Guru Das Srinagesh <quic_gurus@xxxxxxxxxxx> writes: > 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. No problem, I'll do that in my v2. Regards, Aidan
