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From: Wolfram Sang <wsa@the-dreams.de>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/4] clk: shmobile: add CPG driver for rz-platforms
Date: Mon, 03 Mar 2014 16:27:31 +0000	[thread overview]
Message-ID: <20140303162731.GA3732@katana> (raw)
In-Reply-To: <1722697.3h0GnbWuD3@avalon>

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> 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?

> > 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.


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WARNING: multiple messages have this Message-ID (diff)
From: wsa@the-dreams.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/4] clk: shmobile: add CPG driver for rz-platforms
Date: Mon, 3 Mar 2014 17:27:31 +0100	[thread overview]
Message-ID: <20140303162731.GA3732@katana> (raw)
In-Reply-To: <1722697.3h0GnbWuD3@avalon>


> 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?

> > 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.

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  reply	other threads:[~2014-03-03 16:27 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 [this message]
2014-03-03 16:27           ` Wolfram Sang
2014-03-04 11:02           ` Laurent Pinchart
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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