VAR-SOM-MX6 SPI

VAR-SOM-MX6 - SPI

Testing SPI from user space require some changes.

• Configure your kernel (using "make menuconfig", for example) and add spidev driver: Device Drivers -> SPI support -> <*> User mode SPI device driver support
  
• Add spidev and pinctrl to your device tree
  

For VAR-SOM-MX6, edit arch/arm/boot/dts/imx6qdl-var-som.dtsi
For DART-MX6, edit arch/arm/boot/dts/imx6qdl-var-dart.dtsi

&ecspi1 {
	fsl,spi-num-chipselects = <1>;
	cs-gpios = <&gpio4 9 0>;
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_ecspi1_1>;
	status = "okay";

        chip1: spidev@0 {
               compatible = "spidev";
               spi-max-frequency = <12000000>;
               reg = <0>;
        };
/*
        chip2: spidev@1 {
               compatible = "spidev";
               spi-max-frequency = <20000000>;
               reg = <1>;
	};
*/
};

pinctrl_ecspi1_1: ecspi1grp {
	fsl,pins = <
		MX6QDL_PAD_KEY_COL1__ECSPI1_MISO	0x100b1
		MX6QDL_PAD_KEY_ROW0__ECSPI1_MOSI	0x100b1
		MX6QDL_PAD_KEY_COL0__ECSPI1_SCLK	0x100b1
		MX6QDL_PAD_KEY_ROW1__GPIO4_IO09      0x80000000
	>;
};

Pick and choose the right chip select and you can also have multiple chip selects.

• Continue following the Build Linux from source code guide to build the kernel and device trees and to copy them to your SD card. Don't forget to also build and install the kernel modules.
• For testing use the application:
  https://raw.githubusercontent.com/varigit/linux-2.6-imx/master/Documentation/spi/spidev_test.c