Disabling Video PLL in DM8168

Massimiliano Cialdi

Expert 1995 points

I do not use any of the video peripheral (HDVPSS).

If I try to disable Video PLL in u-boot the processor hangs.

the slice of code is:

static void video_pll_init_ti816x(u32 sil_index, u32 clk_index)
{
	u32 video_pll_ctrl=0;

	/* Video PLL is and all clocks are disabled */
	
	video_pll_ctrl = __raw_readl(VIDEOPLL_CTRL);
	video_pll_ctrl &= 0xFFFFFFFB;
	video_pll_ctrl |= 4;	// Put PLL in ByPass mode
	__raw_writel(video_pll_ctrl, VIDEOPLL_CTRL);
	
	video_pll_ctrl = __raw_readl(VIDEOPLL_CTRL);
	video_pll_ctrl &= 0xFFFFFFF7;	// Disable PLL
	__raw_writel(video_pll_ctrl, VIDEOPLL_CTRL);
	
	__raw_writel(0x0E,DDRPLL_PWD); // PWR down clock 1 & 2 & 3
	
}

Can I safetly powerdown Video PLL? How? Or do I need to setup in some way?

best regards

max

over 10 years ago

0 Pavel Botev over 10 years ago

TI__Guru**** 170625 points

Hi Max,

The VIDEOPLL is not enabled in u-boot, thus their is no need to disable it. Or you mean that you have first enable it and then trying to disable?

Regards,
Pavel

0 Massimiliano Cialdi over 10 years ago in reply to Pavel Botev

Expert 1995 points

Hi Pavel,

I tryed to read the Video PLL registers from inside u-boot console:

U-Boot#md.l 0x48140470 1
48140470: 006e0288    ..n.
U-Boot#md.l 0x48140474 1 
48140474: 00000000    ....

0x48140470 is VIDEOPLL_CTRL and tells that Video PLL is enabled and locked

0x48140474 is VIDEOPLL_PWD. All PLL clocks are enabled.

Maybe is the Rom Code?

BTW, regardless who enable PLL, how could I disable it? Is it possible?

As said before if I try to disable Video PLl Clocks (with the code in the fist post) the processor hangs.

best regards

max

0 Pavel Botev over 10 years ago

TI__Guru**** 170625 points

mastupristi said:
__raw_writel(0x0E,DDRPLL_PWD); // PWR down clock 1 & 2 & 3

May be you make power down to the DDR PLL? Can you try with power down the Video PLL?

__raw_writel(0x0E,VIDEOPLL_PWD); // PWR down clock 1 & 2 & 3

BR
Pavel

0 Pavel Botev over 10 years ago in reply to Massimiliano Cialdi

TI__Guru**** 170625 points

mastupristi said:
Maybe is the Rom Code?

I found who set up the Video PLL, it is the EZSDK u-boot:

ti-ezsdk_dm816x-evm_5_05_02_00/board-support/u-boot-2010.06-psp04.04.00.01/drivers/video/ti816x_logo.c

static void ti816x_video_pll( ..)

This Video PLL set up is specific for the EZSDK, as this set up does not exist in the generic TI81xx u-boot code base:

http://arago-project.org/git/projects/u-boot-omap3.git?p=projects/u-boot-omap3.git;a=shortlog;h=refs/heads/ti81xx-master

Regards,
Pavel

0 Massimiliano Cialdi over 10 years ago in reply to Pavel Botev

Expert 1995 points

Pavel Botev said:

mastupristi

Maybe is the Rom Code?

I found who set up the Video PLL, it is the EZSDK u-boot:

ti-ezsdk_dm816x-evm_5_05_02_00/board-support/u-boot-2010.06-psp04.04.00.01/drivers/video/ti816x_logo.c

static void ti816x_video_pll( ..)

This Video PLL set up is specific for the EZSDK, as this set up does not exist in the generic TI81xx u-boot code base:

arago-project.org/.../u-boot-omap3.git;a=shortlog;h=refs/heads/ti81xx-master

I do not use u-boot from ezsdk, my u-boot is the arago project one.

best regards

0 Pavel Botev over 10 years ago in reply to Massimiliano Cialdi

TI__Guru**** 170625 points

Max,

Do you fix that issue with the proposal of the below post?
e2e.ti.com/.../1505163

Regards,
Pavel

0 Massimiliano Cialdi over 10 years ago in reply to Pavel Botev

Expert 1995 points

Yes and it works

thanks

best regards

max

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Disabling Video PLL in DM8168