VAR-SOM-MX6 SPI: Difference between revisions

Latest revision as of 19:25, 28 April 2023

VAR-SOM-MX6 - SPI

Testing SPI from user space require some changes.

Configure your kernel (using "make menuconfig", for example) and make sure the spidev driver (SPI_SPIDEV) is included: 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 tools folder of the kernel source tree: tools/spi/spidev_test.c (in older kernels: Documentation/spi/spidev_test.c)

@@ Line 1: / Line 1: @@
-{{PageHeader|VAR-SOM-MX6 - SPI}} {{DocImage|category1=VAR-SOM-MX6|category2=Yocto}} __toc__
+{{PageHeader|VAR-SOM-MX6 - SPI}} {{DocImage|category1=Yocto|category2=Debian}} [[category:VAR-SOM-MX6]] __toc__
 Testing SPI from user space require some changes.
-* Configure your kernel and add spidev driver. Device Drivers -> SPI support -> <*>   User mode SPI device driver support<br>
+* Configure your kernel (using "make menuconfig", for example) and make sure the spidev driver (SPI_SPIDEV) is included: Device Drivers -> SPI support -> <*>   User mode SPI device driver support<br>
-* Add spidev to your device tree<br>
+* Add spidev and pinctrl to your device tree<br>
+For VAR-SOM-MX6, edit arch/arm/boot/dts/imx6qdl-var-som.dtsi<br>
+For DART-MX6, edit arch/arm/boot/dts/imx6qdl-var-dart.dtsi<br>
 <pre>&ecspi1 {
 	fsl,spi-num-chipselects = <1>;
 	cs-gpios = <&gpio4 9 0>;
 	pinctrl-names = "default";
-	pinctrl-0 = <&pinctrl_ecspi1_2>;
+	pinctrl-0 = <&pinctrl_ecspi1_1>;
 	status = "okay";
@@ Line 24: / Line 26: @@
 */
 };</pre>
-Pick and choose the right chip select and you can also have multiple chip selects.
-* Compile the Linux kernel and device tree.
+<pre>
-* For testing use the application:<br>https://raw.githubusercontent.com/varigit/linux-2.6-imx/master/Documentation/spi/spidev_test.c
+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
+	>;
+};
+</pre>
+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 tools folder of the kernel source tree: tools/spi/spidev_test.c (in older kernels: Documentation/spi/spidev_test.c)