The PSCI cpuidle driver does not require the creation of a platform
device. Originally, this approach was chosen for simplicity when the
driver was first implemented.
With the introduction of the lightweight faux device interface, we now
have a more appropriate alternative. Migrate the driver to utilize the
faux bus, given that the platform device it previously created was not
a real one anyway. This will simplify the code, reducing its footprint
while maintaining functionality.
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/cpuidle/cpuidle-psci.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2562dc001fc1de69732ef28f383d2809262a3d96..3e38f712dab3785d5caa8d103fd0146156005921 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -16,7 +16,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
-#include <linux/platform_device.h>
+#include <linux/device/faux.h>
#include <linux/psci.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
@@ -404,14 +404,14 @@ static int psci_idle_init_cpu(struct device *dev, int cpu)
* to register cpuidle driver then rollback to cancel all CPUs
* registration.
*/
-static int psci_cpuidle_probe(struct platform_device *pdev)
+static int psci_cpuidle_probe(struct faux_device *fdev)
{
int cpu, ret;
struct cpuidle_driver *drv;
struct cpuidle_device *dev;
for_each_possible_cpu(cpu) {
- ret = psci_idle_init_cpu(&pdev->dev, cpu);
+ ret = psci_idle_init_cpu(&fdev->dev, cpu);
if (ret)
goto out_fail;
}
@@ -431,26 +431,18 @@ static int psci_cpuidle_probe(struct platform_device *pdev)
return ret;
}
-static struct platform_driver psci_cpuidle_driver = {
+static struct faux_device_ops psci_cpuidle_ops = {
.probe = psci_cpuidle_probe,
- .driver = {
- .name = "psci-cpuidle",
- },
};
static int __init psci_idle_init(void)
{
- struct platform_device *pdev;
- int ret;
+ struct faux_device *fdev;
- ret = platform_driver_register(&psci_cpuidle_driver);
- if (ret)
- return ret;
-
- pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
- if (IS_ERR(pdev)) {
- platform_driver_unregister(&psci_cpuidle_driver);
- return PTR_ERR(pdev);
+ fdev = faux_device_create("psci-cpuidle", NULL, &psci_cpuidle_ops);
+ if (!fdev) {
+ pr_err("Failed to create psci-cpuidle device\n");
+ return -ENODEV;
}
return 0;
--
2.34.1On Mon, Mar 17, 2025 at 11:13 AM Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> The PSCI cpuidle driver does not require the creation of a platform
> device. Originally, this approach was chosen for simplicity when the
> driver was first implemented.
>
> With the introduction of the lightweight faux device interface, we now
> have a more appropriate alternative. Migrate the driver to utilize the
> faux bus, given that the platform device it previously created was not
> a real one anyway. This will simplify the code, reducing its footprint
> while maintaining functionality.
>
> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: linux-pm@vger.kernel.org
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Do you want me to pick up this one?
> ---
> drivers/cpuidle/cpuidle-psci.c | 26 +++++++++-----------------
> 1 file changed, 9 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index 2562dc001fc1de69732ef28f383d2809262a3d96..3e38f712dab3785d5caa8d103fd0146156005921 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -16,7 +16,7 @@
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/of.h>
> -#include <linux/platform_device.h>
> +#include <linux/device/faux.h>
> #include <linux/psci.h>
> #include <linux/pm_domain.h>
> #include <linux/pm_runtime.h>
> @@ -404,14 +404,14 @@ static int psci_idle_init_cpu(struct device *dev, int cpu)
> * to register cpuidle driver then rollback to cancel all CPUs
> * registration.
> */
> -static int psci_cpuidle_probe(struct platform_device *pdev)
> +static int psci_cpuidle_probe(struct faux_device *fdev)
> {
> int cpu, ret;
> struct cpuidle_driver *drv;
> struct cpuidle_device *dev;
>
> for_each_possible_cpu(cpu) {
> - ret = psci_idle_init_cpu(&pdev->dev, cpu);
> + ret = psci_idle_init_cpu(&fdev->dev, cpu);
> if (ret)
> goto out_fail;
> }
> @@ -431,26 +431,18 @@ static int psci_cpuidle_probe(struct platform_device *pdev)
> return ret;
> }
>
> -static struct platform_driver psci_cpuidle_driver = {
> +static struct faux_device_ops psci_cpuidle_ops = {
> .probe = psci_cpuidle_probe,
> - .driver = {
> - .name = "psci-cpuidle",
> - },
> };
>
> static int __init psci_idle_init(void)
> {
> - struct platform_device *pdev;
> - int ret;
> + struct faux_device *fdev;
>
> - ret = platform_driver_register(&psci_cpuidle_driver);
> - if (ret)
> - return ret;
> -
> - pdev = platform_device_register_simple("psci-cpuidle", -1, NULL, 0);
> - if (IS_ERR(pdev)) {
> - platform_driver_unregister(&psci_cpuidle_driver);
> - return PTR_ERR(pdev);
> + fdev = faux_device_create("psci-cpuidle", NULL, &psci_cpuidle_ops);
> + if (!fdev) {
> + pr_err("Failed to create psci-cpuidle device\n");
> + return -ENODEV;
> }
>
> return 0;
>
> --
> 2.34.1
>
On Wed, Apr 09, 2025 at 08:03:32PM +0200, Rafael J. Wysocki wrote: > On Mon, Mar 17, 2025 at 11:13 AM Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > The PSCI cpuidle driver does not require the creation of a platform > > device. Originally, this approach was chosen for simplicity when the > > driver was first implemented. > > > > With the introduction of the lightweight faux device interface, we now > > have a more appropriate alternative. Migrate the driver to utilize the > > faux bus, given that the platform device it previously created was not > > a real one anyway. This will simplify the code, reducing its footprint > > while maintaining functionality. > > > > Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> > > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> > > Cc: linux-pm@vger.kernel.org > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > Do you want me to pick up this one? > Yes you can pick this up. Just checked again, this is v1 and correct version. -- Regards, Sudeep
On Wed, Apr 9, 2025 at 9:18 PM Sudeep Holla <sudeep.holla@arm.com> wrote: > > On Wed, Apr 09, 2025 at 08:03:32PM +0200, Rafael J. Wysocki wrote: > > On Mon, Mar 17, 2025 at 11:13 AM Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > > > The PSCI cpuidle driver does not require the creation of a platform > > > device. Originally, this approach was chosen for simplicity when the > > > driver was first implemented. > > > > > > With the introduction of the lightweight faux device interface, we now > > > have a more appropriate alternative. Migrate the driver to utilize the > > > faux bus, given that the platform device it previously created was not > > > a real one anyway. This will simplify the code, reducing its footprint > > > while maintaining functionality. > > > > > > Cc: Lorenzo Pieralisi <lpieralisi@kernel.org> > > > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > > > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> > > > Cc: linux-pm@vger.kernel.org > > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > > > Do you want me to pick up this one? > > > > Yes you can pick this up. > > Just checked again, this is v1 and correct version. Applied as 6.16 material, thanks!
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