On Mon, Aug 13, 2018 at 08:18:08PM +0200, Sam Ravnborg wrote: > Hi Nicholas. > > On Mon, Aug 13, 2018 at 05:54:48PM +0200, Nicolas Ferre wrote: > > On 12/08/2018 at 20:41, Sam Ravnborg wrote: > > >New DRM based driver for at91sam9 SOC's that uses the > > >Atmel LCDC IP core. > > > > I'm delighted to see this work: Thanks a lot Sam! > Glad to hear. > I was a bit worried that the response would be "this is > waste of time as we have a working driver already". > > > > > >This is first version of a patch set that adds > > >drivers for the Atmel LCDC IP core. > > >Posted for review as the basics works now. > > > > > >The LCDC IP core contains two devices: > > >- a PWM often used for backlight > > >- a LCD display controller > > > > > >Both devices are supported today by the atmel_lcdfb driver. > > >For this new set of drivers the compatible strings was > > >selected to avoid clash with the existing compatible > > >strings used for the atmel_lcdfb driver to allow them > > >to co-exist. > > > > Would be good to have a plan to phase-out the old atmel_lcdfb fbdev > > driver when this one addresses some TODO items that make sense. > Agree on this. > One approach could be to say that when all in-kernel users of atmel_lcdfb > are ported, then the old driver could be dropped after a kernel release. > > > The mfd suffix seems strange to me. What about "atmel,at91sam9263-lcdc-mfd" > > => "atmel,at91sam9263-lcd" (or "microchip,at91sam9263-lcdc"). > The "-mfd" suffix was added to avoid clashing with the current > compatible string used by the atmel_lcdfb driver. I don't know that 2 registers for a backlight PWM constitute an MFD. A single node can be both an LCD controller and a PWM. The fact that the OS has 2 drivers is irrelevant to the binding and DT is not a way to select drivers. Your choice with Linux is either kconfig or manual module loading. > I susggest we do the following: > - use the microchip prefix, as this is now owned by microchip > - and add the driver to a drm/microchip/ directory > (Then we can only hope that microchip do not change name or > are purchased by someone else). I would not do that. Then you have a dts with a mixture based on when you got around to writing each binding. i.MX has continued using 'fsl' even on new chips today. Probably a good choice had the QCom acq had gone thru. Rob
