[beagleboard] Help with PRU on Beaglebone Black

[jcalvinowens]

Hello all,

I'm trying to get the PRU on the BBB working. I want to use it to drive two 
pairs of 4 select lines for a couple analog multiplexer/demultiplexers.

I've followed the instructions here with no success:
http://www.element14.com/community/community/knode/single-board_computers/next-gen_beaglebone/blog/2013/05/22/bbb--working-with-the-pru-icssprussv2

This is my device tree file:

/dts-v1/;
/plugin/;
/ {
        compatible = "ti,beaglebone", "ti,beaglebone-black";
        part-number = "BB-BONE-PRU";
        version = "00A0";
        exclusive-use =
                "P8.39",
                "P8.40",
                "P8.41",
                "P8.42",
                "P8.43",
                "P8.44",
                "P8.45",
                "P8.46",
                "pruss"; 
        fragment@0 {
                target = <&am33xx_pinmux>;
                __overlay__ {
                        pru_wcsp_pins: wcsp_select_lines {
                                pinctrl-single,pins = <
                                        0xA0 0x05 // P8:45 
(pr1_pru1_pru_r30_0)
                                        0xA4 0x05 // P8:46 
(pr1_pru1_pru_r30_1)
                                        0xA8 0x05 // P8:43 
(pr1_pru1_pru_r30_2)
                                        0xAC 0x05 // P8:44 
(pr1_pru1_pru_r30_3)
                                        0xB0 0x05 // P8:41 
(pr1_pru1_pru_r30_4)
                                        0xB4 0x05 // P8:42 
(pr1_pru1_pru_r30_5)
                                        0xB8 0x05 // P8:39 
(pr1_pru1_pru_r30_6)
                                        0xBC 0x05 // P8:40 
(pr1_pru1_pru_r30_7)
                                >;
                        };
                };
        };
        fragment@1 {
                target = <&ocp>;
                __overlay__ {
                        dh_helper: helper {
                                compatible = "bone-pinmux-helper";
                                pinctrl-names = "default";
                                pinctrl-0 = <&pru_wcsp_pins>;
                                status = "okay";
                        };
                };
        };
};

Since the pins I need conflict with the EMMC and the HDMI outputs, I've 
used the kernel command line option "capemgr.disable_partno" to prevent 
them from being loaded.

The PRU mapping appears to work using the TI library, but nothing 
whatsoever happens at the outputs. 

The tree seems to apply:

> [ 1367.507694] bone-capemgr bone_capemgr.9: part_number 
> 'BB-BONE-PRU-WCSP', version 'N/A'
> [ 1367.516818] bone-capemgr bone_capemgr.9: slot #9: generic override
> [ 1367.523347] bone-capemgr bone_capemgr.9: bone: Using override eeprom 
> data at slot 9
> [ 1367.531357] bone-capemgr bone_capemgr.9: slot #9: 'Override Board 
> Name,00A0,Override Manuf,BB-BONE-PRU-WCSP'
> [ 1367.541824] bone-capemgr bone_capemgr.9: slot #9: Requesting part 
> number/version based 'BB-BONE-PRU-WCSP-00A0.dtbo
> [ 1367.552655] bone-capemgr bone_capemgr.9: slot #9: Requesting firmware 
> 'BB-BONE-PRU-WCSP-00A0.dtbo' for board-name 'Override Board Name', version 
> '00A0'
> [ 1367.568311] bone-capemgr bone_capemgr.9: slot #9: dtbo 
> 'BB-BONE-PRU-WCSP-00A0.dtbo' loaded; converting to live tree
> [ 1367.579926] bone-capemgr bone_capemgr.9: slot #9: #2 overlays
> [ 1367.586354] bone-capemgr bone_capemgr.9: slot #9: Applied #2 overlays.


... but the content of /sys/kernel/debug/pinctrl/44e10800.pinmux/pins never 
changes, so it would seem something isn't happening that is supposed to.

Any thoughts?

Thanks very much,
Calvin

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