From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from db9outboundpool.messaging.microsoft.com (mail-db9lp0253.outbound.messaging.microsoft.com [213.199.154.253]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id CE9802C00C5 for ; Fri, 18 Oct 2013 03:24:58 +1100 (EST) Message-ID: <1382027085.7979.774.camel@snotra.buserror.net> Subject: Re: [PATCH v5] powerpc/mpc85xx: Update the clock nodes in device tree From: Scott Wood To: Tang Yuantian-B29983 Date: Thu, 17 Oct 2013 11:24:45 -0500 In-Reply-To: References: <1381300704-4238-1-git-send-email-Yuantian.Tang@freescale.com> <20131010100331.GE26954@e106331-lin.cambridge.arm.com> <20131011092526.GE3910@e106331-lin.cambridge.arm.com> <1381518433.7979.536.camel@snotra.buserror.net> <1381788786.7979.643.camel@snotra.buserror.net> <1381858855.7979.693.camel@snotra.buserror.net> <1381942009.7979.727.camel@snotra.buserror.net> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: Mark Rutland , Wood Scott-B07421 , "linuxppc-dev@lists.ozlabs.org" , Li Yang-Leo-R58472 , "devicetree@vger.kernel.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2013-10-16 at 21:08 -0500, Tang Yuantian-B29983 wrote: > > > > That shows the dividers as being somewhere in between the PLL and the > > MUX. > > > > The MUX is where the divider is selected. There's nothing in the > > > > PLL's programming interface that relates to the dividers. As such > > > > it's simpler to model it as being part of the MUX. > > > > > > > > -Scott > > > > > > > I don't know whether it is simpler, but "modeling divider as being part > > of the MUX" > > > is your guess, right? > > > If the "divider" is included in MUX, the MUX would not be called "MUX". > > > > It's still selecting from multiple PLLs. > > > > > I don't know whether "divider" module exists or not. If it exists, it > > > should be part of PLL or between PLL and MUX. wherever it was, the > > device tree binding is appropriate. > > > > The device tree binding is unnecessarily complicated. > > > > > The P3041RM shows exactly each PLL has 2 outputs which definitely have > > no "divider" at all. > > > > That diagram is a bit weird -- one of the outputs is used as is, and the > > other is split into 1/2 and 1/4. It doesn't really matter though; the > > end result is the same. We're describing the programming interface, not > > artwork choices in the manual. > > > > -Scott > > > If the device tree needs to be modified, could you give me your suggestions? My suggestion is to have only one output per PLL node. The MUX node would have one input per PLL. Dividers would be handled internally to the MUX driver. -Scott