On Thu, Jun 25, 2015 at 12:44:02PM +0200, Maxime Ripard wrote: > On Tue, Jun 23, 2015 at 07:02:28PM +0200, Karsten Merker wrote: > > The MSI Primo81 is an A31s based tablet, with 1G RAM, 16G NAND, > > 1024x768 IPS LCD display, mono speaker, 0.3 MP front camera, 2.0 MP > > rear camera, 3500 mAh battery, gt911 touchscreen, mma8452 accelerometer > > and rtl8188etv usb wifi. Has "power", "volume+" and "volume-" buttons > > (both volume buttons are also connected to the UBOOT_SEL pin). The > > external connectors are represented by MicroSD slot, MiniHDMI, MicroUSB > > OTG and 3.5mm headphone jack. More details are available at > > http://linux-sunxi.org/MSI_Primo81 > > > > This initial dts file only provides support for mmc, wifi and uart > > (there is no external connector for uart though). Graphics can be used > > via simplefb. However, without usb otg, there are no reasonable means > > to handle user input yet. > > > > Signed-off-by: Siarhei Siamashka <siarhei.siamashka@xxxxxxxxx> > > Signed-off-by: Karsten Merker <merker@xxxxxxxxxx> [...] > > +/ { > > + model = "MSI Primo81 tablet"; > > + compatible = "msi,primo81", "allwinner,sun6i-a31s"; > > + > > + aliases { > > + serial0 = &uart0; > > + }; > > + > > + chosen { > > + stdout-path = "serial0:115200n8"; > > + }; > > + > > +}; > > + > > +&ehci0 { > > + /* rtl8188etv wifi is connected here */ > > No need to mention it, it's what discoverable buses are made for. Hello Maxime, using the same reasoning that caused you to ask for a description of the uart0 config (no external connector available, so why is there a uart0 enabled and how is it usable), I think it makes sense to leave this comment in the dts. The Primo 81 doesn't have any external USB host connectors and the fact that the internal Realtek USB WLAN chip is connected there is the only reason that the EHCI controller gets enabled in the dts at all. If you really prefer, I'll remove the comment in a V5; in that case please let me know. > > + status = "okay"; > > +}; [...] > > +&uart0 { > > + /* The default uart0 pins (PH20: TX, PH21: RX) are not accessible > > + * on an external connector. Possible ways to get physical access > > + * to uart0 include: > > + * - disabling mmc0, changing the pinmuxing for the SD card pins > > + * to the uart0 function (PF2: TX, PF4: RX) and using an SD card > > + * breakout board > > + * - opening the case and finding appropriate test points connected > > + * to PH20 and PH21 > > + */ > > You already made a choice here, so just document the choice you > made. I'm guessing from what you said that it's the latter, in which > case please document which test points you're talking about. Upwards in this thread you wrote: > [Karsten Merker wrote] > > I have tagged this patch RFC as I am unsure what to do with the > > /chosen/stdout-path node. For now, I have set Siarhei's original > > choice (first serial port), but I am unsure whether this is the > > right thing to do as the Primo81 does by default not have a > > user-accessible serial port. The only way to get a serial > > console is to either break the case open and find some test > > points that carry the RX/TX lines (which with the Primo81 case > > poses a high risk of breaking the display glass), or to use an SD > > card breakout board and change the pinmuxing for the SD card pins > > to the "serial" function. The latter would not work without > > modifying the dts, so the SD-breakout case doesn't really count > > for setting the default stdout-path in the general use case. > > Having that as a comment on top of whatever uart you've been using > would be great, so that people know where to look at on their device > to find it. Maybe I have misunderstood you, but to my understanding the comment I added represents exactly what you asked me to do above? I cannot tell which test points carry the TX/RX lines from PH20 and PH21 as I have not opened the case (and to my knowledge nobody else @linunx-sunxi has done that), due to the fact that the Primo 81 doesn't have one of typical cheap two-part plastic cases which can be easily opened without destroying anything, but a one-part aluminum case which fits tightly with the display glass. To pry open the aluminium case one would have to apply pressure to the glass and I don't want to void my warranty and risk breaking the display while doing that. The u-boot and the android kernel that come preinstalled on the tablet use PH20 and PH21 for uart0, so there is an extremely high probability that there are test points on the board that carry these lines, but I cannot tell which ones. So the same question as above: if you really want me to do that, I'll remove the SD card breakout info in a V5 (just tell me so), but I think it makes sense to leave it in the dts. Regards, Karsten -- Gem. Par. 28 Abs. 4 Bundesdatenschutzgesetz widerspreche ich der Nutzung sowie der Weitergabe meiner personenbezogenen Daten für Zwecke der Werbung sowie der Markt- oder Meinungsforschung. -- 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
