From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] MFD: TWL4030: changes for TRITON glitch fix Date: Wed, 21 Apr 2010 14:22:03 -0700 Message-ID: <20100421212202.GL18272@atomide.com> References: <1270809191-17007-1-git-send-email-leslyam@ti.com> <877ho1d8se.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-01-ewr.mailhop.org ([204.13.248.71]:58536 "EHLO mho-01-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754450Ab0DUVWG (ORCPT ); Wed, 21 Apr 2010 17:22:06 -0400 Content-Disposition: inline In-Reply-To: <877ho1d8se.fsf@deeprootsystems.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Kevin Hilman Cc: Lesly A M , linux-omap@vger.kernel.org, Nishanth Menon , David Derrick , Samuel Ortiz * Kevin Hilman [100420 16:01]: > Lesly A M writes: > > > Fix for TWL5030 Silicon Errata 27 & 28: > > 27 - VDD1, VDD2, may have glitches when their output value is updated. > > 28 - VDD1 and / or VDD2 DCDC clock may stop working when internal clock > > is switched from internal to external. > > > > Workaround requires the TWL DCDCs to use HFCLKIN instead of internal oscillator. > > > > There is a chance for VDD1/VDD2 to collapse to 0 Volt, > > if we switch the TWL DCDCs to internal oscillator form HFCLKIN > > while VDD1/VDD2 is active. So during first time when we switch TWLDCDC to > > HFCLKIN, TWL watchdog timer is used to recover if the VDD1/VDD2 stop working. > > > > Using HFCLKIN for TWL DCDCs uncovers another issue when going in and > > out of OFF mode, if HFCLK is disabled in OFFMODE. So the sleep/wakeup > > sequence and setuptimes are modified to make sure the switching will > > happen only when HFCLKIN is stable. > > > > This fix is required for TWL5030 Silicon version less than or equal to ES1.1 > > Since the IDCODE register on TWL5030 Si is not updated correctly, > > version check may not be correct. So if someone want to disable the > > glitch fix changes during menuconfig, the changes are done under the macro > > CONFIG_TWL5030_GLITCH_FIX. > > > > Changes taken from Nishanth Menons gaia glitch fix patch. > > > > Signed-off-by: Lesly A M > > Cc: Nishanth Menon > > Cc: David Derrick > > Cc: Samuel Ortiz > > --- > > Thanks for the much improved changelog. > > Also, this is better called an errata workaround instead of a glitch > fix. I'd rather see "glitch" here replaced by the errata numbers. > Down the road we'll be asking "which glitch?" > > As in the first review, I don't like the Kconfig option. This errata > workaround should be in common code and enabled by an optional > flag in board code. More on this below... Me neither. This needs to be set dynamically based on the twl version. Tony