Re: [RFE PATCH 2/2] rtc, add write functionality to sysfs

From: John Stultz
Date: Thu Feb 28 2013 - 13:51:40 EST

On 02/24/2013 09:03 AM, Prarit Bhargava wrote:

On 02/23/2013 06:11 PM, Alessandro Zummo wrote:
On 22/feb/2013, at 22:05, John Stultz <john.stultz@xxxxxxxxxx> wrote:

On 02/22/2013 12:55 PM, Prarit Bhargava wrote:
On 02/22/2013 03:43 PM, John Stultz wrote:
On 02/14/2013 09:02 AM, Prarit Bhargava wrote:
/sys/class/rtc/rtcX/date and /sys/class/rtc/rtcX/time currently have
read-only access. This patch introduces write functionality which will
set the rtc time.

Usage: echo YYYY-MM-DD > /sys/class/rtc/rtcX/date
echo HH:MM:SS > /sys/class/rtc/rtcX/time
Why do we want to add a new interface here?

I'm not adding a new interface. The current date/time interface only handles
read and I'm introducing write.

Right, but what benefit does that provide?
(I'm not saying there isn't any, its just not clear from your patch why this is a good thing.)

Sorry John, I misunderstood your question.

Also CC'ing Alessandro for his input.
I'd like to keep the interfaces as simple as possible but I'm open to improvements if there are good use cases.

AFAICT there is no way for me to "test" or use the write from userspace.
hwclock uses the SET_TIME ioctl, which is a different code path AFAICT.

Yea, per your other email, I'd rather we drop this change for now.

If possible, instead of adding redundant userland interfaces, I'd rather we consolidate the redundant internal code paths.


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