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From:   Jitao Shi <jitao.shi@mediatek.com>
To:     Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
        "Mark Rutland" <mark.rutland@arm.com>,
        Ian Campbell <ijc+devicetree@hellion.org.uk>,
        <linux-pwm@vger.kernel.org>, David Airlie <airlied@linux.ie>,
        "Matthias Brugger" <matthias.bgg@gmail.com>
CC:     Jitao Shi <jitao.shi@mediatek.com>,
        Thierry Reding <treding@nvidia.com>,
        Ajay Kumar <ajaykumar.rs@samsung.com>,
        Inki Dae <inki.dae@samsung.com>,
        "Rahul Sharma" <rahul.sharma@samsung.com>,
        Sean Paul <seanpaul@chromium.org>,
        "Vincent Palatin" <vpalatin@chromium.org>,
        Andy Yan <andy.yan@rock-chips.com>,
        "Philipp Zabel" <p.zabel@pengutronix.de>,
        Russell King <rmk+kernel@arm.linux.org.uk>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
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        <srv_heupstream@mediatek.com>,
        "Sascha Hauer" <kernel@pengutronix.de>,
        <yingjoe.chen@mediatek.com>, <eddie.huang@mediatek.com>,
        <cawa.cheng@mediatek.com>, <bibby.hsieh@mediatek.com>,
        <ck.hu@mediatek.com>, <stonea168@163.com>
Subject: [PATCH v5 2/4] drm/mediatek: dpi dual edge support
Date:   Wed, 7 Aug 2019 14:02:55 +0800
Message-ID: <20190807060257.57007-3-jitao.shi@mediatek.com>
In-Reply-To: <20190807060257.57007-1-jitao.shi@mediatek.com>
References: <20190807060257.57007-1-jitao.shi@mediatek.com>
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Sender: linux-kernel-owner@vger.kernel.org
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DPI sample the data both rising and falling edge.
It can reduce half data io pins.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dpi.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
index bacd989cc9aa..743230864ba0 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -72,6 +72,7 @@ struct mtk_dpi {
 	enum mtk_dpi_out_bit_num bit_num;
 	enum mtk_dpi_out_channel_swap channel_swap;
 	int refcount;
+	bool dual_edge;
 };
 
 static inline struct mtk_dpi *mtk_dpi_from_encoder(struct drm_encoder *e)
@@ -345,6 +346,13 @@ static void mtk_dpi_config_disable_edge(struct mtk_dpi *dpi)
 		mtk_dpi_mask(dpi, dpi->conf->reg_h_fre_con, 0, EDGE_SEL_EN);
 }
 
+static void mtk_dpi_enable_dual_edge(struct mtk_dpi *dpi)
+{
+	mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE,
+		     DDR_EN | DDR_4PHASE);
+	mtk_dpi_mask(dpi, DPI_OUTPUT_SETTING, EDGE_SEL, EDGE_SEL);
+}
+
 static void mtk_dpi_config_color_format(struct mtk_dpi *dpi,
 					enum mtk_dpi_out_color_format format)
 {
@@ -436,7 +444,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
 	pll_rate = clk_get_rate(dpi->tvd_clk);
 
 	vm.pixelclock = pll_rate / factor;
-	clk_set_rate(dpi->pixel_clk, vm.pixelclock);
+	clk_set_rate(dpi->pixel_clk,
+		     vm.pixelclock * (dpi->dual_edge ? 2 : 1));
 	vm.pixelclock = clk_get_rate(dpi->pixel_clk);
 
 	dev_dbg(dpi->dev, "Got  PLL %lu Hz, pixel clock %lu Hz\n",
@@ -501,6 +510,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
 	mtk_dpi_config_color_format(dpi, dpi->color_format);
 	mtk_dpi_config_2n_h_fre(dpi);
 	mtk_dpi_config_disable_edge(dpi);
+	if (dpi->dual_edge)
+		mtk_dpi_enable_dual_edge(dpi);
 	mtk_dpi_sw_reset(dpi, false);
 
 	return 0;
@@ -686,6 +697,7 @@ static int mtk_dpi_probe(struct platform_device *pdev)
 
 	dpi->dev = dev;
 	dpi->conf = (struct mtk_dpi_conf *)of_device_get_match_data(dev);
+	dpi->dual_edge = of_property_read_bool(dev->of_node, "dpi_dual_edge");
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dpi->regs = devm_ioremap_resource(dev, mem);
-- 
2.21.0