[PATCH 4/4] drm/mediatek: add dsi module reset driver

[Jitao Shi]

Reset dsi HW to default when power on. Prevent the setting differet
between bootloader and kernel.

Signed-off-by: Jitao Shi <jitao.shi at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 36 +++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 455fe582c6b5..113438ddd4cc 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -7,10 +7,12 @@
 #include <linux/component.h>
 #include <linux/iopoll.h>
 #include <linux/irq.h>
+#include <linux/mfd/syscon.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 
 #include <video/mipi_display.h>
 #include <video/videomode.h>
@@ -143,6 +145,8 @@
 #define DATA_0				(0xff << 16)
 #define DATA_1				(0xff << 24)
 
+#define MMSYS_SW_RST_DSI_B BIT(25)
+
 #define NS_TO_CYCLE(n, c)    ((n) / (c) + (((n) % (c)) ? 1 : 0))
 
 #define MTK_DSI_HOST_IS_READ(type) \
@@ -186,7 +190,8 @@ struct mtk_dsi {
 	struct drm_bridge *next_bridge;
 	struct drm_connector *connector;
 	struct phy *phy;
-
+	struct regmap *mmsys_sw_rst_b;
+	u32 sw_rst_b;
 	void __iomem *regs;
 
 	struct clk *engine_clk;
@@ -272,6 +277,16 @@ static void mtk_dsi_disable(struct mtk_dsi *dsi)
 	mtk_dsi_mask(dsi, DSI_CON_CTRL, DSI_EN, 0);
 }
 
+static void mtk_dsi_reset_all(struct mtk_dsi *dsi)
+{
+	regmap_update_bits(dsi->mmsys_sw_rst_b, dsi->sw_rst_b,
+			   MMSYS_SW_RST_DSI_B, 0);
+	usleep_range(1000, 1100);
+
+	regmap_update_bits(dsi->mmsys_sw_rst_b, dsi->sw_rst_b,
+			   MMSYS_SW_RST_DSI_B, MMSYS_SW_RST_DSI_B);
+}
+
 static void mtk_dsi_reset_engine(struct mtk_dsi *dsi)
 {
 	mtk_dsi_mask(dsi, DSI_CON_CTRL, DSI_RESET, DSI_RESET);
@@ -985,6 +1000,8 @@ static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
 
 	ret = mtk_dsi_encoder_init(drm, dsi);
 
+	mtk_dsi_reset_all(dsi);
+
 	return ret;
 }
 
@@ -1007,6 +1024,7 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct drm_panel *panel;
 	struct resource *regs;
+	struct regmap *regmap;
 	int irq_num;
 	int ret;
 
@@ -1022,6 +1040,22 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
+						 "mediatek,syscon-dsi");
+	ret = of_property_read_u32_index(dev->of_node, "mediatek,syscon-dsi", 1,
+					 &dsi->sw_rst_b);
+
+	if (IS_ERR(regmap))
+		ret = PTR_ERR(regmap);
+
+	if (ret) {
+		ret = PTR_ERR(regmap);
+		dev_err(dev, "Failed to get mmsys registers: %d\n", ret);
+		return ret;
+	}
+
+	dsi->mmsys_sw_rst_b = regmap;
+
 	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
 					  &panel, &dsi->next_bridge);
 	if (ret)
-- 
2.25.1