From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [PATCH] ARM: tegra: Remove 3.3V supply and modem regulators Date: Tue, 7 Jan 2014 17:44:01 +0530 Message-ID: <52CBEF89.6090901@nvidia.com> References: <1389021933-6675-1-git-send-email-treding@nvidia.com> <52CB192F.2020700@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <52CB192F.2020700-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren , Thierry Reding Cc: "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: linux-tegra@vger.kernel.org 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.