On Monday 14 July 2014 09:53 PM, Tony Lindgren wrote:
* Lokesh Vutla <lokeshvutla@xxxxxx> [140714 07:47]:
Hi Tony,
On Wednesday 09 July 2014 04:36 PM, Keerthy wrote:
On Wednesday 09 July 2014 04:30 PM, Tony Lindgren wrote:
* Keerthy <a0393675@xxxxxx> [140709 03:59]:
On Wednesday 09 July 2014 04:20 PM, Tony Lindgren wrote:
* Keerthy <a0393675@xxxxxx> [140709 03:39]:
On Wednesday 09 July 2014 03:39 PM, Tony Lindgren wrote:
* Keerthy <a0393675@xxxxxx> [140709 02:36]:
On Wednesday 09 July 2014 02:42 PM, Tony Lindgren wrote:
* Lokesh Vutla <lokeshvutla@xxxxxx> [140709 01:37]:
--- a/arch/arm/boot/dts/dra7-evm.dts
+++ b/arch/arm/boot/dts/dra7-evm.dts
@@ -249,6 +249,7 @@
regulator-min-microvolt = <1050000>;
regulator-max-microvolt = <1050000>;
regulator-boot-on;
+ regulator-always-on;
};
Is this regulator really always on?
This feeds on to RTC which is a free running clock. So i guess always on is
justified no?
Well the dts entries should describe the hardware. If the
regulator can be enabled and disabled, we should not claim it's
always on.
From the PMIC perspective every regulator can be enabled and
disabled. From a Board perspective there are some which need
to be always on. For Ex: SMPS123 which feeds on to the MPU.
Right, and we already have regulator-boot-on for those. Or are
you seeing some issue with that?
regulator-boot-on describes that at boot a particular regulator is on.
It does not guarantee that it will be on for the rest of the time. The
regulator framework can go ahead and disable it if no one has requested
for it. In case of RTC we do not want that to happen.
That's a bug in the RTC driver then. The driver should request a
regulator if it's specified.
In my experiments I observed that when RTC regulator is switched
off and switched on, there is an abort while accessing RTC registers.
Right, then you know you have the right regulator :)
After discussing with hardware team, it is confirmed that this
LDO9 regulator powering RTC cannot be turned off when
SoC is active and expected to be always on.
Hmm but sounds like you already proved it can be idled? So
the regulator really should be managed by the driver?
Tony,
Lokesh and i tried disabling the ldo9 regulator and then re-enabling it
post boot via driver as well as through I2C tools. Once we disable and
re-enable
we see that we can not access the RTC related registers any further.
So we checked with the hardware team and they confirmed that it should
never be disabled.
Regards,
Keerthy
Regards,
Tony
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