[PATCH v2 0/2] Support building tegra124-cpufreq as a module

[PATCH v2 0/2] 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. It also converts use of an unexported
function to a more sane alternative.

Signed-off-by: Aaron Kling <webgeek1234@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 (2):
      cpufreq: tegra124: Remove use of disable_cpufreq
      cpufreq: tegra124: Allow building as a module

 drivers/cpufreq/Kconfig.arm        |  2 +-
 drivers/cpufreq/tegra124-cpufreq.c | 31 ++++++++++++++++++++++++++-----
 2 files changed, 27 insertions(+), 6 deletions(-)
---
base-commit: 91e5bfe317d8f8471fbaa3e70cf66cae1314a516
change-id: 20250401-tegra124-cpufreq-fd944fdce62c

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

[PATCH v2 1/2] cpufreq: tegra124: Remove use of disable_cpufreq

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

Instead, unregister the cpufreq device for this fatal fail case.

Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
---
 drivers/cpufreq/tegra124-cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
index 514146d98bca2d8aa59980a14dff3487cd8045f6..dc83b1631b13ec428f3b6bbea89462448a62adb4 100644
--- a/drivers/cpufreq/tegra124-cpufreq.c
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -168,7 +168,8 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
 disable_dfll:
 	clk_disable_unprepare(priv->dfll_clk);
 disable_cpufreq:
-	disable_cpufreq();
+	if (!IS_ERR(priv->cpufreq_dt_pdev))
+		platform_device_unregister(priv->cpufreq_dt_pdev);
 
 	return err;
 }

-- 
2.48.1

[PATCH v2 2/2] cpufreq: tegra124: Allow building as a module

[Aaron Kling via B4 Relay]

From: Aaron Kling <webgeek1234@gmail.com>

This requires three changes:
* A soft dependency on cpufreq-dt as this driver only handles power
  management and cpufreq-dt does the real operations
* 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 | 28 ++++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 5 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 dc83b1631b13ec428f3b6bbea89462448a62adb4..17f51592bf9fe75921ab4fc4125908e5d941e468 100644
--- a/drivers/cpufreq/tegra124-cpufreq.c
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -16,6 +16,8 @@
 #include <linux/pm_opp.h>
 #include <linux/types.h>
 
+static struct platform_device *platform_device;
+
 struct tegra124_cpufreq_priv {
 	struct clk *cpu_clk;
 	struct clk *pllp_clk;
@@ -174,6 +176,14 @@ 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);
+}
+
 static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
 				tegra124_cpufreq_resume)
@@ -183,12 +193,12 @@ 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")))
@@ -202,15 +212,25 @@ 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 (!IS_ERR(platform_device))
+		platform_device_unregister(platform_device);
+	platform_driver_unregister(&tegra124_cpufreq_platdrv);
+}
+module_exit(tegra_cpufreq_module_exit);
+
+MODULE_SOFTDEP("pre: cpufreq-dt");
 MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
 MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
+MODULE_LICENSE("GPL");

-- 
2.48.1

Re: [PATCH v2 1/2] cpufreq: tegra124: Remove use of disable_cpufreq

[Viresh Kumar]

On 21-04-25, 03:13, Aaron Kling via B4 Relay wrote:
> From: Aaron Kling <webgeek1234@gmail.com>
> 
> Instead, unregister the cpufreq device for this fatal fail case.
> 
> Signed-off-by: Aaron Kling <webgeek1234@gmail.com>
> ---
>  drivers/cpufreq/tegra124-cpufreq.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
> index 514146d98bca2d8aa59980a14dff3487cd8045f6..dc83b1631b13ec428f3b6bbea89462448a62adb4 100644
> --- a/drivers/cpufreq/tegra124-cpufreq.c
> +++ b/drivers/cpufreq/tegra124-cpufreq.c
> @@ -168,7 +168,8 @@ static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
>  disable_dfll:
>  	clk_disable_unprepare(priv->dfll_clk);
>  disable_cpufreq:
> -	disable_cpufreq();
> +	if (!IS_ERR(priv->cpufreq_dt_pdev))
> +		platform_device_unregister(priv->cpufreq_dt_pdev);

What if someone tries to remove the module after this ? Won't we try
this again ? Shouldn't we set the cpufreq_dt_pdev to some sort of
error to skip doing that ?

-- 
viresh

Re: [PATCH v2 2/2] cpufreq: tegra124: Allow building as a module

[Viresh Kumar]

On 21-04-25, 03:13, Aaron Kling via B4 Relay wrote:
> +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);
> +}

Ideally this should undo everything probe() would have done. There are
a lot of clk_put() calls in the error path of probe, I think they must
be done here ?

Also I would require an Ack from Thierry or some other maintainer of
the driver to get these changes in.

Thanks.

-- 
viresh