On 01.07.2018 21:01, Linus Walleij wrote: > On Wed, Jun 27, 2018 at 7:21 PM Rob Herring <robh@xxxxxxxxxx> wrote: >> On Thu, Jun 21, 2018 at 08:49:41PM +0200, Linus Walleij wrote: >>> +This panel driver can driver a variety of panels. It requires >> s/can driver/can drive/ >> >> Though what a driver supports is irrelevant to the binding... > It it not a software driver the text is referring to. It is a > electrical interface to a panel. Like how a TTL circuit connected > to a LED is referred to as a "LED driver", it's simply what the > industry calls these things. > > So there are two things: the panel driver and the panel, the > same panel driver is used with several panels. What the > electronics engineer will do is put a panel driver like this > into his design and then connect some panel s/he finds > in the right quantity in the streets of Shenzhen. > >> If you remove timings, how does it drive a variety of panels? Just by >> compatible? > Yes. > > Like we did for > Documentation/devicetree/bindings/display/panel/ilitek,ili9322.txt > which is similar to this. > > In fact I think many panel drivers are just sloppily slipping in > under the radar as "panels" in our bindings. > >> That would mean "tpo,tpg110" alone is not valid nor useful >> as a fallback. > Actually it is. The hardware is wired up to the desired > resolution with hardware straps, which appear in > the registers the (software) driver can read out so > this is ideally self-describing hardware. > > But for the event that something needs tweaking in the > future, like we overspecify say SoCs, I include the > exact system on which it is deployd as a separate > compatible string. > >>> +a few GPIO lines for control of its reset line and custom serial >>> +protocol. >>> >>> Required properties: >>> -- compatible : "tpo,tpg110" >>> +- compatible : one of: >>> + "ste,nomadik-nhk15-display", "tpo,tpg110" >>> + "tpo,tpg110" >>> - grestb-gpios : panel reset GPIO >>> - scen-gpios : serial control enable GPIO >>> - scl-gpios : serial control clock line GPIO >>> - sda-gpios : serial control data line GPIO >> I2C? That should be done differently... > It is not I2C, the lines are just named confusingly > similar. None of the I2C (-like) protocols apply. > I was similarly confused when I first implemented it. > > (Maybe I should add a comment to explain this.) I have grepped Internet, out of curiosity, and it seems it is so-called 3-wire spi [1]. [1]: http://aitendo3.sakura.ne.jp/aitendo_data/product_img/lcd/tft/T43P00/TPG110%20Customer%20Spec_0.6.pdf Regards Andrzej > > Yours, > Linus Walleij > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- 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
