David:
  Thanks.  I did not.  How do I discover what those values ( 1 500000 0) 
are?

--Mark

On Thursday, October 3, 2019 at 2:57:38 PM UTC-4, David Lechner wrote:
>
> Did you also change pwms = <&ehrpwm1 *0* 500000 0>; to pwms = <&ehrpwm1 
> *1* 500000 0>; ? 
>
>
>
>
> On 10/3/19 9:44 AM, Mark A. Yoder wrote:
>
> 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]> 
>> 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]> wrote: 
>> >> 
>> >> On 02/21/2018 01:18 PM, Drew Fustini wrote: 
>> >>> 
>> >>> On Wed, Feb 21, 2018 at 11:01 AM, David Lechner <[email protected]> 
>>
>> >>> 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>;. 
>> >> 
>> >> 
>> > 
>>
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