From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 23 Feb 2017 13:14:26 +0100 From: Alexandre Belloni To: Michal Simek Cc: rtc-linux@googlegroups.com Subject: Re: [rtc-linux] RTC used as a module Message-ID: <20170223121426.i24ssrlwitrvb32h@piout.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: List-ID: Hi Michal, I've been thinking about this issue (and meaning to actually test). On 08/12/2016 at 14:02:36 +0100, Michal Simek wrote: > Hi guys, > > I am trying to find out reason for this behavior. If rtc-zynqmp is used > as module for the first time it is correctly probed based on aliases > setting. (rtc5 for log below). But then driver is removed and add again > rtc5 is still not freed. rtc_device_release() is not called that's why > rtc->id can't be used again. > > sh-4.3# modprobe rtc-zynqmp > [ 42.468565] rtc_zynqmp ffa60000.rtc: rtc core: registered > ffa60000.rtc as rtc5 > sh-4.3# rmmod rtc-zynqmp > sh-4.3# modprobe rtc-zynqmp > [ 48.648222] rtc_zynqmp ffa60000.rtc: /aliases ID 5 not available > [ 48.654280] rtc_zynqmp ffa60000.rtc: rtc core: registered > ffa60000.rtc as rtc0 > > > I didn't try different rtc drivers but it looks like that someone keeps > reference that's why release function is not called. > > Can someone check this with different RTC module? I'll do that soon. > Or is this expected behavior? > I don't think so :) Can you clarify a few things: - is this the only rtc with a driver on your system ? - is it selected as the RTC_SYSTOHC_DEVICE or RTC_HCTOSYS_DEVICE. I've checked the code and I don't think this is the issue but it is worth testing. Thanks, -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com