Re: [rtc-linux] Re: [RFC PATCH 2/3] rtc: Add Amlogic Virtual Wake RTC

On 03/11/2016 at 15:36:48 +0000, Mark Rutland wrote :

quoted

In order to be able to reuse the RTC wakealarm feature, this
driver implements a fake RTC device which uses the system time
to deduce a suspend delay.

This sounds like an always-on oneshot timer device, not an RTC.

quoted

+static int meson_vrtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned long local_time;
+	struct timeval time;
+
+	do_gettimeofday(&time);
+	local_time = time.tv_sec - (sys_tz.tz_minuteswest * 60);
+	rtc_time_to_tm(local_time, tm);
+
+	return 0;
+}

... if this were a timer, you wouldn't need this hack.

The main issue I think is that the clockevents are not able to wakeup a
platform so it doesn't really fit as a timer inside the kernel.

I think it may be fine to handle that in the RTC subsystem for now.

The same issue can be seen with the flextimer on LS1021A:

http://lists.infradead.org/pipermail/linux-arm-kernel/2015-August/365597.html

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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