[4/9] efi: register EFI rtc platform device only when available

Drop the separate driver that registers the EFI rtc on all EFI
systems that have runtime services available, and instead, move
the registration into the core EFI code, and make it conditional
on whether the actual time related services are available.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-rtc@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/efi.c     |  3 ++
 drivers/rtc/Makefile           |  4 ---
 drivers/rtc/rtc-efi-platform.c | 35 --------------------
 3 files changed, 3 insertions(+), 39 deletions(-)

On 19/02/2020 18:19:02+0100, Ard Biesheuvel wrote:
> Drop the separate driver that registers the EFI rtc on all EFI
> systems that have runtime services available, and instead, move
> the registration into the core EFI code, and make it conditional
> on whether the actual time related services are available.
> 
> Cc: Alessandro Zummo <a.zummo@towertech.it>
> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Cc: linux-rtc@vger.kernel.org
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

> ---
>  drivers/firmware/efi/efi.c     |  3 ++
>  drivers/rtc/Makefile           |  4 ---
>  drivers/rtc/rtc-efi-platform.c | 35 --------------------
>  3 files changed, 3 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index abf4c02e0201..69a585106d30 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -321,6 +321,9 @@ 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/Makefile b/drivers/rtc/Makefile
> index 4ac8f19fb631..24c7dfa1bd7d 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -12,10 +12,6 @@ obj-$(CONFIG_RTC_CLASS)		+= rtc-core.o
>  obj-$(CONFIG_RTC_MC146818_LIB)	+= rtc-mc146818-lib.o
>  rtc-core-y			:= class.o interface.o
>  
> -ifdef CONFIG_RTC_DRV_EFI
> -rtc-core-y			+= rtc-efi-platform.o
> -endif
> -
>  rtc-core-$(CONFIG_RTC_NVMEM)		+= nvmem.o
>  rtc-core-$(CONFIG_RTC_INTF_DEV)		+= dev.o
>  rtc-core-$(CONFIG_RTC_INTF_PROC)	+= proc.o
> diff --git a/drivers/rtc/rtc-efi-platform.c b/drivers/rtc/rtc-efi-platform.c
> deleted file mode 100644
> index 6c037dc4e3dc..000000000000
> --- a/drivers/rtc/rtc-efi-platform.c
> +++ /dev/null
> @@ -1,35 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Moved from arch/ia64/kernel/time.c
> - *
> - * Copyright (C) 1998-2003 Hewlett-Packard Co
> - *	Stephane Eranian <eranian@hpl.hp.com>
> - *	David Mosberger <davidm@hpl.hp.com>
> - * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
> - * Copyright (C) 1999-2000 VA Linux Systems
> - * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
> - */
> -
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -
> -#include <linux/init.h>
> -#include <linux/kernel.h>
> -#include <linux/module.h>
> -#include <linux/efi.h>
> -#include <linux/platform_device.h>
> -
> -static struct platform_device rtc_efi_dev = {
> -	.name = "rtc-efi",
> -	.id = -1,
> -};
> -
> -static int __init rtc_init(void)
> -{
> -	if (efi_enabled(EFI_RUNTIME_SERVICES))
> -		if (platform_device_register(&rtc_efi_dev) < 0)
> -			pr_err("unable to register rtc device...\n");
> -
> -	/* not necessarily an error */
> -	return 0;
> -}
> -module_init(rtc_init);
> -- 
> 2.17.1
>