Re: [PATCH 1/2] mux: Turn 'mux' into a flexible array in 'struct mux_chip'

[Dan Carpenter]

On Sun, Nov 26, 2023 at 09:08:11AM +0100, Christophe JAILLET wrote:
> The 'mux' array stored in 'struct mux_chip' can be changed into a flexible
> array.
> 
> This saves:
>    - a pointer in the structure
>    - an indirection when accessing the array
>    - some pointer arithmetic when computing and storing the address in
>      'mux'
> 
> It is also now possible to use __counted_by() and struct_size() for
> additional safety.
> 
> The address for the 'priv' memory is computed with mux_chip_priv(). It
> should work as good with a flexible array.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> The struct_size() goodies only work if sizeof_priv is 0. Adding an
> additional size_add() would make it safe in all cases but would make code
> less readable (IMHO).

Once people start using size_add() then we'll get used to reading it.

The controllers value comes from device tree.  For example, in
mux_mmio_probe().

	ret = of_property_count_u32_elems(np, "mux-reg-masks");

I should make Smatch parse device trees.  So that it will know the
correct range for ret in that assignment.  Eventually, I will.

KTODO: make Smatch understand device tree values

regards,
dan carpenter