From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> To: linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 3/4] clk: shmobile: add CPG driver for rz-platforms Date: Tue, 04 Mar 2014 11:02:31 +0000 [thread overview] Message-ID: <2207635.bd10VfTU6U@avalon> (raw) In-Reply-To: <20140303162731.GA3732@katana> [-- Attachment #1: Type: text/plain, Size: 1476 bytes --] Hi Wolfram, On Monday 03 March 2014 17:27:31 Wolfram Sang wrote: > > While the parent is indeed selected at boot time only, and only one parent > > is thus needed, parent selection could be performed by a DIP switch > > connected to MD_CLK on the board for instance. In that case both parents > > should be available in DT, as selection will be done by the kernel at > > boot time, not at DT compile time. > > OK, I understand the case. I still wonder about specifying two parents, > though. If a board uses USB_X1, it then has to spefify a dummy EXTAL > clock (or an empty one), just because USB_X1 is enumerated as second > entry? That's a good question. Mike, would it be possible to support "holes" in the DT clocks lists, like the GPIO DT bindings do ? > > > Again, now that I already coded it, what is the gain to remove it? The > > > drawback is that other people might get encouraged to find reasons to > > > allow them sloppy practices. > > > > It will make the kernel binary smaller by removing code that is not needed > > in practice. > > Sounds like a micro-optimazation to me. If you insist, we should BUG() > right away in that case, to make the code comprehensible. Returning with > a leak and saying "we will probably fail somewhere" should really be > avoided IMO. It's a micro-optimization indeed, but a simple one, so I believe it makes sense. I'll leave it up to you in the end. -- Regards, Laurent Pinchart [-- Attachment #2: This is a digitally signed message part. --] [-- Type: application/pgp-signature, Size: 490 bytes --]
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From: laurent.pinchart@ideasonboard.com (Laurent Pinchart) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/4] clk: shmobile: add CPG driver for rz-platforms Date: Tue, 04 Mar 2014 12:02:31 +0100 [thread overview] Message-ID: <2207635.bd10VfTU6U@avalon> (raw) In-Reply-To: <20140303162731.GA3732@katana> Hi Wolfram, On Monday 03 March 2014 17:27:31 Wolfram Sang wrote: > > While the parent is indeed selected at boot time only, and only one parent > > is thus needed, parent selection could be performed by a DIP switch > > connected to MD_CLK on the board for instance. In that case both parents > > should be available in DT, as selection will be done by the kernel at > > boot time, not at DT compile time. > > OK, I understand the case. I still wonder about specifying two parents, > though. If a board uses USB_X1, it then has to spefify a dummy EXTAL > clock (or an empty one), just because USB_X1 is enumerated as second > entry? That's a good question. Mike, would it be possible to support "holes" in the DT clocks lists, like the GPIO DT bindings do ? > > > Again, now that I already coded it, what is the gain to remove it? The > > > drawback is that other people might get encouraged to find reasons to > > > allow them sloppy practices. > > > > It will make the kernel binary smaller by removing code that is not needed > > in practice. > > Sounds like a micro-optimazation to me. If you insist, we should BUG() > right away in that case, to make the code comprehensible. Returning with > a leak and saying "we will probably fail somewhere" should really be > avoided IMO. It's a micro-optimization indeed, but a simple one, so I believe it makes sense. I'll leave it up to you in the end. -- Regards, Laurent Pinchart -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 490 bytes Desc: This is a digitally signed message part. URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140304/e2ea5833/attachment.sig>
next prev parent reply other threads:[~2014-03-04 11:02 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-02-28 21:09 [PATCH 0/4] CCF support for Renesas r7s72100 Wolfram Sang 2014-02-28 21:09 ` Wolfram Sang 2014-02-28 21:09 ` [PATCH 1/4] ARM: r7s72100: add clock nodes to dtsi Wolfram Sang 2014-02-28 21:09 ` Wolfram Sang 2014-02-28 21:09 ` [PATCH 2/4] ARM: r7s72100: genmai: populate extal clock node Wolfram Sang 2014-02-28 21:09 ` Wolfram Sang 2014-02-28 21:09 ` [PATCH 3/4] clk: shmobile: add CPG driver for rz-platforms Wolfram Sang 2014-02-28 21:09 ` Wolfram Sang 2014-03-02 22:15 ` Laurent Pinchart 2014-03-02 22:15 ` Laurent Pinchart 2014-03-03 9:19 ` Wolfram Sang 2014-03-03 9:19 ` Wolfram Sang 2014-03-03 10:59 ` Laurent Pinchart 2014-03-03 10:59 ` Laurent Pinchart 2014-03-03 16:27 ` Wolfram Sang 2014-03-03 16:27 ` Wolfram Sang 2014-03-04 11:02 ` Laurent Pinchart [this message] 2014-03-04 11:02 ` Laurent Pinchart 2014-03-04 11:07 ` Wolfram Sang 2014-03-04 11:07 ` Wolfram Sang 2014-03-04 11:13 ` Laurent Pinchart 2014-03-04 11:13 ` Laurent Pinchart 2014-03-04 11:56 ` Wolfram Sang 2014-03-04 11:56 ` Wolfram Sang 2014-03-05 13:54 ` Wolfram Sang 2014-03-05 13:54 ` Wolfram Sang 2014-03-05 13:59 ` Laurent Pinchart 2014-03-05 13:59 ` Laurent Pinchart 2014-03-05 15:07 ` Wolfram Sang 2014-03-05 15:07 ` Wolfram Sang 2014-02-28 21:09 ` [PATCH 4/4] ARM: shmobile: r7s72100: use workaround for non DT-clocks Wolfram Sang 2014-02-28 21:09 ` Wolfram Sang 2014-03-02 22:21 ` Laurent Pinchart 2014-03-02 22:21 ` Laurent Pinchart 2014-03-03 9:22 ` Wolfram Sang 2014-03-03 9:22 ` Wolfram Sang 2014-03-03 10:58 ` Laurent Pinchart 2014-03-03 11:00 ` Laurent Pinchart
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