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by PhilE
Thu Jul 22, 2021 8:26 am
Forum: Device Tree
Topic: CM4 BQ25890 dtoverlay help
Replies: 7
Views: 417

Re: CM4 BQ25890 dtoverlay help

I think your problem is that there is an I2C multiplexer enabled by default which the i2c0 partially (but not completely) disables. Out of the box, the "i2c0" DT label and /dev/i2c-0 both select the I2C0 hardware interface enabled on GPIOs 0 & 1. I2C0 on GPIOs 44 & 45 is available ...
by PhilE
Thu Jul 22, 2021 7:36 am
Forum: Device Tree
Topic: CM4 BQ25890 dtoverlay help
Replies: 7
Views: 417

Re: CM4 BQ25890 dtoverlay help

Does the device appear in the output of "i2cdetect -y 0"?
by PhilE
Wed Jul 21, 2021 11:20 am
Forum: Compute Module
Topic: spi-gpio35-39 does not set CE
Replies: 7
Views: 329

Re: spi-gpio35-39 does not set CE

The spi-gpio35-39 overlay is behaving as intended, even though the end result isn't what you hoped for. I suggest you get help from your device supplier - I don't have time to debug it for you.
by PhilE
Wed Jul 21, 2021 11:05 am
Forum: Compute Module
Topic: spi-gpio35-39 does not set CE
Replies: 7
Views: 329

Re: spi-gpio35-39 does not set CE

The bcm2835 SPI driver is configured to use arbitrary GPIOs for software CS/CE. Switching to alt0 on GPIO35 bypasses that at least partially - I suspect the kernel is still trying to waggle the GPIO line "manually", but having no effect because the GPIO function isn't enabled. What do you ...
by PhilE
Wed Jul 21, 2021 10:34 am
Forum: Compute Module
Topic: spi-gpio35-39 does not set CE
Replies: 7
Views: 329

Re: spi-gpio35-39 does not set CE

Post the output of the following commands:

Code: Select all

$ sudo apt install gpiod
$ raspi-gpio get 35-39
$ gpioinfo gpiochip0
by PhilE
Tue Jul 20, 2021 5:58 pm
Forum: Compute Module
Topic: [SOLVED] CM4 PMIC not switched off
Replies: 8
Views: 559

Re: CM4 PMIC not switched off

The kernel reboot/halt/poweroff handler uses the watchdog hardware but does not need the userspace watchdog utilities.
by PhilE
Tue Jul 20, 2021 9:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

I think that's a wise choice. And technically it's only ~12% slower. ;)
by PhilE
Tue Jul 20, 2021 9:37 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

You have three options:
1. Submit a patch to the bcm2835 driver that allows it (if a suitable Device Tree property is present) to fall back multiple stops and starts in the way that the i2c-bcm2708 driver does.
2. Continue to use i2c-bcm2708.
3. Live with the 14% slower operation.
by PhilE
Tue Jul 20, 2021 8:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

Yes, for some values of "working". It may be doing what you want it to do, but it's not doing what it should because it is releasing the bus between the reads. Why are you using i2ctransfer? Is it for speed or convenience? If the single-transfer isn't important to you then you may find it ...
by PhilE
Mon Jul 19, 2021 2:45 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

Oh - you're using I2C0. Try "dtoverlay=i2c0,combine=off" to see if it makes a difference, but I think the "i2c-bcm2708" overlay should be extended to also change the compatible string for I2C0. pi@raspberrypi:~$ dtoverlay -h i2c0 Name: i2c0 Info: Change i2c0 pin usage. Not all pi...
by PhilE
Mon Jul 19, 2021 12:19 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

The dtoverlay line appears to have not worked. What does "sudo vcdbg log msg |& grep dt" show?
by PhilE
Mon Jul 19, 2021 10:41 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

From https://i2c.info/i2c-bus-specification: https://i2c.info/wp-content/images/i2c.info/7-bit-address-writing-reading.gif There is no suggestion that restarts must only be used for write->read switchovers. I tried with the old i2c-bcm2708 driver and using i2ctransfer for two reads worked. However, ...
by PhilE
Sun Jul 18, 2021 9:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

Well, the i2ctransfer manpage (https://manpages.debian.org/unstable/i2c-tools/i2ctransfer.8.en.html) says: i2ctransfer is a program to create I2C messages and send them combined as one transfer. For read messages, the contents of the received buffers are printed to stdout, one line per read message....
by PhilE
Sun Jul 18, 2021 6:48 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: multiple IO with i2ctransfer not working
Replies: 18
Views: 738

Re: multiple IO with i2ctransfer not working

I haven't verified this, but my suspicion is that either the I2C hardware can't handle multiple restarts, only a single transition from a write phase to a read phase (the documentation is sketchy), or the author of the driver mistakenly thought that was the case. I don't see any such restriction in ...
by PhilE
Sat Jul 17, 2021 12:10 pm
Forum: Device Tree
Topic: @PhilE, can you help pls.
Replies: 2
Views: 376

Re: @PhilE, can you help pls.

I am aware. It's probably a limitation of the driver, but I can't check now.
by PhilE
Fri Jul 16, 2021 1:52 pm
Forum: Device Tree
Topic: Problems with setting Interrupt Pin to Active Low
Replies: 3
Views: 274

Re: Problems with setting Interrupt Pin to Active Low

now the PIN is again staying at HIGH. So something with the interrupt /GPIO configuration is wrong
You can only say there is something wrong with the configuration if the pin is toggling as expected and the interrupt is not being detected.
by PhilE
Fri Jul 16, 2021 12:26 pm
Forum: Device Tree
Topic: Problems with setting Interrupt Pin to Active Low
Replies: 3
Views: 274

Re: Problems with setting Interrupt Pin to Active Low

This bit of the overlay looks wrong: irq-gpio = <&gpio 4 0x2>; /* IRQF_TRIGGER_FALLING */ interrupts = <4 2>; /* high-to-low edge triggered */ interrupt-parent = <&gpio>; interrupt-controller; The "irq-gpio" property is probably ignored and should be deleted. The "interrupts&q...
by PhilE
Thu Jul 15, 2021 12:55 pm
Forum: Device Tree
Topic: Pi 4B u-boot devicetree loading issues on rev 1.4 boards
Replies: 3
Views: 365

Re: Pi 4B u-boot devicetree loading issues on rev 1.4 boards

However using os_prefix for example would mean I would need to swap files on the boot partition and somehow patch the config.txt which seems to be quite fragile. You're right - but with a there is one final piece of the puzzle that helps with this. Since mid-April the standard boot EEPROM image sup...
by PhilE
Wed Jul 14, 2021 11:36 am
Forum: Troubleshooting
Topic: Only sound for animated movies
Replies: 5
Views: 218

Re: Only sound for animated movies

Putting a new question at the end of an old one is a good way to get ignored. Please start a new topic.
by PhilE
Tue Jul 13, 2021 12:52 pm
Forum: Device Tree
Topic: Pi 4B u-boot devicetree loading issues on rev 1.4 boards
Replies: 3
Views: 365

Re: Pi 4B u-boot devicetree loading issues on rev 1.4 boards

I don't recommend the use of a static DTB loaded by U-boot - there are several changes applied by the firmware that allow us to reduce the number of DTBs that shipped with each kernel and take advantage of early processing time by the VPU, including generating a KASLR seed. You didn't say why you we...
by PhilE
Sun Jul 11, 2021 5:18 pm
Forum: Compute Module
Topic: [SOLVED] CM4 PMIC not switched off
Replies: 8
Views: 559

Re: CM4 PMIC not switched off

Thanks - I understood that bit, but don't have any suggestions yet.
by PhilE
Sun Jul 11, 2021 1:01 pm
Forum: Compute Module
Topic: [SOLVED] CM4 PMIC not switched off
Replies: 8
Views: 559

Re: CM4 PMIC not switched off

Don't use gpio-poweroff unless you have external hardware to cut the power - it will have the opposite effect and prevent shutdown (unless you are running a very new kernel which allows a fallback to a normal shutdown after a 3 second timeout).
by PhilE
Fri Jul 09, 2021 2:31 pm
Forum: Device Tree
Topic: [SOLVED] How to connect GT911 touch display on Compute Module 4 with I2C1 interface ?
Replies: 12
Views: 710

Re: How to connect GT911 touch display on Compute Module 4 with I2C1 interface ?

Note that it isn't necessary to open the README file and search for an overlay - the dtoverlay command can do that for you: pi@raspberrypi:~$ dtoverlay -h goodix Name: goodix Info: Enables I2C connected Goodix gt9271 multiple touch controller using GPIOs 4 and 17 (pins 7 and 11 on GPIO header) for i...
by PhilE
Wed Jul 07, 2021 8:27 pm
Forum: Compute Module
Topic: CM4 NVME Boot Setup Fail - SOLVED
Replies: 13
Views: 652

Re: CM4 NVME Boot Setup Fail

There is a pending change to the documentation that should help to avoid confusion: https://github.com/raspberrypi/document ... 86bb9a4faf
by PhilE
Wed Jul 07, 2021 4:04 pm
Forum: Troubleshooting
Topic: USB not working, VL805 CURRENT: 00000000
Replies: 29
Views: 1495

Re: USB not working, VL805 CURRENT: 00000000

Unfortunately that means the EEPROM also thinks the USB interface is faulty. As a result it won't even try the card reader (I didn't expect you to buy one specially - I hope you find some other use for it).

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