Wiring up an ili9341 2.4" TFT LCD display to the Black

[Mark A. Yoder]

I'm trying to drive a ili9341 display via the frame buffer, but have hit a snag.  There are a number of gpio pins I want to use the are already exported.

bone$ cd /sys/class/gpio/

/sys/class/gpio /sys/devices/platform/ocp

bone$  ls

export   gpio116  gpio22  gpio35  gpio46  gpio62  gpio70  gpio78  gpio89

gpio10   gpio117  gpio23  gpio36  gpio47  gpio63  gpio71  gpio79  gpio9

gpio11   gpio12   gpio3   gpio37  gpio48  gpio65  gpio72  gpio8   gpiochip0

gpio110  gpio13   gpio30  gpio38  gpio49  gpio66  gpio73  gpio80  gpiochip32

gpio111  gpio14   gpio31  gpio39  gpio5   gpio67  gpio74  gpio81  gpiochip64

gpio113  gpio15   gpio32  gpio4   gpio50  gpio68  gpio75  gpio86  gpiochip96

gpio114  gpio2    gpio33  gpio44  gpio51  gpio69  gpio76  gpio87  unexport

gpio115  gpio20   gpio34  gpio45  gpio60  gpio7   gpio77  gpio88

I can't unexport them. 

bone$ echo 115 > unexport 

-bash: echo: write error: Invalid argument

 

How do I reclaim these?

--Mark

bone$ sudo /opt/scripts/tools/version.sh 

git:/opt/scripts/:[29878c8f9a13833ac69956ecc086c95b99726dde]

eeprom:[A335BNLTGW1ABBGW16052042]

model:[TI_AM335x_BeagleBone_Green_Wireless]

dogtag:[BeagleBoard.org Debian Image 2018-07-29]

bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2018.03-00002-gac9cce7c6a]:[location: dd MBR]

kernel:[4.14.58-ti-r65]

nodejs:[v6.14.3]

uboot_overlay_options:[enable_uboot_overlays=1]

uboot_overlay_options:[disable_uboot_overlay_video=1]

uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-14-TI-00A0.dtbo]

uboot_overlay_options:[enable_uboot_cape_universal=1]

pkg check: to individually upgrade run: [sudo apt install --only-upgrade <pkg>]

pkg:[bb-cape-overlays]:[4.4.20180727.0-0rcnee0~stretch+20180727]

pkg:[bb-wl18xx-firmware]:[1.20180517-0rcnee0~stretch+20180517]

pkg:[kmod]:[23-2rcnee1~stretch+20171005]

pkg:[librobotcontrol]:[1.0.0-git20180726.0-0rcnee0~stretch+20180727]

pkg:[firmware-ti-connectivity]:[20170823-1rcnee1~stretch+20180328]

groups:[debian : debian adm kmem dialout cdrom floppy audio dip video plugdev users systemd-journal i2c bluetooth netdev cloud9ide gpio pwm eqep admin spi tisdk weston-launch xenomai]

cmdline:[console=ttyO0,115200n8 bone_capemgr.uboot_capemgr_enabled=1 root=/dev/mmcblk0p1 ro rootfstype=ext4 rootwait coherent_pool=1M net.ifnames=0 quiet]

dmesg | grep pinctrl-single

[    1.046339] pinctrl-single 44e10800.pinmux: 142 pins at pa f9e10800 size 568

dmesg | grep gpio-of-helper

[    1.057509] gpio-of-helper ocp:cape-universal: ready

END

[Mark A. Yoder]

Robert Nelson has answered my question.  There are a number of pins already used on the BeagleBone Green Wireless that can't otherwise be used.  

I've made a list of them[1].

--Mark

[1] https://elinux.org/EBC_Exercise_10b_Green_Wireless_Pins_Used

[Robert Nelson]

On Tue, Sep 11, 2018 at 12:49 PM Mark A. Yoder <mark.a...@gmail.com> wrote:
>
> Robert Nelson has answered my question. There are a number of pins already used on the BeagleBone Green Wireless that can't otherwise be used.
>
> I've made a list of them[1].
>
> --Mark
>
> [1] https://elinux.org/EBC_Exercise_10b_Green_Wireless_Pins_Used

We should add a few details,

Pins:
P8_11, P8_16, and P8_15 can be recovered, by sticking the wl1835 wifi
module in 1-bit mode vs 4-bit mode..

sudo rm /lib/firmware/BB-BBGW-WL1835-00A0.dtbo
sudo cp /lib/firmware/BB-BBGW-WL1835-1BIT-00A0.dtbo
/lib/firmware/BB-BBGW-WL1835-00A0.dtbo

P8_12 = WL1835: mmc2_dat0
P8_18 = WL1835: mmc2_clk

P8_14 = WL1835: Wireless enabled
P8_17 = WL1835: Wireless IRQ

P9_12 = WL1835: Bluetooth enabled

Pins:
P8_26, P9_30 are "gpio hogged" at startup, not user changeable.

Pins:
P9_28, P9_29, and P9_31 are used by audio, which isn't actually used,
but tied up..

@mark, random thought, do you want to try booting with
P9_28/P9_29/P9_31 removed from bbgw..

for example..

https://github.com/beagleboard/bb.org-overlays/commit/502c3d228dd6a6902cc6d7b32014075b7c6b8eb6

Regards,

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

[Robert Nelson]

Okay, wifi/bluetooth correctly came up on restart and cold boot with
those pins removed from the overlay.

Give them a try with a spi device connected up. If they work without
breaking the wl1835, we will just nuke those 3 audio pins..

[Mark A. Yoder]

Robert:

  I've updated the page[1], but didn't know what to say about recovering 

P8_12, P8_18, P8_1,4, P8_17 and P9_12.  

Do you have to edit the device tree?

--Mark

[1] https://elinux.org/EBC_Exercise_10b_Green_Wireless_Pins_Used

[Mark A. Yoder]

How do I removed the audio pins so I can test it?

--Mark