Commit 426701d0 authored by Russell King's avatar Russell King
Browse files

drm: bridge/dw_hdmi: adjust pixel clock values in N calculation 



Adjust the pixel clock values in the N calculation to match the more
accurate clock values we're given by the DRM subsystem, which are the
kHz pixel rate, with any fractional kHz rounded down in the case of
the non-240, non-480 line modes, or rounded up for the others.  So,

	 25.20 / 1.001 =>  25175
	 27.00 * 1.001 =>  27027
	 74.25 / 1.001 =>  74176
	148.50 / 1.001 => 148352

DRM derives these rates from the EDID CEA mode identifiers, which are
looked up in the tables in drivers/gpu/drm/drm_edid.c.  The values on
the right are the clock values found in these tables, and are
currently expected to be passed to the HDMI driver unchanged.

Tested-by: default avatarFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent d0c96d16

drivers/gpu/drm/bridge/dw_hdmi.c

+10 −10
Original line number Diff line number Diff line
@@ -230,11 +230,11 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, 


	switch (freq) {

	case 32000:

		if (pixel_clk == 25170000)

		if (pixel_clk == 25175000)

			n = (ratio == 150) ? 9152 : 4576;

		else if (pixel_clk == 27020000)

		else if (pixel_clk == 27027000)

			n = (ratio == 150) ? 8192 : 4096;

		else if (pixel_clk == 74170000 || pixel_clk == 148350000)

		else if (pixel_clk == 74176000 || pixel_clk == 148352000)

			n = 11648;

		else

			n = 4096;
@@ -242,11 +242,11 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, 
		break;



	case 44100:

		if (pixel_clk == 25170000)

		if (pixel_clk == 25175000)

			n = 7007;

		else if (pixel_clk == 74170000)

		else if (pixel_clk == 74176000)

			n = 17836;

		else if (pixel_clk == 148350000)

		else if (pixel_clk == 148352000)

			n = (ratio == 150) ? 17836 : 8918;

		else

			n = 6272;
@@ -254,13 +254,13 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk, 
		break;



	case 48000:

		if (pixel_clk == 25170000)

		if (pixel_clk == 25175000)

			n = (ratio == 150) ? 9152 : 6864;

		else if (pixel_clk == 27020000)

		else if (pixel_clk == 27027000)

			n = (ratio == 150) ? 8192 : 6144;

		else if (pixel_clk == 74170000)

		else if (pixel_clk == 74176000)

			n = 11648;

		else if (pixel_clk == 148350000)

		else if (pixel_clk == 148352000)

			n = (ratio == 150) ? 11648 : 5824;

		else

			n = 6144;

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