Re: [PATCH v2 2/6] gpio: pca953x: Add PCAL953X as a separate chip type

[Levente Révész <levente.revesz@xxxxxxxxxx>]

On Thu, 28 Oct 2022 20:57 +0200, Levente Révész wrote:
> I went through all the datasheets and created this note listing
> chip functions and register layouts.

On Thu, 27 Oct 2022 20:03:21 +0300, Andy Shevchenko wrote
> PCA_PCAL is about having latched interrupts, it doesn't suggest
> the layout. So, somebody needs to take a pen and draw the current
> list of possible combinations of the features and layouts and then
> we can see what can be done as a type and what's not.

The note in my previous email lists the functions of each chip this
driver supports. The currently supported features are the following:

    - basic interrupt (no registers)
    - interrupt status and mask registers
    - bias (pull-up, pull-down)
    - input latch

Proposed chip types to allow implementing these functions for all chips
that have them:

    1. PCA953X without interrupt
        also covers some MAX731X chips
    2. PCA953X
        also covers some MAX731X chips
    3. PCA950X
        also covers PCA9698
    4. PCAL953X
        also covers PCAL652X
    5. PCAL653X
    6. PCA957X
    7. XRA120X

Other functions which could be used for pinconfig, but are not currently
implemented for any of the chips in the driver:

    - interrupt on specific edges
    - drive mode (push-pull or open-drain)
    - drive strength
    - debounce

Proposed chip types to allow implementing all of these functions for
all chips that support them:

    1. PCA953X without interrupt
        also covers some MAX731X chips
    2. PCA953X
        also covers some MAX731X chips
    3. PCA950X
    4. PCA9698
    5. PCAL953X
    6. PCAL652X
    7. PCAL653X
    8. PCA957X
    9. XRA120X

Should the chip type take all relevant chip functions into account, or
just the currently implemented functions?


---
Best Regards,
Levente