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by PhilE
Fri Feb 23, 2018 4:19 pm
Forum: Linux Kernel
Topic: Can't find `arch/arm/boot/dts/overlays` when building kernel
Replies: 7
Views: 243

Re: Can't find `arch/arm/boot/dts/overlays` when building kernel

Let me know how it goes - I've not got further than building and booting the RT kernel because I don't have any use cases for it.
by PhilE
Fri Feb 23, 2018 1:52 pm
Forum: Linux Kernel
Topic: Can't find `arch/arm/boot/dts/overlays` when building kernel
Replies: 7
Views: 243

Re: Can't find `arch/arm/boot/dts/overlays` when building kernel

I was going to say that it should all just work, but the final step of patching the defconfigs hasn't been done yet, so for now you will still need to use menuconfig (or equivalent).
by PhilE
Fri Feb 23, 2018 10:53 am
Forum: Linux Kernel
Topic: Can't find `arch/arm/boot/dts/overlays` when building kernel
Replies: 7
Views: 243

Re: Can't find `arch/arm/boot/dts/overlays` when building kernel

Your problem is this line: git checkout 81d0cc85caabe062991ea45ddada814835d47fb0 That commit, titled "Linux 4.4.18" is in an upstream branch and thus has no Raspberry Pi modifications (including the overlays). The downstream branches exist in parallel, with pointers (merge commits) back into upstrea...
by PhilE
Wed Feb 21, 2018 9:23 pm
Forum: Linux Kernel
Topic: Can't find `arch/arm/boot/dts/overlays` when building kernel
Replies: 7
Views: 243

Re: Can't find `arch/arm/boot/dts/overlays` when building kernel

My build script is based on these instructions: https://www.raspberrypi.org/documentati ... uilding.md
Without seeing your build script I'm not sure in what way you've broken it. Post it here and I'll tell you.
by PhilE
Wed Feb 21, 2018 9:19 pm
Forum: Compute Module
Topic: Setting up dual UARTs on CM3
Replies: 3
Views: 138

Re: Setting up dual UARTs on CM3

And as mentioned in a neighbouring topic, if you want to use UART1 on a CM3 you will also need to explicitly stop the core clock frequency from changing. I would recommend adding "core_freq=250" to config.txt, but "force_turbo=1" would also work.
by PhilE
Wed Feb 21, 2018 8:49 pm
Forum: Compute Module
Topic: Setting up dual UARTs on CM3
Replies: 3
Views: 138

Re: Setting up dual UARTs on CM3

It's not immediately obvious why UART0 was duplicated like that. If you want to find out then run:

Code: Select all

$ sudo apt-get install pastebinit
$ dtc -I fs -O dts /proc/device-tree | pastebinit
and post the URL here for me to check.
by PhilE
Wed Feb 21, 2018 8:07 pm
Forum: Compute Module
Topic: Setting up dual UARTs on CM3
Replies: 3
Views: 138

Re: Setting up dual UARTs on CM3

You shouldn't need custom overlays if your kernel is recent because there are two existing overlays that should do the job. Type these commands for usage information: $ dtoverlay -h uart0 Name: uart0 Info: Change the pin usage of uart0 Load: dtoverlay=uart0,<param>=<val> Params: txd0_pin GPIO pin fo...
by PhilE
Tue Feb 20, 2018 9:55 pm
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

The patched driver and updated overlay are in the current rpi-update release.
by PhilE
Tue Feb 20, 2018 11:58 am
Forum: Device Tree
Topic: Confirmation of gpio-poweroff Behavior
Replies: 7
Views: 633

Re: Confirmation of gpio-poweroff Behavior

Read the first post in this topic, run "dtoverlay -h gpio-poweroff" and "dtoverlay -h gpio-shutdown", then post again if you still have questions.
by PhilE
Tue Feb 20, 2018 11:23 am
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

The bus IDs are derived from Device Tree aliases, but the current overlay parameter mechanism isn't flexible enough to be able to generate matching aliases. Instead I've added a small patch to the i2c-gpio driver that allows the "reg" property to be used as the real bus number (unless there is a cla...
by PhilE
Mon Feb 19, 2018 8:30 pm
Forum: Device Tree
Topic: [solved] Overlay for multiple i2c_gpio bitbanging buses
Replies: 6
Views: 1099

Re: [solved] Overlay for multiple i2c_gpio bitbanging buses

FYI the updated overlay with the bus parameter is now in the rpi-4.14.y tree and will be included in the next firmware release.
by PhilE
Mon Feb 19, 2018 8:21 pm
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

I tried to make it clear that this is a bit of a grey area. I'll have a look and see if there's a way to force an order (at least), but if it's like MMC/SD interfaces then it's first come first served (in the upstream kernel - we have a patch to force particular instance numbers).
by PhilE
Mon Feb 19, 2018 5:47 pm
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

Sorry for the delay, but I have a solution for you know. The 4.14 kernel tree now includes a modified i2c-gpio with a new parameter - "bus" - which defaults to zero. You can add multiple instances provided they all have unique bus values. In my test I found the busses (i.e. /dev/i2c-*) were given nu...
by PhilE
Mon Feb 19, 2018 5:20 pm
Forum: Device Tree
Topic: @i2c device tree drive
Replies: 5
Views: 133

Re: @i2c device tree drive

A bit of optimism never hurts. ;)
by PhilE
Mon Feb 19, 2018 4:56 pm
Forum: Device Tree
Topic: @i2c device tree drive
Replies: 5
Views: 133

Re: @i2c device tree drive

The thing I noticed particularly is that the driver appears to be explicitly getting a GPIO pin from the Device Tree and making an interrupt source out of it, whereas in a modern kernel you would just call "platform_get_irq" and it would automatically look for an "interrupts" property and take all t...
by PhilE
Mon Feb 19, 2018 11:02 am
Forum: Device Tree
Topic: @i2c device tree drive
Replies: 5
Views: 133

Re: @i2c device tree drive

That's an old-looking driver - I'm not sure how well its going to integrate with a 4.9 kernel. This overlay should make the expected device tree changes: /dts-v1/; /plugin/; / { fragment@0 { target = <&i2c1>; __overlay__ { status = "okay"; #address-cells = <1>; #size-cells = <0>; pn547: pn547@28 { c...
by PhilE
Thu Feb 15, 2018 10:47 pm
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

I'm sure it will be possible - there are many board .dts files with multiple i2c-gpio instances - it is just a question of figuring out the bus numbering and whether we can use one standard overlay repeatedly or whether it must be a custom overlay.
by PhilE
Thu Feb 15, 2018 9:57 pm
Forum: Device Tree
Topic: i2c-gpio dtoverlay bus number
Replies: 11
Views: 347

Re: i2c-gpio dtoverlay bus number

Can you really not get the three I2C devices (or at least two of them) to share the hardware I2C bus? It would be more efficient.
by PhilE
Thu Feb 15, 2018 4:06 pm
Forum: Device Tree
Topic: Possibility for multiple instances of LIRC?
Replies: 13
Views: 527

Re: Possibility for multiple instances of LIRC?

One thing I just noticed is that the gpio-ir overlay is missing the (required) pinctrl-0 and (optional) pinctrl-names properties - the -tx overlays have them. Could you add these to gpio-ir-overlay.dts?
You're quite right - that's fixed now.
by PhilE
Thu Feb 15, 2018 2:09 pm
Forum: Device Tree
Topic: Possibility for multiple instances of LIRC?
Replies: 13
Views: 527

Re: Possibility for multiple instances of LIRC?

Thanks for covering the lircd daemon, HiassofT - it's not something I've played with yet other than in the most basic way. vicary - we like curiosity around these parts, so keep on asking questions. My reply assumed too much knowledge, so I'll try to correct that now. The change I've made should mak...
by PhilE
Thu Feb 15, 2018 9:53 am
Forum: Device Tree
Topic: Possibility for multiple instances of LIRC?
Replies: 13
Views: 527

Re: Possibility for multiple instances of LIRC?

HiassofT was right to steer you towards gpio-ir and gpio-ir-tx - lirc-rpi isn't built in the 4.15 kernel tree.

To make it easier to use multiple gpio-ir instances the overlays (gpio-ir and gpio-ir-tx) now use the magic "reg" property to prevent name clashes.
by PhilE
Mon Feb 12, 2018 4:43 pm
Forum: Device Tree
Topic: [Custom Kernel] after compilation dtb modules are missing
Replies: 19
Views: 3462

Re: [Custom Kernel] after compilation dtb modules are missing

What are you building on? I'm not near a computer, but you should at least include ARCH=arm in the make command line.
by PhilE
Thu Feb 08, 2018 9:57 am
Forum: Device Tree
Topic: external watchdog on GPIO output
Replies: 34
Views: 4883

Re: external watchdog on GPIO output

There are many reasons to want to use the existing watchdog interface: * It should be (marginally) less code. * Any code that uses it will be portable to other Linux systems because the API is separated from the hardware by multiple layers of abstraction - the fact that the watchdog is reached via G...
by PhilE
Thu Feb 08, 2018 9:51 am
Forum: Compute Module
Topic: CM with LAN chip - use RPi Foundation OUI
Replies: 2
Views: 342

Re: CM with LAN chip - use RPi Foundation OUI

Thanks for asking - we are happy for CM customers to use the Pi OUI with an Ethernet interface of their choice. The firmware writes the MAC address into the Device Tree if there is a node with the label "ethernet0", but if you are unable to make use of this mechanism then allocating MAC addresses by...

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