SK-AM62: accessing SPI onto sk-am62 board from linux

Hey Emanuele,

Thank you for your question, my name is Andrew and I would be happy to assist with this.  I have relayed your question to the team and hope to have a response for you within the next 1-2 business days.  While I look into this, has there been any updates/developments to this problem on your end that we should take into consideration?

Best regards,

Andrew

Hi Andrew,

thank you for following this case: actually i am looking into "psdk/board-support/linux-rt-5.10.109+gitAUTOINC+d9ee8a25c2-gd9ee8a25c2/tools/spi/" folder where there is a file spidev_test.c I am trying to run this to see if something happens. actually i see no devices under /dev/ that seems like a spi. This make me think that i need to recompile kernel with CONFIG_SPIDEV support.

I understand now that this question is more like "linux" related, rather that "Processor SDK" related, so feel free to close discussion ifyou need.

Kind Regards

Emanuele Peruzzi

Hi, i have marked as solved, but it s not!

I have successfully recompiled kernel with SPIDEV enabled, but i cannot still see the device in /dev/ folder in linux.

Please guide through adding a spidev peripheral in dtb file, so that i can see the device in /dev/folder from linux. and make some test from command line.

In the docs you provided, there is written:

&spi1 {
        status = "okay";
        pinctrl-names = "default";
        pinctrl-0 = <&spi1_pins_s0>;
        spidev@1 {
                spi-max-frequency = <24000000>;
                reg = <0>;
                compatible = "rohm,dh2228fv";
        };
};

but where should i put this code, and this will impact on other peripherals?? Otherwise how to enable that spi dev somehow, for example from command line directly?

Please consider that i am newbie in linux, and need help.

Kind Regards

Emanuele P.

Hello,

now i m back from vacation, and trying to proceed further in testing SPI peripheral. Now i have compiled device tree and i am able to see a 

spidev3.0 device in /dev/ folder in am625-sk. I am trying to see signals on SPI physical bus, with no success. Here are my steps:

- i have cross compiled program spidev_test.c and copied on a folder on sdcard inserted in am625-sk.

- i have lauched the program spidev_test with following options

./spidev_test -s 1000000 -p aa55

and the program show no error, here is output:

root@am62xx-evm:~/ti_ema/spi# ./spidev_test -s 1000000 -p aa55
spi mode: 0x0
bits per word: 8
max speed: 1000000 Hz (1000 kHz)

but when i put probes onto SPI0 lines (pins 19, pin 21, pin 23, pin 24 of 40 pins connector) i see nothing, no datas there. Why? What i need to do to see the transmitted message onto physical pins??

here is my configuration on dts file:

    /* parte inserita per SPI 0 */
	main_spi0_pins_default: main-spi0-pins-default {
		pinctrl-single,pins = <
			// parte copiata da am64x
			AM62X_IOPAD(0x01C0, PIN_OUTPUT, 0) /* (B13) SPI0_D0 */
			AM62X_IOPAD(0x01C4, PIN_INPUT, 0) /* (B14) SPI0_D1 */
			AM62X_IOPAD(0x01B4, PIN_OUTPUT, 0) /* (A13) SPI0_CS0 */
			AM62X_IOPAD(0x01BC, PIN_OUTPUT, 0) /* (A14) SPI0_CLK */			
		>;
	};

...

&main_spi0 {
        status = "okay";
        pinctrl-names = "default";
        pinctrl-0 = <&main_spi0_pins_default>;
        spidev@0 {
                spi-max-frequency = <10000000>;
                reg = <0>;
                compatible = "rohm,dh2228fv";
        };
};

please give some hint

Emanuele Peruzzi

it works, i probed the wrong pins. Ty