From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM: tegra: Remove 3.3V supply and modem regulators
Date: Tue, 07 Jan 2014 09:43:43 -0700 [thread overview]
Message-ID: <52CC2EBF.60106@wwwdotorg.org> (raw)
In-Reply-To: <52CBEF89.6090901@nvidia.com>
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?
next prev parent reply other threads:[~2014-01-07 16:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-06 15:25 [PATCH] ARM: tegra: Remove 3.3V supply and modem regulators Thierry Reding
2014-01-06 20:59 ` Stephen Warren
2014-01-07 12:14 ` Laxman Dewangan
2014-01-07 16:43 ` Stephen Warren [this message]
2014-01-08 13:04 ` Laxman Dewangan
2014-01-08 13:41 ` Thierry Reding
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