On 02.05.2014 21:35, Doug Anderson wrote:
Arnd,
On Fri, May 2, 2014 at 11:52 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
On Friday 02 May 2014 18:33:39 Arun Kumar K wrote:
From: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
Exynos5800 clock structure is mostly similar to 5420 with only
a small delta changes. So the 5420 clock file is re-used for
5800 also. The common clocks for both are seggreagated and few
clocks which are different for both are separately initialized.
Signed-off-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>
Signed-off-by: Arun Kumar K <arun.kk@xxxxxxxxxxx>
This isn't about your specific patch, but every time I see a new
exynos variant get supported, it comes with a clock driver patch
that is at least as big as all the other patches combined.
New variants come out all the time now, and we are starting to
accumulate huge amounts of clock definitions both in the source
and the binary. I think we should try to come up with a better
way to represent the clocks. I don't think any other SoC
family is nearly as bad as Exynos, either because they have
much fewer models, or because they abstract their clocks more
and put all the tables into DT.
I'm definitely not saying no to the exynos5800 addition for this,
but I'm starting to get a little annoyed, and I think it would be
good to come up with a new clock binding before we see 64-bit
Exynos variants.
One thing to note: your suggestion will almost certainly not be
conducive to get stable device trees. IMHO there's pretty much a zero
chance that you could properly describe all of the exynos clocks in
the first, second, third, or twentieth attempt. That means that if
anyone ever took it in their head to actually ship a device tree that
wasn't bundled with the kernel that it would probably be wrong.
Declaring just "I have exynos5800 clocks" means that you're not
relying on the device tree.
The clocks are pretty table-based as-is, and I think that's about the
best you're going to get.
+1 and similarly to pinctrl stuff. Both full-DT and table-based
approaches were being discussed long time ago when moving Exynos to DT
and generic frameworks and the conclusion was clearly in favor of the
latter.
Moreover, I don't think we should really be concerned about this,
because we already have far less changes (not counting device tree
sources) needed to support a SoC than we had before, in board file
times. Not even saying that new SoCs are not being added that often.
NOTE: one could argue that possibly the 5420 and 5800 are different
enough that they ought to have separate tables. I don't feel like I'm
in enough of an ownership position to make that tradeoff either way,
though.
I don't have the datasheets, but looking at the changes needed, they
don't seem to be more different than Exynos4210 and Exynos4x12. The
approach taken looks fine for me.
Best regards,
Tomasz
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