Drew, David: I've adapted the tinyDRM dtc to work with the Adafruit 2.4" TFT LCD display. It's working fine with SPI 1. Currently it uses P9_14 for the backlight.
How do I switch it to use P9_16 for the backlight? I've tried changing all the P9_14's to P9_16s, but that doesn't work. P9_14 is the A side of the pwm and P9_16 is the B side, so I think there's a bit I need to flip, but don't know what it is. --Mark p.s. The exercise for my students will be to switch it to SPI 0! [1] https://github.com/MarkAYoder/BeagleBoard-exercises/tree/master/displays/ili9341/tinyDRM On Thursday, February 22, 2018 at 4:27:10 AM UTC-5, Drew Fustini wrote: > > fyi - I've created a bb.org-overlays pull request to add an overlay > named BB-LCD-ADAFRUIT-18-SPI1-00A0.dts for the Adafruit 1.8" LCD on > SPI1: > > https://github.com/beagleboard/bb.org-overlays/pull/68 > > On Wed, Feb 21, 2018 at 11:34 PM, Drew Fustini <[email protected] > <javascript:>> wrote: > > Thanks! I had DC and Reset swapped in the overlay file. I've fixed and > the > > display is now working! The console is displayed after bootup and > libdrm > > modetest is able to display color bars OK. > > > > Here is the updated dts: > > https://gist.github.com/pdp7/aee5664598059c9b9a9020f107957f80 > > > > Thanks, > > Drew > > > > On Feb 21, 2018 1:53 PM, "David Lechner" <[email protected] > <javascript:>> wrote: > >> > >> On 02/21/2018 01:18 PM, Drew Fustini wrote: > >>> > >>> On Wed, Feb 21, 2018 at 11:01 AM, David Lechner <[email protected] > <javascript:>> > >>> wrote: > >>>> > >>>> Are you sure your phandles are correct here? They don't match the > >>>> comments. > >>>> Should it be <&gpio1 16 0> instead? > >>>> > >>>>> + reset-gpios = <&gpio1 16 0>; /* > >>>>> reset:60 P9.12 GPIO1_28 */ > >>>> > >>>> > >>>> And then <&gpio1 28 0> here? > >>> > >>> Here is the full BB-SPIDEV1-00A0.dts: > >>> https://gist.github.com/pdp7/aee5664598059c9b9a9020f107957f80 > >>> > >>> I have P9.12 connected to LCD reset pin. I have P9.15 connected to > >>> LCD dc pin. For fbtft driver, this translated to GPIO_60 for reset > >>> and GPIO_48 for dc. This is based on this pinout diagram: > >>> https://elinux.org/File:Cape_expansion_headers.PNG > >>> > >>> For this dts file, I was trying to figure out what appropriate gpio > >>> phandle. I looked at this table for the P9 header: > >>> https://elinux.org/File:H9Pinout.PNG > >>> > >>> I believe that gpio1[16] corresponds to P9.15 which is LCD dc pin, and > >>> gpio1[28] corresponds to P9.12 which is LCD reset pin. > >>> > >>> My understanding of those mappings may be incorrect, so I'd appreciate > >>> any additional feedback. > >>> > >> You understand correct, but I think you have swapped the values in your > >> device tree overlay. You say "gpio1[16] corresponds to P9.15 which is > LCD dc > >> pin", but in the overlay, you have dc-gpios = <&gpio1 28 0>;. Likewise > >> "gpio1[28] corresponds to P9.12 which is LCD reset pin.", but you have > >> reset-gpios = <&gpio1 16 0>;. > >> > >> > > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4d796e35-4967-453e-8d92-759f448755bb%40googlegroups.com.
