57 lines
2.4 KiB
Diff
57 lines
2.4 KiB
Diff
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From 63d794d460040c24526b2263af24421087721e35 Mon Sep 17 00:00:00 2001
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From: Yakir Yang <ykk@rock-chips.com>
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Date: Mon, 11 Jul 2016 19:05:39 +0800
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Subject: [PATCH 07/14] drm/rockchip: dw_hdmi: adjust cklvl & txlvl for RF/EMI
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Dut to the high HDMI signal voltage driver, Mickey have meet
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a serious RF/EMI problem, so we decided to reduce HDMI signal
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voltage to a proper value.
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The default params for phy is cklvl = 20 & txlvl = 13 (RF/EMI failed)
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ck: lvl = 13, term=100, vlo = 2.71, vhi=3.14, vswing = 0.43
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tx: lvl = 20, term=100, vlo = 2.81, vhi=3.16, vswing = 0.35
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1. We decided to reduce voltage value to lower, but VSwing still
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keep high, RF/EMI have been improved but still failed.
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ck: lvl = 6, term=100, vlo = 2.61, vhi=3.11, vswing = 0.50
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tx: lvl = 6, term=100, vlo = 2.61, vhi=3.11, vswing = 0.50
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2. We try to keep voltage value and vswing both lower, then RF/EMI
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test all passed ;)
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ck: lvl = 11, term= 66, vlo = 2.68, vhi=3.09, vswing = 0.40
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tx: lvl = 11, term= 66, vlo = 2.68, vhi=3.09, vswing = 0.40
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When we back to run HDMI different test and single-end test, we see
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different test passed, but signle-end test failed. The oscilloscope
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show that simgle-end clock's VL value is 1.78v (which remind LowLimit
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should not lower then 2.6v).
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3. That's to say there are some different between PHY document and
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measure value. And according to experiment 2 results, we need to
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higher clock voltage and lower data voltage, then we can keep RF/EMI
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satisfied and single-end & differen test passed.
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ck: lvl = 9, term=100, vlo = 2.65, vhi=3.12, vswing = 0.47
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tx: lvl = 16, term=100, vlo = 2.75, vhi=3.15, vswing = 0.39
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Signed-off-by: Yakir Yang <ykk@rock-chips.com>
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Reviewed-by: Douglas Anderson <dianders@chromium.org>
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---
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drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
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index 7d7ee5b26..3cd86070f 100644
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--- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
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+++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
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@@ -168,7 +168,7 @@ static const struct dw_hdmi_curr_ctrl rockchip_cur_ctr[] = {
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static const struct dw_hdmi_phy_config rockchip_phy_config[] = {
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/*pixelclk symbol term vlev*/
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{ 74250000, 0x8009, 0x0004, 0x0272},
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- { 148500000, 0x802b, 0x0004, 0x028d},
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+ { 165000000, 0x802b, 0x0004, 0x0209},
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{ 297000000, 0x8039, 0x0005, 0x028d},
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{ ~0UL, 0x0000, 0x0000, 0x0000}
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};
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--
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2.26.2
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