Hello, on this post I will explain how to record separated audio channels using an 8MIC-RPI-MX8 Board. As background about how to setup the board to record and play audio using i.MX boards, I suggest you take a look on the next post: How to configure, record and play audio using an 8MIC-RPI-MX8 Board. Requirements: I.MX 8M Mini EVK. Linux Binary Demo Files - i.MX 8MMini EVK. 8MIC-RPI-MX8 Board. Serial console emulator (Tera Term, Putty, etc.). Headphones/speakers. Waveform Audio Format WAV, known for WAVE (Waveform Audio File Format), is a subset of Microsoft’s Resource Interchange File Format (RIFF) specification for storing digital audio files. This format does not apply compression to the information and stores the audio with different sampling rates and bitrates. WAV files are larger in size compared to other formats such as MP3 which uses compression to reduce the file size while maintaining a good audio quality but, there is always some lose on quality since audio information is too random to be compressed with conventional methods, the main advantage of this format is provide an audio file without losses that is also widely used on studio. This files starts with a file header with data chunks. A WAV file consists of two sub-chunks: fmt chunk: data format. data chunk: sample data. So, is structured by a metadata that is called WAV file header and the actual audio information. The header of a WAV (RIFF) file is 44 bytes long and has the following format: How to separate the channels? To separate each audio channel from the recording we need to use the next command that will record raw data of each channel. arecord -D plughw:<audio device> -c<number of chanels> -f <format> -r <sample rate> -d <duration of the recording> --separate-channels <output file name>.wav arecord -D plughw:2,0 -c8 -f s16_le -r 48000 -d 10 --separate-channels sample.wav This command will output raw data of recorded channels as is showed below. This raw data cannot be used as a “normal” .wav file because the header information is missing. It is possible to confirm it if import raw data to a DAW and play recorded samples: So, to use this information we need to create the header for each file using WAVE library on python. Here the script that I used: import wave import os name = input("Enter the name of the audio file: ") os.system("arecord -D plughw:2,0 -c8 -f s16_le -r 48000 -d 10 --separate-channels " + name + ".wav") for i in range (0,8): with open(name + ".wav." + str(i), "rb") as in_file: data = in_file.read() with wave.open(name + "_channel_" + str(i) +".wav", "wb") as out_file: out_file.setnchannels(1) out_file.setsampwidth(2) out_file.setframerate(48000) out_file.writeframesraw(data) os.system("mkdir output_files") os.system("mv " + name + "_channel_" + "* " + "output_files") os.system("rm " + name + ".wav.*") If we run the script, will generate a directory with the eight audio channels in .wav format. Now, we will be able to play each channel individually using an audio player. References IBM, Microsoft Corporation. (1991). Multimedia Programming Interface and Data Specifications 1.0. Microsoft Corporation. (1994). New Multimedia Data Types and Data Techniques. Standford University. (2024, January 30). Retrieved from WAVE PCM sound file format: http://hummer.stanford.edu/sig/doc/classes/SoundHeader/WaveFormat/

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.

P3T1755DP is a ±0.5°C accurate temperature-to-digital converter with a -40 °C to +125 °C range. It uses an on-chip band gap temperature sensor and an A-to-D conversion technique with overtemperature detection. The temperature register always stores a 12-bit two's complement data, giving a temperature resolution of 0.0625 °C P3T1755DP which can be configured for different operation conditions: continuous conversion, one-shot mode, or shutdown mode.   The device has very good features but, unfortunately, is not supported by Linux yet!   The P31755 works very similarly to LM75, pct2075, and other compatibles.   We can add support to P3T1755 in the LM75.c program due to the process to communicate with the device is the same as LM75 and equivalents.   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.55-2.2.0/drivers/hwmon/lm75.c route: drivers/hwmon/lm75.c   The modifications that we have to do are the next:    1. We have to add the configurations to the kernel on the imx_v8_defconfig file CONFIG_SENSORS_ARM_SCMI=y CONFIG_SENSORS_ARM_SCPI=y CONFIG_SENSORS_FP9931=y +CONFIG_SENSORS_LM75=m +CONFIG_HWMON=y +CONFIG_I2C=y +CONFIG_REGMAP_I2C=y CONFIG_SENSORS_LM90=m CONFIG_SENSORS_PWM_FAN=m CONFIG_SENSORS_SL28CPLD=m    2. Add the part on the list of parts compatible with the driver LM75.c enum lm75_type { /* keep sorted in alphabetical order */ max6626, max31725, mcp980x, + p3t1755, pct2075, stds75, stlm75,   3. Add the configuration in the structure lm75_params device_params[]. .default_resolution = 9, .default_sample_time = MSEC_PER_SEC / 18, }, + [p3t1755] = { + .default_resolution = 12, + .default_sample_time = MSEC_PER_SEC / 10, + }, [pct2075] = { .default_resolution = 11, .default_sample_time = MSEC_PER_SEC / 10,   Notes: You can change the configuration of the device using .set_mask and .clear_mask, see more details on LM75.c lines 57 to 78   4. Add the ID to the list in the structure i2c_device_id lm75_ids and of_device_id __maybe_unused lm75_of_match    { "max31725", max31725, }, { "max31726", max31725, }, { "mcp980x", mcp980x, }, + { "p3t1755", p3t1755, }, { "pct2075", pct2075, }, { "stds75", stds75, }, { "stlm75", stlm75, },   + { + .compatible = "nxp,p3t1755", + .data = (void *)p3t1755 + },   5. In addition to all modifications, I modify the device tree of my iMX8MP-EVK to connect the Sensor in I2C3 of the board.  https://github.com/nxp-imx/linux-imx/blob/lf-6.1.55-2.2.0/arch/arm64/boot/dts/freescale/imx8mp-evk.dts   }; }; + + p3t1755: p3t1755@48 { + compatible = "nxp,p3t1755"; + reg = <0x48>; + }; + };   Connections: We will use the expansion connector of the iMX8MP-EVK and J9 of the P3T1755DP-ARD board.   P3T1755DP-ARD board   iMX8MP-EVK   P3T1755DP-ARD ----> iMX8MP-EVK J9              ---------->            J21 +3v3 (Pin 9) ---> +3v3 (Pin 1) GND(Pin 7) ---> GND (PIN 9) SCL (Pin 4) ---> SCL (Pin 5) SDA (Pin 3) ---> SDA (Pin 3)     Reading the Sensor We can read the sensor using the next commands:   Read Temperature: $ cat /sys/class/hwmon/hwmon1/temp1_input Reading maximum temperature: $ cat /sys/class/hwmon/hwmon1/temp1_max Reading hysteresis: $ cat /sys/class/hwmon/hwmon1/temp1_max_hyst   https://www.nxp.com/design/design-center/development-boards-and-designs/analog-toolbox/arduino-shields-solutions/p3t1755dp-arduino-shield-evaluation-board:P3T1755DP-ARD    

Sometime need standalone compile device tree. Only Linux headers and device tree directory are needed.         

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.

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. 

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

  Environment i.MX8MP EVK, SDK2.15   The default rpmsg buffer size in SDK is 512Bytes(16 Bytes header + 496Bytes payload). This knowledge base will try to change the default buffer size in rpmsg framework. Steps:   1.Modify rpmsg payload size in SDK PATH: SDK\evkmimx8mp_rpmsg_lite_str_echo_rtos_imxcm7\rpmsg_config.h     //! RL_BUFFER_PAYLOAD_SIZE //! //! Size of the buffer payload, it must be equal to (240, 496, 1008, ...) //! [2^n - 16]. Ensure the same value is defined on both sides of rpmsg //! communication. The default value is 496U. #define RL_BUFFER_PAYLOAD_SIZE (1008)     2. Modify buffer size in rpmsg linux framework and buffer pool in dts. PATH: drivers/rpmsg/virtio_rpmsg_bus.c            arch/arm64/boot/dts/freescale/imx8mp-evk-rpmsg.dts   Test steps:   Modify the send buffer in imx_rpmsg_tty.c     #define MSG "hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world! hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world! hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!"       Modify buffer limitation in SDK PATH: evkmimx8mp_rpmsg_lite_str_echo_rtos_imxcm7\main_remote.c     /* Globals */ static char app_buf[1024]; /* Each RPMSG buffer can carry less than 512 payload */       Terminal output We can see that the MAX buffer size received in SDK is not limited to 512Bytes     Nameservice sent, ready for incoming messages... Get Message From Master Side : "hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world! hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world! hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!hello world!" [len : 674]       If we use a larger buffer like 2022 Bytes, we will see error when driver load.     [ 2673.447384] imx_rpmsg_tty virtio0.rpmsg-virtual-tty-channel-1.-1.30: message is too big (2022) [ 2673.456271] imx_rpmsg_tty virtio0.rpmsg-virtual-tty-channel-1.-1.30: rpmsg_send failed: -90 [ 2673.465556] imx_rpmsg_tty virtio0.rpmsg-virtual-tty-channel-1.-1.30: rpmsg_dev_probe: failed: -90 [ 2673.474496] imx_rpmsg_tty: probe of virtio0.rpmsg-virtual-tty-channel-1.-1.30 failed with error -90          

In the IMX8MM SDK unfortunately we cannot find any example about of use a GPIO as an input with interrupt.  To use a GPIO as input with interrupt we need to keep in mind how the GPIO IRQs works in the ARM Cortex M4.   We can find in Table 7-2 (CM4 Interrupt Summary) of IMX8MMRM (IMX8MM Reference Manual) the GPIOs IRQs are divided by two parts:     Combined interrupt indication for GPIOn signal 0 throughout 15  Combined interrupt indication for GPIOn signal 16 throughout 31    This basically means, the pines of GPIOn from 0 to 15 are handled by Combined interrupt indication for GPIOn signal 0 throughout 15 and the pines from 16 to 31 are handled by Combined interrupt indication for GPIOn signal 16 throughout 31.    In SDK we can find these definitions in:  <SDK root>/devices/MIMX8MM6/MIMX8MM6_cm4.h (Remember this is for IM8MM SDK)    In this example I will use GPIO5_IO12 (ECSPI2_MISO) as Input with IRQ and GPIO5_IO11 (ECSPI_MOSI) as Output of IMX8MM-EVK. I will connect the Output to the Input and will see the behavior of the IRQ in Rising and Falling edge.    For this example I will connect ECSPI2_MOSI (GPIO5_IO11) to ECSPI_MISO (GPIO5_IO12):   See the below definitions:   #define IN_GPIO   GPIO5  This define the GPIO base of the IN pin  #define IN_GPIO_PIN  12u  This define the pin number (for in)  #define IN_IRQ  GPIO5_Combined_0_15_IRQn  This define the IRQ number (72 in this case)  #define GPIO_IRQ_HANDLER  GPIO5_Combined_0_15_IRQHandler  This is a "pointer" to function that will handle the interrupt  #define IN_NAME  "IN GPIO5_IO12"  This is only a name or description for the pin    See below definitions:    #define OUT_GPIO  GPIO5  This is the GPIO base of OUT pin  #define OUT_GPIO_PIN  11u  This define the pin number (for out)  #define OUT_NAME  "OUT GPIO5_IO11"  This is only a name or description for the pin      Now the below section is the IRQ handler (which was defined before)😞   The GPIO_ClearPinsInterruptFlags(IN_GPIO, 1u << IN_GPIO_PIN); refers to GPIOx_ISR register:      For this example, the IRQ Handler will print "IRQ detected ............" in each interrupt.    We will create two different GPIOs config, one for Output and other one for Input with IRQ Falling edge:    Then configure the GPIOs and IRQ:     EnableIRQ refers to enable the 72 IRQ.   GPIO_PortEnableInterrupts refers to GPIOx_IMR: Finally, the example put the out GPIO5_IO11 in High state and then in low state many. First the IRQ is configured as Falling edge, then as Rising edge.     I will attach the complete source file.    To compile it you can use ARMGCC toolchain directly, but I like to use VSCode with MCUXpresso integration.  Once, when you have your .bin file (in my case igpio_led_output.bin) you can load to board with UUU tool: In your Linux machine: sudo uuu -b fat_write igpio_led_output.bin mmc 2:1 gpio.bin In U-boot board: u-boot=> fastboot 0   Then, when the .bin file was loaded, you can load to the CORTEX M4 in U-boot whit: u-boot=> fatload mmc 2:1 ${loadaddr} gpio.bin 7076 bytes read in 14 ms (493.2 KiB/s) u-boot=> cp.b 0x80000000 0x7e0000 0x10000 u-boot=> bootaux 0x7e0000 ## No elf image ar address 0x007e0000 ## Starting auxiliary core stack = 0x20020000, pc = 0x1FFE02CD... u-boot=>   NOTE: You can load the binary to cortex m4 with Custom bootscripts for practicity.   Once the binary loaded in M4 core you should see in seria terminal this logs (Remember GPIO5_IO11 and GPIO5_IO12 must be connected to get the same logs):    And the logs when you disconnect the GPIO5_IO11 and GPIO5_IO12 in execution time:  🔴Disconnection (Red color) 🔵Reconnection (Blue color)   I hope this can helps.     Best regards!    Salas. 

some customers doesn't have any issue on old bsp, but have bring up issue on new 6.1 bsp, this article is about this and how to fix this

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.

  NXP的OpenWRT方案：连接未来的智能网络体验   在数字化时代，智能家居、物联网等概念正不断演进，而要实现这些愿景，一个强大而高效的网络基础设施变得至关重要。OpenWRT以其开源自由、高度可定制和卓越稳定性，成为引领未来网络发展的关键一环。NXP作为全球领先的半导体技术创新公司，以其在嵌入式系统和通信领域的卓越技术积累，推出的基于OpenWRT的智能网络解决方案，为蓬勃发展的智能家居、物联网赋能。本文将介绍NXP公司芯片对OpenWRT方案支持的现状及获取途径，为读者应用OpenWRT去构建全新的下一代网络构建坚实的基础。 1、OpenWRT的独特特性 1.1、开源自由的崇高价值 OpenWRT以其开放源代码的本质脱颖而出。用户享有无限的自由，可以自由获取、修改和分享源代码，释放出创新的巨大潜力。这种开放性既推动了技术的不断进步，也使用户能够更主动地掌控网络的方向，也节约了用户的成本。 1.2、稳定可靠的网络基石 建立在成熟的Linux内核之上，OpenWRT经过长时间的演化和精细调整，确保系统的出色稳定性。这意味着更少的网络故障、更长的设备使用寿命，为各类网络需求提供了坚实的支撑。这一特性使得OpenWRT成为构建可靠家庭网络的理想选择，用户不用担心网络不稳定或崩溃的问题。 1.3 强大的软件包管理 OpenWRT引以为傲的软件包管理系统给用户带来了极大的灵活性。用户可以根据需求自由安装、更新和卸载各类应用程序和服务，从而实现网络环境的高度个性化，实现更智能的网络体验。OpenWRT允许用户安装各种网络服务和应用程序，如VPN、代理服务器等，以满足特定的网络需求。这为用户提供了更大的自由度，使他们能够创建符合个人或家庭需求的网络环境。 1.4 强大的社区支持 OpenWRT庞大的社区是其强大动力的源泉。用户可以在社区中交流心得、解决问题，甚至参与到项目的开发中。这种协作精神推动了OpenWRT的不断创新和进步。   2、NXP OpenWRT方案的应用 2.1 智能家居生态系统的构建 NXP OpenWRT方案与NXP Matter方案无缝结合为用户提供了构建智能家居生态系统的理想平台。通过其强大的定制能力，用户可以轻松连接、管理和控制各类智能设备，打造一个高度智能化的家居环境。该方案完整集成了NXP的Bluetooth和WIFI的芯片驱动，如：IW612， 88W9098， 88W8997等。 用户只需勾选相应的驱动即可轻松构建一个基于OpenWRT的Matter的OpenThread Border Router （OTBR）或者Zigbee Bridge。   2.2 定制化的网络服务 NXP OpenWRT方案支持各类网络服务和应用程序的定制安装。用户可以根据个人需求，轻松创建个性化的网络服务，如VPN、代理服务器，家庭路由器或网关等，实现更灵活的网络体验。 2.3 高清晰度视频流的传输 智能家居中高清晰度视频流的传输对网络性能提出了更高的要求。NXP OpenWRT方案通过其卓越的网络性能，结合NXP的工业级IP Camera方案， 确保用户能够流畅地享受高清视频流，为家庭娱乐带来更为优质的体验。 2.4 智能安防系统的构建 安防系统是不可或缺的一部分。NXP OpenWRT方案通过其高级网络安全功能，为用户打造了更可靠、更智能的安防系统，提高家庭的安全性。 3、NXP对OpenWRT的支持现状 基于OpenWRT众多优点及广阔的应用场景，NXP也很早就对OpenWRT实现了适配。不但实现了全部Layerscape系列处理器对OpenWRT的支持，目前主流的IMX处理器也得到了支持。具体支持的IMX平台及细节如下所示： Processor and Board Support ARMv8                                             ARMv7       I.MX93EVK                                •      I.MX6ULL       I.MX8MPlus       I.MX8MMini       I.MX8MNano       I.MX8MQuad OpenWrt Version       Based on OpenWrt v23.05 from mainline (tag: v23.05.0-rc1) Toolchain: ARMV8: gcc-11.3, binutils-2.37 ARMV7: gcc-12.3, binutils-2.40 U-Boot Boot Loader       IMX LF release, tag: lf-5.15.71-2.2.1 v2022.04 Linux Kernel       OpenWrt kernel 5.15.114 based on IMX SDK release kernel v5.15.71_2.2.1 Firmware       firmware-imx-8.18       firmware-sentinel-0.5.1 Main Features       Squashfs rootfs support on SD card.       Supported CLI and web configuation.       U-Boot Boot Loader - U-Boot: lf-5.15.71-2.2.1. - Arm Trusted firmware (TF-A) integration. - Boot from SDHC       Linux Kernel Core - Linux kernel 5.15.114 - Cortex-A53 (AARCH64), little endian for imx8m platform - Cortex-A55 (AARCH64), little endian for imx93 platform - Cortex-A7, little endian for imx6ull platform - 64-bit effective kernel addressing [Cortex-A53/A55]       Linux Kernel Drivers - SDIO 3.0 / eMMC5.1 - USB 3.0/2.0 Dual-Role with PHY type C - 32-bit LPDDR4 - 2x Gigabit Ethernet with AVB, IEEE 1588, EEE   and 1x w/ TSN - PCIe Gen 3 + WIFI - CAN FD - Dual-ch. QuadSPI (XIP) or 1x OctalSPI(XIP) - RTC Licensing       The majority of the software included in the OpenWrt release is licensed under a form of open source license (e.g. GPL, BSD).       Some software is licensed under the NXP EULA license. 4、如何开始部署和使用OpenWRT？ 如果想体验Layerscape系列芯片的OpenWRT强大功能，请从OpenWRT官方下载，即：https://git.openwrt.org/openwrt/openwrt.git。Layerscape的OpenWRT支持代码已经全部集成到了OpenWRT官方代码库。 此处以IMX8MMini-EVK为例说明OpenWRT在IMX平台的部署步骤，编译环境为Ubuntu22.04。 4.1 从github.com上获取源码 https://github.com/nxp-imx/imx_openwrt Tag: imx_v23.05_v5.15.114 4.2 编译，安装，配置OpenWRT $ ./scripts/feeds update -a; ./scripts/feeds install -a; cp config.default .config; make -j $ sudo dd if=/mnt/tftpboot/imx8/matter_20230908/openwrt-imx-imx8-imx8mmini-squashfs-sdcard.img of=/dev/sdX bs=1M && sync 这样就有生成了一个可以SD卡启动的OpenWRT了启动盘了。 可以直接用SD卡来启动体验OpenWRT. 更多的编译帮助请参考源代码中的README文件：target/linux/imx/README。 4.3 配置和个性化 用户可通过Web界面或SSH访问OpenWRT设备，开始配置和个性化网络环境。包括设置网络规则、安装软件包等，确保设备按照个人需求运行。下图为安装删除软件的界面。是不是很简单，很方便！       4.4 遇到问题怎么办？ 首先可以到OpenWRT社区这个充满活力的地方获得支持。 当然也可以分享自己的开发或使用经验，甚至参与到项目的开发中。这个开放的社区为用户提供了更多学习和发展的机会，共同推动OpenWRT不断向前。 还可以参与到NXP官方社区https://community.nxp.com/t5/i-MX-Processors/bd-p/imx-processors 进行提问和技术分享。有专业的工程师为您排忧解难。NXP OpenWRT期待您的参与！   免责声明 此OpenWRT发布是NXP系统工程倡议的一部分，不属于NXP为其MPU平台的Linux基础支持策略。NXP不对本发布及其后续版本的质量负责，包括添加对新平台的支持，这完全由系统工程团队自行决定。对于具体需求或问题，请通过以下电子邮件地址联系NXP的系统工程团队：“andy.tang@nxp.com”.

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.

Information about the transition from the NXP Demo Experience to GoPoint for i.MX Application Processors.

BSP: L6.1.36 Some customer need use adb under usb ffs. The adb in Yocto can greatly improves development efficiency. This is a demo for enabling adb on Yocto.   Yocto local.conf IMAGE_INSTALL:append = "android-tools android-tools-adbd" PREFERRED_PROVIDER_android-tools-conf = "android-tools-conf-configfs"   Test script for launching adbd modprobe g_ffs idVendor=0x1fc9 idProduct=0x0146 iSerialNumber="ZhimingLiu" mkdir -p /dev/usb-ffs/adb mount -t functionfs adb /dev/usb-ffs/adb -o uid=2000,gid=2000 adbd &   Test on Windows: PS C:\Users\Administrator\Desktop\platform-tools> .\adb.exe devices List of devices attached ZhimingLiu device PS C:\Users\Administrator\Desktop\platform-tools> .\adb.exe shell sh-5.2# uname -a Linux imx8mp-lpddr4-evk 6.1.36+g04b05c5527e9 #1 SMP PREEMPT Fri Nov 24 04:46:22 UTC 2023 aarch64 GNU/Linux sh-5.2# ls config ffs t.sh test2.sh sh-5.2# cd / sh-5.2# ls bin dev home lost+found mnt proc run srv tmp usr boot etc lib media opt root sbin sys unit_tests var sh-5.2#

Platform: Demo images, i.MX8MPlus EVK   Some customer need test ffs gadget function on i.MX8MPlus EVK. Here is demo for ffs test, please connect EVK and Ubuntu PC before test.   Test script: #!/bin/sh # Setup the device (configfs) modprobe libcomposite mkdir -p config mount none config -t configfs cd config/usb_gadget/ mkdir g1 cd g1 echo 0x1fc9 >idVendor echo 0x0146 >idProduct mkdir strings/0x409 echo 12345 >strings/0x409/serialnumber echo "Signal 11" >strings/0x409/manufacturer echo "Test" >strings/0x409/product mkdir configs/c.1 mkdir configs/c.1/strings/0x409 echo "Config1" >configs/c.1/strings/0x409/configuration # Setup functionfs mkdir functions/ffs.usb0 ln -s functions/ffs.usb0 configs/c.1 cd ../../../ mkdir -p ffs mount usb0 ffs -t functionfs cd ffs ffs-test 64 & # from the Linux kernel, with mods! sleep 3 cd .. # Enable the USB device echo 38100000.usb > config/usb_gadget/g1/UDC   EVK log root@imx8mpevk:~# ./test2.sh [ 17.859597] file system registered ffs-test: dbg: ep0: writing descriptors (in v2 format) ffs-test: dbg: ep0: writing strings ffs-test: dbg: ep1: starting ffs-test: dbg: ep2: starting ffs-test: dbg: ep1: starts ffs-test: dbg: ep0: starts ffs-test: dbg: ep2: starts Event BIND Event ENABLE Ubuntu PC log: lzm@lzm-GL552VW:~$ lsusb -D /dev/bus/usb/001/008 Device: ID 1fc9:0146 NXP Semiconductors Test Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.10 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x1fc9 NXP Semiconductors idProduct 0x0146 bcdDevice 6.01 iManufacturer 1 Signal 11 iProduct 2 Test iSerial 3 12345 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0020 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 4 Config1 bmAttributes 0x80 (Bus Powered) MaxPower 2mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 255 Vendor Specific Class bInterfaceSubClass 0 bInterfaceProtocol 0 iInterface 5 Source/Sink Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes bInterval 1 Binary Object Store Descriptor: bLength 5 bDescriptorType 15 wTotalLength 0x0016 bNumDeviceCaps 2 USB 2.0 Extension Device Capability: bLength 7 bDescriptorType 16 bDevCapabilityType 2 bmAttributes 0x0000010e BESL Link Power Management (LPM) Supported BESL value 256 us SuperSpeed USB Device Capability: bLength 10 bDescriptorType 16 bDevCapabilityType 3 bmAttributes 0x00 wSpeedsSupported 0x000f Device can operate at Low Speed (1Mbps) Device can operate at Full Speed (12Mbps) Device can operate at High Speed (480Mbps) Device can operate at SuperSpeed (5Gbps) bFunctionalitySupport 1 Lowest fully-functional device speed is Full Speed (12Mbps) bU1DevExitLat 0 micro seconds bU2DevExitLat 0 micro seconds Device Status: 0x0001 Self Powered  

Usually, device tree source files are not a signal pure dts file. It could include dtsi, dts or C code heads .h files. Need C compiler finish the pre-compile to a pure dts file first. It is integrated inside the like Linux build system(Makefile, etc.). This document shows the original way to compile device tree. This document will show compile device tree under windows.    

How to use UART4 on iMX8M from Linux User Space   The UART4 on iMX8MM-EVK and iMX8MN-EVK are thinking of debugging the M core which is not usable on Linux user space by default on pre-compiled images.   To use the UART4 on Linux user space you have to do the next modifications on the device tree and atf to assign that peripheral to Linux User Space     https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c     iMX8MN-EVK   imx8mn_bl31_setup.c   https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c   /* Master domain assignment */ RDC_MDAn(RDC_MDA_M7, DID1), /* peripherals domain permission */ - RDC_PDAPn(RDC_PDAP_UART4, D1R | D1W), + RDC_PDAPn(RDC_PDAP_UART4, D0R | D0W), RDC_PDAPn(RDC_PDAP_UART2, D0R | D0W), RDC_PDAPn(RDC_PDAP_RDC, D0R | D0W | D1R),       Device tree configurations for iMX8MN-EVK   iMX8MN-EVK.dtsi   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi   &uart3 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_uart3>; assigned-clocks = <&clk IMX8MN_CLK_UART3>; assigned-clock-parents = <&clk IMX8MN_SYS_PLL1_80M>; uart-has-rtscts; status = "okay"; }; + &uart4 { + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_uart4>; + assigned-clocks = <&clk IMX8MN_CLK_UART4>; + assigned-clock-parents = <&clk IMX8MN_SYS_PLL1_80M>; + status = "okay"; + }; ********************** pinctrl_uart3: uart3grp { fsl,pins = < MX8MN_IOMUXC_ECSPI1_SCLK_UART3_DCE_RX 0x140 MX8MN_IOMUXC_ECSPI1_MOSI_UART3_DCE_TX 0x140 MX8MN_IOMUXC_ECSPI1_SS0_UART3_DCE_RTS_B 0x140 MX8MN_IOMUXC_ECSPI1_MISO_UART3_DCE_CTS_B 0x140 >; }; + pinctrl_uart4: uart4grp { + fsl,pins = < + MX8MN_IOMUXC_UART4_RXD_UART4_DCE_RX 0x140 + MX8MN_IOMUXC_UART4_TXD_UART4_DCE_TX 0x140 + >; + };   iMX8MM-EVK   https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c   imx8mm_bl31_setup.c   /* Master domain assignment */ RDC_MDAn(RDC_MDA_M7, DID1), /* peripherals domain permission */ - RDC_PDAPn(RDC_PDAP_UART4, D1R | D1W), + RDC_PDAPn(RDC_PDAP_UART4, D0R | D0W), RDC_PDAPn(RDC_PDAP_UART2, D0R | D0W), RDC_PDAPn(RDC_PDAP_RDC, D0R | D0W | D1R),   Device tree configurations for iMX8MM-EVK   iMX8MM-EVK.dtsi   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mm-evk.dtsi   &uart3 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_uart3>; assigned-clocks = <&clk IMX8MM_CLK_UART3>; assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>; uart-has-rtscts; status = "okay"; }; + &uart4 { + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_uart4>; + assigned-clocks = <&clk IMX8MM_CLK_UART4>; + assigned-clock-parents = <&clk IMX8MM_SYS_PLL1_80M>; + status = "okay"; + }; ********************** pinctrl_uart3: uart3grp { fsl,pins = < MX8MM_IOMUXC_ECSPI1_SCLK_UART3_DCE_RX 0x140 MX8MM_IOMUXC_ECSPI1_MOSI_UART3_DCE_TX 0x140 MX8MM_IOMUXC_ECSPI1_SS0_UART3_DCE_RTS_B 0x140 MX8MM_IOMUXC_ECSPI1_MISO_UART3_DCE_CTS_B 0x140 >; }; + pinctrl_uart4: uart4grp { + fsl,pins = < + MX8MM_IOMUXC_UART4_RXD_UART4_DCE_RX 0x140 + MX8MM_IOMUXC_UART4_TXD_UART4_DCE_TX 0x140 + >; + };   iMX8MP-EVK   https://github.com/nxp-imx/imx-atf/blob/lf_v2.6/plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c   imx8mp_bl31_setup.c   RDC_MDAn(RDC_MDA_M7, DID1), RDC_MDAn(RDC_MDA_LCDIF, DID2), RDC_MDAn(RDC_MDA_LCDIF2, DID2), RDC_MDAn(RDC_MDA_HDMI_TX, DID2), /* peripherals domain permission */ + RDC_PDAPn(RDC_PDAP_UART4, D0R | D0W), RDC_PDAPn(RDC_PDAP_UART2, D0R | D0W), RDC_PDAPn(RDC_PDAP_WDOG1, D0R | D0W), RDC_PDAPn(RDC_PDAP_RDC, D0R | D0W | D1R),   Device tree configurations for iMX8MP-EVK   iMX8MP-EVK.dts   https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx8mp-evk.dts   &uart3 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_uart3>; assigned-clocks = <&clk IMX8MP_CLK_UART3>; assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_80M>; fsl,uart-has-rtscts; status = "okay"; }; + &uart4 { + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_uart4>; + assigned-clocks = <&clk IMX8MP_CLK_UART4>; + assigned-clock-parents = <&clk IMX8MP_SYS_PLL1_80M>; + status = "okay"; + }; ************************************ pinctrl_uart3: uart3grp { fsl,pins = < MX8MP_IOMUXC_ECSPI1_SCLK__UART3_DCE_RX 0x140 MX8MP_IOMUXC_ECSPI1_MOSI__UART3_DCE_TX 0x140 MX8MP_IOMUXC_ECSPI1_SS0__UART3_DCE_RTS 0x140 MX8MP_IOMUXC_ECSPI1_MISO__UART3_DCE_CTS 0x140 >; }; + pinctrl_uart4: uart4grp { + fsl,pins = < + MX8MP_IOMUXC_UART4_RXD__UART4_DCE_RX 0x140 + MX8MP_IOMUXC_UART4_TXD__UART4_DCE_TX 0x140 + >; + };     After compiling the image with the changes previously shown, we obtained this result:      

test ov5640 with 480p, raw10 via ISP on imx8mp