topic Re: LVDS display and touch panel bringup | Custom Sabreauto based board in i.MX Processors

LVDS display and touch panel bringup | Custom Sabreauto based board

soorajs — Tue, 06 Feb 2018 05:51:53 GMT

The LVDS display and touch are on same pins as sabreauto .
We are using Displaytech DT070BTFT-PTS1 link to datasheet .
Panel power sequence

V01=VADD, V02=VGL, V03=VGH, VCOM=VCOM. DVDD is obviously applied first.

We are able to power the display and it shows u-boot splash logo by running following commands in u-boot

• For display power sequencing
i2c dev 2 - First enable the I2c expanders and i2c port3
i2c mw 30 1 3b 1    - set the default value to i2c expander output
i2c mw 30 3 00 1    - set all the ports of i2c expander as output
i2c mw 30 1 b9 1    - enable AVDD and VGL
i2c mw 30 1 f9 1 - enable VGH
i2c mw 30 1 fd 1     - enable LED back light supply

mw 20e0250 00000015 1    - setting GPIO7_13 enable
gpio set gpio7_13 - enabling the display
mw 20e0254 00000015 1    - setting GPIO4_05 enable
gpio set gpio4_05                   - wake up display from standby state

• For turn offing the Display, need to follow the below steps in order
i2c mw 30 1 f9 1 - disable back light
i2c mw 30 1 b9 1 - disable VGH
i2c mw 30 1 3b 1 - disable AVDD and VGL

But iam not able to make these changes in u-boot and kernel .

Re: LVDS display and touch panel bringup | Custom Sabreauto based board

igorpadykov — Tue, 06 Feb 2018 10:18:38 GMT

Hi Sooraj

power-up lcd changes can be implemented in

uboot/board/freescale/mx6qsabreauto/mx6qsabreauto.c

uboot-imx.git - Freescale i.MX u-boot Tree

also one can check logo patches and attached Porting Guide

Patch to support uboot logo keep from uboot to kernel for NXP Linux and Android BSP (HDMI, LCD and LVDS)

Best regards
igor
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Re: LVDS display and touch panel bringup | Custom Sabreauto based board

soorajs — Tue, 06 Feb 2018 12:33:49 GMT

Hello Igor,

you mean in uboot/board/freescale/mx6qsabreauto/mx6qsabreauto.c setup_display function ?

please help with writing power-up lcd changes in u-boot.
which document i need to look to write these values to the register ?