[PATCH 6/9] rtc: stmp3xxx: add sysfs entries for persistent regs

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:

quoted

On Mon, Mar 4, 2013 at 10:05 PM, Steffen Trumtrar
[off-list ref] wrote:

quoted

The persistent registers 1-5 are completely software defined. To have access
from userspace, export them via sysfs.

Signed-off-by: Steffen Trumtrar <redacted>

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.

quoted

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

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