On 12/15/2013 06:35 AM, Mike Turquette wrote:
Quoting Tero Kristo (2013-11-26 00:05:41)
Hi,
Hi Tero,
Thanks for your long suffering patience on this series. The clock
patches look very good to me with exception of a few small comments. Let
me know how I can help with the hierarchal DT stuff since I think that
has been the gating factor for this series for the past few revisions.
Changes compared to v9:
- rebased on top of 3.13-rc1
- modified the low level clk register API to provide SoC specific clk_readl
and clk_writel support which can be registered during boot, TI SoC variant
uses regmap on low level
Regarding regmap, will that be dropped for V11? I don't care whether it
stays or goes but the approach you took is probably too top-level. Patch
#1 sets clk_reg_ops system-wide which probably isn't right. Different
clock drivers might compete to set those ops and the last one to write
wins.
I will be dropping regmap for v11. However...
A better approach is to support regmap ops on a per-clock basis (for
clocks that use the generic implementations like clk-divider and
clk-gate; obviously this is overkill for entirely hardware-specific
clocks). Stephen Boyd's approach is a better solution[1][2] but
unfortunately that approach dumps crap into struct clk_hw which is bad.
Anyways if you decide against regmap for V11 then the whole issue is
avoided.
Not avoided, some sort of solution is still needed to wrap the register
reads/writes. Alternatives are basically top level clk_ops or some stuff
like the patches you referred to, however it needs to be expanded to
support also the basic clock types.
-Tero
Regards,
Mike
[1] http://article.gmane.org/gmane.linux.ports.arm.kernel/273742
[2] http://article.gmane.org/gmane.linux.ports.arm.kernel/273744
- dropped regmap parameter from clock init calls, instead a helper is used
for getting regmap index along with the register offset from DT
- dropped regmap parameter from clock structs, instead platform specific
clk_readl / clk_writel are used to parse reg parameter according to
platform, for TI SoC:s, this is encoded as:
struct clk_omap_reg {
u16 offset; /* register offset */
u16 index; /* regmap index */
}
- Nishanth's comments to v9 mostly addressed, except for the CLK_OF_DECLARE
tweak which I would actually want some feedback upon, basically the problem
is I need to return status from the clk init functions so I can see if
-EAGAIN is passed, in which case init will be retried later, maybe some of
this can be made generic, like converting all the CLK_OF_DECLARE type
functions to return status
Testing done:
- omap3-beagle : boot + suspend/resume
- omap3-beagle-xm : boot (thanks to Nishanth)
- omap4-panda-es : boot + suspend/resume
- omap5-uevm : boot
- dra7-evm : boot
- am335x-bone : boot
Separate branches available at https://github.com/t-kristo/linux-pm.git
- full: 3.13-rc1-dt-clks-v10 (should be merged last, contains everything)
- clk driver only: 3.13-rc1-dt-clks-v10-for-mike
- DT data only: 3.13-rc1-dt-clks-v10-for-benoit
-Tero
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