topic Re: Define UART in Device Tree in i.MX Processors

Define UART in Device Tree

till_klocke — Wed, 03 Dec 2014 16:37:07 GMT

Hello together,

Currently I am using a board based on the Phytec PhyFlex PFLA02 with a imx6DL. We have already most of the things we need working. But I currently try to get UART1 working and I am stuck. I modified the device tree so we use correct pins for this uart. But when I try to communicate with the device we have behind this UART, I receive no answer. We analysed this with an oscilloscope and we can see that I am able to send the bytes I want to send and that our device is responding accordingly. But when I try to read from the serial port I receive not a single byte. So I guess my device tree configuration is wrong somehow.

I hope someone here can point me in the right direction what I am missing. Here is the pinctrl config for UART 1:

pinctrl_uart1: uart1grp {

fsl,pins = <

MX6QDL_PAD_SD3_DAT6__UART1_TX_DATA 0x1b0b1

MX6QDL_PAD_SD3_DAT7__UART1_RX_DATA 0x1b0b1

};

and here is the &uart1 config:

&uart1 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_uart1>;
        status = "okay";
};

I hope that this is only a simple mistake.

And I have another question to deepen my understanding of the device tree: What does the 0x1b0b1 mean?

Thanks in advance

Re: Define UART in Device Tree

igorpadykov — Fri, 05 Dec 2014 01:19:01 GMT

Hi Till

configuration seems as correct and

0x1b0b1 device tree is well described below

http://www.kosagi.com/w/index.php?title=Definitive_GPIO_guide

However as far as I know this board has not uart1 routed externally,

had you changed/disabled in software these signals (may be they are used

somewhere else ?).

~igor

Re: Define UART in Device Tree

till_klocke — Thu, 11 Dec 2014 15:36:39 GMT

Hi!

Actually the processor board itself brings all UARTs to its connector and we are using a custom board on it. But my problem was in the end a simple typo. I needed to define RX and TX exactly the other way round.

Thanks :smileyhappy: