Re: [yocto] Meta-raspberrypi - how to configure device tree for MCP251x

Re: [yocto] Meta-raspberrypi - how to configure device tree for MCP251x

[Chris Tapp]

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Sorry, I meant to add that I have tried adding the following to local.conf:

RPI_EXTRA_CONFIG = ' \n \
    dtparam=spi=on \n \
    dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25 \n \
    dtoverlay=mcp2515-can1,oscillator=16000000,interrupt=23 \n \
    '

However, this did not make any difference to the interrupts.

Since then, I have manually changed mcp2515-can1-overlay.dts in the kernel build tree (after running bitbake - c do_configure virtual/kernel) and rebuilt the kernel / image. This does result in the interrupt mapping changing, and both CAN channels then operate correctly.

Does anyone know why RPI_EXTRA_CONFIG doesn’t appear to be taking effect?

--

Chris Tapp
opensource@keylevel.com
www.keylevel.com

----
You can tell you're getting older when your car insurance gets real cheap!

> On 1 Oct 2021, at 22:38, Chris Tapp <opensource@keylevel.com> wrote:
> 
> I am having trouble getting the Waveshare 2-CH CAN HAT working with an RPI4. Channel 0 does not come up, channel 1 does, but it will only send one message (eventually reporting "write: No buffer space available”) and not receive anything.
> 
> Looking at the mcp2515-can0-overlay.dts and mcp2515-can1-overlay.dts device tree files in /tmp/work-shared/raspberrypi4/kernel-source/arch/arm/boot/dts/overlays/, it looks as if the interrupts are not mapped as required for the board.
> 
>       DTS               HAT
> CAN0  brcm,pins = <25>  PIN23
> CAN1  brcm,pins = <25>  PIN25
> 
> This doesn’t look right, and seems consistent with the behaviour I am seeing.
> 
> I would also like to check the device chip select signals, but I can't see how (if) they are mapped in the dts files.
> 
> How can I override these settings when I build the image?
> 
> --
> 
> Chris Tapp
> opensource@keylevel.com <mailto:opensource@keylevel.com>
> www.keylevel.com
> 
> 
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Re: [yocto] Meta-raspberrypi - how to configure device tree for MCP251x

[Khem Raj]

can you check boot/config.txt and see fi your changes are there in your target ?

On Mon, Oct 4, 2021 at 1:21 AM Chris Tapp <opensource@keylevel.com> wrote:
>
> Sorry, I meant to add that I have tried adding the following to local.conf:
>
> RPI_EXTRA_CONFIG = ' \n \
>     dtparam=spi=on \n \
>     dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25 \n \
>     dtoverlay=mcp2515-can1,oscillator=16000000,interrupt=23 \n \
>     '
>
> However, this did not make any difference to the interrupts.
>
> Since then, I have manually changed mcp2515-can1-overlay.dts in the kernel build tree (after running bitbake - c do_configure virtual/kernel) and rebuilt the kernel / image. This does result in the interrupt mapping changing, and both CAN channels then operate correctly.
>
> Does anyone know why RPI_EXTRA_CONFIG doesn’t appear to be taking effect?
>
> --
>
> Chris Tapp
> opensource@keylevel.com
> www.keylevel.com
>
> ----
> You can tell you're getting older when your car insurance gets real cheap!
>
> On 1 Oct 2021, at 22:38, Chris Tapp <opensource@keylevel.com> wrote:
>
> I am having trouble getting the Waveshare 2-CH CAN HAT working with an RPI4. Channel 0 does not come up, channel 1 does, but it will only send one message (eventually reporting "write: No buffer space available”) and not receive anything.
>
> Looking at the mcp2515-can0-overlay.dts and mcp2515-can1-overlay.dts device tree files in /tmp/work-shared/raspberrypi4/kernel-source/arch/arm/boot/dts/overlays/, it looks as if the interrupts are not mapped as required for the board.
>
>       DTS               HAT
> CAN0  brcm,pins = <25>  PIN23
> CAN1  brcm,pins = <25>  PIN25
>
> This doesn’t look right, and seems consistent with the behaviour I am seeing.
>
> I would also like to check the device chip select signals, but I can't see how (if) they are mapped in the dts files.
>
> How can I override these settings when I build the image?
>
> --
>
> Chris Tapp
> opensource@keylevel.com
> www.keylevel.com
>
>
>
>
>
>
> -=-=-=-=-=-=-=-=-=-=-=-
> Links: You receive all messages sent to this group.
> You automatically follow any topics you start or reply to.
> View/Reply Online (#54936): https://lists.yoctoproject.org/g/yocto/message/54936
> Mute This Topic: https://lists.yoctoproject.org/mt/86011706/1997914
> Group Owner: yocto+owner@lists.yoctoproject.org
> Unsubscribe: https://lists.yoctoproject.org/g/yocto/unsub [raj.khem@gmail.com]
> -=-=-=-=-=-=-=-=-=-=-=-
>

Re: [yocto] Meta-raspberrypi - how to configure device tree for MCP251x

[Chris Tapp]

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Hi Khem,

There is nothing in /boot once the system has started, but if I mount /dev/mmcblk0p1 I can see a config.txt that includes:

     dtparam=spi=on 
     dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25 
     dtoverlay=mcp2515-can1,oscillator=16000000,interrupt=23 

This is what I could expect.

On a quick scan, this appears to be the same as the one in tmp/deploy/images/raspberrypi4/bootfiles - the timestamp for this file indicated it was old, so I had manually cleaned and rebuilt rpi-bootfiles for changes to RPI_EXTRA_CONFIG to propagate.

However, if I bring the CAN interface up:

ip link set can1 up type can bitrate 100000

and look in /proc/interrupts, I see:

 66:          0          0          0          0  pinctrl-bcm2835  25 Level     spi0.0

even though can1 is on spi0.1.

--

Chris Tapp
opensource@keylevel.com
www.keylevel.com

> On 4 Oct 2021, at 17:49, Khem Raj <raj.khem@gmail.com> wrote:
> 
> can you check boot/config.txt and see fi your changes are there in your target ?
> 
> On Mon, Oct 4, 2021 at 1:21 AM Chris Tapp <opensource@keylevel.com> wrote:
>> 
>> Sorry, I meant to add that I have tried adding the following to local.conf:
>> 
>> RPI_EXTRA_CONFIG = ' \n \
>>    dtparam=spi=on \n \
>>    dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25 \n \
>>    dtoverlay=mcp2515-can1,oscillator=16000000,interrupt=23 \n \
>>    '
>> 
>> However, this did not make any difference to the interrupts.
>> 
>> Since then, I have manually changed mcp2515-can1-overlay.dts in the kernel build tree (after running bitbake - c do_configure virtual/kernel) and rebuilt the kernel / image. This does result in the interrupt mapping changing, and both CAN channels then operate correctly.
>> 
>> Does anyone know why RPI_EXTRA_CONFIG doesn’t appear to be taking effect?
>> 
>> --
>> 
>> Chris Tapp
>> opensource@keylevel.com
>> www.keylevel.com
>> 
>> ----
>> You can tell you're getting older when your car insurance gets real cheap!
>> 
>> On 1 Oct 2021, at 22:38, Chris Tapp <opensource@keylevel.com> wrote:
>> 
>> I am having trouble getting the Waveshare 2-CH CAN HAT working with an RPI4. Channel 0 does not come up, channel 1 does, but it will only send one message (eventually reporting "write: No buffer space available”) and not receive anything.
>> 
>> Looking at the mcp2515-can0-overlay.dts and mcp2515-can1-overlay.dts device tree files in /tmp/work-shared/raspberrypi4/kernel-source/arch/arm/boot/dts/overlays/, it looks as if the interrupts are not mapped as required for the board.
>> 
>>      DTS               HAT
>> CAN0  brcm,pins = <25>  PIN23
>> CAN1  brcm,pins = <25>  PIN25
>> 
>> This doesn’t look right, and seems consistent with the behaviour I am seeing.
>> 
>> I would also like to check the device chip select signals, but I can't see how (if) they are mapped in the dts files.
>> 
>> How can I override these settings when I build the image?
>> 
>> --
>> 
>> Chris Tapp
>> opensource@keylevel.com
>> www.keylevel.com
>> 
>> 
>> 
>> 
>> 
>> 
>> -=-=-=-=-=-=-=-=-=-=-=-
>> Links: You receive all messages sent to this group.
>> You automatically follow any topics you start or reply to.
>> View/Reply Online (#54936): https://lists.yoctoproject.org/g/yocto/message/54936
>> Mute This Topic: https://lists.yoctoproject.org/mt/86011706/1997914
>> Group Owner: yocto+owner@lists.yoctoproject.org
>> Unsubscribe: https://lists.yoctoproject.org/g/yocto/unsub [raj.khem@gmail.com]
>> -=-=-=-=-=-=-=-=-=-=-=-
>> 


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