Embedded module TQMa335x - PTXdist Linux BSP documentation

Extract u-boot sources (in ptxdist use: ptxdist extract u-boot). Then open the file include/configs/tqma335x.h and add the following line anywhere in that file (recommended in the CPU section at line 320):

#define CONFIG_SYS_MPUCLK	800

Then call:

$ ptxdist drop u-boot prepare

Copy the gzipped SD-Card image to the rootfs of the SD-Card:

gzip sd.hdimg
cp sd.hdimg.gz $SD_MOUNT

On the target:

dd if=sd.hdimg | gunzip | dd of=/dev/mmcblk1

Alternative: copy the running image from SD-Card to the MMC:

dd if=/dev/mmcblk0 of=/dev/mmcblk1 bs=1M count=400

3 Displays are supported in the basic configuration of the BSP. By default ETM0700 is selected in the device tree configuration.
To change the default display the device tree source file has to be modified, it's located inside your bsproot
/platform-MBa335x/built-target/linux.x.xx/arch/arm/boot/dts/mba335x.dts.
Within the CONF section at line 13 uncommend the display you would like to use.

...
11  /dts-v1/;
12
13  /* CONF - SELECT 1 (max) */
14  //#define CONFIG_ET0700		1
15  #define CONFIG_ETM0700	1
16  //#define CONFIG_CHIMEI		1
17  /* CONF END */
...

There are two RTC's on the TQMa335x:

• rtc0 = RTC Sitara AM335x
• rtc1 = RTC Module PMIC

hwclock -w hwclock -f /dev/rtc0 -w

hwclock -f /dev/rtc0 --show

hwclock -w hwclock -f /dev/rtc1 -w

hwclock -f /dev/rtc1 --show

Devicetree can be edit with the fdt commands under U-Boot.

1) At first the fdt file has to be loaded from the current boot medium (mmc) into RAM.

U-Boot# run loadfdt

2) Next step is to set the predefined U-Boot environment variable fdtaddr through the fdt addr command.

U-Boot# fdt addr $fdtaddr

3) Afterwards the size of the fdt has to be increased (to the next 4K divider) in order to have some space for modifications. This is simply done by entering:

U-Boot# fdt resize 

4) List device in the tree you want to change to have a look at the default settings.

Example

U-Boot# fdt list /leds
leds {
        compatible = "gpio-leds";
        lvds_shtdn {
        };
        backlight {
        };
};
U-Boot# fdt print /leds
leds {
        compatible = "gpio-leds";
        lvds_shtdn {
                gpios = <0x0000003a 0x00000003 0x00000002>;
                default-state = "on";
        };
        backlight {
                gpios = <0x0000003a 0x00000004 0x00000002>;
                default-state = "on";
        };
};

5) To modify a value of a propertie use the fdt set command.

U-Boot# fdt set <path> <property> <value> 

Example

U-Boot# fdt set /leds/backlight default-state off 

6) Optional: If you want to save your modified Devicetree back to mmc you'll have to run the following command:

U-Boot# fatwrite mmc $bootpart $fdtaddr $fdtfile <totalsize> 

You can find out <totalsize> of the modified fdt by entering the command fdt header

Otherwise you can boot your module with the changed Devicetree right after the modification.