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 This patch is v5 of a previous posting: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-June/177150.html v5 changes: - Completely removed vexpress-config interface waiting for refactoring based on regmap - Removed frequency scaling interface and operating points programming retrieval - Trimmed the driver code and DT bindings v4 changes: - Applied review comments (trimmed function names, added comments, refactored some APIs) - Added comments throughout the set - Fixed irq handler bug in checking the transaction status - Improved commit log to explain early init synchro scheme - Created a single static structure for variables dynamically allocated to remove usage of static - Improved Kconfig entry v3 changes: - added __refdata to spc_check_loaded pointer - removed some exported symbols - added node pointer check in vexpress_spc_init() v2 changes: - Dropped timeout interface patch - Converted interfaces to non-timeout ones, integrated and retested - Removed mutex used at init - Refactored code to work around init sections warning - Fixed two minor bugs Lorenzo Pieralisi (1): drivers: mfd: vexpress: add Serial Power Controller (SPC) support Documentation/devicetree/bindings/mfd/vexpress-spc.txt | 36 ++ drivers/mfd/Kconfig | 10 + drivers/mfd/Makefile | 1 + drivers/mfd/vexpress-spc.c | 253 ++++++++++ include/linux/vexpress.h | 17 + 5 files changed, 317 insertions(+) create mode 100644 Documentation/devicetree/bindings/mfd/vexpress-spc.txt create mode 100644 drivers/mfd/vexpress-spc.c -- 22.214.171.124 -- 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/