On Fri, Jun 03, 2022 at 02:57:05PM +0100, Aidan MacDonald wrote: > Add a new callback, get_irq_reg, for regmap IRQ chips, to support devices > with unusual register layouts. This is required in the rare cases where > the offset of an IRQ register is not constant with respect to the base > register. This is probably best illustrated with an example: > > mask status > IRQ0 0x40 0x44 > IRQ1 0x41 0x45 > IRQ2 0x42 0x46 > IRQ3 0x43 0x47 > IRQ4 0x4a 0x4d > > If we set mask_base = 0x40 and status_base = 0x44, the offsets of each > register relative to the base are: > > mask status > IRQ0 0 0 > IRQ1 1 1 > IRQ2 2 2 > IRQ3 3 3 > IRQ4 10 9 > > The existing mapping mechanisms can't include IRQ4 in the same irqchip > as IRQ0-3 because the offset of IRQ4's register depends on which type > of register we're asking for, ie. which base register is used. > > The get_irq_reg callback allows drivers to specify an arbitrary mapping > of (base register, register index) pairs to register addresses, instead > of the default linear mapping "base_register + register_index". This > allows unusual layouts, like the one above, to be handled using a single > regmap IRQ chip. > > The drawback is that when get_irq_reg is used, it's impossible to use > bulk reads for status registers even if some of them are contiguous, > because the mapping is opaque to regmap-irq. This should be acceptable > for the case of a few infrequently-polled status registers. This patch does two things: 1. Add a new callback `get_irq_reg` 2. Replace unmask_offset calculation with call to sub_irq_reg() Could you please split the patch into two to better reflect this? Thank you. Guru Das.
