>From the schematic you can see that thi spin is used as th eclock input for
the HDMI. Please read the note.

Gerald
:



[image: Inline image 1]




On Wed, Mar 12, 2014 at 11:24 AM, Bit Pusher <[email protected]> wrote:

> BBB Ubuntu 3.8.13-bone28 cross compiled from Robert Nelson's source
>
> I have been trying to use P9-25 as a GPIO output (gpio3_21), but couldn't
> change it's mode. I tried to do this with an overlay file and got the error
> message (in dmesg)
>
> [177534.038798] bone-capemgr bone_capemgr.9: slot #10: generic override
> [177534.038816] bone-capemgr bone_capemgr.9: bone: Using override eeprom
> data at slot 10
> [177534.038834] bone-capemgr bone_capemgr.9: slot #10: 'Override Board
> Name,00A0,Override Manuf,cape-bone-pru'
> [177534.040746] bone-capemgr bone_capemgr.9: slot #10: Requesting part
> number/version based 'cape-bone-pru-00A0.dtbo
> [177534.040775] bone-capemgr bone_capemgr.9: slot #10: Requesting firmware
> 'cape-bone-pru-00A0.dtbo' for board-name 'Override Board Name', version
> '00A0'
> [177534.041685] bone-capemgr bone_capemgr.9: slot #10: dtbo
> 'cape-bone-pru-00A0.dtbo' loaded; converting to live tree
> [177534.041964] bone-capemgr bone_capemgr.9: slot #10: cape-bone-pru
> conflict P9.25 (#5:BB-BONELT-HDMI)
> [177534.051650] bone-capemgr bone_capemgr.9: slot #10: Failed verification
>
> But from the BBB technical reference P9.25 is not one of the HDMI reserved
> pins. My guess (after lots of looking around etc.) is the HDMI is loaded by
> the following lines in
> am335x-boneblack.dts (after uncompiling from *.dtb) in /boot/dtbs:
>
>                         slot@101 {
>                                 ti,cape-override;
>                                 priority = <0x1>;
>                                 compatible = "ti,beaglebone-black";
>                                 board-name = "Bone-Black-HDMI";
>                                 version = "00A0";
>                                 manufacturer = "Texas Instruments";
>                                 part-number = "BB-BONELT-HDMI";
>                         };
>
> My guess? is this loads an appropriate *.dtbo /lib/firmware that has a
> line:
>         part-number = "BB-BONELT-HDMI";
> in the header section of it's */dts file; could someone confirm my
> understanding here?
>
> Going to /lib/firmware I ran >grep -i BB-BONELT-HDMI *
> and found the canditates:
> Binary file cape-boneblack-hdmi-00A0.dtbo matches
> Binary file cape-boneblack-hdmin-00A0.dtbo matches
>
> In the file cape-boneblack-hdmi-00A0.dts (after un-compiling) are the
> lines:
>
>         exclusive-use = "P9.25", "P9.28", "P9.29", "P9.31", "P8.45",
> "P8.46", "P8.43", "P8.44", "P8.41", "P8.42", "P8.39", "P8.40", "P8.37",
> "P8.38", "P8.36", "P8.34", "P8.35", "P8.33", "P8.31", "P8.32", "P8.27",
> "P8.29", "P8.28", "P8.30", "gpio1_27", "mcasp0", "lcd";
>
>         fragment@0 {
>                 target = <0xdeadbeef>;
>
>                 __overlay__ {
>
>                         nxp_hdmi_bonelt_pins {
>                                 pinctrl-single,pins = <0x1b0 0x3 0xa0 0x8
> 0xa4 0x8 0xa8 0x8 0xac 0x8 0xb0 0x8 0xb4 0x8 0xb8 0x8 0xbc 0x8 0xc0 0x8
> 0xc4 0x8 0xc8 0x8 0xcc 0x8 0xd0 0x8 0xd4 0x8 0xd8 0x8 0xdc 0x8 0xe0 0x0
> 0xe4 0x0 0xe8 0x0 0xec 0x0>;
>                                 linux,phandle = <0x1>;
>                                 phandle = <0x1>;
>                         };
>
> It appears to me that the pinctrl-single,pins do correspond to Table 13 in
> section 7.10.1 of the BeagleBone Black System Reference Manual, but there
> appears to be too many
> values for exclusive-use, and that these values do not correspond to
> the pinctrl-single,pins values. In particular there should not be any
> header pins from P9, and I also do understand why
> "gpio1_27", "mcasp0", "lcd" are included. Indeed, gpio1_27 is not even a
> possibility for the headers. (I'm also wondering why pinctrl-single,pins
> appear to be a random order?).
> After backing up cape-boneblack-hdmi-00A0.dts, I edited it take
> out "P9.25", "P9.28", "P9.29", "P9.31" from exclusive-use, and then
> re-compiled using:
>  sudo sh -c "dtc -@ -O dtb -o cape-boneblack-hdmi-00A0.dtbo
> cape-boneblack-hdmi-00A0.dts"
> After re-booting (and waiting 5 minutes before I could ssh in - I sure
> wish I could fix this and/or get the usb-ether working), I then loaded the
> overlay again, but I still had the conflict
>
> /lib/firmware\> dmesg | tail -2
> [  196.851263] bone-capemgr bone_capemgr.9: slot #7: cape-bone-pru
> conflict P9.25 (#5:BB-BONELT-HDMI)
> [  196.860761] bone-capemgr bone_capemgr.9: slot #7: Failed verification
> /lib/firmware\>
>
> It looks like my guess on where the exclusive-use is loaded from is
> incorrect. Any suggestions on what to try next? Is it necessary to
> recompile the kernel to change the exclusive-use
> pins determined at boot? If so, any links to help with this? Thanks.
> Bit_Pusher
>
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