Dear all,
I have a wandboard Quad rev B1 with ubuntu and kernel 4.9.35. I need to use 2 I2C different ports. I developed a code that works well in I2C2, but fails in I2C1. I remember having read many people saying that I2C1 is not properly working because of the hdmi CEC (which shouldn't affect me because I am not using a monitor), so I decided to enable I2C3 while I try to figure what is wrong with I2C1. I also want to enable spidev to get /dev/spidev0.0.
I must say I am a newbie in the world of embedded systems and device trees.
To do so, I firstly followed Robert's Nelson tutorial, and then I modified imx6q-wandboard-revb1.dts from the files I with the following code:
/*
* Copyright 2013 Freescale Semiconductor, Inc.
*
* Author: Fabio Estevam <fabio.estevam@freescale.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
/dts-v1/;
#include "imx6q.dtsi"
#include "imx6qdl-wandboard-revb1.dtsi"
/ {
model = "Wandboard i.MX6 Quad Board rev B1";
compatible = "wand,imx6q-wandboard", "fsl,imx6q";
memory {
reg = <0x10000000 0x80000000>;
};
};
&sata {
status = "okay";
};
&ecspi1 {
fsl,spi-num-chipselects = <1>;
cs-gpios = <&gpio2 30 0>; /* EIM_EB2 */
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_ecspi1>;
status = "okay";
spidev@0 {
compatible = "rohm,dh2228fv";
spi-max-frequency = <10000000>;
reg = <0>;
};
};
&i2c3 {
clock-frequency = <100000>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_i2c3>;
status = "okay";
};
&iomuxc {
pinctrl-names = "default";
imx6q-wandboard-revb1 {
pinctrl_ecspi1: ecspi1grp-1 {
fsl,pins = <
MX6QDL_PAD_EIM_D17__ECSPI1_MISO 0x100b1
MX6QDL_PAD_EIM_D18__ECSPI1_MOSI 0x100b1
MX6QDL_PAD_EIM_D16__ECSPI1_SCLK 0x100b1
MX6QDL_PAD_EIM_EB2__GPIO2_IO30 0x000f0b0
MX6QDL_PAD_KEY_COL2__GPIO4_IO10 0x000f0b0
>;
};
pinctrl_i2c3: i2c3grp {
fsl,pins = <
MX6QDL_PAD_GPIO_5__I2C3_SCL 0x4001b8b1
MX6QDL_PAD_GPIO_16__I2C3_SDA 0x4001b8b1
>;
};
};
};
Then I execute
make imx6q-wandboard-revb1.dtb
and I copy it to /boot/dtbs/4.9.35-armv7-x4/imx6q-wandboard-revb1.dtb
/dev/i2c-2 now appears, but always gives timeout when I try to write on it. With an oscilloscope I don't see any change in the voltage of the lines that theoretically are assigned to the pins I chose. Besides, Ethernet stops working. All this makes me thing I am using the wrong pins, but according to the page 17 on the schematics, I2C3 is wired to GPIO5 and GPIO16...
What am I doing wrong?
Thank you very much
