On Fri, Apr 26, 2024 at 10:56 AM Andreas Kemnade <andreas@xxxxxxxxxxxx> wrote: > On Thu, 25 Apr 2024 22:54:13 -0400 > Felix Kaechele <felix@xxxxxxxxxxx> wrote: > > On 2024-04-25 12:54, Andreas Kemnade wrote: > > > On Fri, 5 Apr 2024 20:21:19 +0300 > > > Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: > > >> On Fri, Apr 5, 2024 at 7:28 PM Andreas Kemnade <andreas@xxxxxxxxxxxx> wrote: >>> On Fri, 5 Apr 2024 18:13:45 +0300 > > >>> Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote: ... > > >>>> Why a different vendor prefix? > > > > >>> I sorted by the numbers. Looking at datasheets for other controllers I see >>> https://www.displayfuture.com/Display/datasheet/controller/FT5x06.pdf > > >>> it only mentions FocalTech Systems Co., Ltd. > > >> > > >> But does the driver use that? AFAICS it uses edt. Perhaps it's due to > > >> a business split, not to my knowledge anyway. > > > > I've been looking into this over the past few weeks as I was working on > > mainline support for an Android device. > > And please forgive me if any of the following is not fully accurate, I'm > > not an industry expert. > > > > After some research, my understanding of this is as follows: > > > > - There are companies that make touch ICs, LCD driver ICs and sometimes > > even ICs that are both. Focaltech or Himax are examples of such companies. > > > > - There are companies that make LCMs. These are complete assemblies of > > panel, backlight, touch layer and driver circuitry PCBs. This is what > > OEMs generally purchase when they design a consumer device. Emerging > > Display Technologies Corp. (EDT) is such a LCM manufacturing company. > > More often than not LCM manufacturers do not make their own driver ICs. > > > > LCM manufacturers include ICs from Focaltech in their LCMs. > > To my knowledge Focaltech is not a manufacturer of LCMs. > > > > As such, an interpretation of the compatible string "edt,edt-ft5406" > > could be: Unspecified EDT LCM with Focaltech FT5406 IC. > > > > From my perspective, more correct would either be something like > > "edt,etm070001bdh6" (the LCM by EDT that contains this IC, especially if > > it had model specific quirks) or "focaltech,ft5406". > > But "edt,edt-ft5406" is incorrect if being specific is the goal here. > > Given that the driver predates much of the DT binding rigour it's what > > we have now though. > > > I think focaltech,ft5406 is better because it is consistent with other drivers/ > bindings. We do not specify the display it is used on on other touchscreen > bindings. We do not specify the actual LEDs behind a LED interface chip. > And often the chip name is more easily to find out than the name of a > display. I'm _not_ a DT person, you should clarify this with them. I just pointed out the possible mistake (from Linux / DT perspective), and not hardware / business related one. If they are fine with focaltech prefix, then it's fine to me as well! -- With Best Regards, Andy Shevchenko
