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by PhilE
Sun Jan 19, 2020 10:27 pm
Forum: Compute Module
Topic: CM3 Plus and WiFi/BT CYW43455
Replies: 63
Views: 10554

Re: CM3 Plus and WiFi/BT CYW43455

Either "sudo vcdbg log msg" or "dmesg -l err" should give a clue.
by PhilE
Fri Jan 17, 2020 1:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2S clock rate question
Replies: 2
Views: 60

Re: I2S clock rate question

[ Split off into a separate topic ]
by PhilE
Wed Jan 15, 2020 10:29 am
Forum: Compute Module
Topic: Rare comms failure with enc28j60 and compute module "netdev watchdog: eth0 ("enc28j60"): transmit queue 0 timed out"
Replies: 8
Views: 2286

Re: Rare comms failure with enc28j60 and compute module "netdev watchdog: eth0 ("enc28j60"): transmit queue 0 timed out"

4.19 and 4.14 are virtually identical with regards to the spi-bcm2835 driver. 4.19 has a bug fix for 3-wire mode and supports shared interrupts, but that's it. It's more likely that a change elsewhere in the kernel (interrupt handling, for example) could have caused a regression. One option for you ...
by PhilE
Tue Jan 14, 2020 1:11 pm
Forum: Compute Module
Topic: CM3+ EMMC Corruptions?
Replies: 6
Views: 188

Re: CM3+ EMMC Corruptions?

Sometimes when it is powered up or rebooted it seems like the data has corrupted on the EMMC, however other times it boots up perfectly fine. To avoid any confusion, do you always have to fix the corruption before it will boot successfully? In other words, is this occasional corruption caused by a ...
by PhilE
Tue Jan 14, 2020 11:38 am
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 53
Views: 14796

Re: Pi-4 Activating additional UART ports

I wrote:
(at the point of probing, which is after the "gpio ..." handling)
by PhilE
Tue Jan 14, 2020 11:05 am
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 53
Views: 14796

Re: Pi-4 Activating additional UART ports

Did I understand right, that without a customized dt-blob, (I will not yet go into the experience of compiling a new one yet), the HAT probing will occur anyway? No, not if you have used the gpio directive to change to some pin function other than input. And if you haven't used either a custom dt-b...
by PhilE
Tue Jan 14, 2020 9:52 am
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 53
Views: 14796

Re: Pi-4 Activating additional UART ports

So we still have got an apparent contradiction between the Pi4 specs for UART2 with ALT4 and the statement on the schematic: There's no contradiction - the GPIO capabilities are a feature of the 2711 SoC, while the pin usage is a feature of the Pi 4 board. The 2711 has potentially wider application...
by PhilE
Tue Jan 14, 2020 8:49 am
Forum: Device Tree
Topic: Touch-triggered display dimming
Replies: 1
Views: 51

Re: Touch-triggered display dimming

I'm not aware of a kernel feature like that - it sounds more like a screen saver configuration option, i.e. up in userland at the desktop or application level.
by PhilE
Mon Jan 13, 2020 9:35 pm
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 53
Views: 14796

Re: Pi-4 Activating additional UART ports

Yes, I believe that's all correct.
by PhilE
Mon Jan 13, 2020 1:03 pm
Forum: Compute Module
Topic: some questions about schematics for the Compute Module IO board (CMIO)
Replies: 4
Views: 125

Re: some questions about schematics for the Compute Module IO board (CMIO)

PP means Probe Point - it's a place to measure the signal with a scope or logic analyser.
NF means Not Fitted - there is no component fitted there.
by PhilE
Fri Jan 10, 2020 9:52 am
Forum: Device Tree
Topic: shutdown script will not change the status of the LED
Replies: 8
Views: 344

Re: shutdown script will not change the status of the LED

After reading around a bit, I think this might work (but I've not tried): [Unit] Description=This service sets the indicator LED into the heartbeat mode on shutdown. DefaultDependencies=no After=final.target [Service] Type=oneshot ExecStart=/webroot/gStation/sh/heartbeat_indicator.sh [Install] Wante...
by PhilE
Thu Jan 09, 2020 8:07 pm
Forum: Device Tree
Topic: shutdown script will not change the status of the LED
Replies: 8
Views: 344

Re: shutdown script will not change the status of the LED

My guess would be that because systemd knows the service has exited, it won't try to stop it.

It ought to be possible to get actions performed at shutdown in a more direct way, but right now I couldn't say what that way is.
by PhilE
Thu Jan 09, 2020 5:53 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

Have a look in /etc/systemd/logind.conf for HandlePowerKey. The default value (if nothing is specified) is "poweroff", but it might have been changed by something. This page explains the options: https://www.freedesktop.org/software/sy ... .conf.html
by PhilE
Thu Jan 09, 2020 5:01 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

That worked for me on a Pi 4: [email protected]:~$ raspi-gpio get 0-27 GPIO 0: level=1 fsel=0 func=INPUT pull=UP GPIO 1: level=1 fsel=0 func=INPUT pull=UP GPIO 2: level=1 fsel=0 func=INPUT pull=UP GPIO 3: level=1 fsel=0 func=INPUT pull=UP GPIO 4: level=1 fsel=0 func=INPUT pull=UP GPIO 5: level=0 fsel=0...
by PhilE
Thu Jan 09, 2020 3:44 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

You almost got it. What you didn't figure out is that the "leds" node replaces your rp41_pins node, i.e.: // Overlay for rp41 gpio line names /dts-v1/; /plugin/; /{ compatible = "brcm,bcm2835"; [email protected] { target = <&leds>; __overlay__ { pinctrl-names = "default"; pinctrl-0 = <&rp41_gpio>; }; }; fr...
by PhilE
Thu Jan 09, 2020 1:37 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

Things have certainly changed somewhat since I wrote my first Unix device driver way back in the 1970s.
Wow - you must be even older than I am. Or a very precocious young coder. ;)
by PhilE
Thu Jan 09, 2020 1:09 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

We need an active driver to hang pinctrl requests on, preferably one which doesn't already use pinctrl. In the absence of a driver specific to your application, the gpio-leds driver is a suitable candidate (but be aware that other overlays may try the same trick). The vga666 overlay is an example of...
by PhilE
Thu Jan 09, 2020 9:11 am
Forum: Device Tree
Topic: shutdown script will not change the status of the LED
Replies: 8
Views: 344

Re: shutdown script will not change the status of the LED

[ This isn't a Device Tree question, but it does at least refer to overlays so I'll allow it. ;) ]

What does "sudo systemctl status heartbeat_indicator" report before and after the service is stopped?
by PhilE
Wed Jan 08, 2020 9:58 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

Indeed - it seems that the KEY_POWER is being generated but that nothing is responding to it. Strange.
by PhilE
Wed Jan 08, 2020 9:52 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

Your new DT node (rp41_pins) has no compatible string - without one it will be ignored. pinctrl claims and configures pins on behalf of a driver, but releases them if the driver doesn't initialise (probe) correctly.
by PhilE
Wed Jan 08, 2020 9:24 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

One other thing I just noticed: something does happen when I assert GPIO17 - the red LED goes off. But that's it. That could be an indication that the voltage is dropping too low, briefly. Do you have a too-small resistor in there somewhere? I don't have a Pi to hand, so this is a bit vague, but th...
by PhilE
Wed Jan 08, 2020 9:06 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

Yes, that all looks as expected.
by PhilE
Wed Jan 08, 2020 8:31 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

Re: the default pull, the overlay overrides the default behaviour so it pulls up (which wouldn't work well if active_low=0, but it isn't so you are ok). Does xev show any activity when you ground the pin? Is the gpio-key module loaded? Does gpioinfo show the GPIO as being claimed? (You may need to "...
by PhilE
Wed Jan 08, 2020 8:18 pm
Forum: Device Tree
Topic: gpio-shutdown overlay not working
Replies: 18
Views: 319

Re: gpio-shutdown overlay not working

Another factor to consider is that gpio 17 pulls low by default. Run "raspi-gpio get 17" to confirm that the input is low all the time, which will cause the gpio-key driver to ignore that input as a stuck key.
by PhilE
Wed Jan 08, 2020 5:32 pm
Forum: Device Tree
Topic: Problem with gpio-hog
Replies: 19
Views: 515

Re: Problem with gpio-hog

raspi-gpio gives a more accurate picture of the current GPIO state. gpioinfo shows what Linux thinks it is set to, but since it doesn't read back the start-of-day state anything changed via dt-blob or config.txt won't show up.

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