On 4/8/22 21:19, Javier Martinez Canillas wrote: [snip] >> >> There's also no reason to put the bus interface into the compatible as >> the same compatible will work on different buses. But since you want to >> add SPI, just using the 'i2c' one will confuse people. For that reason >> you could add 'solomon,ssd1305', etc. for both SPI support and I2C DRM. > > That's not really true. There's a reason to add per bus compatible strings > at least in Linux. And is that there's no information about the bus types > in module aliases that are reported to user-space for module auto-loading. > Forgot to mention that in this particular case it will work but just because the SPI subsystem always report a module alias of the form "spi:device" even for devices that are registered through OF. So having a single "solomon,ssd1306" would work because for I2C the module alias will be "of:NoledT(null)Csolomon,ssd1306" and for SPI it will be "spi:ssd1306". But if ever the SPI subsystem is fixed to report proper OF module aliases things will break. And since the DT bindings is an ABI, it's safer to have "-i2c" and "-spi" compatible strings variants. -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat
