Messages in this thread | | | From | Javier Martinez Canillas <> | Subject | Re: [PATCH v2 2/5] dt-bindings: display: ssd1307fb: Remove default width and height values | Date | Sat, 10 Jun 2023 19:51:35 +0200 |
| |
Conor Dooley <conor@kernel.org> writes:
> On Fri, Jun 09, 2023 at 07:09:37PM +0200, Javier Martinez Canillas wrote: >> A default resolution in the ssd130x driver isn't set to an arbitrary 96x16 >> anymore. Instead is set to a width and height that's controller dependent. > > Did that change to the driver not break backwards compatibility with > existing devicetrees that relied on the default values to get 96x16? >
It would but I don't think it is an issue in pratice. Most users of these panels use one of the multiple libraries on top of the spidev interface.
For the small userbase that don't, I believe that they will use the rpif kernel and ssd1306-overlay.dtbo DTB overlay, which defaults to width=128 and height=64 [1]. So those users will have to explicitly set a width and height for a 96x16 panel anyways.
The intersection of users that have a 96x16 panel, assumed that default and consider the DTB a stable ABI, and only update their kernel but not the DTB should be very small IMO.
[1]: https://github.com/raspberrypi/linux/blob/rpi-6.1.y/arch/arm/boot/dts/overlays/ssd1306-overlay.dts
> Cheers, > Conor. >
-- Best regards,
Javier Martinez Canillas Core Platforms Red Hat
| |