Hi Scott, Please see my replay inline. > -----Original Message----- > From: linux-arm-kernel <linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx> > On Behalf Of Scott Wood > Sent: 2018年9月4日 4:34 > To: Andy Tang <andy.tang@xxxxxxx>; Vabhav Sharma > <vabhav.sharma@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; > devicetree@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; > mark.rutland@xxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; mturquette@xxxxxxxxxxxx; > sboyd@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; viresh.kumar@xxxxxxxxxx; > linux-clk@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; > linux-kernel-owner@xxxxxxxxxxxxxxx; catalin.marinas@xxxxxxx; > will.deacon@xxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; arnd@xxxxxxxx; > kstewart@xxxxxxxxxxxxxxxxxxx; yamada.masahiro@xxxxxxxxxxxxx > Cc: Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx>; > linux@xxxxxxxxxxxxxxx; Varun Sethi <V.Sethi@xxxxxxx>; Udit Kumar > <udit.kumar@xxxxxxx> > Subject: Re: [PATCH 3/5] drivers: clk-qoriq: Add clockgen support for > lx2160a > > On Mon, 2018-09-03 at 01:17 +0000, Andy Tang wrote: > > Hi Scott, > > > > Please see my replay in line. > > > > > -----Original Message----- > > > From: Linuxppc-dev > > > <linuxppc-dev-bounces+b29983=freescale.com@xxxxxxxxxxxxxxxx> On > > > Behalf Of Scott Wood > > > Sent: 2018年9月1日 4:29 > > > To: Andy Tang <andy.tang@xxxxxxx>; Vabhav Sharma > > > <vabhav.sharma@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; > > > devicetree@xxxxxxxxxxxxxxx; robh+dt@xxxxxxxxxx; > > > mark.rutland@xxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; mturquette@xxxxxxxxxxxx; > > > sboyd@xxxxxxxxxx; rjw@xxxxxxxxxxxxx; viresh.kumar@xxxxxxxxxx; > > > linux-clk@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; > > > linux-kernel-owner@xxxxxxxxxxxxxxx; catalin.marinas@xxxxxxx; > > > will.deacon@xxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; arnd@xxxxxxxx; > > > kstewart@xxxxxxxxxxxxxxxxxxx; yamada.masahiro@xxxxxxxxxxxxx > > > Cc: Yogesh Narayan Gaur <yogeshnarayan.gaur@xxxxxxx>; > > > linux@xxxxxxxxxxxxxxx; Udit Kumar <udit.kumar@xxxxxxx>; Varun > Sethi > > > <V.Sethi@xxxxxxx> > > > Subject: Re: [PATCH 3/5] drivers: clk-qoriq: Add clockgen support > > > for lx2160a > > > > > > On Fri, 2018-08-31 at 06:12 +0000, Andy Tang wrote: > > > > We don't want to increase NUM_CMUX each time new soc with > more > > > > > > cmuxes added. > > > > > > You don't want to have to make a trivial change each time you exceed > > > a limit that has yet to be exceeded once since NUM_CMUX was added? > > > This isn't ABI or in any other way hard to change. It's right in > > > the same file as the chip description you'd be adding. > > > > > > And even if a chip did come along with 16 cmuxes, you'd then need to > > > increase the array to 17 to hold the -1 if you don't want to leave a > > > situation like the > > > p4080 is in now, where a chip's cmux array could be broken by > > > increasing NUM_CMUX further. > > > > > > > [Andy] Adding buffer to a limitation number is always a good habit > > when coding. We often forget to increase this value when a new chip > > with more cmuxes added. > > "often"? There has never been a new chip added with more cmuxes > than p4080's 8, and if one does come along and you forget, the compiler > should complain about exceeding the array length with a static initializer. > This isn't like an array that is filled with a runtime-determined length. > > > Like this patch, we didn't increase this value at first. We spent a > > lot of time finding out that NUM_CMUX needs to be increased too. > > Are you talking about some other chip that you haven't sent a patch for > yet? > Or is the cmux array for this chip wrong? What specifically did you see > happen "at first"? > [Andy] Sorry, "Often" is not a right word. I meant we tend to add new soc without updating NUM_CMUX. > > It is a personal preference how to set this value. I think it is > > better to increase it to 16, not NUM_CMUX+1 as long as we fix the > > P4080 issue even though it is a trivial change. And I agree the > > description needs to be updated. > > I'm not the clock maintainer, so it's not up to me, but I don't see the point > in setting it to an arbitrary number, and I do not agree that increasing > NUM_CMUX is a suitable replacement for NUM_CMUX+1 in > cmux_to_group[], as that array should be one larger than cmux[] in order > to allow every chip to have a > -1 terminator. In any case, any change to NUM_CMUX should be a > separate patch because it's not required for lx2160a support (assuming > lx2160a was correctly described by this patch). [Andy] I don't see any impropriate about your suggestion. so we are going to do in your way. Thanks, Andy > > -Scott > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flist > s.infradead.org%2Fmailman%2Flistinfo%2Flinux-arm-kernel&data=02 > %7C01%7Candy.tang%40nxp.com%7Cdbc824fc39674711316208d611dcf > 61b%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63671603 > 8060797113&sdata=iCLKGMEzRX2dpH5%2Bf4NWIiPDc5L5NpTcpZ7X > usehdIw%3D&reserved=0
