On Tue, Jul 09, 2019 at 04:58:35PM +0800, Icenowy Zheng wrote: > > > 于 2019年7月9日 GMT+08:00 下午4:55:32, Maxime Ripard <maxime.ripard@xxxxxxxxxxx> 写到: > >On Mon, Jul 08, 2019 at 05:49:21PM -0700, Vasily Khoruzhick wrote: > >> > > Maybe instead of edp-connector one would introduce integrator's > >specific > >> > > connector, for example with compatible > >"olimex,teres-edp-connector" > >> > > which should follow edp abstract connector rules? This will be at > >least > >> > > consistent with below presentation[1] - eDP requirements depends > >on > >> > > integrator. Then if olimex has standard way of dealing with > >panels > >> > > present in olimex/teres platforms the driver would then create > >> > > drm_panel/drm_connector/drm_bridge(?) according to these rules, I > >guess. > >> > > Anyway it still looks fishy for me :), maybe because I am not > >> > > familiarized with details of these platforms. > >> > > >> > That makes sense yes > >> > >> Actually, it makes no sense at all. Current implementation for > >anx6345 > >> driver works fine as is with any panel specified assuming panel > >delays > >> are long enough for connected panel. It just doesn't use panel > >timings > >> from the driver. Creating a platform driver for connector itself > >looks > >> redundant since it can't be reused, it doesn't describe actual > >> hardware and it's just defeats purpose of DT by introducing > >> board-specific code. > > > >I'm not sure where you got the idea that the purpose of DT is to not > >have any board-specific code. > > > >It's perfectly fine to have some, that's even why there's a compatible > >assigned to each and every board. > > > >What the DT is about is allowing us to have a generic behaviour that > >we can detect: we can have a given behaviour for a given board, and a > >separate one for another one, and this will be evaluated at runtime. > > > >This is *exactly* what this is about: we can have a compatible that > >sets a given, more specific, behaviour (olimex,teres-edp-connector) > >while saying that this is compatible with the generic behaviour > >(edp-connector). That way, any OS will know what quirk to apply if > >needed, and if not that it can use the generic behaviour. > > > >And we could create a generic driver, for the generic behaviour if > >needed. > > > >> There's another issue: if we introduce edp-connector we'll have to > >> specify power up delays somewhere (in dts? or in platform driver?), > >so > >> edp-connector doesn't really solve the issue of multiple panels with > >> same motherboard. > > > >And that's what that compatible is about :) > > Maybe we can introduce a connector w/o any driver just like hdmi-connector? Ironically, a driver for it has been sent yesterday :) But yeah, we can definitely do that too. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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