MFD currently has one over-complicated user. CS5535 uses a mixture of cell cloning, reference counting and subsystem-level call-backs to achieve its goal of requesting an IO memory region only once across 3 consumers. The same can be achieved by handling the region centrally during the parent device's .probe() sequence. Releasing can be handed in a similar way during .remove().
While we're here, take the opportunity to provide some clean-ups and error checking to issues noticed along the way. This also paves the way for clean cell disabling via Device Tree being discussed at [0] [0] https://lkml.org/lkml/2019/10/18/612. Lee Jones (9): mfd: cs5535-mfd: Use PLATFORM_DEVID_* defines and tidy error message mfd: cs5535-mfd: Remove mfd_cell->id hack mfd: cs5535-mfd: Request shared IO regions centrally mfd: cs5535-mfd: Register clients using their own dedicated MFD cell entries mfd: mfd-core: Remove mfd_clone_cell() x86: olpc: Remove invocation of MFD's .enable()/.disable() call-backs mfd: mfd-core: Protect against NULL call-back function pointer mfd: mfd-core: Remove usage counting for .{en,dis}able() call-backs mfd: mfd-core: Move pdev->mfd_cell creation back into mfd_add_device() arch/x86/platform/olpc/olpc-xo1-pm.c | 6 -- drivers/mfd/cs5535-mfd.c | 124 +++++++++++++-------------- drivers/mfd/mfd-core.c | 113 ++++-------------------- include/linux/mfd/core.h | 20 ----- 4 files changed, 79 insertions(+), 184 deletions(-) -- 2.17.1
