cpuidle: psci: Transition to the faux device interface

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.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://patch.msgid.link/20250317-plat2faux_dev-v1-1-5fe67c085ad5@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index b46a83f5ffe463d1a54c56f9cdb1ab620dc04d8f..ee35ac816321f2c42eb2bd35561eb534523437c2 100644 (file)
--- 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>
@@ -407,14 +407,14 @@ deinit:
  * 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_present_cpu(cpu) {
-               ret = psci_idle_init_cpu(&pdev->dev, cpu);
+               ret = psci_idle_init_cpu(&fdev->dev, cpu);
                if (ret)
                        goto out_fail;
        }
@@ -434,26 +434,18 @@ out_fail:
        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;