Hi, Am 15.01.2015 um 15:38 schrieb Sebastian Reichel <sre@xxxxxxxxxx>: > Hi, > > On Thu, Jan 15, 2015 at 08:36:44AM +0100, Dr. H. Nikolaus Schaller wrote: >>> 1. Perform conversion in input core rather than individual drivers. I >>> think we should allocate a new bitmaps for some transformations and have >>> the code do X/Y flip/clip of the coordinates. >> >> Do you have a suggestion where this should be (I have no clue how >> the input system works or is structured - we just know how to extend a >> driver that uses it)? >> >>> 2. Standardize on bindings. We already have of-touchscreen.c doing >>> rudimentary parsing, we shoudl look into extending it rather than >>> creating myriad of driver-specific bindings. >> >> Ok, looks reasonable. > > Documentation is in > > Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt > >>> Also, do we need swap and flip or do we simply need rotation (like the >>> proposed Broadcom iproc driver has)? >> >> Well, since the DT should describe hardware, there are 3 sets of wires which >> can have a cross-over: X+ and X-, Y+ and Y-, X and Y. >> >> So IMHO hardware has no “rotation”, just crossover of wires. Rotation is an >> interpretation of the result of these connections in combination with some >> panel the touch is glued to and should therefore not be represented in the DT. >> >> As a result we have proposed a scheme without explicit rotation. We specify what >> coordinates X- and X+ should report at their ends (min, max) because the DT >> programmer has to specify them anyways. Flipping is a result of defining these >> coordinates in an ascending or descending way. Only swapping of the X and Y >> wires can’t be implicitly defined so it has its own property. So the scheme we >> have proposed tries to optimize the efforts needed to adapt new boards and write >> DTs and focus the DT on hardware description. >> >> As a bonus we also specify the min and max value to be reported for the touch >> pressure (Z axis) using the same basic principle. >> >> And it is a pure add-on on top of the existing driver so that it attempts not >> to break existing device trees. > > from what I can see there are no in-tree-users using any of the > new properties. Not yet. But our [patch 2/3] of this series defines the DT entry for the GTA04 devices: https://lkml.org/lkml/2014/9/30/663 > >> Maybe could you accept it as a first step for this specific driver (and let’s do >> the big standardization work later on)? > > That does not work, since you create an ABI. Hm. I don’t understand what you mean with creating an ABI? -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
