DHCOM STM32MP1 Linux

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Linux virtual machine for development

Linux Kernel

How to build a Kernel

Get sources from Github

1. Start the Console on Linux
2. git clone https://github.com/dh-electronics/linux-stm32mp1.git --branch dev/5.4.69_dhsom
3. cd linux-stm32mp1

Configure and build the Device Tree + Kernel

4. ARCH=arm CROSS_COMPILE=/opt/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/bin/arm-linux-gnueabihf- make stm32mp1_dhsom_defconfig
5. ARCH=arm CROSS_COMPILE=/opt/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/bin/arm-linux-gnueabihf- make menuconfig (optional: If you want to add/remove Kernel features)
6. ARCH=arm CROSS_COMPILE=/opt/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/bin/arm-linux-gnueabihf- make dtbs
7. ARCH=arm CROSS_COMPILE=/opt/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/bin/arm-linux-gnueabihf- make zImage

Create the FIT-image with our script (Download link)

Interactive mode for selecting device trees Device trees are set as parameter

8. create_fitimage
Enter the numbers (space seperated) of the device trees to include (e.g. if you want to include the device tree for the PDK2 include the number of ./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2.dtb (usually 3).
Enter the numbers (space seperated) of the device trees overlays to include (e.g. for the PDK2 enter the files which contain PDK2 (usually 8 9 10 11 12 13 14).

(Example is for the PDK2)
8. create_fitimage --dtb ./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2.dtb --dtbo ./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-460-200-x11.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-497-200-x12.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-505-200-x12-ch101olhlwh.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-531-100-x21.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-531-100-x22.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-560-200-x12.dtbo,./arch/arm/boot/dts/stm32mp157c-dhcom-pdk2-overlay-638-100-x12-rpi7inch.dtbo

Kernel Userspace Interfaces to Access Hardware

Control GPIOs

Show gpio definition in Linux
gpioinfo
Note:
gpiochip0 = STM port-A, gpiochip1 = STM port-B, ...
DHCOM Name: alt. DHCOM Name: SO-DIMM Pin# CPU Pad Name
GPIO A 154 PF3
GPIO B 156 PD6
GPIO C 162 PG0
GPIO D 163 PD12
GPIO E 164 PC6
GPIO F 165 PD11
GPIO G 167 PI0
GPIO H 173 PI2
GPIO I 175 PI3
GPIO J CIF HSYNC 74 PH8
GPIO K CIF PCLK 72 PA6
GPIO L CIF MCLK 70 PG8
GPIO M CIF VSYNC 68 PI5
GPIO N CIF D9 66 PH7
GPIO O CIF D8 64 PI1
GPIO P CIF D7 62 PE6
GPIO Q CIF D6 60 PB8
GPIO R CIF D5 58 PI4
GPIO S CIF D4 56 PH14
GPIO T CIF D3 54 PH12
GPIO U CIF D2 52 PH11
GPIO V CIF D1 50 PH10
GPIO W CIF D0 48 PH9
INT HIGHEST PRIORITY 151 PI8

RS-485 on picoITX

RS-485 device
DHCOM UART 2 /dev/ttySTM2
Compilation on target
gcc tty_rs485_test_v1.1.c -o tty_rs485_test
gcc tty_rs485_flags_v1.0.c -o tty_rs485_flags
Show UART flags
./tty_rs485_flags /dev/ttySTM2
Set tty device to raw mode
stty -F /dev/ttySTM2 115200 raw -echo -echoe
Send data with demo program
echo -n -e "\n\rHallo RS485 Welt!" ¦ ./tty_rs485_test /dev/ttySTM2
Receive data with demo program
./tty_rs485_test /dev/ttySTM2
Download example source code

CAN interface

Setup CAN interface with baudrate 500kbit/sec.
ip link set can0 up type can bitrate 500000
Start to listen on CAN port
candump can0
Send test message
cansend can0 100#11.2233.44556677.88
Deinitialize CAN port
ip link set can0 down

UART Interfaces

DHCOM UART 1 /dev/ttySTM0
DHCOM UART 2 /dev/ttySTM2
DHCOM UART 3 /dev/ttySTM1

I2C Interfaces

DHCOM I2C 1 /dev/i2c-1
DHCOM I2C 2 /dev/i2c-0
On Module Devices /dev/i2c-2

FAQ

USB 1.1 problems: Custom board without USB 2.0 hub inbetween the MP1 USB host port?

And in that case, have a look at arch/arm/boot/dts/stm32mp15xx-dhcom-picoitx.dtsi and how the OHCI (!) is enabled there. And of course, make sure the kernel config options are enabled accordingly (like for the PicoITX machine)

meta-dhsom-stm32-bsp$ git grep OHCI

recipes-kernel/linux/linux-stable/5.10/dh-stm32mp1-common/dh-stm32mp1-dhsom-common.cfg:CONFIG_USB_OHCI_HCD=y
recipes-kernel/linux/linux-stable/5.10/dh-stm32mp1-common/dh-stm32mp1-dhsom-common.cfg:CONFIG_USB_OHCI_HCD_PLATFORM=y

arch/arm/boot/dts/stm32mp15xx-dhcom-picoitx.dtsi snippet:

&usbh_ehci {
         phys = <&usbphyc_port0>;
         status = "okay";
};

&usbh_ohci { // <---------------- HERE
         phys = <&usbphyc_port0>;
         status = "okay";
};

&usbotg_hs {
         dr_mode = "otg";
         pinctrl-0 = <&usbotg_hs_pins_a>;
         pinctrl-names = "default";
         phy-names = "usb2-phy";
         phys = <&usbphyc_port1 0>;
         vbus-supply = <&vbus_otg>;
         status = "okay";
};

&usbphyc {
         status = "okay";
};

&usbphyc_port0 {
         phy-supply = <&vdd_usb>;
         vdda1v1-supply = <&reg11>;
         vdda1v8-supply = <&reg18>;
};

&usbphyc_port1 {
         phy-supply = <&vdd_usb>;
         vdda1v1-supply = <&reg11>;
         vdda1v8-supply = <&reg18>;
};

System stability or USB Host problems?

If a display with higher resolution and pixel clock > 48 MHz is used, then this can case USB host and/or system stability problems.

Workaround: The OSPEEDR must be set to OSPEEDR = 1 for LCD_CLK and OSPEEDR = 0 for all other LTDC signals.

&pinctrl {
	ltdc_pins_ customhmi: ltdc-dh-1 {
		pins1 {
			pinmux = <STM32_PINMUX('I', 14, AF14)>; /* LCD_CLK */
			bias-disable;
			drive-push-pull;
			slew-rate = <1>;
		};
		pins2 {
				pinmux = <STM32_PINMUX('I', 12, AF14)>, /* LCD_HSYNC */
				 <STM32_PINMUX('I', 13, AF14)>, /* LCD_VSYNC */
                                 ...
				 <STM32_PINMUX('K',  6, AF14)>; /* LCD_B7 */
			bias-disable;
			drive-push-pull;
			slew-rate = <0>;
		};
	};
	
	ltdc_sleep_pins_ customhmi: ltdc-sleep-dh-1 {
		pins {
			pinmux = <STM32_PINMUX('I', 14, ANALOG)>, /* LCD_CLK */
                                 ...
				 <STM32_PINMUX('K',  6, ANALOG)>; /* LCD_B7 */
		};
	};	
};

USB OTG: Custom board where the USB-OTG port is only used as host?

On the DHCOM standard, the second USB port of the STM32MP1 is usually an USB-OTG port. If you have a custom board where you want to use the USB-OTG port in host mode only, you should consider the following:

The USB-OTG controller on the STM32MP1, DWC2, does support host mode but is rather inefficient (in comparison to a dedicated USB host controller). The following block diagram shows, that it is possible on the STM32MP1 to alter the pinmuxing, so that the USB-OTG port is used with the USB Host controller of the STM32MP1 (instead of using the DWC2 OTG controller):

   Host port#1: EHCI/OHCI controller _________ HS PHY port #1 (SoC balls D+/D- #1)
      
      
   Host port#2: EHCI/OHCI controller __ 
                                        \   
                                        |_____ HS PHY port #2 (SoC balls D+/D- #2)
   DWC2 OTG controller_________________/|
                                        |
           UTIM switch__________________|

This change can be made in the device tree with disabling the DWC2 controller and adding the second usb_phyc port to the nodes of usbh_ehci and (if applicable) usbh_ohci. These nodes are usually in the .dtsi file of the board (e.g. for the PicoITX: arch/arm/boot/dts/stm32mp15xx-dhcom-picoitx.dtsi). Here a is snippet how this could look like:

&usbh_ehci {
         phys = <&usbphyc_port0>, <&usbphyc_port1 1>; // <-------- HERE
         status = "okay";
};

&usbh_ohci { 
         phys = <&usbphyc_port0>, <&usbphyc_port1 1>; // <-------- HERE
         status = "okay";
};

&usbotg_hs {
         status = "disabled"; // <-------- HERE
};

&usbphyc {
         status = "okay";
};

&usbphyc_port0 {
         phy-supply = <&vdd_usb>;
         vdda1v1-supply = <&reg11>;
         vdda1v8-supply = <&reg18>;
};

&usbphyc_port1 {
         phy-supply = <&vdd_usb>;
         vdda1v1-supply = <&reg11>;
         vdda1v8-supply = <&reg18>;
};

How to try QtWebengine

The QtWebengine is part of the DH default images. Please stop the Weston desktop, before the start of the Browser.

Older images: "systemctl stop weston@root.service"  
Newer images: "systemctl stop weston.service"

How to start the Browser:

QT_QPA_PLATFORM=eglfs QT_QPA_EGLFS_ALWAYS_SET_MODE=1 QT_QPA_EGLFS_KMS_CONFIG=/etc/default/qt5-eglfs-kms.json qtwebengine-minimal http://YOUR-TEST-PAGE/ --no-sandbox

How is the Browser Perfomance on the STM32MP1?

STM32MP1 Browser Performance