linux-kernel - [PATCH v6 2/4] drm/mediatek: dpi dual edge support

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Date:   Fri, 21 Feb 2020 19:28:26 +0800
From:   Jitao Shi <jitao.shi@...iatek.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
CC:     <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>, <yingjoe.chen@...iatek.com>,
        <eddie.huang@...iatek.com>, <cawa.cheng@...iatek.com>,
        <bibby.hsieh@...iatek.com>, <ck.hu@...iatek.com>,
        <stonea168@....com>, <huijuan.xie@...iatek.com>,
        Jitao Shi <jitao.shi@...iatek.com>
Subject: [PATCH v6 2/4] drm/mediatek: dpi dual edge support

DPI sample the data both rising and falling edge.
It can reduce half data io pins.

Signed-off-by: Jitao Shi <jitao.shi@...iatek.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 01fa8b8d763d..36e4dbd27d1b 100644
--- a/drivers/gpu/drm/mediatek/mtk_dpi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
@@ -75,6 +75,7 @@ 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)
@@ -348,6 +349,13 @@ 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)
 {
@@ -439,7 +447,8 @@ 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",
@@ -504,6 +513,8 @@ 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;
@@ -689,6 +700,7 @@ 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