SPI Not working with am3352.

Sudipta Kumar Sahoo

Other Parts Discussed in Thread: AM3352

I have configured the SPI0 pins for our coustom board.

below is the pin muxing for spi in .dts file

                  0x150 0x30  /* spi0_sclk, INPUT_PULLUP | MODE0 */
                  0x154 0x30  /* spi0_d0, INPUT_PULLUP | MODE0 */
                  0x158 0x10  /* spi0_d1, OUTPUT_PULLUP | MODE0 */
                  0x15c 0x10  /* spi0_cs0, OUTPUT_PULLUP | MODE0 */

I also able to see the "spidev1.0 " in /dev folder.
But when ever I am trying to test "spidev_test" application as suggested in the below url, I am not able to transmit the data.
I followed the url as mentioned elinux.org/BeagleBone_Black_Enable_SPIDEV

When I probed the Tx and CLK of SPI in my custom board by running the test application, I am not getting any pulse triggers.
To verify any H/W problem, I disabled the SPI and then exported those pins as GPIO. After that when I tried to toggle the pins I could able to see the change in voltage level in Oscilloscope.

can any one help me in resolving the issue to make the SPI work.

Regards
Sudipta.

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Please post the entire SPI section from the .dts

0 Sudipta Kumar Sahoo over 9 years ago in reply to Biser Gatchev-XID

Intellectual 360 points

Hi Biser

The SPI section of my .dts file looks as follow

mcspi0_pins_default: pinmux_mcspi0_pins {
pinctrl-single,pins = <
0x150 (PIN_INPUT_PULLUP | MUX_MODE0)
0x154 (PIN_INPUT_PULLUP | MUX_MODE0)
0x158 (PIN_OUTPUT_PULLUP | MUX_MODE0)
0x15C (PIN_OUTPUT_PULLUP | MUX_MODE0)
>;
};

mcspi0_pins_sleep: pinmux_mcspi0_pins {
pinctrl-single,pins = <
  0x150 (PIN_INPUT_PULLUP | MUX_MODE7)
  0x154 (PIN_INPUT_PULLUP | MUX_MODE7)
  0x158 (PIN_OUTPUT_PULLUP | MUX_MODE7)
  0x15C (PIN_OUTPUT_PULLUP | MUX_MODE7)
>;
};

&spi0 {
pinctrl-names = "default", "sleep";
  pinctrl-0 = <&mcspi0_pins_default>;
  pinctrl-1 = <&mcspi0_pins_sleep>;
  status = "okay";
      spidev0:spi@0 {
              compatible = "spidev";
              spi-max-frequency = <48000000>;
              reg = <0>;
              status = "okay";
              };
  };

0 Yordan Kovachev over 9 years ago in reply to Sudipta Kumar Sahoo

TI__Guru**** 161600 points

Hi,

You should use:

spidev@0

instead of

spidev0:spidev@0

Also you should have:

compatible = "linux, spidev";

Configured this way, you should see spidev0.0 in /dev, can you confirm?

Best Regards,
Yordan

0 Yordan Kovachev over 9 years ago in reply to Yordan Kovachev

TI__Guru**** 161600 points

Hi,

I tested this on BBB (with am3352 on it).

Here is how i configured my spidev:

spi0_pins: spi0_pins {

pinctrl-single,pins = <

0x150 (PIN_INPUT_PULLUP | MUX_MODE0)

0x154 (PIN_INPUT_PULLUP | MUX_MODE0)

0x158 (PIN_OUTPUT_PULLUP | MUX_MODE0)

0x15C (PIN_OUTPUT_PULLUP | MUX_MODE0)

};

&spi0 {

pinctrl-names = "default";

pinctrl-0 = <&spi0_pins>;

status = "okay";

spidev@0 {

compatible = "linux,spidev";

spi-max-frequency = <48000000>;

reg = <0>;

status = "okay";

};

Also in drivers/spi/spidev.c, I had to add:

static const struct of_device_id spidev_dt_ids[] = {

{ .compatible = "rohm,dh2228fv" },

{ .compatible = "linux,spidev"},

{},

}

Another option is tu use compatible = "rohm,dh2228fv", instead of compatible = "linux,spidev" in your spidev dts node.

As a result, I got /dev/spi1.0.

Spi pins are outputted on P9_17 -> spi0_cs0 (0x15C), P9_18 -> spi0_d1 (0x158) & P9_22 -> spi0_sclk (0x150).

When I execute:
echo "DEADBEEF" > /dev/spi1.0

I can see activity on the spi pins listed above, see scope screen:

Hope this helps.

Best Regards,
Yordan

0 Sudipta Kumar Sahoo over 9 years ago in reply to Yordan Kovachev

Intellectual 360 points

Hi Yordan,

Thanks for your help. It worked.

Regards

Sudipta.

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SPI Not working with am3352.