PROCESSOR-SDK-AM62X: sk-am62-lp LVDS Tianma display interfacing

Umang Gajjar

Tool/software: Linux

Hello experts,

i am newly started to work with texas board am62x-lp. i just bring-up the am62x-lp custom board. now i want to interface the tianma display that is connected to my board with 40 pin connector of LVDS. also one thing i notice that when i connect lcd with board or disconnect the board dmesg does not detect any changes. is there is a way to detect it like in hdmi hotplugin detection?
how to start interface it please guide me.

refer below attachment of tianma display
part number : YX-TFTRFQ-ZX-20230313001
display : 7’TFT with CTP TFT-LCD Module
YX-TFTRFQ-ZX-20230313001 pre-Spec V1.0 (1).pdf

2 months ago

0 Divyansh Mittal 2 months ago

TI__Expert 8150 points

Hi,
LVDS and DPI by nature do not wait for any handshaking with display panel, if you start video streaming, they will start streaming signal even if display is not connected (hence you can probe these signals if you want to). But in case of HDMI, there is a bridge driver that first reads EDID from the display via I2C, configures the timing parameters and then enables video streaming.

0 Umang Gajjar 2 months ago in reply to Divyansh Mittal

Prodigy 30 points

thank you for your response. how to start with LVDS display should i need to chnage the device tree? which is in the following logs to change in pmux0

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1128751/am625-oldi-driver-or-dts-example/4198123#4198123

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1463465/am625-single-channel-lvds-oldi-panel-display-change-in-sdk-10-1

my bootup logs
5140.boot_log.txt

my printenv

Fullscreen 8461.printenv_log.txt Download

U-Boot 2024.04-dirty (Jul 01 2025 - 16:55:30 +0000)                           
                                                                              
SoC:   AM62X SR1.0 HS-FS                                                      
Model: Texas Instruments AM62x LP SK                                          
EEPROM not available at 0x50, trying to read at 0x51                          
Reading on-board EEPROM at 0x51 failed -121                                   
DRAM:  2 GiB                                                                  
Core:  83 devices, 32 uclasses, devicetree: separate                          
NAND:  0 MiB                                                                  
MMC:   mmc@fa10000: 0, mmc@fa00000: 1                                         
Loading Environment from nowhere... OK                                        
In:    serial                                                                 
Out:   serial                                                                 
Err:   serial                                                                 
EEPROM not available at 0x50, trying to read at 0x51                          
Reading on-board EEPROM at 0x51 failed -121                                   
Net:   eth0: ethernet@8000000port@1                                           
Hit any key to stop autoboot:  0                                              
=>                                                                            
=> printenv                                                                   
addr_fit=0x90000000                                                           
arch=arm                                                                      
args_all=setenv optargs ${optargs} earlycon=ns16550a,mmio32,0x02800000 ${mtdp}
args_mmc=run finduuid;setenv bootargs console=${console} ${optargs} root=PART}
args_ospi_nand=setenv bootargs console=${console} ${optargs} ubi.mtd=${ospi_ns
baudrate=115200                                                               
board=am62x                                                                   
board_name=am62x_skevm                                                        
board_rev=unknown                                                             
board_serial=unknown                                                          
board_software_revision=unknown                                               
boot=mmc                                                                      
boot_fdt=try                                                                  
boot_fit=0                                                                    
boot_rprocs=if test ${dorprocboot} -eq 1 && test ${boot} = mmc; then rproc in;
boot_rprocs_mmc=env set rproc_id; env set rproc_fw; env set secure_suffix; ife
boot_targets=mmc0 mmc1 usb pxe dhcp                                           
bootcmd=run envboot; run bootcmd_ti_mmc; bootflow scan -lb                    
bootcmd_ti_mmc=run init_${boot}; run update_do_main_cpsw0_qsgmii_phyinit; if ;
bootdelay=2                                                                   
bootdir=/boot                                                                 
bootenvfile=uEnv.txt                                                          
bootm_size=0x10000000                                                         
bootpart=0:1                                                                  
bootscript=echo Running bootscript from mmc${mmcdev} ...; source ${loadaddr}  
console=ttyS2,115200n8                                                        
cpu=armv8                                                                     
dfu_alt_info_emmc=rawemmc raw 0 0x800000 mmcpart 1; rootfs part 0 1; tiboot3.1
dfu_alt_info_mmc=boot part 1 1; rootfs part 1 2; tiboot3.bin fat 1 1; tispl.b1
dfu_alt_info_nand=NAND.tiboot3 part 0 1; NAND.tispl part 0 2; NAND.tiboot3.ba7
dfu_alt_info_ospi=tiboot3.bin raw 0x0 0x080000; tispl.bin raw 0x080000 0x20000
dfu_alt_info_ospi_nand=ospi_nand.tiboot3 part 1; ospi_nand.tispl part 2; ospi7
dfu_alt_info_ram=tispl.bin ram 0x80080000 0x200000; u-boot.img ram 0x810000000
dorprocboot=0                                                                 
dtboaddr=0x89000000                                                           
envboot=if mmc dev ${mmcdev}; then if mmc rescan; then echo SD/MMC found on d;
ethaddr=04:25:e8:be:9d:26                                                     
fdt_addr_r=0x88000000                                                         
fdtaddr=0x88000000                                                            
fdtcontroladdr=fde8afa0                                                       
fdtfile=ti/k3-am62-lp-sk.dtb                                                  
fdtoverlay_addr_r=0x89000000                                                  
findfdt=echo WARN: fdtfile already set. Stop using findfdt in script          
finduuid=part uuid ${boot} ${bootpart} uuid                                   
get_fdt_mmc=load mmc ${bootpart} ${fdtaddr} ${bootdir}/dtb/${fdtfile}         
get_fdt_ospi_nand=ubifsload ${fdtaddr} ${bootdir}/dtb/${fdtfile};             
get_fit_config=setexpr name_fit_config gsub / _ conf-${fdtfile}               
get_fit_mmc=load mmc ${bootpart} ${addr_fit} ${bootdir}/${name_fit}           
get_fit_ospi_nand=ubifsload ${addr_fit} ${bootdir}/${name_fit}                
get_fit_overlaystring=for overlay in $name_overlays; do; setexpr name_fit_ove;
get_kern_mmc=load mmc ${bootpart} ${loadaddr} ${bootdir}/${name_kern}         
get_kern_ospi_nand=ubifsload ${loadaddr} ${bootdir}/${name_kern}              
get_overlay_mmc=fdt address ${fdtaddr}; fdt resize 0x100000; for overlay in $;
get_overlay_ospi_nand=fdt address ${fdtaddr} fdt resize 0x100000; for overlay;
importbootenv=echo Importing environment from mmc${mmcdev} ...; env import -t}
init_mmc=run args_all args_mmc                                                
init_ospi_nand=run args_all args_ospi_nand ospi_nand_ubi_init                 
kernel_addr_r=0x82000000                                                      
loadaddr=0x82000000                                                           
loadbootenv=fatload mmc ${mmcdev} ${loadaddr} ${bootenvfile}                  
loadfdt=load ${devtype} ${bootpart} ${fdtaddr} ${bootdir}/dtb/${fdtfile}      
loadimage=load ${devtype} ${bootpart} ${loadaddr} ${bootdir}/${bootfile}      
mmcboot=if mmc dev ${mmcdev}; then devnum=${mmcdev}; devtype=mmc; if mmc resc;
mmcdev=1                                                                      
mmcloados=if test ${boot_fdt} = yes || test ${boot_fdt} = try; then if run ge;
mmcrootfstype=ext4 rootwait                                                   
mtdids=spi-nand0=spi-nand0                                                    
mtdparts=mtdparts=spi-nand0:512k(ospi_nand.tiboot3),2m(ospi_nand.tispl),4m(os)
name_fit=fitImage                                                             
name_kern=Image                                                               
ospi_nand_bootpart=ospi_nand.rootfs                                           
ospi_nand_bootvolume=ubi0:rootfs                                              
ospi_nand_ubi_init=ubi part ${ospi_nand_bootpart}; ubifsmount ${ospi_nand_boo;
partitions=name=rootfs,start=0,size=-,uuid=${uuid_gpt_rootfs}                 
pxefile_addr_r=0x80100000                                                     
ramdisk_addr_r=0x88080000                                                     
rd_spec=-                                                                     
rdaddr=0x88080000                                                             
rproc_fw_binaries= 0 /lib/firmware/am62-mcu-m4f0_0-fw                         
rproc_load_and_boot_one=if load mmc ${bootpart} $loadaddr ${rproc_fw}; then ii
run_fit=run get_fit_config; bootm ${addr_fit}#${name_fit_config}${overlaystri}
run_kern=booti ${loadaddr} ${rd_spec} ${fdtaddr}                              
scriptaddr=0x80000000                                                         
secure_rprocs=0                                                               
serial#=0000000000000000                                                      
soc=k3                                                                        
splashfile=ti_logo_414x97_32bpp.bmp.gz                                        
splashimage=0x80200000                                                        
splashpos=m,m                                                                 
splashsource=mmc                                                              
update_do_main_cpsw0_qsgmii_phyinit=setenv do_main_cpsw0_qsgmii_phyinit 0;    
update_to_fit=setenv loadaddr ${addr_fit}; setenv bootfile ${name_fit}        
vendor=ti                                                                     
                                                                              
Environment size: 6581/131068 bytes

and kmsprint

Fullscreen kmsprint_log.txt Download

root@am62xx-lp-evm:~# kmsprint                                                
terminate called after throwing an instance of '[  127.273202] kauditd_printkd
std::runtime_error'                                                           
  what():  No modesetting DRM card found                                      
[  127.273232] audit: type=1701 audit(1736373723.040:20): auid=4294967295 uid1
[  127.312843] audit: type=1334 audit(1736373723.080:21): prog-id=20 op=LOAD  
[  127.319741] audit: type=1334 audit(1736373723.088:22): prog-id=21 op=LOAD  
[  127.326611] audit: type=1334 audit(1736373723.092:23): prog-id=22 op=LOAD  
Aborted (core dumped)                                                         
root@am62xx-lp-evm:~# [  127.647457] audit: type=1334 audit(1736373723.416:24D
[  127.654498] audit: type=1334 audit(1736373723.416:25): prog-id=21 op=UNLOAD
[  127.661482] audit: type=1334 audit(1736373723.416:26): prog-id=20 op=UNLOAD

please guide me

one more thing i see some people do the dtso and bringup display but how to generate it with my tianma display
software-dl.ti.com/.../How_to_enable_Microtips_LVDS_Panel.html

0 Divyansh Mittal 2 months ago in reply to Umang Gajjar

TI__Expert 8150 points

Hi,
Please use the this dtso: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am625-sk-microtips-mf101hie-panel.dtso?h=ti-linux-6.12.y as a reference. This is also included in the processor SDK.

Please try defining timing parameters with panel-simple as shown in https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/gpu/drm/panel/panel-simple.c?h=ti-linux-6.1.y#n2722

Seems like you are using a single link panel? In that case omit the following lines from the above dtso

dual-lvds-odd-pixels;
dual-lvds-even-pixels;
ti,companion-oldi = <&oldi1>;
ti,secondary-oldi;

You may refer to https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1534759/am623-lvds-panel-configuration-on-6-12-kernel for similar query.

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PROCESSOR-SDK-AM62X: sk-am62-lp LVDS Tianma display interfacing