Re: [PATCH linux v1 4/4] arm: dts: Add dt-binding to support seven segment display on zaius

From: Linus Walleij
Date: Thu Dec 15 2016 - 18:07:44 EST

On Wed, Dec 14, 2016 at 12:40 PM, Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxx> wrote:

> Looking at this more, it's a SPI driver, presumably because the first
> case where it appeared was on a SPI bus.
> However, it's not a SPI device as such, it's a piece of standard,
> general purpose logic that's been around for many years, pre-dating
> the SPI bus.


> I think a much more sensible approach would be to turn the GPIO side
> of the 74x164 driver into a library, which can be re-used by multiple
> bus-specific drivers - one for SPI which allows it to be used in its
> current form, one for our platform bus which takes the GPIO lines for
> the data, clock and clear signals.
> I also don't see why they shouldn't use the same compatible - they're
> the same _device_ at the end of the day, just wired up differently.
> It makes the binding documentation a little fun wrt what are required
> and optional properties, but nothing that shouldn't be too difficult.

I agree on both accounts.

Sorry for not seeing this in the first place, I was well aware that this
is a standard component and may be connected in a myriad of ways,
so I should have known better :(

Linus Walleij