i.MX 93 BSP Manual PD24.1.1 Documentation Rev.: imx8mp-pd22.1.2-51-ga548be7d
• We can check RTC BSM (Backup Switchover Mode) with:
target:~$ hwclock --param-get bsm
The RTC parameter 0x2 is set to 0x1.
• We can set RTC BSM with:
target:~$ hwclock --param-set bsm=0x2
The RTC parameter 0x2 will be set to 0x2.
What BSM values mean translates to these values:
#define RTC_BSM_DISABLED 0
#define RTC_BSM_DIRECT 1
#define RTC_BSM_LEVEL 2
#define RTC_BSM_STANDBY 3
Tip
You should set BSM mode to DSM or LSM for RTC to switch to backup power source when the
initial power source is not available. Check RV-3028 RTC datasheet to read what LSM (Level
Switching Mode) and DSM (Direct Switching Mode) actually mean.
DT representation for I²C RTCs: https://git.phytec.de/linux-imx/tree/arch/arm64/boot/dts/freescale/
imx93-phyboard-segin.dts?h=v6.1.55_2.2.0-phy3#n173 or https://git.phytec.de/linux-imx/tree/arch/
arm64/boot/dts/freescale/imx93-phyboard-nash.dts?h=v6.1.55_2.2.0-phy3#n122
7.11 USB Host Controller
The USB controller of the i.MX 93 SoC provides a low-cost connectivity solution for numerous consumer
portable devices by providing a mechanism for data transfer between USB devices with a line/bus speed of
up to 480 Mbps (HighSpeed ‘HS’). The USB subsystem has two independent USB controller cores. Both
cores are capable of acting as a USB peripheral device or a USB host, but on the phyBOARD-Segin/Nash
i.MX 93 one of them is used as a host-only port (USB-A connector).
The unied BSP includes support for mass storage devices and keyboards. Other USB-related device drivers
must be enabled in the kernel conguration on demand. Due to udev, all mass storage devices connected
get unique IDs and can be found in /dev/disk/by-id. These IDs can be used in /etc/fstab to mount the
dierent USB memory devices in dierent ways.
The OTG port provides an additional pin for over-current protection, which is not used on the phyBOARD-
Segin/Nash i.MX 93. Since it’s not used, the driver part is also disabled from within the device tree. In case
this pin is used, activate this over-current in the device tree and set the correct polarity (active high/low)
according to the device specication. For the correct setup, please refer to the Kernel documentation under
Linux/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt.
DT representation for USB Host: https://git.phytec.de/linux-imx/tree/arch/arm64/boot/dts/freescale/
imx93-phyboard-segin.dts?h=v6.1.55_2.2.0-phy3#n190 or https://git.phytec.de/linux-imx/tree/arch/
arm64/boot/dts/freescale/imx93-phyboard-nash.dts?h=v6.1.55_2.2.0-phy3#n180
Accessing Peripherals 63
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