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by PhilE
Wed May 23, 2018 8:24 pm
Forum: Device Tree
Topic: wiringpi, aarch64, /proc/cpuinfo, /proc/device-tree...
Replies: 2
Views: 84

Re: wiringpi, aarch64, /proc/cpuinfo, /proc/device-tree...

aarch64 has abandoned the board-specific machine/board files (which is where the downstream kernel sets the serial number), and we don't want to change that. However we can guarantee that the firmware will continue to set the property in Device Tree, so that is the most future-proof place to retriev...
by PhilE
Wed May 23, 2018 4:16 pm
Forum: Device Tree
Topic: Loading of kernel module with overlay
Replies: 12
Views: 225

Re: Loading of kernel module with overlay

At least we're on the right track.

Googling for "linux kernel udev modprobe kmod" (and subsets thereof) turns up quite a bit of useful information.
by PhilE
Wed May 23, 2018 9:09 am
Forum: Device Tree
Topic: Loading of kernel module with overlay
Replies: 12
Views: 225

Re: Loading of kernel module with overlay

The kernel has the ability to request that a specific named module is loaded, which it does by spawning an instance of /sbin/modprobe to load it; on Raspbian this is a symlink to /bin/kmod. The executable can also be changed by writing the preferred path to /proc/sys/kernel/modprobe. You can debug w...
by PhilE
Tue May 22, 2018 8:34 pm
Forum: Device Tree
Topic: Loading of kernel module with overlay
Replies: 12
Views: 225

Re: Loading of kernel module with overlay

You can grab binaries of dtoverlay and libdtovl.so from opt/vc/bin and opt/vc/lib in the firmware repo.
by PhilE
Tue May 22, 2018 8:21 pm
Forum: Device Tree
Topic: Loading of kernel module with overlay
Replies: 12
Views: 225

Re: Loading of kernel module with overlay

It does sound like something is wrong with your system. When the kernel encounters a device node it essentially sends a message containing an alias, causing a module to be loaded. You can monitor this by running: udevadm monitor > udev.txt & (or run it without the redirection in another shell) This ...
by PhilE
Tue May 22, 2018 7:38 pm
Forum: Device Tree
Topic: Loading of kernel module with overlay
Replies: 12
Views: 225

Re: Loading of kernel module with overlay

The README entry for the mcp3008 overlay (which you can get by running "$ dtoverlay -h mcp3008" under Raspbian) says: Name: mcp3008 Info: Configures MCP3008 A/D converters For devices on spi1 or spi2, the interfaces should be enabled with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays. Load: d...
by PhilE
Tue May 22, 2018 3:44 pm
Forum: Compute Module
Topic: Installing Image on CM3 twice failing
Replies: 13
Views: 270

Re: Installing Image on CM3 twice failing

Assuming that the second and third results are genuinely identical and not a cut-and-paste error, the next thing I would try would be to compare the boot partitions between the two Alpine images: sudo mount /dev/sdb1 /mnt; sudo find /mnt -type f -exec md5sum {} \; > sums.txt; sudo umount /mnt (or si...
by PhilE
Tue May 22, 2018 2:13 pm
Forum: Compute Module
Topic: Installing Image on CM3 twice failing
Replies: 13
Views: 270

Re: Installing Image on CM3 twice failing

You're more likely to get answers if you can detail the steps in making your custom image, but you could start by posting the output from: $ sudo fdisk -l /dev/mmcblk0 from 1. a working Raspbian, 2. a working Alpine OS installed clean from one of your images, and 3. with the CM3 in slave mode, plugg...
by PhilE
Tue May 22, 2018 1:00 pm
Forum: Beginners
Topic: Why are my questions not being seen on this forum?
Replies: 12
Views: 379

Re: Why are my questions not being seen on this forum?

Like JamesH I don't see any sarcasm here, just the kind of answers one should expect given the spirit in which the question was asked.

The entry in the Moderator logs for the original post says "trolling" - somebody mustn't have liked the tone...
by PhilE
Tue May 22, 2018 12:47 pm
Forum: Compute Module
Topic: Installing Image on CM3 twice failing
Replies: 13
Views: 270

Re: Installing Image on CM3 twice failing

It sounds baffling.

1. Can you clarify what happens when you install Raspbian over the broken Alpine OS?

2. What evidence is there to suggest that you can't simplify your report to say "Installing Alpine OS on CM3 doesn't work"?
by PhilE
Sun May 20, 2018 4:39 pm
Forum: Device Tree
Topic: enable_uart=1 does NOT set core_freq=250
Replies: 3
Views: 168

Re: enable_uart=1 does NOT set core_freq=250

Yes, you've got it. This is a subject that often causes confusion - the goal was to get the best performance out of the system while still giving control to the users, but this had led to a subtle interconnection between the enable_uart and core_freq settings and various uart- and bluetooth-related ...
by PhilE
Fri May 18, 2018 11:57 am
Forum: Compute Module
Topic: Please help to Remap pin Uart 0
Replies: 26
Views: 1655

Re: Please help to Remap pin Uart 0

I've been looking into the issue of why the UART is left maped to GPIOs 14 and 15, and the answer is essentially because the firmware is not expecting it to move. Only Compute Modules are able to make use of the GPIOs above 27, so the firmware assumes that the primary UART (the one not used by Bluet...
by PhilE
Thu May 17, 2018 5:24 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

Yes, your understanding is correct - the CM uses a 1.8V voltage reference for the SD interface on 48-53. I haven't found a code path where providing a fixed 1.8V vqmmc makes a useful difference - it will just run more core before returning an error - but in terms of describing the hardware it is mor...
by PhilE
Thu May 17, 2018 3:08 pm
Forum: Compute Module
Topic: Please help to Remap pin Uart 0
Replies: 26
Views: 1655

Re: Please help to Remap pin Uart 0

Having had a chance to try myself, I can see that the problem is your alt function for 36 and 37. Alt3 (7) for 36 and 37 is SD1_DAT0&1 - you want Alt2 (6), which works once you set 14 and 15 to inputs. I hope to have an answer to the lack of unmapping of 14 and 15 soon.
by PhilE
Thu May 17, 2018 2:24 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

I never said it's changeable.
Then please explain this statement:
Without providing a fixed regulator the MMC core doesn't have any chance to know the IO line power and assume 3.3 V. This is correct for most of the Raspberry Pis except the Compute Modules.
by PhilE
Thu May 17, 2018 2:00 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

> Without providing a fixed regulator the MMC core doesn't have any chance to know the IO line power and assume 3.3 V. This is correct for most of the Raspberry Pis except the Compute Modules.

What makes you think it is changeable? The EMMC is hard-wired to GPIOs 48-53, which aren't affected by J3.
by PhilE
Thu May 17, 2018 1:37 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

The regulator voltages are correct, but the bindings document says: Controllers may implement power control from both the connected cards and the IO signaling (for example to change to high-speed 1.8V signalling). If the system supports this, then the following two properties should point to valid r...
by PhilE
Thu May 17, 2018 1:21 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

That's correct - the EMMC RSTN is tied high. I'm not sure why you would be confused, since the schematics are published here . GPIO47 provides the SoC's input to the logic that allows the user to choose to boot from EMMC or USB (but with the ability to access EMMC after boot). It also drives the ACT...
by PhilE
Thu May 17, 2018 12:52 pm
Forum: Device Tree
Topic: Review: eMMC part on CM1
Replies: 11
Views: 196

Re: Review: eMMC part on CM1

What is your intention with the EMMC pwrseq support? Lowering EMMC_DISABLE_N won't reset the EMMC device, only disconnect the CMD line.
by PhilE
Wed May 16, 2018 11:15 am
Forum: Compute Module
Topic: Please help to Remap pin Uart 0
Replies: 26
Views: 1655

Re: Please help to Remap pin Uart 0

Having the same pin function, especially input functions, mapped to multiple pins is usually a bad idea, so I think the investigation is going to split into two halves: does unmapping the UART from 14 and 15 allow it to work on 36 and 37, and how to automatically unmap it from 14 and 15. For 1, afte...
by PhilE
Mon May 14, 2018 8:17 am
Forum: Device Tree
Topic: enable_uart=1 does NOT set core_freq=250
Replies: 3
Views: 168

Re: enable_uart=1 does NOT set core_freq=250

You need to read that section of the documentation together with the preceding paragraph: Also, when the Linux console uses the mini UART (Raspberry Pi 3, Raspberry Pi Zero W), as a consequence of the UART being disabled, the console is also disabled. The Linux console can be re-enabled by adding en...
by PhilE
Sun May 13, 2018 7:06 pm
Forum: Device Tree
Topic: Two drivers using same gpio pin
Replies: 10
Views: 725

Re: Two drivers using same gpio pin

I've merged the PR, so the updated driver and overlay will be in the next firmware release.
by PhilE
Sat May 12, 2018 10:18 am
Forum: General discussion
Topic: Controlling LAN LEDs individually
Replies: 34
Views: 14566

Re: Controlling LAN LEDs individually

This is currently a Pi 3B+-specific feature. The default LED modes weren't very useful so we had to change the LAN7800 driver anyway, and making the modes user-selectable was a simple extension.
by PhilE
Fri May 11, 2018 2:29 pm
Forum: Linux Kernel
Topic: How to enable wlan0 in raspberry pi3
Replies: 6
Views: 185

Re: How to enable wlan0 in raspberry pi3

Thanks for the correction!
by PhilE
Fri May 11, 2018 11:57 am
Forum: Device Tree
Topic: ads7846 on spi1
Replies: 44
Views: 1549

Re: ads7846 on spi1

The swap-xy parameter swaps the axes - x becomes y and vice versa, whereas we want to invert both axes. As I understand it, lcd_rotate reprograms the panel to change the orientation, which is more efficient than rotating the framebuffer, but I can see why it may not work for an arbitrary display. Yo...

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