Subject: [PATCH] ARM: tegra: Remove 3.3V supply and modem regulators

From: [email-masked] (Stephen Warren)
Date: Tue, 07 Jan 2014 09:43:43 -0700

On 01/07/2014 05:14 AM, Laxman Dewangan wrote:
> On Tuesday 07 January 2014 02:29 AM, Stephen Warren wrote:
>> On 01/06/2014 08:25 AM, Thierry Reding wrote:
>>> GPIO 1 and 2 of the PMIC are not used for the described purpose, so
>>> remove them.
>> As far as I can tell, this patch is correct, since those GPIOs are in
>> fact used to discharge the rails after disabling them, rather than to
>> enable/disable the rails.
>>
>> Equally, these GPIOs affect multiple rails at once, so listing the GPIO
>> as a property of a single regulator seems wrong either way.
>>
>> However, PMU_REGEN1 does seem to feed the "EN" pin of U13C1, a DC/DC
>> switcher for power rail 3.3v_modem, so perhaps there's more going on
>> here than I see?
>>
>> In summary, I need Laxman to comment on this and ack the change, and
>> explain why these GPIOs were listed as regulator enables when it doesn't
>> seem that they are.
>>
> PMU_REGEN1 is going to U13C1 (DCDC switcher). So if EN is 0, the output
> will be 0 and when it is 1, the output will be 3.3V.
> Because this is coming from GPIO, it is added as the fixed regulator.

What about PMU_REGEN3, for which that isn't the case, and what about the
fact that PMU_REGEN1 does a lot more than just enable that DC/DC switcher?