From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.trumtrar@pengutronix.de (Steffen Trumtrar) Date: Wed, 6 Mar 2013 14:27:44 +0100 Subject: [PATCH 6/9] rtc: stmp3xxx: add sysfs entries for persistent regs In-Reply-To: <20130305080252.GA7042@pengutronix.de> References: <1362405948-12992-1-git-send-email-s.trumtrar@pengutronix.de> <1362405948-12992-7-git-send-email-s.trumtrar@pengutronix.de> <20130305080252.GA7042@pengutronix.de> Message-ID: <20130306132744.GC13810@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Mar 05, 2013 at 09:02:52AM +0100, Steffen Trumtrar wrote: > Hi Grant! > > On Mon, Mar 04, 2013 at 11:14:54PM +0800, Grant Likely wrote: > > On Mon, Mar 4, 2013 at 10:05 PM, Steffen Trumtrar > > wrote: > > > The persistent registers 1-5 are completely software defined. To have access > > > from userspace, export them via sysfs. > > > > > > Signed-off-by: Steffen Trumtrar > > > > Hi Steffen, > > > > A few comments on this. First and foremost, any additions to the > > kernel sysfs interface must be accompanied with documentation in > > Documentation/ABI/. Second, adding attributes to an existing device > > Okay. I forgot that and will add it in the next version. > > > that has already been registered is almost guaranteed to be wrong. The > > attributes need to be added all at the same time so they are available > > immediately when the new device uevent is issued by the kernel. > > > > Instead, the correct thing to do is add an attribute_group to the > > child device before the device gets registered. See the 'attributes' > > section of Documentation/driver-model/device.txt to see how to do > > this. > > > > (I also see that the rtc core code is doing the wrong thing here also. > > rtc_sysfs_add_device(), rtc_sysfs_add_device() should also be replaced > > with an attribute group so that the sysfs files get added > > automatically; but that is outside the scope of this patch) > > > > Hm, I modeled it after other rtcs and the rtc_sysfs. Seems that I have to > rework this. Okay. Wait. I looked at it again. What I want to do is adding the persistent registers as a binary-attribute. Basically having nvram like other rtcs. Is that even possible with attribute group? Would I add the attr inside the bin_attribute to the group then? Or is it wrong to add these regs as binary? Thanks, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |