Linux Kernel - 5.15

Linux 5.15 for MPU source code

The Linux kernel for Microchip ARM-Based MPUs (aka AT91) is distributed as a GIT tree hosted on GitHub as a fork of the official Linus Torvalds' git tree. The objective of the Microchip Linux team is to integrate all the AT91-related material in the official Linux Kernel.
Before completing this inclusion process, which can take time, this website provides the Linux4SAM Linux Kernel git tree for AT91 devices at:
and now on:


linux4microchip-2022.04 tag

Enhancements are added on top of the official v5.15 Linux kernel tag where most of the Microchip SoC features are already supported. Note as well that we re-integrate each and every stable kernel release on top of this Long Term Support (LTS) kernel revision. This means that each v5.15.x version is merged in our branch.

Here is a little summary of the main additional enhancements:

  • Integration of stable kernel updates up to v5.15.32
  • Addition of the new SAMA7G54 SoC as part of the SAMA7G5 family
  • WILC: Update driver & firmware to 15.7 with WPA3 security support
  • Add support for Sony imx274 camera sensor
  • ISC driver moved to media controller paradigm for image acquisition pipeline (MIPI CSI-2)
  • Support for External Interrupt Controller (EIC) available on SAMA7G5
  • Add Dinamic and Voltage Scaling (DVFS) support with Operating Performance Points (OPP) for 90MHz, 250MHz, 600MHz, 800MHz, 1GHz frequencies for SAMA7G5
  • Refactored clocks' suspend/resume
  • Support for power management modes: WFI (standby), ULP0, ULP1, BSR for SAMA7G5
  • Low power mode for on board crystal oscillators in ULP0 and ULP1 to reduce overall power consumption
  • GEMAC support with RGMII and MII for SAMA7G5
  • Fix GEMAC Wake On LAN on ulp0, ulp1 for SAMA7G5
  • Increased PIT64B clockevent timer frequency to 5MHz for better timers resolution on
  • CPU Idle support with minimized CPU frequency and DDRAM in self-refresh for SAMA7G5 family
  • Use ADC reworked driver from mainline
  • ADC support for reading temperature channel available on SAMA7G5
  • Support for accessing memory backed by OTP controller (modeled as NVMEM driver) for SAMA7G5
  • Thermal management support for SAMA7G5
  • Add QSPI / Octal SPI driver for SAMA7G5 (Single, Dual, Quad, Octal DTR modes), tested with mx66lm1g45g
  • Add NAND support for SAMA7G5 and test it with 29F4G08ABAEA
  • Add support for mx66lm1g45g NOR Flash, implement byte swap to fix endianness in 8D-8D-8D(Octal DTR)
  • Enable crypto engines on SAMA7G5: AES, TDES, SHA with same features as on sama5d2 SoC
  • Cleanup and runtime PM support for atmel-rng driver
  • Fix deadlocks on AT91 DMA driver
  • Reset controller support for USB PHY on SAMA7G5
  • Improve USB PHY clock handling when used by both Host and Device for SAMA7G5
  • Add SAMA7G5 audio interfaces drivers: SPDIF-TX, SPDIF-RX, I2S, SCC
  • Add Asynchronous Sample Rate Converter (ASRC) audio driver for SAMA7G5
  • Implement microphone PDMC driver using DMA mode for SAMA7G5
  • Enable CAN driver for SAMA7G5

Getting Kernel sources

To get the source code, you have to clone the repository:

$ git clone
Cloning into 'linux'...
remote: Enumerating objects: 8587836, done.
remote: Total 8587836 (delta 0), reused 0 (delta 0), pack-reused 8587836
Receiving objects: 100% (8587836/8587836), 3.49 GiB | 13.44 MiB/s, done.
Resolving deltas: 100% (7117887/7117887), done.
Updating files: 100% (70687/70687), done.
$ cd linux

The source code has been taken from the master branch which is pointing on the latest branch we use.

Pointing hand Note that you can also add this Linux4SAM repository as a remote GIT repository to your usual Linux git tree. It will save you a lot of bandwidth and download time:

$ git remote add linux4microchip
$ git remote update linux4microchip
Fetching linux4icrochip
 * [new branch]                linux-5.10-mchp -> linux4microchip/linux-5.10-mchp
 * [new branch]                linux-5.15-mchp -> linux4microchip/linux-5.15-mchp
 * [new branch]                master     -> linux4microchip/master

If you want to use another branch, you can list them and use one of them by doing this:

$ git branch -r
  origin/HEAD -> origin/master
$ git checkout origin/linux-5.15-mchp -b linux-5.15-mchp
Branch linux-5.15-mchp set up to track remote branch linux-5.15-mchp from origin.
Switched to a new branch 'linux-5.15-mchp'

Configure and Build the Linux kernel

Now you have to configure the Linux kernel according to your hardware. We have two default configuration at91 SoC in arch/arm/configs

  • at91_dt_defconfig: for SAM9 (ARM926) series chips
  • sama5_defconfig: for SAMA5 series chips
  • sama7_defconfig: for SAMA7 series chips

Now we Configure and Build kernel for board:

$ make ARCH=arm sama5_defconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  SHIPPED scripts/kconfig/
  SHIPPED scripts/kconfig/zconf.lex.c
  SHIPPED scripts/kconfig/zconf.hash.c
  HOSTCC  scripts/kconfig/
  HOSTLD  scripts/kconfig/conf
# configuration written to .config

At this step, you can modify default configuration using the menuconfig

$ make ARCH=arm menuconfig
Now, in the menuconfig dialog, you can easily add or remove some features. Once done, Move to <Exit> with arrows and press this button hitting the Enter key to exit from this screen.

Build the Linux kernel image, before you build you need set up the cross compile toolchain, check this section.

$ make ARCH=arm


  Kernel: arch/arm/boot/Image is ready
  Kernel: arch/arm/boot/zImage is ready

Now you have an usable compressed kernel image zImage.

If you need an uImage you can run this additional step:

make ARCH=arm uImage LOADADDR=0x20008000


  Kernel: arch/arm/boot/zImage is ready
  UIMAGE  arch/arm/boot/uImage
Image Name:   Linux-5.15.32-linux4microchip-20
Created:      Wed May  4 21:18:58 2022
Image Type:   ARM Linux Kernel Image (uncompressed)
Data Size:    5069704 Bytes = 4950.88 KiB = 4.83 MiB
Load Address: 20008000
Entry Point:  20008000
  Kernel: arch/arm/boot/uImage is ready

make ARCH=arm dtbs


  DTC     arch/arm/boot/dts/at91-kizbox2-2.dtb
  DTC     arch/arm/boot/dts/at91-kizbox3-hs.dtb
  DTC     arch/arm/boot/dts/at91-nattis-2-natte-2.dtb
  DTC     arch/arm/boot/dts/at91-sama5d27_som1_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d27_wlsom1_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_icp.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_ptc_ek.dtb
  DTC     arch/arm/boot/dts/at91-sama5d2_xplained.dtb
  DTC     arch/arm/boot/dts/at91-sama5d3_xplained.dtb
  DTC     arch/arm/boot/dts/at91-dvk_som60.dtb
  DTC     arch/arm/boot/dts/at91-gatwick.dtb
  DTC     arch/arm/boot/dts/at91-tse850-3.dtb
  DTC     arch/arm/boot/dts/at91-wb50n.dtb
  DTC     arch/arm/boot/dts/sama5d31ek.dtb
  DTC     arch/arm/boot/dts/sama5d33ek.dtb
  DTC     arch/arm/boot/dts/sama5d34ek.dtb
  DTC     arch/arm/boot/dts/sama5d35ek.dtb
  DTC     arch/arm/boot/dts/sama5d36ek.dtb
  DTC     arch/arm/boot/dts/sama5d36ek_cmp.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4_ma5d4evk.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4_xplained.dtb
  DTC     arch/arm/boot/dts/at91-sama5d4ek.dtb
  DTC     arch/arm/boot/dts/at91-vinco.dtb
  DTC     arch/arm/boot/dts/at91-sama7g5ek.dtb


If the building process is successful, the final images can be found under arch/arm/boot/ directory.

Recent FAQ

r5 - 13 May 2022 - 12:55:45 - CristianBirsan
Linux & Open Source for AT91 Microchip Microprocessors

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