[PATCH v5 0/3] Support building tegra124-cpufreq as a module

[PATCH v5 0/3] Support building tegra124-cpufreq as a module

[Aaron Kling via B4 Relay]

This adds remove and exit routines that were not previously needed when
this was only available builtin.

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
Changes in v5:
- Add register helper function to cpufreq-dt for kernel users to use to
  establish a depmod dependency
- Drop patch that removes use of disable_cpufreq and re-add the patch to
  export said function
- Link to v4: https://lore.kernel.org/r/20250508-tegra124-cpufreq-v4-0-d142bcbd0234@gmail.com

Changes in v4:
- Move clock puts to remove instead of exit
- Link to v3: https://lore.kernel.org/r/20250421-tegra124-cpufreq-v3-0-95eaba968467@gmail.com

Changes in v3:
- In patch 1, set cpufreq_dt_pdev to an error after unregister on fail
  to prevent a potential double unregister on remove
- In patch 2, clean up clocks on exit
- Link to v2: https://lore.kernel.org/r/20250421-tegra124-cpufreq-v2-0-2f148cefa418@gmail.com

Changes in v2:
- Replace patch 1 with a patch to not use the unexported function
- Update patch 2 to add remove and exit routines
- Link to v1: https://lore.kernel.org/r/20250420-tegra124-cpufreq-v1-0-0a47fe126091@gmail.com

---
Aaron Kling (3):
      cpufreq: Export disable_cpufreq()
      cpufreq: dt: Add register helper
      cpufreq: tegra124: Allow building as a module

 drivers/cpufreq/Kconfig.arm        |  2 +-
 drivers/cpufreq/cpufreq-dt.c       | 11 ++++++++++
 drivers/cpufreq/cpufreq-dt.h       |  2 ++
 drivers/cpufreq/cpufreq.c          |  1 +
 drivers/cpufreq/tegra124-cpufreq.c | 44 +++++++++++++++++++++++++++++---------
 5 files changed, 49 insertions(+), 11 deletions(-)
---
base-commit: 91e5bfe317d8f8471fbaa3e70cf66cae1314a516
change-id: 20250401-tegra124-cpufreq-fd944fdce62c

Best regards,
-- 
Aaron Kling <webgeek1234@gmail.com>

[PATCH v5 1/3] cpufreq: Export disable_cpufreq()

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

This is used by the tegra124-cpufreq driver.

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 drivers/cpufreq/cpufreq.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0cf5a320bb5e864709b259249fb1af8bfbc0b04b..78cddc78ee98630f99ccc332c64c94f437297177 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -109,6 +109,7 @@ void disable_cpufreq(void)
 {
 	off = 1;
 }
+EXPORT_SYMBOL_GPL(disable_cpufreq);
 static DEFINE_MUTEX(cpufreq_governor_mutex);
 
 bool have_governor_per_policy(void)

-- 
2.50.0

[PATCH v5 2/3] cpufreq: dt: Add register helper

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

Cpufreq-dt currently exports no functions. This means that drivers that
are based on cpufreq-dt have no way of establishing a depmod dependency
on it. This helper allows that link.

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 drivers/cpufreq/cpufreq-dt.c | 11 +++++++++++
 drivers/cpufreq/cpufreq-dt.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index e80dd982a3e23f6e678d691daba2d8bfda28d93c..506437489b4db241a7a6259274ae84e688772e66 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -329,6 +329,17 @@ static struct platform_driver dt_cpufreq_platdrv = {
 };
 module_platform_driver(dt_cpufreq_platdrv);
 
+struct platform_device *cpufreq_dt_pdev_register(struct device *dev)
+{
+	struct platform_device_info cpufreq_dt_devinfo = {};
+
+	cpufreq_dt_devinfo.name = "cpufreq-dt";
+	cpufreq_dt_devinfo.parent = dev;
+
+	return platform_device_register_full(&cpufreq_dt_devinfo);
+}
+EXPORT_SYMBOL_GPL(cpufreq_dt_pdev_register);
+
 MODULE_ALIAS("platform:cpufreq-dt");
 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
diff --git a/drivers/cpufreq/cpufreq-dt.h b/drivers/cpufreq/cpufreq-dt.h
index 28c8af7ec5ef3ad0aa94f43ad9129600ca094329..fc1889aeb4f1f15fa7c46c2380021bbf40b62f11 100644
--- a/drivers/cpufreq/cpufreq-dt.h
+++ b/drivers/cpufreq/cpufreq-dt.h
@@ -22,4 +22,6 @@ struct cpufreq_dt_platform_data {
 	int (*resume)(struct cpufreq_policy *policy);
 };
 
+struct platform_device *cpufreq_dt_pdev_register(struct device *dev);
+
 #endif /* __CPUFREQ_DT_H__ */

-- 
2.50.0

[PATCH v5 3/3] cpufreq: tegra124: Allow building as a module

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

This requires three changes:
* Using the cpufreq-dt register helper to establish a hard dependency
  for depmod to track
* Adding a remove routine to remove the cpufreq-dt device
* Adding a exit routine to handle cleaning up the driver

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 drivers/cpufreq/Kconfig.arm        |  2 +-
 drivers/cpufreq/tegra124-cpufreq.c | 44 +++++++++++++++++++++++++++++---------
 2 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 4f9cb943d945c244eb2b29f543d14df6cac4e5d4..625f6fbdaaf5fd774e3b0bb996eb7ce980da41ee 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -238,7 +238,7 @@ config ARM_TEGRA20_CPUFREQ
 	  This adds the CPUFreq driver support for Tegra20/30 SOCs.
 
 config ARM_TEGRA124_CPUFREQ
-	bool "Tegra124 CPUFreq support"
+	tristate "Tegra124 CPUFreq support"
 	depends on ARCH_TEGRA || COMPILE_TEST
 	depends on CPUFREQ_DT
 	default y
diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
index 514146d98bca2d8aa59980a14dff3487cd8045f6..ebce62be9a9c17724d50dadeea1bb2ec81538421 100644
--- a/drivers/cpufreq/tegra124-cpufreq.c
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -16,6 +16,10 @@
 #include <linux/pm_opp.h>
 #include <linux/types.h>
 
+#include "cpufreq-dt.h"
+
+static struct platform_device *platform_device;
+
 struct tegra124_cpufreq_priv {
 	struct clk *cpu_clk;
 	struct clk *pllp_clk;
@@ -55,7 +59,6 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
 	struct device_node *np __free(device_node) = of_cpu_device_node_get(0);
 	struct tegra124_cpufreq_priv *priv;
 	struct device *cpu_dev;
-	struct platform_device_info cpufreq_dt_devinfo = {};
 	int ret;
 
 	if (!np)
@@ -95,11 +98,7 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_put_pllp_clk;
 
-	cpufreq_dt_devinfo.name = "cpufreq-dt";
-	cpufreq_dt_devinfo.parent = &pdev->dev;
-
-	priv->cpufreq_dt_pdev =
-		platform_device_register_full(&cpufreq_dt_devinfo);
+	priv->cpufreq_dt_pdev = cpufreq_dt_pdev_register(&pdev->dev);
 	if (IS_ERR(priv->cpufreq_dt_pdev)) {
 		ret = PTR_ERR(priv->cpufreq_dt_pdev);
 		goto out_put_pllp_clk;
@@ -173,6 +172,21 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
 	return err;
 }
 
+static void tegra124_cpufreq_remove(struct platform_device *pdev)
+{
+	struct tegra124_cpufreq_priv *priv = dev_get_drvdata(&pdev->dev);
+
+	if (!IS_ERR(priv->cpufreq_dt_pdev)) {
+		platform_device_unregister(priv->cpufreq_dt_pdev);
+		priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
+	}
+
+	clk_put(priv->pllp_clk);
+	clk_put(priv->pllx_clk);
+	clk_put(priv->dfll_clk);
+	clk_put(priv->cpu_clk);
+}
+
 static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
 				tegra124_cpufreq_resume)
@@ -182,12 +196,12 @@ static struct platform_driver tegra124_cpufreq_platdrv = {
 	.driver.name	= "cpufreq-tegra124",
 	.driver.pm	= &tegra124_cpufreq_pm_ops,
 	.probe		= tegra124_cpufreq_probe,
+	.remove		= tegra124_cpufreq_remove,
 };
 
 static int __init tegra_cpufreq_init(void)
 {
 	int ret;
-	struct platform_device *pdev;
 
 	if (!(of_machine_is_compatible("nvidia,tegra124") ||
 		of_machine_is_compatible("nvidia,tegra210")))
@@ -201,15 +215,25 @@ static int __init tegra_cpufreq_init(void)
 	if (ret)
 		return ret;
 
-	pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
-	if (IS_ERR(pdev)) {
+	platform_device = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
+	if (IS_ERR(platform_device)) {
 		platform_driver_unregister(&tegra124_cpufreq_platdrv);
-		return PTR_ERR(pdev);
+		return PTR_ERR(platform_device);
 	}
 
 	return 0;
 }
 module_init(tegra_cpufreq_init);
 
+static void __exit tegra_cpufreq_module_exit(void)
+{
+	if (platform_device && !IS_ERR(platform_device))
+		platform_device_unregister(platform_device);
+
+	platform_driver_unregister(&tegra124_cpufreq_platdrv);
+}
+module_exit(tegra_cpufreq_module_exit);
+
 MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
 MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
+MODULE_LICENSE("GPL");

-- 
2.50.0

Re: [PATCH v5 3/3] cpufreq: tegra124: Allow building as a module

[Viresh Kumar]

On 02-07-25, 02:46, Aaron Kling via B4 Relay wrote:
> +static struct platform_device *platform_device;

Maybe initialize this to an error value...

> +static void __exit tegra_cpufreq_module_exit(void)
> +{
> +	if (platform_device && !IS_ERR(platform_device))

... and then this could be simplified ?

Or use !IS_ERR_OR_NULL .

-- 
viresh

Re: [PATCH v5 3/3] cpufreq: tegra124: Allow building as a module

[Aaron Kling]

On Wed, Jul 2, 2025 at 3:12 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
>
> On 02-07-25, 02:46, Aaron Kling via B4 Relay wrote:
> > +static struct platform_device *platform_device;
>
> Maybe initialize this to an error value...
>
> > +static void __exit tegra_cpufreq_module_exit(void)
> > +{
> > +     if (platform_device && !IS_ERR(platform_device))
>
> ... and then this could be simplified ?
>
> Or use !IS_ERR_OR_NULL .

Latter sounds better to me. I'll queue that up and send a new patchset
in a couple days, pending any further comments.

Aaron

Re: [PATCH v5 3/3] cpufreq: tegra124: Allow building as a module

[Jon Hunter]

On 02/07/2025 08:46, Aaron Kling via B4 Relay wrote:
> From: Aaron Kling <webgeek1234@gmail.com>
> 
> This requires three changes:
> * Using the cpufreq-dt register helper to establish a hard dependency
>    for depmod to track
> * Adding a remove routine to remove the cpufreq-dt device
> * Adding a exit routine to handle cleaning up the driver

And populate the license?

> 
> Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> ---
>   drivers/cpufreq/Kconfig.arm        |  2 +-
>   drivers/cpufreq/tegra124-cpufreq.c | 44 +++++++++++++++++++++++++++++---------
>   2 files changed, 35 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 4f9cb943d945c244eb2b29f543d14df6cac4e5d4..625f6fbdaaf5fd774e3b0bb996eb7ce980da41ee 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -238,7 +238,7 @@ config ARM_TEGRA20_CPUFREQ
>   	  This adds the CPUFreq driver support for Tegra20/30 SOCs.
>   
>   config ARM_TEGRA124_CPUFREQ
> -	bool "Tegra124 CPUFreq support"
> +	tristate "Tegra124 CPUFreq support"
>   	depends on ARCH_TEGRA || COMPILE_TEST
>   	depends on CPUFREQ_DT
>   	default y
> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> index 514146d98bca2d8aa59980a14dff3487cd8045f6..ebce62be9a9c17724d50dadeea1bb2ec81538421 100644
> --- a/drivers/cpufreq/tegra124-cpufreq.c
> +++ b/drivers/cpufreq/tegra124-cpufreq.c
> @@ -16,6 +16,10 @@
>   #include <linux/pm_opp.h>
>   #include <linux/types.h>
>   
> +#include "cpufreq-dt.h"
> +
> +static struct platform_device *platform_device;

I think that this could do with a better name than just 
'platform_device'. Maybe something like tegra124_cpufreq_pdev?

> +
>   struct tegra124_cpufreq_priv {
>   	struct clk *cpu_clk;
>   	struct clk *pllp_clk;
> @@ -55,7 +59,6 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
>   	struct device_node *np __free(device_node) = of_cpu_device_node_get(0);
>   	struct tegra124_cpufreq_priv *priv;
>   	struct device *cpu_dev;
> -	struct platform_device_info cpufreq_dt_devinfo = {};
>   	int ret;
>   
>   	if (!np)
> @@ -95,11 +98,7 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto out_put_pllp_clk;
>   
> -	cpufreq_dt_devinfo.name = "cpufreq-dt";
> -	cpufreq_dt_devinfo.parent = &pdev->dev;
> -
> -	priv->cpufreq_dt_pdev =
> -		platform_device_register_full(&cpufreq_dt_devinfo);
> +	priv->cpufreq_dt_pdev = cpufreq_dt_pdev_register(&pdev->dev);
>   	if (IS_ERR(priv->cpufreq_dt_pdev)) {
>   		ret = PTR_ERR(priv->cpufreq_dt_pdev);
>   		goto out_put_pllp_clk;
> @@ -173,6 +172,21 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
>   	return err;
>   }
>   
> +static void tegra124_cpufreq_remove(struct platform_device *pdev)
> +{
> +	struct tegra124_cpufreq_priv *priv = dev_get_drvdata(&pdev->dev);
> +
> +	if (!IS_ERR(priv->cpufreq_dt_pdev)) {
> +		platform_device_unregister(priv->cpufreq_dt_pdev);
> +		priv->cpufreq_dt_pdev = ERR_PTR(-ENODEV);
> +	}
> +
> +	clk_put(priv->pllp_clk);
> +	clk_put(priv->pllx_clk);
> +	clk_put(priv->dfll_clk);
> +	clk_put(priv->cpu_clk);
> +}
> +
>   static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
>   	SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
>   				tegra124_cpufreq_resume)
> @@ -182,12 +196,12 @@ static struct platform_driver tegra124_cpufreq_platdrv = {
>   	.driver.name	= "cpufreq-tegra124",
>   	.driver.pm	= &tegra124_cpufreq_pm_ops,
>   	.probe		= tegra124_cpufreq_probe,
> +	.remove		= tegra124_cpufreq_remove,
>   };
>   
>   static int __init tegra_cpufreq_init(void)
>   {
>   	int ret;
> -	struct platform_device *pdev;
>   
>   	if (!(of_machine_is_compatible("nvidia,tegra124") ||
>   		of_machine_is_compatible("nvidia,tegra210")))
> @@ -201,15 +215,25 @@ static int __init tegra_cpufreq_init(void)
>   	if (ret)
>   		return ret;
>   
> -	pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
> -	if (IS_ERR(pdev)) {
> +	platform_device = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
> +	if (IS_ERR(platform_device)) {
>   		platform_driver_unregister(&tegra124_cpufreq_platdrv);
> -		return PTR_ERR(pdev);
> +		return PTR_ERR(platform_device);
>   	}
>   
>   	return 0;
>   }
>   module_init(tegra_cpufreq_init);
>   
> +static void __exit tegra_cpufreq_module_exit(void)
> +{
> +	if (platform_device && !IS_ERR(platform_device))
> +		platform_device_unregister(platform_device);
> +
> +	platform_driver_unregister(&tegra124_cpufreq_platdrv);
> +}
> +module_exit(tegra_cpufreq_module_exit);
> +
>   MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
>   MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
> +MODULE_LICENSE("GPL");
> 

-- 
nvpublic