UART4 on colibri VF50 doesn't work under Linux

Hi,

I have actived UART4 in the device tree (using vf-colibri-dual-eth.dtsi).
But I can’t send and receive any characters on UART4 (/dev/ttyLP4).
In /proc/interrupts no interrupts are shown for ttyLP4 (device tree interrupt of UART4 is 65),
when I try to send characters (with screen or minicom).

cat /proc/interrupts  
           CPU0  
 16:    5064122       GIC  27 Edge      gt  
 17:          0  vf610-gpc   8 Edge      eDMA tx
 18:          0  vf610-gpc   9 Edge      eDMA err
 20:       1759  vf610-gpc  61 Edge      fsl-lpuart
 23:         12  vf610-gpc  64 Edge
 25:          1  vf610-gpc  53 Edge      4003b000.adc
 34:          0  vf610-gpc  92 Edge      wkpu-vf610
 35:          0  vf610-gpc  75 Edge      40034000.usb
 37:          0  vf610-gpc  10 Edge      eDMA tx
 38:          0  vf610-gpc  11 Edge      eDMA err
 39:          0  vf610-gpc 100 Edge      rtc alarm
 41:          1  vf610-gpc  54 Edge      400bb000.adc
 42:          0  vf610-gpc  76 Edge      400b4000.usb
 43:         64  vf610-gpc  78 Edge      400d0000.ethernet
 44:       9945  vf610-gpc  79 Edge      400d1000.ethernet
 46:       5542  vf610-gpc  83 Edge      vf610_nfc
Err:          0

cat /proc/tty/driver/fsl-lpuart 
gives me
serinfo:1.0 driver revision:
0: uart:FSL_LPUART mmio:0x40027000 irq:20 tx:6577 rx:317 RTS|DTR
1: uart:FSL_LPUART mmio:0x40028000 irq:21 tx:0 rx:0
2: uart:FSL_LPUART mmio:0x40029000 irq:22 tx:13 rx:0 RTS|DTR
3: uart:FSL_LPUART mmio:0x4002A000 irq:23 tx:16 rx:0 RTS|DTR
4: uart:FSL_LPUART mmio:0x400A9000 irq:40 tx:10 rx:0 RTS|DTR

UARTA-RI and UARTA-DSR which are using the same CPU pins as UART4 are not configured/used.

Any help would be appreciated.

Regards,
Rupert

I have actived UART4 in the device tree (using vf-colibri-dual-eth.dtsi). But I can’t send and receive any characters on UART4 (/dev/ttyLP4).

Which kernel version are you using ? Also provide the diff of the changes done.

UARTA-RI and UARTA-DSR which are using the same CPU pins as UART4 are not configured/used.

UARTA-RI (SODIMM_37) and UARTA-DSR(SODIMM_29) are muxed as UART3_TX and UART3_RX respectively in dual-eth-board device tree.

Thanks for your fast reply.

In the meantime I was able to solve the problem.

The UART in question is not UART4, but SCI3 (Vybird signal name) or /dev/ttyLP3 under Linux
For that serial port exist two pin-configurations (see http://docs.toradex.com/101355-colibri-vf50-datasheet.pdf page 38). I have used the wrong one at first, not the one which is configured in vf-colibri-dual-eth.dtsi.

Regards,
Rupert

Glad to hear that.