Hi,
First, thank you for all the time you're putting into helping me.
I really do appreciate it, especially since the platform is not currently
supported.
(More below)
On Mon, April 15, 2024 4:49 pm, Peter Robinson wrote:
On Mon, 15 Apr 2024 at 21:38, Derek Atkins <derek(a)ihtfp.com>
wrote:
>
> Hi,
>
> On Mon, April 15, 2024 4:21 pm, Peter Robinson wrote:
>
> >> >> >> me that the JP4 header connects to GPIO3_12, GPIO3_27,
> GPIO6_31,
> >> >> >> CPIO1_24,
> >> >> >> GPIO7_8, GPIO3_26, GPIO_18, and GPIO_19.
> >> >> >>
> >> [snip]
>
> > I've not dug out a pdf to work out the physical pins and how they map
> > to the SOC and hence the DT, I've left that up to you, I was just
> > answering your questions about why some appear to be in use and trying
> > to help you understand as you requested.
By "docs", I am looking at the schematics. Starting at JP4, we have:
JP4 4 -> GPIO3_12 -> MXM Pin 256 -> EIM_DA11 -> IMX6 NVCC_EIM2 EIM_DA11 (M20)
JP4 6 -> GPIO3_27 -> MXM Pin 258 -> GPIO3_27 -> IMX6 NVCC_EIM0 EIM_D27 (E25)
JP4 8 -> GPIO6_31 -> MXM Pin 260 -> GPIO6_31 -> IMX6 NVCC_EIM2 EIM_BCLK (N22)
JP4 10-> GPIO1_24 -> MXM Pin 262 -> MIC_DET -> IMX6 NVCC_ENET ENET_RX_ER
(W23)
JP4 12-> GPIO7_8 -> MXM Pin 264 -> SD3_RST -> IMX6 NVCC_SD3 SD3_RST (D15)
JP4 14-> GPIO3_26 -> MXM Pin 259 -> GPIO3_26 -> IMX6 NVCC_EIM0 EIM_D26 (E24)
JP4 16-> GPIO_18 -> MXM Pin 261 -> EIM_DA8 -> IMX6 NVCC_EIM2 EIM_DA8 (L24)
JP4 18-> GPIO_19 -> MXM Pin 263 -> GPIO_19 -> IMX6 NVCC_GPIO GPIO_19 (P5)
So clearly some of the JP4 pins get "renamed" when crossing the MXM
connector boundary, and some get renamed again when connecting to the
IMX6. However, I still don't know how to map the e.g. IMX6 NVCC_GPIO to a
libgpiod gpiochipN.
In both cases above it should be in the docs, or at the very least
the
DT in combination with the docs. In the later case they should
document what GPIOs are available for use and what the pins on the
header do similar to how the RPi document the 40 pin header there.
One would expect that, but I'm having a heck of a time tracking that down.
-derek
--
Derek Atkins 617-623-3745
derek(a)ihtfp.com
www.ihtfp.com
Computer and Internet Security Consultant