[PATCH v2 0/2] clk: imx95-blk-ctl: Fix runtime PM issues

[PATCH v2 0/2] clk: imx95-blk-ctl: Fix runtime PM issues

[Laurentiu Palcu]

Hi,

These 2 patches belonged to a larger patch-set I sent a couple of weeks
ago([1]) but I decided to break that set into smaller sets, where
possible, as they will be easier to respin, to address any issues, and
will probably be merged faster than the other one.

Also, I addressed all the reviewers' comments received previously for
these patches.

[1] https://lore.kernel.org/imx/20250716081519.3400158-1-laurentiu.palcu@oss.nxp.com/T/#t

Thanks,
Laurentiu

Changes in v2:
 * Collected r-b tags for patch 1/2
 * Changed patch 2/2 commit message to make it clearer;

Laurentiu Palcu (2):
  clk: imx95-blk-ctl: Save platform data in imx95_blk_ctl structure
  clk: imx95-blk-ctl: Save/restore registers when RPM routines are
    called

 drivers/clk/imx/clk-imx95-blk-ctl.c | 57 ++++++++++++++---------------
 1 file changed, 28 insertions(+), 29 deletions(-)

-- 
2.49.0

[PATCH v2 1/2] clk: imx95-blk-ctl: Save platform data in imx95_blk_ctl structure

[Laurentiu Palcu]

Add a platform data (pdata) member to struct imx95_blk_ctl to store the
result of of_device_get_match_data() during probe to avoid redundant
calls in suspend and resume functions.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
---
 drivers/clk/imx/clk-imx95-blk-ctl.c | 36 +++++++++++------------------
 1 file changed, 13 insertions(+), 23 deletions(-)

diff --git a/drivers/clk/imx/clk-imx95-blk-ctl.c b/drivers/clk/imx/clk-imx95-blk-ctl.c
index 7e88877a62451..c72debaf3a60b 100644
--- a/drivers/clk/imx/clk-imx95-blk-ctl.c
+++ b/drivers/clk/imx/clk-imx95-blk-ctl.c
@@ -36,6 +36,7 @@ struct imx95_blk_ctl {
 	void __iomem *base;
 	/* clock gate register */
 	u32 clk_reg_restore;
+	const struct imx95_blk_ctl_dev_data *pdata;
 };
 
 struct imx95_blk_ctl_clk_dev_data {
@@ -349,7 +350,6 @@ static const struct imx95_blk_ctl_dev_data imx94_dispmix_csr_dev_data = {
 static int imx95_bc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	const struct imx95_blk_ctl_dev_data *bc_data;
 	struct imx95_blk_ctl *bc;
 	struct clk_hw_onecell_data *clk_hw_data;
 	struct clk_hw **hws;
@@ -379,25 +379,25 @@ static int imx95_bc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	bc_data = of_device_get_match_data(dev);
-	if (!bc_data)
+	bc->pdata = of_device_get_match_data(dev);
+	if (!bc->pdata)
 		return devm_of_platform_populate(dev);
 
-	clk_hw_data = devm_kzalloc(dev, struct_size(clk_hw_data, hws, bc_data->num_clks),
+	clk_hw_data = devm_kzalloc(dev, struct_size(clk_hw_data, hws, bc->pdata->num_clks),
 				   GFP_KERNEL);
 	if (!clk_hw_data)
 		return -ENOMEM;
 
-	if (bc_data->rpm_enabled) {
+	if (bc->pdata->rpm_enabled) {
 		devm_pm_runtime_enable(&pdev->dev);
 		pm_runtime_resume_and_get(&pdev->dev);
 	}
 
-	clk_hw_data->num = bc_data->num_clks;
+	clk_hw_data->num = bc->pdata->num_clks;
 	hws = clk_hw_data->hws;
 
-	for (i = 0; i < bc_data->num_clks; i++) {
-		const struct imx95_blk_ctl_clk_dev_data *data = &bc_data->clk_dev_data[i];
+	for (i = 0; i < bc->pdata->num_clks; i++) {
+		const struct imx95_blk_ctl_clk_dev_data *data = &bc->pdata->clk_dev_data[i];
 		void __iomem *reg = base + data->reg;
 
 		if (data->type == CLK_MUX) {
@@ -439,7 +439,7 @@ static int imx95_bc_probe(struct platform_device *pdev)
 	return 0;
 
 cleanup:
-	for (i = 0; i < bc_data->num_clks; i++) {
+	for (i = 0; i < bc->pdata->num_clks; i++) {
 		if (IS_ERR_OR_NULL(hws[i]))
 			continue;
 		clk_hw_unregister(hws[i]);
@@ -469,14 +469,9 @@ static int imx95_bc_runtime_resume(struct device *dev)
 static int imx95_bc_suspend(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
-	const struct imx95_blk_ctl_dev_data *bc_data;
 	int ret;
 
-	bc_data = of_device_get_match_data(dev);
-	if (!bc_data)
-		return 0;
-
-	if (bc_data->rpm_enabled) {
+	if (bc->pdata->rpm_enabled) {
 		ret = pm_runtime_get_sync(bc->dev);
 		if (ret < 0) {
 			pm_runtime_put_noidle(bc->dev);
@@ -484,7 +479,7 @@ static int imx95_bc_suspend(struct device *dev)
 		}
 	}
 
-	bc->clk_reg_restore = readl(bc->base + bc_data->clk_reg_offset);
+	bc->clk_reg_restore = readl(bc->base + bc->pdata->clk_reg_offset);
 
 	return 0;
 }
@@ -492,15 +487,10 @@ static int imx95_bc_suspend(struct device *dev)
 static int imx95_bc_resume(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
-	const struct imx95_blk_ctl_dev_data *bc_data;
-
-	bc_data = of_device_get_match_data(dev);
-	if (!bc_data)
-		return 0;
 
-	writel(bc->clk_reg_restore, bc->base + bc_data->clk_reg_offset);
+	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
 
-	if (bc_data->rpm_enabled)
+	if (bc->pdata->rpm_enabled)
 		pm_runtime_put(bc->dev);
 
 	return 0;
-- 
2.49.0

[PATCH v2 2/2] clk: imx95-blk-ctl: Save/restore registers when RPM routines are called

[Laurentiu Palcu]

When runtime PM is used for clock providers that are part of a power
domain, the power domain supply is cut off during runtime suspend. This
causes all BLK CTL registers belonging to that power domain to reset. To
prevent this, save the state of the registers before entering suspend
and restore them on resume. Additionally, disable the APB clock during
suspend to minimize power consumption.

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>
---
 drivers/clk/imx/clk-imx95-blk-ctl.c | 33 ++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/imx/clk-imx95-blk-ctl.c b/drivers/clk/imx/clk-imx95-blk-ctl.c
index c72debaf3a60b..56bed44719954 100644
--- a/drivers/clk/imx/clk-imx95-blk-ctl.c
+++ b/drivers/clk/imx/clk-imx95-blk-ctl.c
@@ -453,15 +453,24 @@ static int imx95_bc_runtime_suspend(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
 
+	bc->clk_reg_restore = readl(bc->base + bc->pdata->clk_reg_offset);
 	clk_disable_unprepare(bc->clk_apb);
+
 	return 0;
 }
 
 static int imx95_bc_runtime_resume(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
+	int ret;
 
-	return clk_prepare_enable(bc->clk_apb);
+	ret = clk_prepare_enable(bc->clk_apb);
+	if (ret)
+		return ret;
+
+	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
+
+	return 0;
 }
 #endif
 
@@ -469,17 +478,12 @@ static int imx95_bc_runtime_resume(struct device *dev)
 static int imx95_bc_suspend(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
-	int ret;
 
-	if (bc->pdata->rpm_enabled) {
-		ret = pm_runtime_get_sync(bc->dev);
-		if (ret < 0) {
-			pm_runtime_put_noidle(bc->dev);
-			return ret;
-		}
-	}
+	if (pm_runtime_suspended(dev))
+		return 0;
 
 	bc->clk_reg_restore = readl(bc->base + bc->pdata->clk_reg_offset);
+	clk_disable_unprepare(bc->clk_apb);
 
 	return 0;
 }
@@ -487,11 +491,16 @@ static int imx95_bc_suspend(struct device *dev)
 static int imx95_bc_resume(struct device *dev)
 {
 	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
+	int ret;
 
-	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
+	if (pm_runtime_suspended(dev))
+		return 0;
 
-	if (bc->pdata->rpm_enabled)
-		pm_runtime_put(bc->dev);
+	ret = clk_prepare_enable(bc->clk_apb);
+	if (ret)
+		return ret;
+
+	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
 
 	return 0;
 }
-- 
2.49.0

Re: [PATCH v2 2/2] clk: imx95-blk-ctl: Save/restore registers when RPM routines are called

[Frank Li]

On Mon, Aug 04, 2025 at 04:14:50PM +0300, Laurentiu Palcu wrote:
> When runtime PM is used for clock providers that are part of a power
> domain, the power domain supply is cut off during runtime suspend. This
> causes all BLK CTL registers belonging to that power domain to reset. To
> prevent this, save the state of the registers before entering suspend
> and restore them on resume. Additionally, disable the APB clock during
> suspend to minimize power consumption.
>
> Signed-off-by: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> ---
>  drivers/clk/imx/clk-imx95-blk-ctl.c | 33 ++++++++++++++++++-----------
>  1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/clk/imx/clk-imx95-blk-ctl.c b/drivers/clk/imx/clk-imx95-blk-ctl.c
> index c72debaf3a60b..56bed44719954 100644
> --- a/drivers/clk/imx/clk-imx95-blk-ctl.c
> +++ b/drivers/clk/imx/clk-imx95-blk-ctl.c
> @@ -453,15 +453,24 @@ static int imx95_bc_runtime_suspend(struct device *dev)
>  {
>  	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
>
> +	bc->clk_reg_restore = readl(bc->base + bc->pdata->clk_reg_offset);
>  	clk_disable_unprepare(bc->clk_apb);
> +
>  	return 0;
>  }
>
>  static int imx95_bc_runtime_resume(struct device *dev)
>  {
>  	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
> +	int ret;
>
> -	return clk_prepare_enable(bc->clk_apb);
> +	ret = clk_prepare_enable(bc->clk_apb);
> +	if (ret)
> +		return ret;
> +
> +	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
> +
> +	return 0;
>  }
>  #endif
>
> @@ -469,17 +478,12 @@ static int imx95_bc_runtime_resume(struct device *dev)
>  static int imx95_bc_suspend(struct device *dev)
>  {
>  	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
> -	int ret;
>
> -	if (bc->pdata->rpm_enabled) {
> -		ret = pm_runtime_get_sync(bc->dev);
> -		if (ret < 0) {
> -			pm_runtime_put_noidle(bc->dev);
> -			return ret;
> -		}
> -	}
> +	if (pm_runtime_suspended(dev))
> +		return 0;
>
>  	bc->clk_reg_restore = readl(bc->base + bc->pdata->clk_reg_offset);
> +	clk_disable_unprepare(bc->clk_apb);
>
>  	return 0;
>  }
> @@ -487,11 +491,16 @@ static int imx95_bc_suspend(struct device *dev)
>  static int imx95_bc_resume(struct device *dev)
>  {
>  	struct imx95_blk_ctl *bc = dev_get_drvdata(dev);
> +	int ret;
>
> -	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
> +	if (pm_runtime_suspended(dev))
> +		return 0;
>
> -	if (bc->pdata->rpm_enabled)
> -		pm_runtime_put(bc->dev);
> +	ret = clk_prepare_enable(bc->clk_apb);
> +	if (ret)
> +		return ret;
> +
> +	writel(bc->clk_reg_restore, bc->base + bc->pdata->clk_reg_offset);
>
>  	return 0;
>  }
> --
> 2.49.0
>