VAR-SOM-MX6 SPI: Difference between revisions

Revision as of 08:44, 1 October 2017

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
	>;
};

Choose the right chip select (you can also have multiple chip selects).

Continue following the "Customizing the Linux kernel" guide to build the kernel and device trees.
For testing use the SPI testing utility in the Documentation folder of the kernel source tree: Documentation/spi/spidev_test.c

@@ Line 38: / Line 38: @@
 </pre>
-Pick and choose the right chip select and you can also have multiple chip selects.
+Choose the right chip select (you can also have multiple chip selects).
-* Continue following the [[VAR-SOM-MX6_Yocto_Jethro_R4_Build_Linux_out_of_tree|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.
+* Continue following the "Customizing the Linux kernel" guide to build the kernel and device trees.
-* For testing use the application:<br>https://raw.githubusercontent.com/varigit/linux-2.6-imx/master/Documentation/spi/spidev_test.c
+* For testing use the SPI testing utility in the Documentation folder of the kernel source tree: Documentation/spi/spidev_test.c