beagleboardgpiodevice-tree

Configuring Pins Mode Beaglebone

In the beagleboard or beaglebone are different modes to work the pin. With the previous kernel they are located in /sys/kernel/debug/omap_mux. Do u know with the last Kernel where are those files?

Solution

  • I found many of the examples provided at hipstercircuits to be a bit overwhelming; especially if you're just looking to adjust the pins to mode 7. If anyone reading this is having the same issue, the following link may help: http://bbbadventures.blogspot.ca/2013/06/pinmuxing.html It provides the most basic template.

    Should the link above break, here's the snippet provided (with a few tweaks for clarity):

    /*
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
/dts-v1/;
/plugin/;

/ { compatible = "ti,beaglebone", "ti,beaglebone-black";
    /* identification */
    part-number = "pinctrl-test-0";
    fragment@0 {
        target = <&am33xx_pinmux>;
        __overlay__ {
            pinctrl_test: pinctrl_test_0_pins {
                pinctrl-single,pins = <
                    0x030 0x07 /* P8_12 OUTPUT | MODE7 */
                    0x034 0x07 /* P8_11 OUTPUT | MODE7 */
                    /* Add more pins here */
                >;
            };
        };
    };

    fragment@1 {
        target = <&ocp>;
        __overlay__ {
            test_helper: helper {
                compatible = "bone-pinmux-helper";
                pinctrl-names = "default";
                pinctrl-0 = <&pinctrl_test>;
                status = "okay";
            };
        };
    };
};

    When adding more pins to the above snippet, you can use the following tables to identify which hex values match the pins:

    Each pin is set by appending an additional entry into pinctrl-single,pins. The format looks like this:

    [offset] [mode]

    Example: 0x030 0x07

    In the two tables linked above refer to the third column, entitled "ADDR/OFFSET", for the offset value.

    I hope this helps :)

    Edit: I should also mention that the answers provided by Martin and Don are both excellent should help cover the rest of the important details.