From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Babic Date: Wed, 11 Feb 2015 09:42:07 +0100 Subject: [U-Boot] [PATCH 07/12] imx:mx6 Support LDO bypass In-Reply-To: References: <1420793987-7621-1-git-send-email-Peng.Fan@freescale.com> <1420793987-7621-8-git-send-email-Peng.Fan@freescale.com> <54D9EA4D.7010307@denx.de> Message-ID: <54DB15DF.6090506@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Tim, On 10/02/2015 15:50, Tim Harvey wrote: > On Tue, Feb 10, 2015 at 3:23 AM, Stefano Babic wrote: >> >> Ok - with this explanation, I would try to understand how the changes >> can be split. If the feature/change works for several boards, it makes >> sense to have it common and general. If it is only for one board, must >> flow into the board directory. > > It should be common as there are several boards which use PMIC's and can use it. > Fully agree. >> I am quite lost. I have searched in kernel (current TOT), and I have not >> found such property. Can you help me to understand ? > > Right - you won't find it because its a Freescale vendor kernel > implementation only. A hack if you ask me to avoid having to doing > ldo-byapss the right way. Exactly, this cannot flow into mainline. > > Here are the threads that I know of regarding ldo-bypass in the > kernel, where it needs to be: > > https://lkml.org/lkml/2014/12/18/255 > https://lkml.org/lkml/2014/10/31/3 Thanks for pointing out ! > > Peng, > > I think what you are trying to do here is to put the anatop regulators > in bypass mode so that the Freescale vendor kernel leaves them > bypassed (which is what the 3.10.x based vendor kernels supporting > device-tree at http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git > do). This is what the Freescale vendor U-Boot does and so they have > created a horrible dependence between kernel and bootloader. > You are perfectly right. > Instead you may be interested in what I did for our BSP's that use the > Freescale vendor kernel. Instead of touching U-Boot, I look for the > fsl,ldo-bypass node in the kernel and enable it just like their > bootloader would have: > https://github.com/Gateworks/linux-imx6/commit/a1af6ac6f00b4da7c8a5656e8ff093d4ab5cadee > Thanks - you are on the right direction ;-) Best regards, Stefano -- ===================================================================== DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de =====================================================================