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authorAlexander Graf <agraf@suse.de>2016-06-05 11:35:56 +0200
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-06-06 17:07:33 +0200
commit7368c69c033ff29e8e766f481748113c7adc1d1b (patch)
tree4ff05dc68c6c84fc66b02854d9ac12ea6ccd852c /drivers/rtc
parent06776c89214a14735fed5519340e2cea88b5b91f (diff)
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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>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-efi.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index 96d38609d803..0130afd7fe88 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -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);