TFT3P5581-E display issues with i.mx7ulp evk

[Jonny_T]

Hi, 

I'm having issues with the TFT3P5581-E display on the i.mx7ulp evaluation board, the backlight on the display comes on but there is nothing displayed on screen.

I'm new to embedded linux development and so have just been trying out the example images including the one that came on the SD card supplied with the board which appears to be version 4.9.88 but I have also tried version 5.10.9.

The terminal print out from 4.9.88 from the SD card supplied with the board relating to the display is below;

backlight supply power not found, using dummy regulator
mipi_dsi_northwest 40a90000.mipi_dsi: i.MX MIPI DSI driver probed
adv7535 probing phase
adv7535 0-003d: main addr = 0x3d
i2c i2c-0: chip_rev = 0x14
adv7535 0-003d: dsi cec addr = 0x78
adv7535 0-003d: adv7535 probe finished
40aa0000.lcdif supply lcd not found, using dummy regulator
mipi_dsi_northwest 40a90000.mipi_dsi: MIPI DSI dispdv inited
mxsfb 40aa0000.lcdif: registered mxc display driver mipi_dsi_northwest
Console: switching to colour frame buffer device 80x30
mxsfb 40aa0000.lcdif: initialized
 

on version 5.10.9 the terminal print gives us;

[ 0.462795] pwm-backlight backlight: supply power not found, using dummy regu lator
[ 0.464262] mipi_dsi_northwest 40a90000.mipi_dsi: i.MX MIPI DSI driver probed
[ 0.464930] adv7535 probing phase
[ 0.464960] adv7535 2-003d: main addr = 0x3d
[ 0.465460] i2c i2c-2: chip_rev = 0x14
[ 0.465921] adv7535 2-003d: dsi cec addr = 0x78
[ 0.479786] adv7535 2-003d: adv7535 probe finished
[ 0.482386] mxsfb 40aa0000.lcdif: supply lcd not found, using dummy regulator
[ 0.609665] mipi_dsi_northwest 40a90000.mipi_dsi: MIPI DSI dispdv inited
[ 0.609708] mxsfb 40aa0000.lcdif: registered mxc display driver mipi_dsi_nort hwest
[ 0.654289] sii902x bound to mxs-lcdif from 40aa0000.lcdif
[ 0.663922] Console: switching to colour frame buffer device 80x30
[ 0.769551] mxsfb 40aa0000.lcdif: initialized
[ 0.775546] 402d0000.serial: ttyLP0 at MMIO 0x402d0010 (irq = 47, base_baud = 1500000) is a FSL_LPUART

I have also tried a demo image supplied from crank software for this board that has the same issue, backlight comes on but nothing is displayed, they seemed to think is was related to the display we are using as their demo image was for the TFT3P5581-T not the TFT3P5581-E that I'm trying to use. 

I was wondering what the difference is between the two and if there is some sort of incompatibility with the display and the evaluation board I'm using which is the MCIMX7ULP-EVK REV B1? Or is this a driver issue as I'm not 100% what driver is needed for this display? 

Is there any reason why this display should work with the latest linux version example images found in 5.10.9?

[Jonny_T]

thank you for the reply, your suggestions worked!

Where is the required hardware changes documented?

Also I'm wondering what drivers I need for the touch input to work? 

[AldoG · Accepted solution]

Hello,

The display should work with both kernel version you're trying with, make sure that you have made the proper hardware changes:

Remove resistors: R41 (0 ohm), R43-R46 (0 ohm), R51 (0 ohm)
Populate the resistors: R30-R35 (0 ohm)

If this is done, then you'll need to select the appropriate dtb, the dtb file you'll need to select will change depending of the board version you're using:

i.MX 7ULP EVK -> imx7ulp-evk-mipi.dtb
i.MX 7ULP EVKB -> imx7ulp-evkb-mipi.dtb

You'll achieve this by stopping at uboot and setting fdt_file to imx7ulp-evk-mipi.dtb or imx7ulp-evkb-mipi.dtb accordingly.

Best regards,
Aldo.