In my project I need 5 UART supports but in Colibri VF50 has only 3 available. How to access remaining 2 UART’s.
Which OS do you intend to use?
currently we are trying to make some serial transactions with UART 3 and 4. We are using both Colibri VF50 and VF61 for tests with the same outcome. BSP is Colibri_VF_LinuxImageV2.5 with a custom DTB. We've followed your Vybrid based device tree customization tutorial (http://developer.toradex.com/device-tree-customization#Vybrid_based_Modules) in order to create another DTB with UART3 and 4 with status = okay (I shall leave the dts and dtb attached).
Can you provide the exact changes done in device tree/s, to enable the additional UART’s ? Output of git diff should be helpful.
Just for a quick test, only DTBs are updated, kernel is left untouched. NAND flashed from SD and /dev/ttyLP3 and /dev/ttyLP4 correctly appear after booting (TFT doesn't work and before login I'm having a info message of task blocked repeating itself every 10 seconds - these are not the issue, for now).
Not sure about which kernel version you are trying to cross-compile, please make sure you update both Linux kernel and device tree blobs to avoid confusions/problems.
Checking Colibri Datasheet, the only reference that I find regarding UART3 and 4 pinout are SODIMM 29/31 for UART3_RX, SODIMM 23/37 for UART3_TX, SODIMM 53 for UART4_RX amd SODIMM 51 for UART4_TX. After getting the ports stty'd , I'm trying to get some data transmitted (echo "foobar" > /dev/ttyLP2) or recieved (cat /dev/ttyLP2) through these pins, but no data is received nor transmitted.
At least ttyLP2 should work out-of-the-box, you are checking on UART_B pins right ? Refer this article for information related to mapping of ttyLPX → UART_X.
My guess is that maybe I'm missing some pinmux set for those UART but I couldn't find any more info saying that in the tutorials, although checking vf-colibri.dtsi I find some interesting fields that seem to set the uart0, uart1 and uart2 pins through pinctrl_uart0, pinctrl_uart1 and pinctrl_uart2, respectively.
As an example, have a look at this device tree which has pin-mux configurations for UART3 and UART4.
How about having a look at our dual Ethernet example device tree which additionally makes use of 5 UARTs?