On Thu, Jan 31, 2013 at 5:27 AM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: > So this looks like a reasonable binding to me. The one issue is that > it's very generic, and if we go this route, we'll probably end up with > tens or hundreds of identical or extremely similar simple bindings, and > associated drivers. > > We can avoid this instead by defining something like a "simple-lcd" > binding, and associated driver, that will work for perhaps 90%, 95%, > 99%, even 100%(?) of panels. That seems totally doable indeed. Actually the right way to do this might be by extending the simple DPI panel driver Laurent included in his patchset. > Just like the above, but with: > > compatible="simple-panel", "chunghwa,claa101wa01a" > > instead, and the driver binding to "simple-panel" rather than > "chunghwa,claa101wa01a". Just out of curiosity, why don't we rather define compatible="chunghwa,claa101wa01a", "simple-panel" in that order? I thought DT compatible strings should go from more to less specific. The device would still bind to "simple-panel" if no more specific driver exists. > The driver can assume that a specific set of supplies (and perhaps > GPIOs) is always present, and that the /sequence/ of manipulating those > is fixed. This will avoid the need for anything like the power sequences > code. If a particular panel doesn't fit those assumptions, including the > exact sequence of manipulations for each state transition (which should > be documented in the binding) then it can get a custom driver, this also > avoiding having to define custom sequences in DT. > > Things that might be parameterized/optional: > > * Perhaps some GPIOs aren't always present. > * If some regulators aren't SW-controllable, DT should still provide a > fixed/dummy regulator so the driver doesn't care. How about making all regulators and GPIO optional in the driver? > * Wait times between regulator/GPIO/... manipulation could be specified > in DT. > * For panels without EDID, CDF DT bindings can provide the list of > supported modes, otherwise we assume that the display controller that > drives the panel has been told how to access the EDID, just like it > would for an "external" display. Excellent. Thanks for the feedback. Alex. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
