imx8mp uboot display logo

[c-luo]

hi NXP:

Recently, I'm debugging a problem about how to display the logo in uboot。I use imx8mp board android11 system.

i find a patch in NXP community :

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Add-i-MX8MP-LVDS-driver-in-uboot/ta-p/14...

This patch said : Current BSP doesn't support LVDS driver in Uboot.

I use the patch, but it no use. At last I found I don't have the driver in uboot about This node：

ldb_phy: phy@32ec0128 {
compatible = "fsl,imx8mp-lvds-phy";
#address-cells = <1>;
#size-cells = <0>;
gpr = <&mediamix_blk_ctl>;
clocks = <&clk IMX8MP_CLK_MEDIA_APB_ROOT>;
clock-names = "apb";
power-domains = <&mediamix_pd>;
status = "disabled";

ldb_phy1: port@0 {
reg = <0>;
#phy-cells = <0>;
};

ldb_phy2: port@1 {
reg = <1>;
#phy-cells = <0>;
};
};

I grep the all uboot, but Nothing there .

I try to delete this driver in kernel (because kernel have  this driver),and i found the screen is not lit.

So, I wonder if the lack of this driver in uboot makes me unable to support this LVDS。

Looking forward to your reply, thank you!

[Zhiming_Liu]

1.为了保持和Linux中dts的一致性，所以这个节点没有删除，和这个PHY驱动本身没有关系。LVDS PHY的寄存器控制已经包含在了imx8mp_lvds.c中，驱动中只打开了LVDS0端口。

2.这个LVDS补丁是基于IT6263（LVDS转HDMI）转接板实现的，这个补丁不包括LVDS屏幕驱动，如果你接了其他LVDS屏幕，需要修改设备树以及仿照67191屏幕驱动做移植。

[shao-gaoyan]

我用了最新patch

https://community.nxp.com/t5/user/viewprofilepage/user-id/151788

imx8mp-evk通过hdmi连接了一台显示器。

启动log 显示 it6263_i2c_reg_read, read err -121 

这个错误原因是我的显示器与你提供patch的参数不一致导致的吗？

[*]-Video Link 0imx8mp_ldb_probe
imx8mp_ldb_probe
lcdifv3_video_probe000
it6263_i2c_reg_read, read err -121
faill to read from it6263 revision, ret -121
(1280 x 720)
[0] lcd-controller@32e90000, video
[1] lvds-channel@0, display
[2] lvds-to-hdmi-bridge@4c, video_bridge
In: serial
Out: serial
Err: serial
SEC0: RNG instantiated

[Zhiming_Liu]

补丁不包括对it6263驱动的修改，你的这个问题和硬件有关，无法建立i2c通信或者是转接板坏了。

[c-luo]

对不起，刚才忘了添加对应的dts附件配置。

[c-luo]

我使用的就是一个普通的lvds屏幕，对应的驱动在uboot里面文件使用是“simple_panel.c”但是在我的uboot里面会有报错：

CPU: i.MX8MP[6] rev1.1 1600 MHz (running at 1200 MHz)
CPU: Industrial temperature grade (-40C to 105C) at 26C
Reset cause: POR
Model: NXP i.MX8MPlus LPDDR4 EVK board
DRAM: 4 GiB
MMC: FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... trying mode widtsignal_voltageh 8 (at 200 MHz)
*** Warning - bad CRC, using default environment

probe video device failed, ret -2

[0] lcd-controller@32e90000, video
[1] lvds-channel@0, display
[2] lvds0_panel, panel

probe video device failed, ret -2
Error: 1 bit/pixel mode, but BMP has 8 bit/pixel
In: serial
Out: serial
Err: serial

这里有一个 probe video device failed, ret -2。 如果这里没有报错，我就会得到对应的vedio设备的分辨率。我自己和同事一起查看这个报错，也尝试去解决，但是并没有什么进度。

对应的报错发现在：

drivers/video/video_link.c文件中

struct udevice *video_link_get_video_device(void)
{
int ret;
if (video_off)
return NULL;

if (curr_video_link >= video_links_num)
return NULL;

if (video_links[curr_video_link].dev_num == 0)
return NULL;

ret = device_probe(video_links[curr_video_link].link_devs[0]);

if (ret) {
printf("probe video device failed, ret %d\n", ret);
return NULL;
}

return video_links[curr_video_link].link_devs[0];
}

另外我试着在uboot的dts中去配置backlight和lvds的供电使能gpio。但是并没有什么作用，于是我在对应的board/freescale/imx8mp_evk/imx8mp_evk.c.里面去拉高gpio，并已经生效。

附件为我的dts配置：imx8mp-evk.dts，我不知道我的dts配置是否会导致上面probe device会有错误。我们之前并没有调试过uboot阶段的dts，请您帮我看看，谢谢！

期待您的回复！

[Zhiming_Liu]

dts配置backlight和lvds的供电使能gpio。但是并没有什么作用

--->因为驱动中没有调用panel_enable_backlight函数，我发给你的新版本已经加上了。

[c-luo]

十分感谢你的帮助，我已经在imx8mp上实现了我的功能

[harlin]

Were you able to get the LVDS running?. 

If yes, can you share the patch pls. 

[c-luo]

hi，这是我这边对应的patch，我已经在我的板子上实现了logo的显示。

希望对你有帮助。

[nancy_zhang]

Hi NXP members:

We user normal lvds display,follow those patchs, lvds device can probe ok,but I can't display info on the screen, Whether some default information will be displayed initially, or how to control the display of some information?

Thanks,

[street2409]

Hello,

How do you calculate the following parameters in your patch:

#define VIDEO_PLL_RATE 995400000U

#define CONFIG_IMX6_PWM_PER_CLK 66000000

Is this something that is specific to the screen I'm trying to implement?

[harlin]

Hello XHHYY, 

Thanks for the patches. Appreciate it.

The clock settings were missing in the original patch.

After applying the patch, start up is stuck after entering the function "imx8mp_lvds_phy_init:"

static int imx8mp_lvds_phy_init(struct udevice *dev)
{
struct imx8mp_ldb_priv *priv = dev_get_priv(dev);

media_blk_write(priv, LVDS_CTRL, CC_ADJ(0x2) | PRE_EMPH_EN | PRE_EMPH_ADJ(0x3));

return 0;
}

did you have similliar issues during debugging?

[c-luo]

No,I didn't have this problem.

Maybe your configuration is wrong, Please check your DTS and clock_imx8mm.c or compare the patch and your codec,  maybe can help you.

I hope you can succeed and good luck.

[harlin]

Hi @c-luo, 

I rechecked clock setting and DTB. 

The function "get_dsi_phy_ref_clk()"  is defined in clcok_imx8mm.c but never used elsewhere. 

get_root_clock(MEDIA_LDB_CLK_ROOT) is never set in my case.

I suspect, the clock settings for the MEDIA BLOCK CONTROL is missing in my case and hence not able to access the LDB phy registers and hangs while read/write to 0x32EC_0000+offset. 

If possible, Could also provide the dm tree output to compare. Additonally, which uboot version did you use? 

[srinu_inaganti1]

Hi harlin, Even we are getting the same issue, could you be able to solve this prob

Regards,

Srinu

[harlin]

Hi, Yes, I was able to solve the issue.

[srinu_inaganti1]

Can you please help us how to resolve this issue..
- Srinu

[srinu_inaganti1]

Hi harlin, 

Great, can you help me on this how to solve, exactly media_blk_write call is failing and could able get write the lvds control register, I have verified both address and value in __write_32 function and both are correct. 

Regards,

Srinu Inaganti

[Zhiming_Liu]

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Add-i-MX8MP-LVDS-driver-in-uboot/ta-p/14...

[huangbaokang]

我们已经成功在imx8mp的UBoot里面显示lvds单通道1280x800 及以下分辨率。现在问题是，如何在UBoot里面配置双通道lvds，实现1920x1080输出呢？我们现在用的屏幕是1920x1080 分辨率，双通道lvds。