The IOMUX module on i.MX 8M enables flexible I/O multiplexing, allowing users to configure each IO pad as one of selectable functions. The CSU (Central Security Unit) module on i.MX 8M can be used to configure some devices as secure only accessible to protect the security of these devices. But as the IOMUX is Non-Secure accessilbe and thus the pad function can be configured dynamicaly, there is one risk if hackers reconfigure the IO pad to make the device connected to other controller which is accessible to Non-Secure world. One solution for this issue is configuring the CSU to limit Non-Secure access to IOMUX, all IOMUX registers write operations are routed to Trusty OS. In the Trusty OS, add all sensitive IO resources to one blacklist, the IOMUX driver in Trusty OS should check and deny any write attemption to sensitive registers from Non-Secure world. One example patch set is attached to show how to assign the IOMUX to secure world and how to route the IOMUX write operations to Trusty OS. In this example, the USB Host pinctrl PAD on i.MX8MP EVK was assigned to secure world. The layout of the example codes are:     . ├── atf │ └── 0001-config-iomux-to-secure-write.patch --> ${MY_ANDROID}/vendor/nxp-opensource/arm-trusted-firmware ├── kernel │ └── 0001-Use-Trusty-OS-to-handle-iomux-registers-written-oper.patch --> ${MY_ANDROID}/vendor/nxp-opensource/kernel_imx/ ├── trusty │ └── 0001-Add-iomux-pinctrl-TEE-handler.patch --> ${MY_TRUSTY}/trusty/hardware/nxp └── u-boot └── 0001-Use-Trusty-OS-to-handle-IOMUX-operation.patch --> ${MY_ANDROID}/vendor/nxp-opensource/uboot-imx      

[中文翻译版] 见附件   原文链接： https://community.nxp.com/docs/DOC-342719 

This is a summary for the software lockup issue found in the following platform: −i.MX8/8X −Linux 4.14.98_2.3.3   Issue description: •Issue happens during the boot procedure, at the systemd stage. •The symptom of the issue: −From user perspective, the symptom varies, but mainly fall into several types: §At the console, there may be login prompt, but no response (only echo) when input user/password. Unable to login. §Some user service in systemd failed to start. E.g. weston. −When checking the task status using sysrq (w/t), many tasks, including some kernel core tasks stays in “D” (uninterruptable sleep) state. E.g. agetty, login, chvt, etc. •Kernel itself is still alive. This can be verified by triggering some drivers, such as plugin a USB device. Issue can be reproduced on MEK through long time stress.   Please refer to the doc/patch attached for details.

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

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.

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-342420 

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

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 

[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.

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. 

[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 

  Solution           

  Introduction   MATTER chip-tool android APK is a very useful tool for commission, control the MATTER network by smart phone. Vendor can add various features into the APK. It supports build by Android Studio and command line. The official build steps can be found here: https://github.com/project-chip/connectedhomeip/blob/master/docs/guides/android_building.md But the official guide does not cover how to build in a non-GUI linux distribution (without Android Studio installed). This article describes how to build under Ubuntu server. Install Android SDK  Install SDK command line from: https://developer.android.com/studio, And follow the steps: https://developer.android.com/tools/sdkmanager to install.  Install the Android-26 SDK and 23 NDK: $./sdkmanager "platforms;android-26" "ndk;23.2.8568313"  Export env  $export ANDROID_HOME=<SDK path>  $export ANDROID_NDK_HOME=<SDK path>/ndk/23.2.8568313/   Install kotlin (1.8.0)  $curl -s https://get.sdkman.io | bash  $sdk install kotlin 1.8.0  $whereis kotlin  $export PATH=$PATH:<patch of bin of kotlin>    Configure proxy for gradle  $ cat ~/.gradle/gradle.properties  # Set the socket timeout to 5 minutes (good for proxies)  org.gradle.internal.http.socketTimeout=300000  # the number of retries (initial included) (default 3)  org.gradle.internal.repository.max.retries=10  # the initial time before retrying, in milliseconds (default 125)  org.gradle.internal.repository.initial.backoff=500  systemProp.http.proxyHost=apac.nics.nxp.com  systemProp.http.proxyPort=8080  systemProp.http.nonProxyHosts=localhost|*.nxp.com  systemProp.https.proxyHost=apac.nics.nxp.com  systemProp.https.proxyPort=8080  systemProp.https.nonProxyHosts=localhost|*.nxp.com    Configure proxy  Configure proxy for download packages during build export FTP_PROXY="http://apac.nics.nxp.com:8080"  export HTTPS_PROXY="http://apac.nics.nxp.com:8080"  export HTTP_PROXY="http://apac.nics.nxp.com:8080"  export NO_PROXY="localhost,*.nxp.com"  export ftp_proxy="http://apac.nics.nxp.com:8080"  export http_proxy="http://apac.nics.nxp.com:8080"  export https_proxy="http://apac.nics.nxp.com:8080"  export no_proxy="localhost,*.nxp.com"    Patch for gradle java option  This step can be skipped if using OpenJDK16.  Otherwise if you're using OpenJDK 17 (Java 61), you have to upgrade the gradle from 7.1.1 to 7.3, and add java.io open to ALL-UNNAMED:  diff --git a/examples/android/CHIPTool/gradle.properties b/examples/android/CHIPTool/gradle.properties  index 71f72db8c8..5bce4b4528 100644  --- a/examples/android/CHIPTool/gradle.properties  +++ b/examples/android/CHIPTool/gradle.properties  @@ -6,7 +6,8 @@  # http://www.gradle.org/docs/current/userguide/build_environment.html  # Specifies the JVM arguments used for the daemon process.  # The setting is particularly useful for tweaking memory settings.  -org.gradle.jvmargs=-Xmx4096m -XX:MaxPermSize=2048m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8  +#org.gradle.jvmargs=-Xmx4096m -XX:MaxPermSize=2048m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8  +org.gradle.jvmargs=-Xmx4096m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8  --add-opens=java.base/java.io=ALL-UNNAMED  # When configured, Gradle will run in incubating parallel mode.  # This option should only be used with decoupled projects. More details, visit  # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects  diff --git a/examples/android/CHIPTool/gradle/wrapper/gradle-wrapper.properties b/examples/android/CHIPTool/gradle/wrapper/gradle-wrapper.properties  index 05679dc3c1..e750102e09 100644  --- a/examples/android/CHIPTool/gradle/wrapper/gradle-wrapper.properties  +++ b/examples/android/CHIPTool/gradle/wrapper/gradle-wrapper.properties  @@ -1,5 +1,5 @@  distributionBase=GRADLE_USER_HOME  distributionPath=wrapper/dists  -distributionUrl=https\://services.gradle.org/distributions/gradle-7.1.1-bin.zip  +distributionUrl=https\://services.gradle.org/distributions/gradle-7.3-bin.zip  zipStoreBase=GRADLE_USER_HOME  zipStorePath=wrapper/dists    Build & Install Clone all the modules from github: $git clone --single-branch --recurse-submodules https://github.com/project-chip/connectedhomeip.git Enviroment setup: $source scripts/bootstrap.sh Build: ./scripts/build/build_examples.py --target android-arm64-chip-tool build Install built apk into phone: $adb install out/android-arm64-chip-tool/outputs/apk/debug/app-debug.apk  

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    

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.