rtc-cmos: export nvram in sysfs
commite07e232cd96ef0092b2bddc72f9b7caf284633cb
authorDavid Brownell <david-b@pacbell.net>
Wed, 6 Feb 2008 09:38:43 +0000 (6 01:38 -0800)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 6 Feb 2008 18:41:13 +0000 (6 10:41 -0800)
tree442ff1cc6f2548e27315ee6c8ad5252132e5d416
parent9974b6ea7b85a32f34f824443f47aa501c85ee8f
rtc-cmos: export nvram in sysfs

This makes rtc-cmos export its NVRAM, like several other RTC drivers.

It still works within the limits of the current CMOS_READ/CMOS_WRITE calls,
which don't understand how to access multiple register banks.  The primary
impact of that limitation is that Linux can't access the uppermost 128
bytes of NVRAM on many systems.

Note that this isn't aiming to be a drop-in replacement for the legacy
/dev/nvram support.  (Presumably that has real users, and isn't just
getting carried forward automatically?) Userspace handles more work:

 - When userspace code updates NVRAM, that will need to include
   updating any platform-specific checksums that may apply.

 - No /proc/driver/nvram file will parse and display NVRAM data
   according to whichever boot firmware your board expects.

Also minor pnp-related updates: update a comment, remove dead code.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rtc/rtc-cmos.c