[PATCH v2] soc: qcom: rpmpd: Allow RPMPD driver to be loaded as a module

[PATCH v2] soc: qcom: rpmpd: Allow RPMPD driver to be loaded as a module

[John Stultz]

This patch allow the rpmpd driver to be loaded as a permenent
module. Meaning it can be loaded from a module, but then cannot
be unloaded.

Ideally, it would include a remove hook and related logic, but
apparently the genpd code isn't able to track usage and cleaning
things up? (See: https://lkml.org/lkml/2019/1/24/38)

So making it a permenent module at least improves things slightly
over requiring it to be a built in driver.

Feedback would be appreciated!

Cc: Todd Kjos <tkjos@google.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v2:
* Fix MODULE_LICENSE to be GPL v2 as suggested by Bjorn
* Leave initcall as core_initcall, since that switches to module_initcall
  only when built as a module, also suggested by Bjorn
* Add module tags taken from Rajendra's earlier patch
---
 drivers/soc/qcom/Kconfig | 4 ++--
 drivers/soc/qcom/rpmpd.c | 6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index d0a73e76d563..af774555b9d2 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -123,8 +123,8 @@ config QCOM_RPMHPD
 	  for the voltage rail.
 
 config QCOM_RPMPD
-	bool "Qualcomm RPM Power domain driver"
-	depends on QCOM_SMD_RPM=y
+	tristate "Qualcomm RPM Power domain driver"
+	depends on QCOM_SMD_RPM
 	help
 	  QCOM RPM Power domain driver to support power-domains with
 	  performance states. The driver communicates a performance state
diff --git a/drivers/soc/qcom/rpmpd.c b/drivers/soc/qcom/rpmpd.c
index 2b1834c5609a..22fe94c03e79 100644
--- a/drivers/soc/qcom/rpmpd.c
+++ b/drivers/soc/qcom/rpmpd.c
@@ -5,6 +5,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
+#include <linux/module.h>
 #include <linux/pm_domain.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -226,6 +227,7 @@ static const struct of_device_id rpmpd_match_table[] = {
 	{ .compatible = "qcom,qcs404-rpmpd", .data = &qcs404_desc },
 	{ }
 };
+MODULE_DEVICE_TABLE(of, rpmpd_match_table);
 
 static int rpmpd_send_enable(struct rpmpd *pd, bool enable)
 {
@@ -422,3 +424,7 @@ static int __init rpmpd_init(void)
 	return platform_driver_register(&rpmpd_driver);
 }
 core_initcall(rpmpd_init);
+
+MODULE_DESCRIPTION("Qualcomm Technologies, Inc. RPM Power Domain Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:qcom-rpmpd");
-- 
2.17.1

Re: [PATCH v2] soc: qcom: rpmpd: Allow RPMPD driver to be loaded as a module

[Saravana Kannan]

On Thu, Mar 19, 2020 at 12:50 PM John Stultz <john.stultz@linaro.org> wrote:
>
> This patch allow the rpmpd driver to be loaded as a permenent
> module. Meaning it can be loaded from a module, but then cannot
> be unloaded.
>
> Ideally, it would include a remove hook and related logic, but
> apparently the genpd code isn't able to track usage and cleaning
> things up? (See: https://lkml.org/lkml/2019/1/24/38)
>
> So making it a permenent module at least improves things slightly
> over requiring it to be a built in driver.
>
> Feedback would be appreciated!
>
> Cc: Todd Kjos <tkjos@google.com>
> Cc: Saravana Kannan <saravanak@google.com>
> Cc: Andy Gross <agross@kernel.org>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Rajendra Nayak <rnayak@codeaurora.org>
> Cc: linux-arm-msm@vger.kernel.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v2:
> * Fix MODULE_LICENSE to be GPL v2 as suggested by Bjorn
> * Leave initcall as core_initcall, since that switches to module_initcall
>   only when built as a module, also suggested by Bjorn
> * Add module tags taken from Rajendra's earlier patch
> ---
>  drivers/soc/qcom/Kconfig | 4 ++--
>  drivers/soc/qcom/rpmpd.c | 6 ++++++
>  2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index d0a73e76d563..af774555b9d2 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -123,8 +123,8 @@ config QCOM_RPMHPD
>           for the voltage rail.
>
>  config QCOM_RPMPD
> -       bool "Qualcomm RPM Power domain driver"
> -       depends on QCOM_SMD_RPM=y
> +       tristate "Qualcomm RPM Power domain driver"
> +       depends on QCOM_SMD_RPM
>         help
>           QCOM RPM Power domain driver to support power-domains with
>           performance states. The driver communicates a performance state
> diff --git a/drivers/soc/qcom/rpmpd.c b/drivers/soc/qcom/rpmpd.c
> index 2b1834c5609a..22fe94c03e79 100644
> --- a/drivers/soc/qcom/rpmpd.c
> +++ b/drivers/soc/qcom/rpmpd.c
> @@ -5,6 +5,7 @@
>  #include <linux/init.h>
>  #include <linux/kernel.h>
>  #include <linux/mutex.h>
> +#include <linux/module.h>
>  #include <linux/pm_domain.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> @@ -226,6 +227,7 @@ static const struct of_device_id rpmpd_match_table[] = {
>         { .compatible = "qcom,qcs404-rpmpd", .data = &qcs404_desc },
>         { }
>  };
> +MODULE_DEVICE_TABLE(of, rpmpd_match_table);
>
>  static int rpmpd_send_enable(struct rpmpd *pd, bool enable)
>  {
> @@ -422,3 +424,7 @@ static int __init rpmpd_init(void)
>         return platform_driver_register(&rpmpd_driver);
>  }
>  core_initcall(rpmpd_init);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies, Inc. RPM Power Domain Driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:qcom-rpmpd");
> --
> 2.17.1
>

I think making it a permanent module is still very useful and a good first step.

Acked-by: Saravana Kannan <saravanak@google.com>

-Saravana