[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....@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