Can't get overlay to set pinmux for IEP

[Andrew P. Lentvorski]

Am I doing something wrong or are my expectations incorrect?

I created an overlay file BB-PRUDAP-00A0 to take over P9_17 and P9_18 and set them to the IEP.

I added it to uEnv.txt and apparently it loaded:

root@beaglebone:~/prudap/lkm/prudap_lkm# ls -al /proc/device-tree/chosen/overlays/
total 0
drwxr-xr-x 2 root root  0 Jan 24 07:11 .
drwxr-xr-x 3 root root  0 Jan 24 07:11 ..
-r--r--r-- 1 root root 25 Jan 24 07:11 AM335X-PRU-RPROC-4-14-TI-00A0
-r--r--r-- 1 root root 25 Jan 24 07:11 BB-ADC-00A0
-r--r--r-- 1 root root 25 Jan 24 07:11 BB-BONE-eMMC1-01-00A0
-r--r--r-- 1 root root 25 Jan 24 07:11 BB-PRUDAP-00A0
-r--r--r-- 1 root root  9 Jan 24 07:11 name

It also seems to have exclusive control over the pins:

root@beaglebone:~# config-pin P9_17 pwm
ERROR: open() for /sys/devices/platform/ocp/ocp:P9_17_pinmux/state failed, No such file or directory

However, when I check the actual pinmux values, I get:

[   77.897980] prudap: spi0_cs0 pinmux state: 0x37
[   77.897986] prudap: spi0_d1  pinmux state: 0x37

That's not what I expect.  I expected to see 0x2E and 0x2D like I requested in the overlay file.

What did I do wrong in the BB-PRUDAP-00A0.dts file.  Those values are not what I wanted, but I can override those values in a kernel module.  However, I expected the pinmux to be already set up due to the overlay file.

Any help would be appreciated.

Thanks.

BB-PRUDAP-00A0.dts file:

/dts-v1/;
/plugin/;

#include <dt-bindings/board/am335x-bbw-bbb-base.h>
#include <dt-bindings/pinctrl/am33xx.h>

/ {
    compatible = "ti,beaglebone", "ti,beaglebone-black", "ti,beaglebone-green";

    // identification
    part-number = "BB-PRUDAP";
    version = "00A0";

    // resources this cape uses
    exclusive-use =
        "P9.17",    // spi0_cs0
        "P9.18",    // spi0_d1

        "pruss_iep";    // hardware ip used

    /*
     * Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
     */
    fragment@0 {
        target-path="/";
        __overlay__ {

            chosen {
                overlays {
                    BB-PRUDAP-00A0 = __TIMESTAMP__;
                };
            };
        };
    };

    /*
     * Free up the pins used by the cape from the pinmux helpers.
     */
    fragment@1 {
        target = <&ocp>;
        __overlay__ {
            P9_17_pinmux { status = "disabled"; };    /* spi0_cs0 */
            P9_18_pinmux { status = "disabled"; };    /* spi0_d1  */
        };
    };

    fragment@2 {
        target = <&am33xx_pinmux>;
        __overlay__ {
            bb_prudap_pins: pinmux_bb_prudap_pins {
                pinctrl-single,pins = <
                    BONE_P9_17 0x2E    /* spi0_cs0.i2c1_scl, SLEWCTRL_FAST | INPUT_EN | PULL_DISABLE | MODE6 (IEP-edio/digio data out 7) */
                    BONE_P9_18 0x2D    /* spi0_d1.i2c1_sda, SLEWCTRL_FAST | INPUT_EN | PULL_DISABLE | MODE5 (IEP-edio/digio data in 6) */
                >;
            };
        };
    };

    fragment@3 {
        target = <&pruss_iep>;
        __overlay__ {
            status = "okay";
            pinctrl-names = "default";
            pinctrl-0 = <&bb_prudap_pins>;
        };
    };
};

/boot/uEnv.txt for completeness:

root@beaglebone:~/prudap/lkm/prudap_lkm# cat /boot/uEnv.txt
#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.14.108-ti-r113
#uuid=
#dtb=

###U-Boot Overlays###
###Documentation: http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Overlays
###Master Enable
enable_uboot_overlays=1
###
###Overide capes with eeprom
#uboot_overlay_addr0=/lib/firmware/<file0>.dtbo
#uboot_overlay_addr1=/lib/firmware/<file1>.dtbo
#uboot_overlay_addr2=/lib/firmware/<file2>.dtbo
#uboot_overlay_addr3=/lib/firmware/<file3>.dtbo
###
###Additional custom capes
uboot_overlay_addr4=/lib/firmware/BB-PRUDAP-00A0.dtbo
#uboot_overlay_addr5=/lib/firmware/<file5>.dtbo
#uboot_overlay_addr6=/lib/firmware/<file6>.dtbo
#uboot_overlay_addr7=/lib/firmware/<file7>.dtbo
###
###Custom Cape
#dtb_overlay=/lib/firmware/<file8>.dtbo
###
###Disable auto loading of virtual capes (emmc/video/wireless/adc)
#disable_uboot_overlay_emmc=1
disable_uboot_overlay_video=1
disable_uboot_overlay_audio=1
#disable_uboot_overlay_wireless=1
#disable_uboot_overlay_adc=1
###
###PRUSS OPTIONS
###pru_rproc (4.4.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo
###pru_rproc (4.14.x-ti kernel)
uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo
###pru_rproc (4.19.x-ti kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-19-TI-00A0.dtbo
###pru_uio (4.4.x-ti, 4.14.x-ti, 4.19.x-ti & mainline/bone kernel)
#uboot_overlay_pru=/lib/firmware/AM335X-PRU-UIO-00A0.dtbo
###
###Cape Universal Enable
enable_uboot_cape_universal=1
###
###Debug: disable uboot autoload of Cape
#disable_uboot_overlay_addr0=1
#disable_uboot_overlay_addr1=1
#disable_uboot_overlay_addr2=1
#disable_uboot_overlay_addr3=1
###
###U-Boot fdt tweaks... (60000 = 384KB)
#uboot_fdt_buffer=0x60000
###U-Boot Overlays###

cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 quiet

#In the event of edid real failures, uncomment this next line:
#cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 quiet video=HDMI-A-1:1024x768@60e

#Use an overlayfs on top of a read-only root filesystem:
#cmdline=coherent_pool=1M net.ifnames=0 rng_core.default_quality=100 quiet overlayroot=tmpfs

##enable Generic eMMC Flasher:
##make sure, these tools are installed: dosfstools rsync
#cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh

[TJF]

I guess your overlay cannot 'disable' pins that're claimed by another overlay. And here you're facing the core problem when working with device trees: you won't get reliable error messages. Everything ends up with trail-and-error bug finding.

I've good reasons why I always drop config-pin and its overlays. Instead I developed and shared libpruio and its pinmuxing. Your target is over the capabilities of the standard tools, but is well covered by the libpruio scope.

[Robert Nelson]

The pruss_ieq doesn't have pinctrl, you need to stick it in the pruss node:

https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/AM335X-PRU-RPROC-4-14-TI-PRUCAPE-00A0.dts#L119-L131

It's really best to copy AM335X-PRU-RPROC-4-14-TI-PRUCAPE-00A0.dts to
your overlay name, and then rip out the pins you don't use..

Regards,


--
Robert Nelson
https://rcn-ee.com/

[Andrew P. Lentvorski]

Much appreciated, Robert.  I updated to the PRUCAPE file and tore out a bunch of stuff I didn't need and that seems to be setting the pinmux correctly.

Is there anything else in this file that can be removed?

Thanks.

// Code shamelessly copied from AM335X-PRU-RPROC-4-14-TI-PRUCAPE-00A0.dts

/dts-v1/;
/plugin/;

/ {
    compatible = "ti,beaglebone", "ti,beaglebone-black", "ti,beaglebone-green";

    // identification
    part-number = "BB-PRUDAP";
    version = "00A0";

    /*

     * Helper to show loaded overlays under: /proc/device-tree/chosen/overlays/
     */

    fragment@0 {
        target-path="/";
        __overlay__ {

            chosen {
                overlays {
                    BB-PRUDAP-00A0 = __TIMESTAMP__;
                };
            };
        };
    };

    /*
     * Free up the pins used by the cape from the pinmux helpers.
     */
    fragment@1 {
        target = <&ocp>;
        __overlay__ {

            P9_18_pinmux { status = "disabled"; };    /* P9_18: spi0_d1 */
            P9_17_pinmux { status = "disabled"; };    /* P9_17: spi0_cs0 */

        };
    };

    fragment@2 {
        target = <&am33xx_pinmux>;
        __overlay__ {
            bb_prudap_pins: pinmux_bb_prudap_pins {
                pinctrl-single,pins = <

                    0x158 0x2D    /* P9_18: spi0_d1.i2c1_sda, SLEWCTRL_FAST | INPUT_EN | PULL_DISABLE | MODE5 (IEP-edio/digio data in 6) */
                    0x15c 0x2E    /* P9_17: spi0_cs0.i2c1_scl, SLEWCTRL_FAST | INPUT_EN | PULL_DISABLE | MODE6 (IEP-edio/digio data out 7) */
                >;
            };
        };
    };

    fragment@3 {
        target-path="/";
        __overlay__ {

            ocp {
                #address-cells = <1>;
                #size-cells = <1>;

                pruss_soc_bus: pruss_soc_bus@4a326004 {
                    compatible = "ti,am3356-pruss-soc-bus";
                    reg = <0x4a326004 0x4>;
                    ti,hwmods = "pruss";
                    #address-cells = <1>;
                    #size-cells = <1>;
                    ranges = <0x0 0x4a300000 0x80000>;
                    status = "okay";

                    pruss: pruss@0 {
                        compatible = "ti,am3356-pruss";
                        reg = <0x0 0x80000>;
                        interrupts = <20 21 22 23 24 25 26 27>;
                        interrupt-names = "host2", "host3", "host4",
                                  "host5", "host6", "host7",
                                  "host8", "host9";
                        #address-cells = <1>;
                        #size-cells = <1>;
                        ranges;

                        status = "okay";
                        pinctrl-names = "default";
                        pinctrl-0 = <&bb_prudap_pins>;

                        pruss_iep: iep@2e000 {
                            compatible = "syscon";
                            reg = <0x2e000 0x31c>;
                        };
                    };
                };
            };
        };
    };
};

[Robert Nelson]

On Fri, Jan 24, 2020 at 8:29 PM Andrew P. Lentvorski <bsd...@gmail.com> wrote:
>
> Much appreciated, Robert. I updated to the PRUCAPE file and tore out a bunch of stuff I didn't need and that seems to be setting the pinmux correctly.
>
> Is there anything else in this file that can be removed?

I'd actually keep the whole "pruss_soc_bus" struct as it was, (with
those 5 or 6 extra nodes..)

More or less to just keep the driver happy..