DART-6UL SPI
In this example we will show how to configure SPI 1 and SPI 2 to work on SOM
Kernel configuration
Verify that the User mode SPI driver (CONFIG_SPI_SPIDEV) is enabled in your kernel configuration:
- In menuconfig: Device Drivers -> SPI support -> <*> User mode SPI device driver support
SPI 1 on 6UL Custom Board and Condcerto Board
Add spidev to your device tree
&ecspi1 { fsl,spi-num-chipselects = <1>; cs-gpios = <&gpio4 26 0>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_ecspi1_1>; status = "okay"; chip1: spidev@0 { compatible = "spidev"; spi-max-frequency = <12000000>; reg = <0>; }; };
Add pin control to your device tree
&iomuxc { pinctrl_ecspi1_1: ecspi1grp { fsl,pins = < MX6UL_PAD_CSI_DATA07__ECSPI1_MISO 0x100b1 MX6UL_PAD_CSI_DATA06__ECSPI1_MOSI 0x100b1 MX6UL_PAD_CSI_DATA04__ECSPI1_SCLK 0x100b1 MX6UL_PAD_CSI_DATA05__GPIO4_IO26 0x100b1 >; }; };
Note: The pins here were set arbitrarily. You should set them based on your hardware design, and make sure they are not conflicting with other devices in the device tree.
you can also have multiple chip selects.
SPI 2 on 6UL Custom Board
Add spidev to your device tree
&ecspi2 { fsl,spi-num-chipselects = <1>; cs-gpios = <&gpio4 22 0>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_ecspi2_1>; status = "okay"; spidev@0 { compatible = "spidev"; spi-max-frequency = <12000000>; reg = <0>; }; };
Add pin control to your device tree
&iomuxc { pinctrl_ecspi2_1: ecspi2grp { fsl,pins = < MX6UL_PAD_CSI_DATA03__ECSPI2_MISO 0x100b1 MX6UL_PAD_CSI_DATA02__ECSPI2_MOSI 0x100b1 MX6UL_PAD_CSI_DATA00__ECSPI2_SCLK 0x100b1 MX6UL_PAD_CSI_DATA01__GPIO4_IO22 0x100b1 >; }; };
Note: The pins here were set arbitrarily. You should set them based on your hardware design, and make sure they are not conflicting with other devices in the device tree.
you can also have multiple chip selects.
SPI 2 on Concerto Board
Add spidev to your device tree
&ecspi2 { fsl,spi-num-chipselects = <1>; cs-gpios = <&gpio1 29 0>; pinctrl-names = "default"; pinctrl-0 = <&pinctrl_ecspi2_1>; status = "okay"; spidev@0 { compatible = "spidev"; spi-max-frequency = <12000000>; reg = <0>; }; };
Add pin control to your device tree
&iomuxc { pinctrl_ecspi2_1: ecspi2grp { fsl,pins = < MX6UL_PAD_UART5_TX_DATA__ECSPI2_MOSI 0x100b1 MX6UL_PAD_UART5_RX_DATA__ECSPI2_MISO 0x100b1 MX6UL_PAD_UART4_TX_DATA__ECSPI2_SCLK 0x100b1 MX6UL_PAD_UART4_RX_DATA__GPIO1_IO29 0x100b1 >; }; };
Note: The pins here were set arbitrarily. You should set them based on your hardware design, and make sure they are not conflicting with other devices in the device tree.
you can also have multiple chip selects.
Compile
Compile the kernel and device tree and update the SOM.
Testing
There's an SPI testing utility C code example in the kernel source tree: tools/spi/spidev_test.c (in older kernels: Documentation/spi/spidev_test.c)
To cross compile it use the following command:
$ $CC ./tools/spi/spidev_test.c -o ./spidev_test
SPI 1
SPI 1 will be accessible on the following EVK pins:
- J11.2 - SPI1.CLK
- J11.6 - SPI1.MISO
- J11.8 - SPI1.MOSI
- J11.4 - SPI1.SS0
SPI 2
SPI 2 will be accessible on the following EVK pins:
- J11.9 - SPI2.CLK
- J13.2 - SPI2.MISO
- J6.7 - SPI2.MOSI
- J6.5 - SPI2.SS0