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by notro
Sat May 21, 2016 4:46 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DMA from parallel FIFO via gpio
Replies: 3
Views: 1291

Re: DMA from parallel FIFO via gpio

I haven't used it myself, but the secondary memory interface has a dma capable driver: https://github.com/raspberrypi/linux/commit/e19c303e7d54d986e0bd3e47107a83e30329c1d0 Servoblaster uses dma to drive gpios and judging from the readme it uses pwm to pace it: https://github.com/richardghirst/PiBits...
by notro
Thu May 19, 2016 11:56 am
Forum: Device Tree
Topic: Pi 3 Problem with stmpe-i2c and device tree
Replies: 8
Views: 3020

Re: Pi 3 Problem with stmpe-i2c and device tree

fragment0 shouldn't be necessary and you need pullup on the irq line unless you have an external pullup. Apart from that I looks ok to me. I don't think you will find anything in the stmpe code since it fails on the very first read: reg=0, but one step further would be to know which of the 2 possibi...
by notro
Thu May 19, 2016 11:21 am
Forum: Device Tree
Topic: Pi 3 Problem with stmpe-i2c and device tree
Replies: 8
Views: 3020

Re: Pi 3 Problem with stmpe-i2c and device tree

It doesn't look that way, but the i2c adapter is really probed before the client. It's just that the bcm2708_i2c probed message is printed after the adapter registration which already has added and probed the client devices. Callchain: bcm2708_i2c_probe -> i2c_add_numbered_adapter -> __i2c_add_numbe...
by notro
Sat Apr 30, 2016 2:05 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DSI LCD
Replies: 14
Views: 37115

Re: DSI LCD

I see that Eric Anholt has done some work on adding dsi support to his vc4 driver.
Development branch: https://github.com/anholt/linux/commits/drm-vc4-dsi
by notro
Sat Mar 12, 2016 2:06 pm
Forum: Device Tree
Topic: Overlay for settiing output high at boot
Replies: 4
Views: 3433

Re: Overlay for settiing output high at boot

A pinctrl node is applied during driver probing, so it has to be connected to a device. You can for instance connect it to the gpio node which is free. However that won't change the output value of the gpio. You can only set function/mux and pull (for inputs): https://www.kernel.org/doc/Documentatio...
by notro
Thu Mar 10, 2016 1:49 pm
Forum: Advanced users
Topic: FBTFT and dynamic loading
Replies: 2
Views: 509

Re: FBTFT and dynamic loading

Is it possible to reinit the screen without rebooting whole raspbian
The only other way is to reload the driver/module.
by notro
Sun Feb 14, 2016 1:49 pm
Forum: Raspbian
Topic: How to deactivate serial connection during boot
Replies: 16
Views: 4577

Re: How to deactivate serial connection during boot

You are booting without DT support: [ 0.000000] Machine: BCM2708 This is what it looks like when you boot with Device Tree: [ 0.000000] Machine model: Raspberry Pi 2 Model B Rev 1.1 And you would have a folder: /proc/device-tree/ The mkknlimg script is used to tag the kernel so the bootloader knows ...
by notro
Sat Feb 13, 2016 8:25 pm
Forum: Raspbian
Topic: How to deactivate serial connection during boot
Replies: 16
Views: 4577

Re: How to deactivate serial connection during boot

How to remove "Uncompressing Linux... done, booting the kernel." on the uart. At least 3 ways: 1. Let the firmware set the uart pins as outputs during decompression and switch to regulart uart function later when the pinctrl driver is probed: https://github.com/raspberrypi/linux/pull/887#issuecommen...
by notro
Mon Feb 08, 2016 1:12 pm
Forum: Advanced users
Topic: Raspberry Pi 2 L2 Cache Controller
Replies: 5
Views: 1513

Re: Raspberry Pi 2 L2 Cache Controller

as far as I can tell there is no custom code in arch/arm/mach-bcm2709
arch/arm/mach-bcm2709/include/mach/memory.h
@popcornmix has provided a detailed explanation here: http://lists.denx.de/pipermail/u-boot/2 ... 08201.html
by notro
Wed Feb 03, 2016 10:06 am
Forum: Official Foundation Display
Topic: How to PWM backlight of rpi-display-overlay
Replies: 1
Views: 1569

Re: How to PWM backlight of rpi-display-overlay

The pwm driver seems to have an issue with the clock so it's not working out-of-the-box yet: https://github.com/raspberrypi/linux/issues/1175
You can do it manually with wiringpi: https://github.com/notro/fbtft/wiki/Bac ... e-of-fbtft
by notro
Tue Jan 26, 2016 6:02 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 50837

Re: HOWTO: Enable USB device mode on Pi Zero

I've made a systemd service that loads g_ether with static mac addresses: https://github.com/RPi-Distro/repo/issu ... -175140984
by notro
Tue Jan 19, 2016 9:33 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 50837

Re: HOWTO: Enable USB device mode on Pi Zero

That will add "dwc2" to the end of /etc/modules I had a play with it the other day and AFAICT you actually don't need that entry in /etc/modules. You're right, dwc2 is automatically loaded by udev, but this happens after /etc/modules is processed so if a gadget module is loaded in /etc/modules, dwc...
by notro
Mon Dec 28, 2015 2:52 pm
Forum: Device Tree
Topic: Cannot get GPIO pulls to work with Overlay
Replies: 11
Views: 3840

Re: Cannot get GPIO pulls to work with Overlay

Ok, gpio hogs can't help you out, because you want control over the gpios later by the application. Any gpio that Linux uses is claimed/requested and can't be used by anyone else, until it's released. Like for instance the led driver has requested gpio 47 for ACT and I can't use it for anything else...
by notro
Mon Dec 28, 2015 10:04 am
Forum: Device Tree
Topic: Cannot get GPIO pulls to work with Overlay
Replies: 11
Views: 3840

Re: Cannot get GPIO pulls to work with Overlay

How about this suggestion (not tried), hogging will request the gpio, so it won't be available for anyone to change the value later. You should get a message in the kernel for each hog (dmesg). /dts-v1/; /plugin/; /{ compatible = "brcm,bcm2708"; [email protected] { target = <&gpio>; #address-cells = <1>; #...
by notro
Sun Dec 27, 2015 9:27 pm
Forum: Device Tree
Topic: Cannot get GPIO pulls to work with Overlay
Replies: 11
Views: 3840

Re: Cannot get GPIO pulls to work with Overlay

AFAIK the only way to set a gpio output value directly from Device Tree without having a driver do it, is to use a gpio hog. I haven't tried it myself. See https://www.kernel.org/doc/Documentation/devicetree/bindings/gpio/gpio.txt The hogging happens during the gpio/pinctrl driver probing. Call chai...
by notro
Thu Dec 17, 2015 6:55 pm
Forum: Advanced users
Topic: Device Tree with 4.1.12 kernel ptxdist build
Replies: 5
Views: 1201

Re: Device Tree with 4.1.12 kernel ptxdist build

How about if an appropriate dtb exists in the boot partition pass it to the kernel and if not use atags?
This way we don't break kernels/os that don't use DT, but with the benefit that we don't have to tag DT kernels.
This would of course have to wait until we only use 2835/2836 dtbs.
by notro
Fri Dec 11, 2015 10:59 pm
Forum: Advanced users
Topic: input events on GPIO
Replies: 15
Views: 4257

Re: input events on GPIO

Verify that the overlay is loaded: sudo vcdbg log msg
You can also check for the DT node: ls -l /proc/device-tree/soc

You set status= "disabled", that is not necessary. Activating the overlay means you want this node, so no need for an extra overlay parameter to activate it.
by notro
Wed Dec 09, 2015 9:50 pm
Forum: Advanced users
Topic: input events on GPIO
Replies: 15
Views: 4257

Re: input events on GPIO

Check if the gpio-keys module is loaded: lsmod I'm not sure if it autoloads. If it doesn't add gpio-keys to /etc/modules Load manually: sudo modprobe gpio-keys When the gpio keyboard is registered it will be a note in the kernel log: dmesg You can use evtest to test input devices (sudo apt-get insta...
by notro
Wed Dec 09, 2015 12:25 pm
Forum: Advanced users
Topic: input events on GPIO
Replies: 15
Views: 4257

Re: input events on GPIO

linux,code It's in the comment preceeeding the fragment: Values for input event code is found under the 'Keys and buttons' heading in include/uapi/linux/input.h https://www.kernel.org/doc/Documentation/devicetree/bindings/input/gpio-keys.txt The pinctrl node is needed only if you want to change the...
by notro
Wed Dec 09, 2015 11:14 am
Forum: Advanced users
Topic: input events on GPIO
Replies: 15
Views: 4257

Re: input events on GPIO

by notro
Wed Nov 18, 2015 12:27 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple spi screens to a single pi
Replies: 7
Views: 1673

Re: Multiple spi screens to a single pi

Then I guess the overlay doesn't support txbuflen as a parameter.
Here's an example of one that does: https://github.com/raspberrypi/linux/bl ... verlay.dts
by notro
Wed Nov 18, 2015 12:31 am
Forum: Advanced users
Topic: systemv init processing in jessie
Replies: 2
Views: 3201

Re: systemv init processing in jessie

I don't know much about systemd so I took this opportunity to have a closer look. On boot systemd converts the init.d/rc scripts to systemd service units using systemd-sysv-generator. Converted scripts have LSB in their description: ~$ systemctl list-units --type=service | grep LSB console-setup.ser...
by notro
Mon Nov 16, 2015 9:06 pm
Forum: Advanced users
Topic: serial port in jessie
Replies: 7
Views: 2583

Re: serial port in jessie

According to http://0pointer.de/blog/projects/serial-console.html it should be enough to remove 'console=' from /boot/cmdline.txt, but I haven't tried this myself (I have a long running test that I don't want to interrupt). ~$ cat /proc/cmdline | tr -s " " "\n" | grep console console=tty1 console=tt...
by notro
Mon Nov 16, 2015 12:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple spi screens to a single pi
Replies: 7
Views: 1673

Re: Multiple spi screens to a single pi

Framerate is an issue though, any ideas how I can overcome that I suggest increasing txbuflen as mentioned here: https://github.com/notro/fbtft/wiki#install You can also set fps=50 (this is really the delay between updates: fps/100 jiffies, default fps=20) And increasing speed as mentioned. https:/...
by notro
Mon Nov 09, 2015 9:40 pm
Forum: Advanced users
Topic: Change GPIO on poweroff
Replies: 9
Views: 2216

Re: Change GPIO on poweroff

What exactly is the purpose of that GPIO overlay?
AFAIK it turns on a gpio at poweroff. I found this post: viewtopic.php?f=107&t=113789

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