[PATCH v2 4/8] rtc: efi: Transition to the faux device interface

Sudeep Holla
2025-03-18T17:02:36Z

The EFI RTC 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: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-rtc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
drivers/firmware/efi/efi.c | 3 ---
drivers/rtc/rtc-efi.c | 16 +++++-----------
2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 7309394b8fc98cf7a3424af209b752f0251c8c89..8aebc747c65bc1b63d514a50fe6f35a9e3c1af0a 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -427,9 +427,6 @@ static int __init efisubsys_init(void)
}
}

- if (efi_rt_services_supported(EFI_RT_SUPPORTED_TIME_SERVICES))
- platform_device_register_simple("rtc-efi", 0, NULL, 0);
-
/* We register the efi directory at /sys/firmware/efi */
efi_kobj = kobject_create_and_add("efi", firmware_kobj);
if (!efi_kobj) {
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index fa8bf82df9488e7d1c23c058b4a3032dde74bc6e..681d917d541e51b37f2d59b0567caf6aa8bf05f4 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -14,7 +14,7 @@
#include <linux/module.h>
#include <linux/stringify.h>
#include <linux/time.h>
-#include <linux/platform_device.h>
+#include <linux/device/faux.h>
#include <linux/rtc.h>
#include <linux/efi.h>

@@ -254,7 +254,7 @@ static const struct rtc_class_ops efi_rtc_ops = {
.proc = efi_procfs,
};

-static int __init efi_rtc_probe(struct platform_device *dev)
+static int __init efi_rtc_probe(struct faux_device *dev)
{
struct rtc_device *rtc;
efi_time_t eft;
@@ -268,7 +268,7 @@ static int __init efi_rtc_probe(struct platform_device *dev)
if (IS_ERR(rtc))
return PTR_ERR(rtc);

- platform_set_drvdata(dev, rtc);
+ faux_device_set_drvdata(dev, rtc);

rtc->ops = &efi_rtc_ops;
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
@@ -282,15 +282,9 @@ static int __init efi_rtc_probe(struct platform_device *dev)
return devm_rtc_register_device(rtc);
}

-static struct platform_driver efi_rtc_driver = {
- .driver = {
- .name = "rtc-efi",
- },
-};
-
-module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe);
+module_faux_driver(rtc_efi, efi_rtc_probe, NULL,
+ efi_rt_services_supported(EFI_RT_SUPPORTED_TIME_SERVICES));

MODULE_AUTHOR("dann frazier <dannf@dannf.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("EFI RTC driver");
-MODULE_ALIAS("platform:rtc-efi");

--
2.34.1