linux-kernel - [PATCH v5 2/3] drm/mediatek: enhance the HDMI driving current

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Message-ID: <1475118135-56780-3-git-send-email-bibby.hsieh@mediatek.com>
Date:   Thu, 29 Sep 2016 11:02:14 +0800
From:   Bibby Hsieh <bibby.hsieh@...iatek.com>
To:     David Airlie <airlied@...ux.ie>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>
CC:     Yingjoe Chen <yingjoe.chen@...iatek.com>,
        Cawa Cheng <cawa.cheng@...iatek.com>,
        Daniel Kurtz <djkurtz@...omium.org>,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        YT Shen <yt.shen@...iatek.com>,
        Thierry Reding <thierry.reding@...il.com>,
        CK Hu <ck.hu@...iatek.com>, Mao Huang <littlecvr@...omium.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        Junzhi Zhao <junzhi.zhao@...iatek.com>
Subject: [PATCH v5 2/3] drm/mediatek: enhance the HDMI driving current

From: Junzhi Zhao <junzhi.zhao@...iatek.com>

In order to improve 4K resolution performance,
we have to enhance the HDMI driving current
when clock rate is greater than 165MHz.

Signed-off-by: Junzhi Zhao <junzhi.zhao@...iatek.com>
Signed-off-by: Bibby Hsieh <bibby.hsieh@...iatek.com>
---
 drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c |   42 +++++++++++++++++-------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
index 8a24754..51cb9cf 100644
--- a/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
+++ b/drivers/gpu/drm/mediatek/mtk_mt8173_hdmi_phy.c
@@ -265,6 +265,9 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct mtk_hdmi_phy *hdmi_phy = to_mtk_hdmi_phy(hw);
 	unsigned int pre_div;
 	unsigned int div;
+	unsigned int pre_ibias;
+	unsigned int hdmi_ibias;
+	unsigned int imp_en;
 
 	dev_dbg(hdmi_phy->dev, "%s: %lu Hz, parent: %lu Hz\n", __func__,
 		rate, parent_rate);
@@ -298,18 +301,31 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 			  (0x1 << PLL_BR_SHIFT),
 			  RG_HDMITX_PLL_BP | RG_HDMITX_PLL_BC |
 			  RG_HDMITX_PLL_BR);
-	mtk_hdmi_phy_clear_bits(hdmi_phy, HDMI_CON3, RG_HDMITX_PRD_IMP_EN);
+	if (rate < 165000000) {
+		mtk_hdmi_phy_clear_bits(hdmi_phy, HDMI_CON3,
+					RG_HDMITX_PRD_IMP_EN);
+		pre_ibias = 0x3;
+		imp_en = 0x0;
+		hdmi_ibias = hdmi_phy->ibias;
+	} else {
+		mtk_hdmi_phy_set_bits(hdmi_phy, HDMI_CON3,
+				      RG_HDMITX_PRD_IMP_EN);
+		pre_ibias = 0x6;
+		imp_en = 0xf;
+		hdmi_ibias = hdmi_phy->ibias_up;
+	}
 	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON4,
-			  (0x3 << PRD_IBIAS_CLK_SHIFT) |
-			  (0x3 << PRD_IBIAS_D2_SHIFT) |
-			  (0x3 << PRD_IBIAS_D1_SHIFT) |
-			  (0x3 << PRD_IBIAS_D0_SHIFT),
+			  (pre_ibias << PRD_IBIAS_CLK_SHIFT) |
+			  (pre_ibias << PRD_IBIAS_D2_SHIFT) |
+			  (pre_ibias << PRD_IBIAS_D1_SHIFT) |
+			  (pre_ibias << PRD_IBIAS_D0_SHIFT),
 			  RG_HDMITX_PRD_IBIAS_CLK |
 			  RG_HDMITX_PRD_IBIAS_D2 |
 			  RG_HDMITX_PRD_IBIAS_D1 |
 			  RG_HDMITX_PRD_IBIAS_D0);
 	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON3,
-			  (0x0 << DRV_IMP_EN_SHIFT), RG_HDMITX_DRV_IMP_EN);
+			  (imp_en << DRV_IMP_EN_SHIFT),
+			  RG_HDMITX_DRV_IMP_EN);
 	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON6,
 			  (hdmi_phy->drv_imp_clk << DRV_IMP_CLK_SHIFT) |
 			  (hdmi_phy->drv_imp_d2 << DRV_IMP_D2_SHIFT) |
@@ -318,12 +334,14 @@ static int mtk_hdmi_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 			  RG_HDMITX_DRV_IMP_CLK | RG_HDMITX_DRV_IMP_D2 |
 			  RG_HDMITX_DRV_IMP_D1 | RG_HDMITX_DRV_IMP_D0);
 	mtk_hdmi_phy_mask(hdmi_phy, HDMI_CON5,
-			  (hdmi_phy->ibias << DRV_IBIAS_CLK_SHIFT) |
-			  (hdmi_phy->ibias << DRV_IBIAS_D2_SHIFT) |
-			  (hdmi_phy->ibias << DRV_IBIAS_D1_SHIFT) |
-			  (hdmi_phy->ibias << DRV_IBIAS_D0_SHIFT),
-			  RG_HDMITX_DRV_IBIAS_CLK | RG_HDMITX_DRV_IBIAS_D2 |
-			  RG_HDMITX_DRV_IBIAS_D1 | RG_HDMITX_DRV_IBIAS_D0);
+			  (hdmi_ibias << DRV_IBIAS_CLK_SHIFT) |
+			  (hdmi_ibias << DRV_IBIAS_D2_SHIFT) |
+			  (hdmi_ibias << DRV_IBIAS_D1_SHIFT) |
+			  (hdmi_ibias << DRV_IBIAS_D0_SHIFT),
+			  RG_HDMITX_DRV_IBIAS_CLK |
+			  RG_HDMITX_DRV_IBIAS_D2 |
+			  RG_HDMITX_DRV_IBIAS_D1 |
+			  RG_HDMITX_DRV_IBIAS_D0);
 	return 0;
 }
 
-- 
1.7.9.5