[PATCH] 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 | 35 ++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c 
b/drivers/gpu/drm/mediatek/mtk_dsi.c
index b00eb2d2e086..39ccb34a7c7f 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -21,10 +21,12 @@
 #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>
 
@@ -146,6 +148,8 @@
 #define T_HS_EXIT      7
 #define T_HS_ZERO      10
 
+#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) \
@@ -165,6 +169,8 @@ struct mtk_dsi {
        struct drm_panel *panel;
        struct drm_bridge *bridge;
        struct phy *phy;
+       struct regmap *mmsys_sw_rst_b;
+       u32 sw_rst_b;
 
        void __iomem *regs;
 
@@ -238,6 +244,16 @@ 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, ~MMSYS_SW_RST_DSI_B);
+       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);
@@ -831,6 +847,8 @@ static int mtk_dsi_create_conn_enc(struct drm_device *drm, 
struct mtk_dsi *dsi)
                        goto err_encoder_cleanup;
        }
 
+       mtk_dsi_reset_all(dsi);
+
        return 0;
 
 err_encoder_cleanup:
@@ -1087,6 +1105,7 @@ static int mtk_dsi_probe(struct platform_device *pdev)
        struct mtk_dsi *dsi;
        struct device *dev = &pdev->dev;
        struct resource *regs;
+       struct regmap *regmap;
        int irq_num;
        int comp_id;
        int ret;
@@ -1139,6 +1158,22 @@ 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;
+
        comp_id = mtk_ddp_comp_get_id(dev->of_node, MTK_DSI);
        if (comp_id < 0) {
                dev_err(dev, "Failed to identify by alias: %d\n", comp_id);
-- 
2.21.0

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