STM32MP157CAA3 LCD ili9881 coupling

[MWoło.2]

Hi,

I try to couple LCD TFT ili9881c (mipi dsi 2 lanes interface) with stm32mp157caa3.

My custom driver seems to be loading correctly.

When I type lsmod I get

Module Size Used by 
cfg80211 651264 0 
usb_f_rndis 24576 2 
u_ether 20480 1 usb_f_rndis 
libcomposite 49152 10 usb_f_rndis 
galcore 516096 2 
panel_ilitek_ili9881c 20480 0 
dwmac_stm32 16384 0 
stmmac_platform 20480 1 dwmac_stm32 
stm32_adc_core 20480 0 
spi_stm32 24576 0 
sch_fq_codel 20480 3 
ip_tables 24576 0 
x_tables 24576 1 ip_tables 
ipv6 512000 42

Unfortunately, the display is not working, only the backlight is working.

I checked twice the dts and looks good, driver is loading well. I can't find anything with 'drm'. What I missed? Shall I add some additional driver in the kernel or something install in the roofs?

In the log, I can see only

[ 0.079013] platform 5a000000.dsi: Fixing up cyclic dependency with 5a001000.display-controller

and

[ 13.730531] [drm] Initialized stm 1.0.0 20170330 for 5a001000.display-controller on minor 0

[Erwan SZYMANSKI]

Hello @Michał Wołowik​ ,

Can you tell me on which linux version you are working on ? 5.10 or 5.15 (DV 3.1 or 4.1 ?)

You mentioned your "custom driver" for ili9881 panel. Does it mean that you did not take the one upstreamed under <linux_folder>/drivers//gpu/drm/panel/panel-ilitek-ili9881c.c ?

Can you also share your device tree ?

Kind regards,

Erwan.

[MWoło.2]

Hi Erwan,

I also measure clk and data lines, completely silent on all.

Here are my dts, defconfig and modified panel-ilitek-ili9881c.c

Latest Openstlinux 4.1 kernel 5.15.

I used the original driver but with my own initialization list and other parameters.

[MWoło.2]

I also check other not modified drivers, the result is the same.

Nothing on the MIPI lines and in the log.

/* compatible = "winstar,WF50DTYA3MNG10", "ilitek,ili9881c"; */
		compatible = "raydium,rm68200";

 I think I missed something due I start designing dts from Cube Mx.

[Erwan SZYMANSKI]

Hello @Michał Wołowik​,

Looking at your shared files, I do not see obvious issue that can explain your problem.

Are you working on a custom board or is it the stm32mp157c-dk2 board ?

Just to get a little bit more information, we can take a look at the following things:

• adding drm.debug="0xff" in Linux Kernel command line to have complete traces of DRM, that can give us some tips (dmesg log level should be as high too to see the logs)
• getting the cat /sys/kernel/debug/clk/clk_summary to check if dsi/ltdc cllks are well prepared and enabled.
• getting the modetest -M stm output to check if the connectors etc.. are well recognized by the system.

Kind regards,

Erwan.

[MWoło.2]

Hi Erwan,

I added logs in the attachment.

This is not DK2 it's my custom board.

In my previous version, I get some errors that the clock is invalid, etc. Here is nothing, it's strange to me.

BR Michal

[Erwan SZYMANSKI]

@Michał Wołowik​ ,

Sorry for the DRM logs I was not really clear. In fact I would like to see the DRM logs at boot time.

You can enable it with adding "drm.debug=0x2" in the Linux commandline (0x2 will display drivers message only).

In ST deliveries, we can modify it on bootfs partition in extlinux.conf files.

For example, with my stm32mp157f-dk2 I will have:

root@stm32mp1:/boot/mmc0_extlinux# cat stm32mp157f-dk2_extlinux.conf
 
# Generic Distro Configuration file generated by OpenEmbedded
menu title Select the boot mode
MENU BACKGROUND /splash.bmp
TIMEOUT 20
DEFAULT OpenSTLinux
LABEL OpenSTLinux
 KERNEL /uImage
 FDTDIR /
 INITRD /uInitrd
 APPEND root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw console=ttySTM0,115200 drm.debug=0x2
LABEL stm32mp157f-dk2-a7-examples
 KERNEL /uImage
 FDT /stm32mp157f-dk2-a7-examples.dtb
 INITRD /uInitrd
 APPEND root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw console=ttySTM0,115200
LABEL stm32mp157f-dk2-m4-examples
 KERNEL /uImage
 FDT /stm32mp157f-dk2-m4-examples.dtb
 INITRD /uInitrd
 APPEND root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw console=ttySTM0,115200

and at boot time, the following DRM traces are displayed:

[ 0.000000] Kernel command line: root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw console=ttySTM0,115200 drm.debug=0x2
[ 3.118656] [drm:ltdc_load] 
[ 3.662669] [drm:ltdc_load] 
[ 4.219836] [drm:ltdc_load] 
[ 4.219954] [drm:ltdc_load] Bridge encoder:31 created
[ 4.220011] [drm:ltdc_load] Bridge encoder:33 created
[ 4.220201] [drm:ltdc_load] ltdc hw version 0x00010300
[ 4.220839] [drm:ltdc_plane_create] plane:35 created
[ 4.220869] [drm:ltdc_load] CRTC:37 created
[ 4.220890] [drm:ltdc_plane_create] plane:38 created
[ 4.220898] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 4.226124] [drm] Driver supports precise vblank timestamp query.
[ 4.233250] [drm] Initialized stm 1.0.0 20170330 for 5a001000.display-controller on minor 0
[ 9.915889] [drm:ltdc_crtc_mode_valid] clk rate target 29700000, available 29700000
[ 9.945755] [drm:ltdc_crtc_mode_valid] clk rate target 29700000, available 29700000
[ 9.945787] [drm:ltdc_crtc_mode_fixup] requested clock 29700kHz, adjusted clock 29700kHz
[ 9.945799] [drm:ltdc_plane_atomic_check] 
[ 9.945815] [drm:ltdc_plane_atomic_check] plane:35 fb:40 (480x800)@(0,0) -> (480x800)@(0,0)
[ 9.945873] [drm:drv_runtime_resume] 
[ 9.945882] [drm:ltdc_resume] 
[ 9.945912] [drm:ltdc_crtc_mode_set_nofb] CRTC:37 mode:480x800
[ 9.945923] [drm:ltdc_crtc_mode_set_nofb] Video mode: 480x800
[ 9.945954] [drm:ltdc_crtc_mode_set_nofb] hfp 98 hbp 98 hsl 32 vfp 15 vbp 14 vsl 10
[ 9.945975] [drm:ltdc_encoder_mode_set] 
[ 9.946107] [drm:dw_mipi_dsi_get_lane_mbps] pll_in 24000kHz pll_out 428000kHz lane_mbps 428MHz
[ 9.958729] [drm:dw_mipi_dsi_mode_set] failed to wait phy lock state
[ 10.015631] [drm:ltdc_plane_atomic_update] fb: phys 0xd2200000
[ 10.015650] [drm:ltdc_crtc_enable_vblank] 
[ 10.015686] [drm:ltdc_crtc_atomic_enable] 
[ 10.814514] [drm:ltdc_encoder_enable] 
[ 10.814534] [drm:dw_mipi_dsi_phy_power_on] 
[ 15.845557] [drm:ltdc_crtc_disable_vblank] 

Kind regards,

Erwan.

[Erwan SZYMANSKI]

Hello @Michał Wołowik​ ,

Are you able to probe the different signals in entry of your panel ?

Do you see the pixel clock etc or nothing ?

Can you provide a full boot log file with "dmsg" command ?

Kind regards,

Erwan.

[MWoło.2]

Hi Erwan,

drm boot log

root@stm32mp1-computer-lcd:~# dmesg | grep drm
[ 0.000000] Kernel command line: root=PARTUUID=491f6117-415d-4f53-88c9-6e0de54deac6 rootwait rw drm.debug="0x02" console=ttySTM0,115200
[ 0.500555] [drm:ltdc_load] 
[ 2.249006] [drm:ltdc_load] 
[ 2.249178] [drm:ltdc_load] Bridge encoder:31 created
[ 2.249483] [drm:ltdc_load] ltdc hw version 0x00010300
[ 2.267527] [drm:ltdc_plane_create] plane:33 created
[ 2.267605] [drm:ltdc_crtc_init] CRTC:37 created
[ 2.267645] [drm:ltdc_plane_create] plane:38 created
[ 2.278255] [drm] Initialized stm 1.0.0 20170330 for 5a001000.display-controller on minor 0
[ 9.426142] systemd[1]: Starting Load Kernel Module drm...
[ 10.745919] [drm:ltdc_crtc_mode_valid] clk rate target 54000000, available 54000000
[ 10.792624] [drm:ltdc_crtc_mode_valid] clk rate target 54000000, available 54000000
[ 10.792725] [drm:ltdc_crtc_mode_fixup] requested clock 54000kHz, adjusted clock 54000kHz
[ 10.792754] [drm:ltdc_plane_atomic_check] 
[ 10.792827] [drm:drv_runtime_resume] 
[ 10.792863] [drm:ltdc_resume] 
[ 10.792914] [drm:ltdc_crtc_mode_set_nofb] CRTC:37 mode:720x1280
[ 10.792938] [drm:ltdc_crtc_mode_set_nofb] Video mode: 720x1280
[ 10.792960] [drm:ltdc_crtc_mode_set_nofb] hfp 48 hbp 48 hsl 9 vfp 12 vbp 12 vsl 5
[ 10.793045] [drm:ltdc_encoder_mode_set] 
[ 10.793146] [drm:dw_mipi_dsi_get_lane_mbps] pll_in 24000kHz pll_out 776000kHz lane_mbps 776MHz
[ 10.807297] [drm:dw_mipi_dsi_mode_set] failed to wait phy lock state
[ 10.867439] [drm:dw_mipi_dsi_phy_power_on] 
[ 10.867508] [drm:ltdc_plane_atomic_update] plane:33 fb:42 (720x1280)@(0,0) -> (720x1280)@(0,0)
[ 10.867575] [drm:ltdc_plane_atomic_update] fb: phys 0xc3900000
[ 10.867615] [drm:ltdc_crtc_atomic_enable] 
[ 11.257293] [drm:ltdc_encoder_enable] 
[ 11.257376] [drm:ltdc_crtc_enable_vblank] 
[ 16.317225] [drm:ltdc_crtc_disable_vblank] 
[ 18.130419] [drm:ltdc_plane_atomic_check] 
[ 18.130532] [drm:drm_atomic_helper_commit_planes] CRTC:37 plane:33
[ 18.130579] [drm:ltdc_crtc_enable_vblank] 
[ 23.197261] [drm:ltdc_crtc_disable_vblank] 
[ 27.588309] [drm:ltdc_crtc_mode_valid] clk rate target 54000000, available 54000000
[ 27.695429] [drm:ltdc_plane_atomic_check] 
[ 27.695491] [drm:ltdc_plane_atomic_check] 
[ 27.749367] [drm:ltdc_plane_atomic_check] 
[ 27.749426] [drm:ltdc_plane_atomic_check] 
[ 27.749556] [drm:ltdc_plane_atomic_update] plane:33 fb:42 (720x1280)@(0,0) -> (720x1280)@(0,0)
[ 27.749634] [drm:ltdc_plane_atomic_update] fb: phys 0xce400000
[ 27.749669] [drm:ltdc_crtc_enable_vblank] 
[ 29.098611] [drm:ltdc_plane_atomic_check] 
[ 29.343705] [drm:ltdc_plane_atomic_check] 
[ 29.343911] [drm:ltdc_plane_atomic_update] plane:33 fb:43 (720x1280)@(0,0) -> (720x1280)@(0,0)

full log in the attachment.

BR Michal

[MWoło.2]

Hi Erwan,

unfortunately, I have nothing on dsi lines completely silent.

Please check my ioc, I have a feeling I missed something.

Thanks

BR Michal

[Erwan SZYMANSKI]

Hi @Michał Wołowik​ ,

I do not see obvious thing in the IOC file and everything looks to work well at boot time.

Just to be sure, can you probe again your entry lanes of the panel after doing this command :

modetest -M stm -s 31:720x1280 -v ?

Kind regards,

Erwan.

[Erwan SZYMANSKI]

Edit: no relevant comment

[MWoło.2]

Hi Erwan,

The result of

modetest -M stm -s 31:720x1280 -v

failed to find mode "720x1280" for connector 31 
failed to create dumb buffer: Invalid argument 
failed to create dumb buffer: Invalid argument

but now after moving to the latest OpenStLinux from v22.11.23 installation I get some waveform on lines

DSI-D0-N DSI-D0-N DSI-D1-N DSI-D1-N.

On line DSI-CK-N(P), I see only a transition from 0 to 1. As I good remember for DSI this is right due to the negotiation phase(command mode), if a correct switch to all lines and high clock(video mode). Besides I saw that during boot-up display some reactions became white and slowly disappeared to black again.

I check again very carefully hardware issues and maybe the initialization list of the display is wrong.

I let know soon.

Thanks

[MWoło.2]

I thnik I found display issue.

When I enable in the U-Boot dts one of the available drivers, I'm able to see during the transition from U-Boot to Kernel data between CPU and Display.

Unfortunately, this initialization comes from the U-Boot driver which has a wrong initialization list.

When I disable the driver in U-Boot I see nothing on the lines which means the Kernel does nothing. I predict that Kernel expects configuration from U-Boot due to displaying blinking unconditioned contents during the transition.

Now the question is how to force the Kernel to reinitialize the display without initialization from the U-Boot?

[MWoło.2]

I decided to go back to this topic due to new issues.

I think I found something I don't understand. I have a function 'static int ili9881c_prepare(struct drm_panel *panel)' in the driver. This function for some reason is not invoked.

I marked some places in it

static int ili9881c_prepare(struct drm_panel *panel)
{
	struct ili9881c *ctx = panel_to_ili9881c(panel);
	unsigned int i;
	int ret;
 
	/* Power the panel */
	ret = regulator_enable(ctx->power);
	if (ret){
		printk(KERN_ERR "MIPI DSI PANEL PREPARE ERROR !!!!!!!!");
		return ret;
	}
	msleep(5);
 
	printk(KERN_ERR "MIPI DSI PANEL PREPARE !!!!!!!!");
 
	/* And reset it */
	gpiod_set_value(ctx->reset, 1);
	printk(KERN_ERR "MIPI DSI PANEL RST ON !!!!!!!!");
	msleep(20);
 
	gpiod_set_value(ctx->reset, 0);
	printk(KERN_ERR "MIPI DSI PANEL RST OFF !!!!!!!!");
	msleep(20);

during the system log, but I can't see any of them.

I go deeper and this driver is used by the drm_panel driver which invokes this prepare function. The question is why this function is not invoked. Besides this, the driver exists in the system and loads correctly and of course the LCD show nothing.