AM57X: Not able to probe SPI driver

Hi,

Rakesh Modi said:

But after a kernel boot I can not see the spidev in /dev/

Make sure that you enable CONFIG_SPI_SPIDEV in your .config, or through menuconfig. I checked my sources (of ti-processor-sdk-linux-am57xx-evm-02.00.00.00) and this is NOT enabled by default. 

After you recompile your kernel see if you have 

sys/class/spi_master/spiX 

sys/class/spidev/ 

and 

dev/spidevX 

Rakesh Modi said:

I also want to add custom device driver i.e. mcp23s08. When I have modified device tree for MCP23S08, as below, it gives error during kernel boot that.

Below is the error:

[    1.610137] spi_master spi32766: cannot find modalias for /ocp/spi@480ba000/mcp23s17@3
[    1.618095] spi_master spi32766: Failed to create SPI device for /ocp/spi@480ba000/mcp23s17@3

In your custom driver, can you try adding:

#ifdef CONFIG_OF
static const struct of_device_id mcp23s17_dt_ids[] = {
         { .compatible = "microchip,mcp23s17" },
         {},
};
MODULE_DEVICE_TABLE(of, mcp23s17_dt_ids);
#endif 

I suggest you take a reference from the spi-omap2-mcspi.c driver.

Hope this helps. 

Best Regards, 
Yordan

Thanks for your reply Yordan. I have enabled CONFIG_SPI_SPIDEV and I can see sys/class/spidev/ & sys/class/spidev/. But I can not see /dev/spidevX. I have also changed the pinmux for spi clock as you suggested. So what could be the problem for this behaviour?

For mcp23s17 I am able to solve the issue. It was error in dts file.

Hi Yordan, 

Could you let me know what you had wrong in the .dts file for using the MCP23S17? How did the device appear in your /dev or /sys directory once you got it working?

I am trying to get the MCP23S18 working with the am335x. I can see some device files but I don't think they can be used for control of the device:

root@am335x-evm:/sys/class/spi_master/spi1/spi1.1/of_node# ls
#gpio-cells gpio-controller reg spi-present-mask
compatible name spi-max-frequency

I was expecting it to register as some sort of gpio device (sys/class/gpio) but I can only find the processor gpio's here.

Basically I am trying to work out if the device is registered with the kernel correctly and how I should communicate with it once it is

I have the CONFIG_SPI_SPIDEV and CONFIG_GPIO_MCP23S08 enabled in .config

A cut down version of my .dts file looks like:

// from the .dtsi file

&am33xx_pinmux {
pinctrl-names = "default";

spi0_pins: pinmux_spi0_pins {
pinctrl-single,pins = <
AM33XX_IOPAD(0x150, PIN_INPUT | MUX_MODE0 ) // (A18) spi0_sclk.spi0_sclk
AM33XX_IOPAD(0x154, PIN_INPUT | MUX_MODE0 ) // (B18) spi0_d0.spi0_d0
AM33XX_IOPAD(0x158, PIN_INPUT | MUX_MODE0 ) // (B17) spi0_d1.spi0_d1
AM33XX_IOPAD(0x15c, PIN_OUTPUT | MUX_MODE0 ) // (A17) spi0_cs0.spi0_cs0
AM33XX_IOPAD(0x160, PIN_OUTPUT | MUX_MODE0 ) // (B16) spi0_cs1.spi0_cs1
>;
};
};

&spi0 {
status = "okay";
pinctrl-names = "default";
pinctrl-0 = <&spi0_pins>;
};

//from my .dts file

&spi0 {

mcp: mcp@1 {
compatible = "mcp,mcp23s17";
reg = <1>;
gpio-controller;
#gpio-cells = <2>;
spi-present-mask = <0x01>;
spi-max-frequency = <1000000>;
};


nvram: nvram {
address-cells = <1>;
#size-cells = <1>;
compatible = "spansion,mr25h10"; //may need to change spansion.
reg = <0>;
spi-max-frequency = <40000000>;
m25p,fast-read;
};

};