Re: [PATCH v3 net-next 3/8] mfd: Add Microchip ZL3073x support

Ivan Vecera
2025-04-17T16:29:16Z

On 17. 04. 25 5:42 odp., Andy Shevchenko wrote:
>>> Would it be acceptable for you something like this:
> V4L2 (or media subsystem) solve the problem by providing a common helpers for
> reading and writing tons of different registers in cameras. See the commit
> 613cbb91e9ce ("media: Add MIPI CCI register access helper functions").
>
> Dunno if it helps here, though.

Bingo, this approach looks very good.

I can use unsigned int (32bit) to encode everything necessary:
Bits 0..15 - register address (virtual range offset, page, offset)
Bits 16..21 - size in bits (enough for max 48)
Bits 22..26 - max items (32 values - enough for any indexed register)
Bits 27..31 - stride between (up to 32 - enough per datasheet)

Only thing I don't like is that MIPI CCI API uses for calls u64 as value:

int cci_read(struct regmap *map, u32 reg, u64 *val, ...);

This forces a caller to use u64 for every register read. I rather to use
'void *val' the same way as regmap_read().

Ivan