If a tag was not added on purpose, please state in the patch changelog
> or cover letter why and what changed.
> </form letter>
> 
> Last part is important.

Sorry I didn't mention that I dropped the existing tags on the cover letter.
I felt that it changed enough in this version that I didn't feel
comfortable preserving the existing tags. The overall change is very simple,
but I didn't want to misrepresent the new work was reviewed by folks.

Brian