Hi Lorenzo, On Tue, Jul 16, 2013 at 05:05:42PM +0100, 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). Could you please elaborate on how will the SPC driver extend into an MFD driver?
Cheers, Samuel. -- Intel Open Source Technology Centre http://oss.intel.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/