[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-345680 

test ov5640 with 480p, raw10 via ISP on imx8mp

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-341996 

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-342420 

Following OTA in Android User Guide would have HASH verification error: update_engine: [0913/085233.421711:ERROR:delta_performer.cc(1140)] Expected: sha256|hex = 685B998E4308F20FEA83D97E60222121FFE27983F013AED5C203709E139AE9DB update_engine: [0913/085233.421760:ERROR:delta_performer.cc(1143)] Calculated: sha256|hex = B1025634138BF2B5378196E364350E1E5FCA126DEE0990A592290CEBFADC3F8B The OTA process that produced the error: * After compiling the images according to the user guide, burn the images in the /out directory into the board * Then build the first target file according to 7.1.1 Building target files, such as PREVIOUS-target_files.zip * Modify part of the code to build the second target file, such as NEW-target_files.zip: * Make a differential upgrade package and perform differential OTA The root cause of the error caused by the above steps: Differential OTA requires that the onboard system.img must be the system.img generated when the target files are created for the first time. Only in this way can the correct hash value be calculated. When we execute the following command to make target files make target-files-package -j4 Will repackage a copy of system.img in the /out directory and this system.img does not meet the requirements. The system.img used by the differential package must be system.img in out/target/product/evk_8mm/obj/PACKAGING/systemimage_intermediates/. Therefore, the system.img we burned in the first step did not meet the requirements, resulting in hash verification errors. Solution 1: After the first step of programming, do a full update. When using the make otapackage -j4 command, a target_files.zip file will also be generated, which we will regard as PREVIOUS-target_files.zip. Modify part of the code and make NEW-target_files.zip. Finally, the differential upgrade can be successful. Solution 2: After finishing the first target_files.zip, copy the system.img in out/target/product/evk_8mm/obj/PACKAGING/systemimage_intermediates/ to the out/target/product/evk_8mm directory, and then use uuu Perform programming. After burning and writing, make the second target_files.zip, and finally you can upgrade by differential.

After rework the board, enable two OTG controllers in Linux DTB file and disable VBUS valid comparator when in suspend mode by clear USB_OTGx_PHY_CTL2 bit 16.  Then we get the following power data on suspend mode  Suspend Mode     ****  The page is under internal check ****

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-343007 

Dynamic debug is designed to allow you to dynamically at runtime  enable/disable  kernel code to obtain additional kernel information. Currently, if ``CONFIG_DYNAMIC_DEBUG`` is set, then all ``pr_debug()``/``dev_dbg()`` and ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically enabled per-callsite.    

[中文翻译版] 见附件   原文链接： eIQ Machine Learning Software for i.MX Linux 4.14.y 

This is a simple document for recording some known-how and tips for building up the Windows 10 IoT development environment for i.MX platform. It can only be used as a complement for official document in BSP package (Guide/Release Note/etc.). Applicable for: Windows 10 IoT, i.MX BSP v1.4.1 (date to Nov/2023) Please refer to the PDF attached.

Debian is a free to use and redistribute Linux distribution that is widely used by the community for industrial and desktop applications.  This distribution started in 1993 as Debian Project with Ian Murdock inviting developers to contribute in one of the first Linux distributions.  Debian takes an important role in Linux world with a clear idea about be a full featured and free distribution with over than 59,000 packages provided as a free to use and distribute that supports a wide range of functionalities.  Currently, Debian 12 supports 9 architectures which makes it in a universal operating system that can be implemented in embedded systems, desktops or servers.  Finally, Debian has been an inspiration for well-known Linux distributions such as Kali and Ubuntu.  In this guide we will check the installation process of Debian 12 for NXP microprocessors i.MX family, specifically for i.MX8M Mini, i.MX8M Nano, i.MX8M Plus and i.MX93.  For this purpose, we divided the document in the following topics: Hardware Requirements Software Requirements Host Preparation SD Card Preparation Copying Bootloader  Copying Kernel and DTB files Debian Installation Configure Base System Boot your target References   Hardware Requirements Linux Host computer (Ubuntu 20.04 or later) USB Card reader or Micro SD to SD adapter SD Card Evaluation Kit Board for the i.MX8M Nano, i.MX8M Mini, i.MX8M Plus or i.MX93   Software Requirements Linux Ubuntu (20.04 and 24.04 tested) or Debian for host BSP version 6.1.55 for your specific target (Embedded Linux for i.MX Applications Processors | NXP Semiconductors)   Host Preparation For Debian installation we will require some specific packages for host.  You can download the packages using the following command: $ sudo apt install debian-archive-keyring debootstrap qemu-user-static We must validate the key to verify the archive using the command: $ sudo apt-key add /usr/share/keyrings/debian-archive-keyring.gpg If running an older release you need to get the unstable keyring package (because the version in your release is probably too old to have the current key) $ wget http://ftp.debian.org/debian/pool/main/d/debian-archive-keyring/debian-archive-keyring_2023.4_all.deb $ sudo dpkg -i debian-archive-keyring_2023.4_all.deb   SD Card Preparation The Linux kernel running on the Linux host assigns a device node to the SD/MMC card reader. The kernel might decide the device node name or udev rules might be used. In the following instructions, it is assumed that udev is not used. To identify the device node assigned to the SD/MMC card, carry out the following command: $ cat /proc/partitions   Partitioning the SD card On most Linux host operating systems, the SD card is mounted automatically upon insertion. Therefore, before running fdisk, make sure that the SD card is unmounted if it was previously mounted (through sudo umount /dev/sdx). Start by running fdisk with root permissions. Use the instructions above to determine the card ID. We are using sdx as an example. $ sudo fdisk /dev/sdx  Type the following parameters (each followed by <ENTER>): $fdisk: p # lists the current partitions $fdisk: d # to delete existing partitions. Repeat this until no unnecessary partitions $fdisk: n # create a new partition $fdisk: p # create a primary partition - use for both partitions $fdisk: 1 # the first partition $fdisk: 20480 # starting at offset sector $fdisk: 1024000 # ending position of the first partition to be used for the boot Images $fdisk: p # to check the partitions $fdisk: n # create a new partition $fdisk: p # create a primary partition $fdisk: 2 # the second partition $fdisk: 1228800 # starting at offset sector, which leaves enough space for the kernel, the bootloader and its configuration data $fdisk: <enter> # using the default value will create a partition that extends to the last sector of the media $fdisk: p # to check the partitions $fdisk: w # this writes the partition table to the media and fdisk exits   Copying Bootloader and Kernel In this section we will copy the bootloader and kernel image to SD card.  First, we can create a new directory to unzip the BSP downloaded from the NXP site.  $ mkdir debian-imx $ cd debian-imx $ unzip ~/Downloads/LF_v6.1.55-2.2.0_images_<board>.zip Where board is: IMX8MPEVK IMX8MNEVK IMX8MMEVK IMX93EVK Then, copy the U-Boot image. $ sudo dd if=<U-Boot_image> of=/dev/sdx bs=1k seek=<offset> conv=fsync Where offset is: 33 - for i.MX 8M Mini 32 - for i.MX 8M Nano, i.MX 8M Plus, and i.MX 9 The sectors of SD/eMMC before the “offset” KB are reserved. It may include the partition table.   Copying Kernel image and DTB files This section describes how to load the kernel image and DTB. The pre-built SD card image uses the VFAT partition for storing kernel image and DTB, which requires a VFAT partition that is mounted as a Linux drive, and the files are copied into it. This is the preferred method. Default: VFAT partition Format partition 1 on the card as VFAT with this command: $ sudo mkfs.vfat /dev/sdx1 Mount the formatted partition with this command: $ mkdir mountpoint $ sudo mount /dev/sdx1 mountpoint Copy the zImage and *.dtb files to the mountpoint by using cp. The device tree names should match $ sudo cp *.dtb mountpoint/ $sudo cp Image-<board_name>.bin mountpoint/Image Where board_name is: imx8mpevk imx8mnevk imx8mmevk imx93evk the one used by the variable specified by U-Boot. Unmount the partition with this command: $ sudo umount mountpoint   Debian Installation For Debian installation we will use the official tool debootstrap. This tool allows us to install Debian without a disk and run the system using qemu in a different architecture.  Before using debootstrap tool we need to format and mount the second partition of the SD card with the commands below: $ sudo mkfs.ext4 /dev/sdx2 $ sudo mount /dev/sdx2 mountpoint/ debootstrap can download the needed files directly from the archive when you run it. You can substitute any Debian archive mirror for http.us.debian.org/debian in the command below, preferably a mirror close to you network-wise. Mirrors are listed at http://www.debian.org/mirror/list $ sudo debootstrap --arch arm64 --foreign bookworm mountpoint/ http://ftp.debian.org/debian This step takes a while and depends on the resources of your host machine.   Configure Base System Now you’ve got a real Debian system, though rather lean, on disk. chroot into it: $ sudo cp /usr/bin/qemu-aarch64-static mountpoint/usr/bin $ sudo LANG=C.UTF-8 chroot mountpoint/ qemu-aarch64-static /bin/bash After chrooting you may need to set the terminal definition to be compatible with the Debian base system, for example: $ export TERM=xterm-color we need to finish the multi-stage boot strap $ /debootstrap/debootstrap --second-stage At this point /dev/ only contains very basic device files. For the next steps of the installation, additional device files may be needed. There are different ways to go about this and which method you should use depends on the host system you are using for the installation, whether you intend to use a modular kernel or not, and whether you want to use dynamic (e.g. using udev) or static device files for the new system. A few of the available options are: install the makedev package, and create a default set of static device files using (after chrooting) $ apt install makedev $ mount none /proc -t proc $ cd /dev $ MAKEDEV generic With these next steps we will be setting up the Debian system:   Setting fstab FSTAB is a configuration table designed to ease the burden of mounting and unmounting file systems to a machine. $ nano /etc/fstab # stock fstab - you probably want to override this with a machine specific one /dev/root / auto defaults 1 1 proc /proc proc defaults 0 0 devpts /dev/pts devpts mode=0620,ptmxmode=0666,gid=5 0 0 tmpfs /run tmpfs mode=0755,nodev,nosuid,strictatime 0 0 tmpfs /var/volatile tmpfs defaults 0 0 # uncomment this if your device has a SD/MMC/Transflash slot #/dev/mmcblk0p1 /media/card auto defaults,sync,noauto 0 0   Setting Timezone The following command allows you to choose your timezone. $ dpkg-reconfigure tzdata   Configure apt Debootstrap will have created a very basic /etc/apt/sources.list that will allow installing additional packages. However, you may want to add some additional sources, for example for source packages and security updates: $ nano /etc/apt/sources.list deb http://deb.debian.org/debian bookworm main non-free-firmware deb-src http://deb.debian.org/debian bookworm main non-free-firmware deb http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware deb-src http://deb.debian.org/debian-security/ bookworm-security main non-free-firmware deb http://deb.debian.org/debian bookworm-updates main non-free-firmware deb-src http://deb.debian.org/debian bookworm-updates main non-free-firmware Make sure to run the apt update after you have made changes to the sources list   Configure locales and keyboard To configure your locale settings to use a language other than English, install the locales support package and configure it. Currently, the use of UTF-8 locales is recommended. $ apt install locales $ dpkg-reconfigure locales To configure your keyboard (if needed): $ apt install console-setup $ dpkg-reconfigure keyboard-configuration Note that the keyboard cannot be set while in the chroot, but will be configured for the next reboot   Adding Users $ apt install sudo $ adduser imx $ usermod -aG sudo imx $ nano /etc/sudoers imx ALL=(ALL:ALL) ALL   Tasksel Installation As mentioned earlier, the installed system will be very basic. If you would like to make the system a bit more mature, there is an easy method to install all packages with “standard” priority: $ tasksel install standard $ apt clean $ exit $ sudo umount mountpoint/ $sync   Boot your target Now, you can boot your target from your SD Card. (Review your specific target documentation)   Configure Networking (after booting target) Based on Debian official documentation for new systems the common names for network interfaces such as eth0 or wlan0 are not used. Therefore, we will need to list the interfaces using: $ ls /sys/class/net To have ethernet connection we will need to create a file in the path etc/network/. $ sudo nano etc/network/interfaces Type the following commands on the file: auto lo iface lo inet loopback auto end0 iface end0 inet dhcp   Install Neofetch (Optional) $ apt install neofetch   Outputs  Debian 12 running on i.MX8MP Debian 12 running on i.MX93   References Chapter 1. Definitions and overview. (2021, January). Retrieved May 30, 2024, from https://www.debian.org/doc/manuals/debian-faq/basic-defs.en.html Debian GNU/Linux Installation Guide. (2024). https://www.debian.org/releases/stable/i386/install.en.pdf Arm64Port. (n.d.). https://wiki.debian.org/Arm64Port i.MX Linux User's Guide (nxp.com)

Why SWPDM?   In order to process human voice, it is required to have the best audio resolution in the incoming data captured by the microphones. This mean, having a resolution of 16bits is not enough to capture all the information to properly process the voice. Voice processing requires a peripheral capable of capture data on a 32bits resolution within the range of the most common sample rates (16kHz, 44.1kHz, 48Khz, etc.). On the i.MX8M family there is a peripheral which fulfill those requirements and is called MICFIL. MICFIL is a peripheral which convert PDM (Pulse Density Modulation) data to PCM (Pulse-Code Modulation) data. The PDM format encode the analog signal in just one bit. Where 1 means the signal is increasing in amplitude while 0 means the opposite. In the other hand, the PCM format encode the data in 8, 16, or 32 bits. The advantage of PDM is that the creation of microphones is cheaper than having PCM microphones but then you will need a software or hardware which do the conversion for PDM to PCM since PDM cannot be processed. This is the reason of the MICFIL peripheral. However, not all the MICFIL's on the difference SOMs are the same. While the i.MX8MPLUS has a resolution of 32bits its smaller brothers do not. i.MX8MMINI and i.MX8MNANO have a MICFIL which only allows a resolution up to 16bits. For most of the cases it will be enough but not for voice processing. Nevertheless, not everything is lost; As mentioned previously, the PDM to PCM conversation can be done by hardware or by software. NXP also have the algorithm in software to do the conversation. Therefore, if a Mini or Nano is being used for voice processing it is fully recommended to use the ALSA SWPDM Plugin and avoid MICFIL peripheral.   Using the Plugin   In order to use the plugin, it is required to change the DTB to  imx8mm-evk-8mic-swpdm.dtb , when using the i.MX8MM or  imx8mn-evk-8mic-swpdm.dtb , when using the i.MX8MN. In order to do so follow the next steps: Please notice below example if for Mini. For Nano will be the same just changing the DTB name to imx8mn-evk-8mic-swpdm.dtb. # Stop at U-boot u-boot=> edit fdtfile edit: imx8mm-evk-8mic-swpmd.dtb u-boot=> saveenv u-boot=> boot   The change in the DTB is required to disable MICFIL so Linux can receive the raw data and sent it to the plugin. However, the plugin is not enabled by default, users need to explicit add the plugin to their ALSA pipeline. The way of doing so is by adding the following device to  /etc/asound.conf : pcm.cic { type cicFilter slave "hw:imxswpdmaudio,0" delay 100000 gain 0 OSR 48 }   Where: pcm.cic : Is an arbitrary name which allow ALSA to find the requested devices when setting the  -D  flag with  arecord  or  aplay . type cicFilter : This is the plugin type which is named with the algorithm name. slave: Name of the physical or virtual device which will be controlled by the cicFilter plugin. The recommendation is to always have the actual hardware connected to this plugin. delay : Amount of time in microsecond which the plugin won't write to the buffer, but it still does the conversion. The value could be between 100us to 1'000,000us. By removing the property from the structure, the delay will be set to 0. gain : A value between 0 and 100. OSR : Is related to the quality of the signal by increasing the PDM sample rate. With a higher valuer a best quality on the audio can be achieved. However, keep in mind than having a higher value will also require more memory to store all the new data due to the oversampling. The valid values for the OSR are: 48, 64, 96, 128, and 192. With all being said, the only thing left is to test the plugin by running the following command: $ arecord -D cic -c4 -r16000 -f s32_le --period-size=96 -d5 -v test.wav   Integration With AFE   The next and final step is integrating the plugin with AFE and VoiceSeeker. The integration of SWPDM requires to apply a patch to the SWPDM repository. The patch changes the amount of period sizes allowed on the plugin. By default, the plugin only allows certain values which are:  48 Samples = 3ch x 4bytes format x 16samples = 192 bytes. 48 Samples = 2ch x 4bytes format x 48samples = 384 bytes. 48 Samples = 4ch x 4bytes format x 48samples = 768 bytes. 96 Samples = 4ch x 4bytes format x 96samples = 1,536 bytes. Although, AFE and VoiceSeeker are extremely configurable, 48 or 96 samples for the algorithm is too small. Meaning that the SWPDM should support a bigger period size, not all the way around. By applying the attached file, the plugin can have a period size from 64 bytes (1ch and 16 samples) up to 16,384 bytes (4ch and 1024 samples). However, the number of samples can vary depending on the OSR value and the number of channels. Once the patch has been applied in must be installed on: /usr/lib/alsa-lib (if the repository is being built on a standalone environment). AFE opens a device called mic  for capture the microphones' input. This device can have anything below it. By default, have the following definition on /etc/asound.conf  (after following the steps described on the TODO.md file). # mic represents the physical source (capture) pcm.mic { type plug slave.pcm "hw:micfilaudio,0" }   The devices opens the MICFIL driver, but on this case MICFIL is disable, which means the definition of the device must change. From above cic  device the definition can be copy and paste and then tweak one parameter. The delay must be set to 0 by removing the property or setting it explicitly on the structure. If this step if forgotten this might cause some underrun issues. The device definition will be: pcm.mic { type cicFilter slave "hw:imxswpdmaudio,0" delay 0 gain 0 OSR 48 }   The last thing to do will be running AFE with VoiceSeeker as usual. $ /unit_tests/nxp-afe/voice_ui_app & $ /unit_tests/nxp-afe/afe libvoiceseekerlight &   Considerations and Restrictions With all that said, there are few things left to mention, which are the considerations and restrictions on the plugin itself. These are good things to know before adding the plugin into any application. The plugin is supported from the Linux BSP 5.15.32. Currently the plugin only supports up to 4 channels. Plugin only outputs a S32_LE format (if required another format please use MICFIL). By applying above patch, the period size must be a multiple of 16, due to a limitation on the algorithm itself, rather than the plugin. The driver only allows to have one microphone per data-line while MICFIL allows to have two microphones per data-line. The SWPDM Plugin is based on the External Plugin: I/O Plugin. This means it also have the restriction of this ALSA plugin, being the following restriction the most important one: "The I/O-type plugin is a PCM plugin to work as the input or output terminal point, i.e. as a user-space PCM driver". In other words, there can't be any device/plugin on top of it, not even a "plug" type. 

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-342837 

[中文翻译版] 见附件   原文链接： Add a new shared memory region on Android Auto P9.0.0_GA2.1.0 BSP 

The purpose of this document is to provide a guide on how to export new symbols using the Bazel Android server instead of the build_abi.sh script. For a better reference how to build Android i.MX image please look at the next chapter 3 Building the Android Platform for i.MX in the Android User's Guide 1. Compile full AOSP or only kernel Build full AOSP: $ source build/envsetup.sh $ lunch evk_8mp-eng $ ./imx-make.sh -j8  Only build the kernel: $ ./imx-make.sh kernel -j8 2. Generic Kernel Image GKI Development Download GKI outside of android_build (MY_ANDROID). # Make sure MY_ANDROID is set to the android_build folder. $ export MY_ANDROID=`pwd` # mkdir gki && cd gki (Make sure folder gki is not inside of ${MY_ANDROID}) $ repo init -u https://android.googlesource.com/kernel/manifest -b common-android14-6.1 $ repo sync $ cd common 3. Export New Symbols Switch the kernel in this common folder from AOSP to its device, and apply the patches required for your project. In this case Android $ cd common $ git remote add device https://github.com/nxp-imx/linux-imx.git $ git remote update $ git fetch device --tags $ git checkout android-14.0.0_1.2.0 $ cd .. $ ln -s ${MY_ANDROID}/vendor/nxp-opensource/verisilicon_sw_isp_vvcam verisilicon_sw_isp_vvcam $ ln -s ${MY_ANDROID}/vendor/nxp-opensource/nxp-mwifiex nxp-mwifiex $ BUILD_FOR_GKI=yes BUILD_CONFIG=common/build.config.imx $ EXT_MODULES_MAKEFILE="verisilicon_sw_isp_vvcam/vvcam/v4l2/Kbuild" $ EXT_MODULES="nxp-mwifiex/mxm_wifiex/wlan_src" Note: Be sure that your Symbolic Link is pointing to the correct folder Open the Makefile in the following path ../gki/nxp-mwifiex/mxm_wifiex/wlan_src/ and erase some ifreq lines that will generate a No such file or directory error. #Automatically determine Android version from build information to streamline diff --git a/mxm_wifiex/wlan_src/Makefile b/mxm_wifiex/wlan_src/Makefile index 3ec5308..7b6ca47 100644 --- a/mxm_wifiex/wlan_src/Makefile +++ b/mxm_wifiex/wlan_src/Makefile @@ -139,20 +139,7 @@ CONFIG_ANDROID_KERNEL=y ifeq ($(ANDROID_PRODUCT_OUT),1) ccflags-y += -DANDROID_SDK_VERSION=$(ANDROID_SDK_VERSION) else -include $(ANDROID_BUILD_TOP)/build/make/core/build_id.mk -ifeq ($(shell echo "$(BUILD_ID)" | cut -c1),R) - ccflags-y += -DANDROID_SDK_VERSION=30 -else ifeq ($(shell echo "$(BUILD_ID)" | cut -c1),S) - ccflags-y += -DANDROID_SDK_VERSION=31 -else ifeq ($(shell echo "$(BUILD_ID)" | cut -c1),T) - ccflags-y += -DANDROID_SDK_VERSION=33 -else ifeq ($(shell echo "$(BUILD_ID)" | cut -c1),U) - ccflags-y += -DANDROID_SDK_VERSION=34 -else - # Default optimization or actions - ANDROID_SDK_VERSION := 0 - ccflags-y += -DANDROID_SDK_VERSION -endif +ccflags-y += -DANDROID_SDK_VERSION=34 endif endif endif -- Then you could update the symbol list by typing the following command. $ tools/bazel run //common:imx_abi_update_symbol_list After the build process is successful, you should get an output like the image below. Build GKI locally. $ tools/bazel run //common:kernel_aarch64_dist  You could follow the next chapters to update the GKI image to your boot image.

  Solution           

This article is rather short that only mentions the script that is needed to make an iMX93EVK act as a USB mass storage device so that whenever you connect your iMX device to a windows/linux system via USB, it should get enumerated something like a usb drive.  The storage that is used in this example is mmc so the expectation is that you have inserted a mmc card in the slot. Below is the script:- #!/bin/sh   # This composite gadget include function: # - MASS STORAGE     # # Exit status is 0 for PASS, nonzero for FAIL # STATUS=0   # Check if there is udc available, if not, return fail UDC_DIR=/sys/class/udc if test "$(ls -A "$UDC_DIR")"; then echo "The available udc:" for entry in "$UDC_DIR"/* do echo "$entry" done else STATUS=1 echo "No udc available!" exit $STATUS; fi   id=1; udc_name=ci_hdrc.0 #back_file=/dev/mmcblk1 back_file=/tmp/lun0.img   mkdir /sys/kernel/config/usb_gadget/g$id cd /sys/kernel/config/usb_gadget/g$id   # Use NXP VID, i.MX8QXP PID echo 0x1fc9 > idVendor echo 0x12cf > idProduct   mkdir strings/0x409 echo 123456ABCDEF > strings/0x409/serialnumber echo NXP > strings/0x409/manufacturer echo "NXP iMX USB Composite Gadget" > strings/0x409/product   mkdir configs/c.1 mkdir configs/c.1/strings/0x409   echo 5 > configs/c.1/MaxPower echo 0xc0 > configs/c.1/bmAttributes   mkdir functions/mass_storage.1 echo $back_file > functions/mass_storage.1/lun.0/file ln -s functions/mass_storage.1 configs/c.1/   echo $udc_name > UDC First execute the script. After that insert the g_mass_storage module in the kernel by executing :- modprobe g_mass_storage file=/dev/mmcblk1 removable=1 In the dmesg output, you will see something like below:-   After that you can connect a C type USB cable to the USB1 port of imx93evk and the other end to any USB ports of a laptop. The moment it is connected, you would be able to see a USB drive similar to what you get when we connect a pen-drive. 

What is LGVL? LVGL is a graphics library to run on devices with limited resources. LVGL is fully open-source and has no external dependencies, works with any modern MCU or MPU, and can be used with any (RT)OS or bare metal setup. https://lvgl.io/   What is Framebuffer? The Linux framebuffer (fbdev) is a Linux subsystem used to show graphics on a display, typically manipulated on the system console   How to write on the frame buffer? The device is listed on de device list typically "fb0" on iMX.   1. Stop the window manager (Weston in our BSP) $ systemctl stop weston   2. Write random data on the frame buffer with the next command: $ cat /dev/urandom > /dev/fb0   You should see colored pixels on the screen   3. Restart the window manager. $ systemctl start weston     Cross-compiling the application   1. On the host computer we will clone the LGVL repo: $ git clone https://github.com/lvgl/lv_port_linux_frame_buffer.git -b release/v8.2 $ cd lv_port_linux_frame_buffer $ git submodule update --init --recursive 2. Configure the screen resolution, rotation, and the touch input.       2.1 The resolution is configured in lines 33 and 34 of the main.c disp_drv.hor_res = 1080; disp_drv.ver_res = 1920;           2.2 Rotation configured is on lines 32 and 57 of main.c. disp_drv.sw_rotate = 3; lv_disp_set_rotation(NULL, LV_DISP_ROT_270);     2.3 The touch input is configured on line 450 of lv_drv_conf.h # define EVDEV_NAME "/dev/input/event2"   Note: In my case is on /dev/input/event2 to check the inputs use the command "evtest"   3. Compile the application using the command "make"   Note: To compile the application on your host computer you have to set the environment.   4. Share the file called "demo" with your board and execute it on the board with the command $ ./demo   Note: You have to stop the weston service to run the application.     Notes: Tested on iMX8MN EVK with BSP 6.1.36 Works on Multimedia and Full image.

Sometimes we need to use an SPI bus to communicate with sensors or another device. Unfortunately, by default on iMX8MN-EVK, we have the ECSPI2 disabled on our BSP.   We can use that peripheral on Linux enabling it in the device tree.   To enable the ECSPI2 on the device tree we have to add the next on imx8mn-evk.dtsi:     status = "okay"; }; +&ecspi2 { + #address-cells = <1>; + #size-cells = <0>; + fsl,spi-num-chipselects = <1>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_ecspi2 &pinctrl_ecspi2_cs>; + cs-gpios = <&gpio5 13 GPIO_ACTIVE_LOW>; + status = "okay"; + + spidev0: spi@0 { + reg = <0>; + compatible = "rohm,dh2228fv"; + spi-max-frequency = <500000>; + }; +}; + &fec1 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_fec1>;   On iomux node:   + pinctrl_ecspi2: ecspi2grp { + fsl,pins = < + MX8MN_IOMUXC_ECSPI2_SCLK_ECSPI2_SCLK 0x82 + MX8MN_IOMUXC_ECSPI2_MOSI_ECSPI2_MOSI 0x82 + MX8MN_IOMUXC_ECSPI2_MISO_ECSPI2_MISO 0x82 + >; + }; + + pinctrl_ecspi2_cs: ecspi2cs { + fsl,pins = < + MX8MN_IOMUXC_ECSPI2_SS0_GPIO5_IO13 0x40000 + >; + }; + pinctrl_ir_recv: ir-recv { fsl,pins = < MX8MN_IOMUXC_GPIO1_IO13_GPIO1_IO13 0x4f    after modifying and compiling the device tree you can see the device active like this:     Connection:   Test: spidev_test -D /dev/spidev1.0 -v       You can use the devsheell of yocto to make the changes:   https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/How-to-use-Devshell-to-compile-device-tree-files/ta-p/1727428

Symptoms   On i.MX8MP, when inputting a 80% duty, 0.4V-1.8V, 3KHz square wave, we observed that the system may hang. We also tested i.MX8MN and i.MX8MM and observed the same phenomenon. In i.MX8MN RM, there's a note in GPC chapter:     We believe that the issue described in this note exists not only in the iMX8MN, but also in the iMX8MP and iMX8MM. Meanwhile, there is not only a problem with power down in this issue, but also a problem with wait mode. Diagnosis   In debugging, we find that avoiding accessing LPCR_A53_AD register in imx_set_cluster_powerdown can fix the issue. So we think that due to frequently power up/down of cores, cores have chances failed to power up. When the IRQ behavior become more complex, because the IRQ is an async event, it will come in any time. if the wait mode is enabled, in some conner case, the GPC internal LPM mode state machine will run into problem, then lead to system failure. Solution   1. A workaround patch that bypass the wait mode setting during the cpuidle.. See the patch attached. 2. Will add the Note about "SCU power down should not be enabled in wait mode" to i.MX8MP and i.MX8MM RM. 3. Will try to identify this issue into errta document, ticket TKT0632147.