TCA9538/PCA9538 Duplicate drivers

[jbehrensnx]

Is your feature request related to a problem? Please describe.

Not sure if this is the correct label.

The TCA9538 and PCA9538 gpio expanders are pin to pin compatible and have the same functionality. Despite that there are currently 2 different drivers for them, gpio_pca_series and gpio_pca953x (the latter having the tca9538 as its only compatible).

This came up recently in PR #90677

Describe the solution you'd like

It might be a good idea to drop one of the drivers. As gpio_pca_series covers severall gpio expanders, dropping gpio_pca953x and adding the TCA9538 compatible to gpio_pca_series is probably the better idea.

As, to my knowledge, the same compatibility is true for the tca9539, tca9554 and tca9555 to their pca counterparts, they could also easily be added to gpio_pca_series.

Describe alternatives you've considered

Leaving it as is. Nothing is broken and neither are there any other issues at the moment besides the increased maintenance of supporting two drivers when one would suffice.

[CkovMk]

Hello, I'm the original author of gpio_pca_series driver. I was intended to unify the pca series driver, but does not have resources to test all the boards and deprecate the other drivers. Btw, with the code I haven't made upstream, gpio_pca_series also deprecates gpio_pcal64xxa driver.

There's also a problem I'd like to discuss: what if several instances of this gpio_pca_series requires different INIT_PRIORITY? This is common challenge due to the board design, where access to one gpio expander could depend on the other gpio expander. The only way I see is to use deferred device init.

[CkovMk]

link #78274