On 02/20/2018 10:19 PM, Drew Fustini wrote:
On Sat, Feb 17, 2018 at 7:06 PM, David Lechner <da...@lechnology.com> wrote:
Hi Drew,
I haven't used it with a BeagleBone. Creating a device tree overlay should
be easy though.
If you want to use the backlight, you need to create a node at the root
level like this:
backlight: backlight {
compatible = "gpio-backlight";
gpios = <&gpio 44 GPIO_ACTIVE_HIGH>;
};
Then add a child node to the SPI device for the display kind of like this:
&spi1 {
status = "okay";
pinctrl-0 = <&ev3_lcd_pins>;
pinctrl-names = "default";
display@0{
status = "okay";
compatible = "jianda,jd-t18003-t01", "sitronix,st7735r";
reg = <0>;
spi-max-frequency = <32000000>;
dc-gpios = <&gpio 43 GPIO_ACTIVE_HIGH>;
reset-gpios = <&gpio 80 GPIO_ACTIVE_HIGH>;
backlight = &backlight;
rotation = <270>;
};
};
Obviously you will need to change some things and put it in DT overlay
format, but it should get you pointed in the right direction.
Thanks for the insights, David.
For comparison, this is how I load fbtft for this 1.8" Adafruit ST7735R TFT LCD:
sudo modprobe fbtft_device busnum=1 name=adafruit18 gpios=dc:48,reset:60
I can then use fbi to display an image on the display.
For TinyDRM, I have now added the display node from your example to
BB-SPIDEV1-00A0.dts:
+
+ display@0{
+ status = "okay";
+ compatible = "jianda,jd-t18003-t01",
"sitronix,st7735r";
+ reg = <0>;
+ spi-max-frequency = <16000000>;
+ /*
https://elinux.org/Beagleboard:Cape_Expansion_Headers */
+ dc-gpios = <&gpio1 28 0>; /* dc:48
P9.15 GPIO1_16 */
Are you sure your phandles are correct here? They don't match the comments. Should it be
<&gpio1 16 0> instead?
+ reset-gpios = <&gpio1 16 0>; /*
reset:60 P9.12 GPIO1_28 */
And then <&gpio1 28 0> here?
+ rotation = <270>;
+ };
+
I then added that overlay to /boot/uEnv.txt:
uname_r=4.16.0-rc2-bone3
enable_uboot_overlays=1
uboot_overlay_addr4=/lib/firmware/BB-SPIDEV1-00A0.dtbo
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
cmdline=coherent_pool=1M net.ifnames=0 quiet
I now see this in dmesg after booting up:
[ 0.980709] omap2_mcspi 481a0000.spi: chipselect 0 already in use
[ 0.986882] spi_master spi1: spi_device register error
/ocp/spi@481a0000/channel@0
[ 0.994544] spi_master spi1: Failed to create SPI device for
/ocp/spi@481a0000/channel@0
[ 21.028802] [drm] Initialized st7735r 1.0.0 20171128 for spi1.0 on minor 0
[ 22.568816] random: crng init done
[ 22.902358] Console: switching to colour frame buffer device 20x16
[ 22.902817] st7735r spi1.0: fb0: frame buffer device
I was quite excited to see it get this far. However, I've been unable
to get anything to appear on the LCD.
Here is some basic exploration I've done:
debian@beaglebone:~/libdrm$ find /dev/dri/
/dev/dri/
/dev/dri/card0
debian@beaglebone:~/libdrm$ sudo fbi -d /dev/dri/card0 -i
using "DejaVu Sans Mono-16", pixelsize=16.67
file=/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
ioctl VT_GETSTATE: Inappropriate ioctl for device (not a linux console?)
debian@beaglebone:~$ ls -ltar /dev/fb*
crw-rw---- 1 root video 29, 0 Feb 20 07:27 /dev/fb0
I do see many lines like this in dmesg:
[ 1260.017213] [drm:mipi_dbi_fb_dirty [mipi_dbi]] Flushing [FB:34]
x1=144, x2=152, y1=72, y2=80
[ 1260.017247] [drm:mipi_dbi_typec3_command [mipi_dbi]] cmd=2a, par=00 90 00 97
[ 1260.017325] [drm:mipi_dbi_typec3_command [mipi_dbi]] cmd=2b, par=00 48 00 4f
[ 1260.017359] [drm:mipi_dbi_typec3_command [mipi_dbi]] cmd=2c, len=128
More information in this gist where I am keeping notes:
https://gist.github.com/pdp7/b1cc9b5a25a0c25153b24e0e75964db0
Any suggestions on how I should troubleshoot this display?
Thanks,
Drew
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