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rtc: efi: Fail probing if RTC reads don't work 

While the EFI spec mandates an RTC, not every implementation actually adheres
to that rule (or can adhere to it - some systems just don't have an RTC).

For those, we really don't want to probe the EFI RTC driver at all, because if
we do we'd get a non-functional driver that does nothing useful but only spills
our kernel log with warnings.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Alexander Graf 2016-06-05 11:35:56 +02:00 committed by Alexandre Belloni
parent 06776c8921
commit 7368c69c03
1 changed files with 6 additions and 0 deletions
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6
drivers/rtc/rtc-efi.c
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@ -259,6 +259,12 @@ static const struct rtc_class_ops efi_rtc_ops = {
static int __init efi_rtc_probe(struct platform_device *dev)
{
struct rtc_device *rtc;
efi_time_t eft;
efi_time_cap_t cap;
/* First check if the RTC is usable */
if (efi.get_time(&eft, &cap) != EFI_SUCCESS)
return -ENODEV;
rtc = devm_rtc_device_register(&dev->dev, "rtc-efi", &efi_rtc_ops,
THIS_MODULE);