Messages in this thread | | | Date | Tue, 16 Jul 2013 23:26:49 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [RFC PATCH v5 0/1] drivers: mfd: Versatile Express SPC support |
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On Tue, 16 Jul 2013, Lorenzo Pieralisi wrote:
> Hello, > > version v5 of VExpress SPC driver, please read on the changelog for major > changes and explanations. > > The probing scheme is unchanged, since after trying the early platform > devices approach it appeared that the end result was no better than the > current one. The only clean solution relies either on changing how > secondaries are brought up in the kernel (later than now) or enable > early platform device registration through DT. Please check this > thread for the related discussion: > > https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-June/036542.html > > The interface was adapted to regmap and again reverted to old driver for > the following reasons: > > - Power down registers locking is hairy and requires arch spinlocks in > the MCPM back end to work properly, normal spinlocks cannot be used > - Regmap adds unnecessary code to manage SPC since it is just a bunch of > registers used to control power management flags, the overhead is just > not worth it (talking about power down registers, not the vexpress config > interface) > - The locking scheme behind regmap requires all registers in the map > to be protected with the same lock, which is not exactly what we want > here > - Given the reasons above, adding a regmap interface buys us nothing from > a driver readability and maintainability perspective (again just talking > about the power interface, a few registers) because for the SPC it would > simply not be used > > /drivers/mfd is probably not the right place for this code as it stands (but > probably will be when the entire driver, with DVFS and config interface, is > complete). > > Thank you for the review in advance, > Lorenzo
I've integrated this patch in my MCPM backend for TC2 patch series.
ACKs from concerned/interested people would be appreciated so I could send this for ARM-SOC inclusion right away.
Nicolas
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