Comments on: Linux Framebuffer fbtft with SPI DMA for Intel Edison

By: Andy Shevchenko

Andy Shevchenko — Wed, 13 May 2020 21:44:38 +0000

There were patches against MRAA for new kernel. But I recommend to use standard kernel interfaces directly. See more details on edison-fw project on GitHub.

By: Andy Shevchenko

Andy Shevchenko — Wed, 13 May 2020 21:41:59 +0000

I have to elaborate, that coming one is for test, fbtft supported in full, I just have no hardware to confirm.

By: Andy Shevchenko

Andy Shevchenko — Wed, 13 May 2020 21:39:51 +0000

It’s done via ACPI GpioIo() resource in recent kernels. I recommend to look at edison-fw project on GitHub.

By: Andy Shevchenko

Andy Shevchenko — Wed, 13 May 2020 21:37:40 +0000

Eventually in v5.7 we will have fbtft driver which can be used from ACPI without any recompilation required! I managed to test three (ili9341, ssd1306, hx8347d) displays myself and one more is coming (ssd1331).

By: Farit

Farit — Mon, 22 May 2017 15:01:54 +0000

This is an older kernel. The MRAA library may require some features that are not available in it. You can also try this Linux 4 kernel https://github.com/andy-shev/linux

By: Gary Gan

Gary Gan — Mon, 22 May 2017 10:23:49 +0000

Thanks for the patch farit! I managed to compile the kernel and get the DMA feature running. One question though, using this kernel version seemed to break the support of using mraa set GPIO? I no longer able to initialize any GPIO context.

By: Andy Shevchenko

Andy Shevchenko — Mon, 02 Jan 2017 21:35:43 +0000

Today I sent contents of my branch to upstream mailing lists. Regarding to GPIO (actually it’s a property of so called FLIS, i.e. pin control, IP) you need to setup pin control configuration tables in your code. The pin control driver is in upstream starting from v4.8.

By: Farit

Farit — Tue, 20 Dec 2016 01:51:27 +0000

Yes, that would be nice.

Could you also add the GPIO pullup code in the kernel? I have one here: http://hobby.farit.ru/connecting-buttons-intel-edison/
There is a function to change the GPIO mode, but not a pullup function.

By: Andy Shevchenko

Andy Shevchenko — Tue, 20 Dec 2016 00:58:23 +0000

I’m fixing this particular issue right now. I’m about to push some stuff to my **eds** branch on GitHub to support iDMA 32-bit and enable it for SPI. Would you be interested in that? (My stuff is targeting upstream kernel, so, sooner or later we will have this code in upstream).