RE: [patch 2.6.17-rc4-omap-git] rtc-omap, rtc framework driver

Johnson, Steve-OMAP
2006-08-15T22:03:02Z

David,

Thanks. I'll let marketing know and ask them to fix the graphic.

Regards,

Steve

> -----Original Message-----
> From: David Brownell [mailto:david-b@pacbell.net]
> Sent: Tuesday, August 15, 2006 5:01 PM
> To: Johnson, Steve-OMAP
> Cc: linux-omap-open-source@linux.omap.com
> Subject: Re: [patch 2.6.17-rc4-omap-git] rtc-omap, rtc
> framework driver
>
> On Tuesday 15 August 2006 10:25 am, Johnson, Steve-OMAP wrote:
> > Hi Dave,
> >
> > For OMAP2 and OMAP3, the RTC is in the Power Management
> companion chip
> > (TWL92230 and TWL4030).
> >
> > Where do you see an RTC on the web site for OMAP2420? The only
> > picture I see shows the RTC in the companion chip.
>
> From www.omap.com, click the left hand option then the
> JavaScript omap2420 link to reach what I suspect is the same
> page you list (despite linewrap
> manglage) and includes this graphic:
>
> http://focus.ti.com/graphics/wtbu/blockdiagrams/l4_omap2420.gif
>
> which is a GIF that shows an RTC on the omap2420 chip, in the
> block labeled "Timers, Interrupt Controllers, RTC". The
> product overview link on that page gives a PDF document which
> agrees. (Agreed that the 2420 gif shows another RTC, on the
> PM chip ... but not for 2430/3430.)
>
> - Dave
>
>
> >
> >
> http://focus.ti.com/general/docs/wtbu/wtbuproductcontent.tsp?templateI
> > d=
> > 6123&navigationId=11990&contentId=4671
> >
> > Regards,
> >
> > Steve
> >
> >
> > > -----Original Message-----
> > > From: linux-omap-open-source-bounces@linux.omap.com
> > > [mailto:linux-omap-open-source-bounces@linux.omap.com] On
> Behalf Of
> > > David Brownell
> > > Sent: Tuesday, August 15, 2006 12:04 PM
> > > To: linux-omap-open-source@linux.omap.com
> > > Subject: [patch 2.6.17-rc4-omap-git] rtc-omap, rtc
> framework driver
> > >
> > > Cleaning out my patch queue ... here's an "rtc class" driver.
> > > Much more suitable for upstream merging than the
> previous version,
> > > even though that code has gotten much cleaner over time.
> > >
> > > Could someone confirm that this RTC can't actually do
> system wakeups
> > > without external hardware support? My documentation isn't at all
> > > clear on that issue. There's certainly an external wakeup signal
> > > available, but text also says that the alarm irq should work the
> > > normal way ... but I don't see that happening. It could
> easily be
> > > just a bug in
> > > enable_irq_wakeup(INT_RTC_ALARM) handling, which ISTR
> looked like a
> > > big NOP last I checked (for almost all IRQs).
> > >
> > > Also, someone with an OMAP2 setup should confirm that the
> Kconfig is
> > > right, and this particular controller isn't provided on
> OMAP2. That
> > > certainly matches the lack of RTC in the .../mach-omap2
> directory,
> > > but the TI website says 2420 (but not {2,3}430) has an
> RTC. Maybe
> > > the OMAP 2420 support is just missing, and it's really the same
> > > RTC...
> > >
> > > - Dave
> > >
> > >
> > > This creates a new RTC-framework driver for the
> RTC/calendar module
> > > found in various OMAP chips, giving a more correct/standard
> > > replacement for the older drivers/char/omap-rtc.c driver.
> > > Differences include:
> > >
> > > - much smaller/simpler, because it reuses shared infrastructure
> > > - the RTC name will normally be "rtc0" not "rtc"
> > > - the /dev node has a different major and minor numbers
> > > - RTC_ALM_SET handled as on PCs (alarm within 24 hours)
> > > - RTC_WKALM_SET handled as on PCs (alarm within this century)
> > > - epoch not changeable (why bother)
> > > - rtc alarm may optionally be a system wakeup event
> > > (board-specific)
> > >
> > > If you use udev and statically link this, some init
> script can just
> > > create a symbolic link (rtc -> rtc0) so tools like "hwclock" will
> > > work as usual.
> > > Or, updates to hwclock (and busybox) are available which
> teach it to
> > > use the /dev/rtc0 path as a backup, and to support "hwclock
> > > --file=/dev/rtc0".
> > >
> > > Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
> > >
> > > ----
> > > Presumably an upstream merge should remove the devices.c
> support for
> > > the older non-framework driver.
> > >
> > > arch/arm/mach-omap1/devices.c | 2
> > > drivers/rtc/Kconfig | 8
> > > drivers/rtc/Makefile | 1
> > > drivers/rtc/rtc-omap.c | 573
> > > ++++++++++++++++++++++++++++++++++++++++++
> > > 4 files changed, 583 insertions(+), 1 deletion(-)
> > >
> > > ... deletia ...
>
>