AM572x VOUT3 issue

Qing

Other Parts Discussed in Thread: AM5728

Hi,

My customization board is based on AM5728, and my LCD use the VOUT3. But it doesn't work! No pixel clock signal and any LCD signal from AM5728 soc. If I use the VOUT1, everything is OK.

I am sure that pinmux is OK, and devicetree configuration is also ok.

and my device tree configure is as follow:

aliases {
		display0 = &lcd0;
	};

lcd0: display {
		compatible = "osddisplays,osd070t1718-19ts", "panel-dpi";

		label = "lcd";

		/* enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;*/

		panel-timing {
			clock-frequency = <33000000>;
			hactive = <1024>;
			vactive = <768>;
			hfront-porch = <32>;
			hback-porch = <228>;
			hsync-len = <60>;
			vback-porch = <21>;
			vfront-porch = <7>;
			vsync-len = <10>;
			hsync-active = <0>;
			vsync-active = <0>;
			de-active = <1>;
			pixelclk-active = <1>;
		};

		port {
			lcd_in: endpoint {
				remote-endpoint = <&dpi_out>;
			};
		};
	};

&dss {
	ports {
		#address-cells = <1>;
		#size-cells = <0>;

		port {
			reg = <2>;

			dpi_out: endpoint {
				remote-endpoint = <&lcd_in>;
				data-lines = <24>;
			};
		};
	};
};

I have seen this new about VOUT2 is not support by cunnrently linux 4.13 driver.

I have traced this dss kernel code, and found this port(VOUT3) is always not enabled! and panel_dpi_probe() has create the correct dpi panel and fb0 has been generated in system directory.

a normal DPI port is always enabled by panel_dpi_enable() in $(kernel)/drivers/video/fbdev/omap2/displays-new/panel-dpi.c,

But If I set the port:reg=2, the panel_dpi_enable() is nerver called.

And what I should do? can you give me some valuable suggestion？

Thank you very much!

Best Regards

Qing

over 9 years ago

0 Qing over 9 years ago

Expert 1385 points

AND I have seen the
"Also, care need to be taken on VOUT3 for hardware design. Refer to AM572x silicon errata i901 - DSS VOUT3 on VDDSHV6 Domain (vin1a Pins) Should Not Be Used in 3.3V Mode" at other thread,
and what's the meaning? and have relation with mine ？

Thank you very much!
B.R
Qing

0 Biser Gatchev-XID over 9 years ago in reply to Qing

TI__Guru**** 393215 points

I will forward this to the software team. As for your second question, Errata i901 can be found in this document: www.ti.com/.../sprz429j.pdf

0 Qing over 9 years ago in reply to Biser Gatchev-XID

Expert 1385 points

Thank you so much！
and othors ？

0 Tomi Valkeinen over 9 years ago

TI__Prodigy 625 points

I tested with TI's latest v4.1 based kernel (4.1.29), using AM5 EVM. I changed the port number to 2, as you do in your .dts snippet, and it works fine for me. I can't actually see if VOUT3 outputs a signal, but all debug outputs looks fine (clocks properly set, panel-dpi gets enabled, refresh rate is 60 Hz).

Which kernel and release are you using? Can you attach a boot log?

0 Qing over 9 years ago in reply to Tomi Valkeinen

Expert 1385 points

Hi,
I used the BSP is ti-processor-sdk-linux-am57xx-evm-02.00.01.07
and the kernel is linux 4.1.13.
and are you sure the panel_dpi_enable() function is called ? but mine is not called.

Thank you!

0 Qing over 9 years ago in reply to Qing

Expert 1385 points

Finaly, I found the result! there is a error in $(kernel)/arm/arm/boot/dts/dra74xx.dtsi

&dss {
	reg = <0x58000000 0x80>,
	      <0x58004054 0x4>,
	      <0x58004300 0x20>,
    /*  ERROR */
         /*  <0x58005054 0x4>,
	      <0x58005300 0x20>; */
 
	      <0x58009054 0x4>,
	      <0x58009300 0x20>;
	reg-names = "dss", "pll1_clkctrl", "pll1",
		    "pll2_clkctrl", "pll2";

	clocks = <&dss_dss_clk>,
		 <&dss_video1_clk>,
		 <&dss_video2_clk>;
	clock-names = "fck", "video1_clk", "video2_clk";
};

When I found that the pll2_clkctrl & pll2 base address in the dts file is not match TRM!

After that, All is OK!

Best Regards

Qing

0 Tomi Valkeinen over 9 years ago in reply to Qing

TI__Prodigy 625 points

Qing said:
Finaly, I found the result! there is a error in $(kernel)/arm/arm/boot/dts/dra74xx.dtsi

Good to hear! That bug in the .dts file has been fixed in (I think) all the recent kernel versions. In the TI 4.1 kernel the fix is fbae0de3359b591a9a471bf71ff306ce1ba43319 ("ARM: dts: DRA74x: fix DSS PLL2 addresses").