ARM: dts: am335x-boneblack: disable RTC-only sleep

Commit Message

Matthijs van Duin June 1, 2015, 7:33 p.m. UTC

On 1 June 2015 at 19:23, Tony Lindgren <[e-mail]> wrote:
> Ah finally you got around doing a proper patch :)

My First Linux Patch(tm) ;-)

> Also, if this is needed as a fix for the mainline kernel to avoid hardware
> damage, please let me know too ASAP.

The damaging configuration is having &rtc { system-power-controller; }
without &tps { ti,pmic-shutdown-controller; }

So 3d76be5b9 also avoids damage, but with the unfortunate side-effect
that the system doesn't power off at all anymore (it just halts). I do
recommend applying this patch (restyled as needed) before reverting
3d76be5b9.

> Hmm no ideas about that, I guess people are using gmail to send email
> with smtps though?

Hmm, setting up mutt turned out less hassle than I remembered...

(Let's hope all goes well)

> Linux usually does not use the // style comments.. Can you please change
> that? And how about have just one section of comments then the entry
> for ti,pmic-shutdown-controller?

Fresh try...

--- 8< -----------------------------------------------------
Fixes: http://bugs.elinux.org/issues/143

Avoid entering "RTC-only mode" at poweroff. It is unsupported by most
versions of BeagleBone, and risks hardware damage.

Reported-by: Matthijs van Duin <[e-mail]>
Tested-by: Matthijs van Duin <[e-mail]>
Signed-off-by: Robert Nelson <[e-mail]>
Cc: Tony Lindgren <[e-mail]>
Cc: Felipe Balbi <[e-mail]>
Cc: Johan Hovold <[e-mail]>
[Matthijs van Duin: added explanatory comments]
Signed-off-by: Matthijs van Duin <[e-mail]>
---
 arch/arm/boot/dts/am335x-bone-common.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Tony Lindgren June 1, 2015, 8:01 p.m. UTC | #1

* Matthijs van Duin <[e-mail]> [150601 12:35]:
> On 1 June 2015 at 19:23, Tony Lindgren <[e-mail]> wrote:
> > Ah finally you got around doing a proper patch :)
> 
> My First Linux Patch(tm) ;-)

Probably easier than trying to get other people to do the right
thing by writing emails ;)
 
> > Also, if this is needed as a fix for the mainline kernel to avoid hardware
> > damage, please let me know too ASAP.
> 
> The damaging configuration is having &rtc { system-power-controller; }
> without &tps { ti,pmic-shutdown-controller; }

OK thanks updating the description with that.
 
> So 3d76be5b9 also avoids damage, but with the unfortunate side-effect
> that the system doesn't power off at all anymore (it just halts). I do
> recommend applying this patch (restyled as needed) before reverting
> 3d76be5b9.
> 
> > Hmm no ideas about that, I guess people are using gmail to send email
> > with smtps though?
> 
> Hmm, setting up mutt turned out less hassle than I remembered...
> 
> (Let's hope all goes well)
> 
> > Linux usually does not use the // style comments.. Can you please change
> > that? And how about have just one section of comments then the entry
> > for ti,pmic-shutdown-controller?
> 
> Fresh try...

Thanks applying into omap-for-v4.1/fixes with Cc stable.

Regards,

Tony

Patch

diff --git a/arch/arm/boot/dts/am335x-bone-common.dtsi b/arch/arm/boot/dts/am335x-bone-common.dtsi
index c3255e0..c0b0c02 100644
--- a/arch/arm/boot/dts/am335x-bone-common.dtsi
+++ b/arch/arm/boot/dts/am335x-bone-common.dtsi
@@ -223,6 +223,24 @@ 
 /include/ "tps65217.dtsi"
 
 &tps {
+	/* Configure pmic to enter OFF-state instead of SLEEP-state ("RTC-only
+	 * mode") at poweroff.  Most BeagleBone versions do not support RTC-only
+	 * mode and risk hardware damage if this mode is entered.
+	 *
+	 * For details, see linux-omap mailing list May 2015 thread
+	 *	[PATCH] ARM: dts: am335x-bone* enable pmic-shutdown-controller
+	 * In particular, messages:
+	 *	http://www.spinics.net/lists/linux-omap/msg118585.html
+	 *	http://www.spinics.net/lists/linux-omap/msg118615.html
+	 *
+	 * You can override this later with
+	 *	&tps {  /delete-property/ ti,pmic-shutdown-controller;  }
+	 * if you want to use RTC-only mode and made sure you are not affected
+	 * by the hardware problems. (Tip: double-check by performing a current
+	 * measurement after shutdown: it should be less than 1 mA.)
+	 */
+	ti,pmic-shutdown-controller;
+
 	regulators {
 		dcdc1_reg: regulator@0 {
 			regulator-name = "vdds_dpr";