soc / drm: mediatek: Move routing control to mmsys device

Provide a mtk_mmsys_ddp_connect() and mtk_mmsys_disconnect() functions to
replace mtk_ddp_add_comp_to_path() and mtk_ddp_remove_comp_from_path().
Those functions will allow DRM driver and others to control the data
path routing.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Acked-by: CK Hu <ck.hu@mediatek.com>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

6 files changed, 17 insertions, 282 deletions

diff --git a/drivers/gpu/drm/mediatek/Kconfig b/drivers/gpu/drm/mediatek/Kconfig
index fa5ffc4fe823..c420f5a3d33b 100644
--- a/drivers/gpu/drm/mediatek/Kconfig
+++ b/drivers/gpu/drm/mediatek/Kconfig
@@ -11,6 +11,7 @@ config DRM_MEDIATEK
 	select DRM_MIPI_DSI
 	select DRM_PANEL
 	select MEMORY
+	select MTK_MMSYS
 	select MTK_SMI
 	select VIDEOMODE_HELPERS
 	help
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index fe85e487e477..fe46c4bac64d 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -6,6 +6,7 @@
 #include <linux/clk.h>
 #include <linux/pm_runtime.h>
 #include <linux/soc/mediatek/mtk-cmdq.h>
+#include <linux/soc/mediatek/mtk-mmsys.h>
 
 #include <asm/barrier.h>
 #include <soc/mediatek/smi.h>
@@ -28,7 +29,7 @@
  * @enabled: records whether crtc_enable succeeded
  * @planes: array of 4 drm_plane structures, one for each overlay plane
  * @pending_planes: whether any plane has pending changes to be applied
- * @config_regs: memory mapped mmsys configuration register space
+ * @mmsys_dev: pointer to the mmsys device for configuration registers
  * @mutex: handle to one of the ten disp_mutex streams
  * @ddp_comp_nr: number of components in ddp_comp
  * @ddp_comp: array of pointers the mtk_ddp_comp structures used by this crtc
@@ -50,7 +51,7 @@ struct mtk_drm_crtc {
 	u32				cmdq_event;
 #endif
 
-	void __iomem			*config_regs;
+	struct device			*mmsys_dev;
 	struct mtk_disp_mutex		*mutex;
 	unsigned int			ddp_comp_nr;
 	struct mtk_ddp_comp		**ddp_comp;
@@ -300,9 +301,9 @@ static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc)
 
 	DRM_DEBUG_DRIVER("mediatek_ddp_ddp_path_setup\n");
 	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
-		mtk_ddp_add_comp_to_path(mtk_crtc->config_regs,
-					 mtk_crtc->ddp_comp[i]->id,
-					 mtk_crtc->ddp_comp[i + 1]->id);
+		mtk_mmsys_ddp_connect(mtk_crtc->mmsys_dev,
+				      mtk_crtc->ddp_comp[i]->id,
+				      mtk_crtc->ddp_comp[i + 1]->id);
 		mtk_disp_mutex_add_comp(mtk_crtc->mutex,
 					mtk_crtc->ddp_comp[i]->id);
 	}
@@ -360,9 +361,9 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
 					   mtk_crtc->ddp_comp[i]->id);
 	mtk_disp_mutex_disable(mtk_crtc->mutex);
 	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
-		mtk_ddp_remove_comp_from_path(mtk_crtc->config_regs,
-					      mtk_crtc->ddp_comp[i]->id,
-					      mtk_crtc->ddp_comp[i + 1]->id);
+		mtk_mmsys_ddp_disconnect(mtk_crtc->mmsys_dev,
+					 mtk_crtc->ddp_comp[i]->id,
+					 mtk_crtc->ddp_comp[i + 1]->id);
 		mtk_disp_mutex_remove_comp(mtk_crtc->mutex,
 					   mtk_crtc->ddp_comp[i]->id);
 	}
@@ -766,7 +767,7 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
 	if (!mtk_crtc)
 		return -ENOMEM;
 
-	mtk_crtc->config_regs = priv->config_regs;
+	mtk_crtc->mmsys_dev = priv->mmsys_dev;
 	mtk_crtc->ddp_comp_nr = path_len;
 	mtk_crtc->ddp_comp = devm_kmalloc_array(dev, mtk_crtc->ddp_comp_nr,
 						sizeof(*mtk_crtc->ddp_comp),
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
index b885f60f474c..014c1bbe1df2 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
@@ -13,26 +13,6 @@
 #include "mtk_drm_ddp.h"
 #include "mtk_drm_ddp_comp.h"
 
-#define DISP_REG_CONFIG_DISP_OVL0_MOUT_EN	0x040
-#define DISP_REG_CONFIG_DISP_OVL1_MOUT_EN	0x044
-#define DISP_REG_CONFIG_DISP_OD_MOUT_EN		0x048
-#define DISP_REG_CONFIG_DISP_GAMMA_MOUT_EN	0x04c
-#define DISP_REG_CONFIG_DISP_UFOE_MOUT_EN	0x050
-#define DISP_REG_CONFIG_DISP_COLOR0_SEL_IN	0x084
-#define DISP_REG_CONFIG_DISP_COLOR1_SEL_IN	0x088
-#define DISP_REG_CONFIG_DSIE_SEL_IN		0x0a4
-#define DISP_REG_CONFIG_DSIO_SEL_IN		0x0a8
-#define DISP_REG_CONFIG_DPI_SEL_IN		0x0ac
-#define DISP_REG_CONFIG_DISP_RDMA2_SOUT		0x0b8
-#define DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN	0x0c4
-#define DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN	0x0c8
-#define DISP_REG_CONFIG_MMSYS_CG_CON0		0x100
-
-#define DISP_REG_CONFIG_DISP_OVL_MOUT_EN	0x030
-#define DISP_REG_CONFIG_OUT_SEL			0x04c
-#define DISP_REG_CONFIG_DSI_SEL			0x050
-#define DISP_REG_CONFIG_DPI_SEL			0x064
-
 #define MT2701_DISP_MUTEX0_MOD0			0x2c
 #define MT2701_DISP_MUTEX0_SOF0			0x30
 
@@ -94,48 +74,6 @@
 #define MUTEX_SOF_DSI2			5
 #define MUTEX_SOF_DSI3			6
 
-#define OVL0_MOUT_EN_COLOR0		0x1
-#define OD_MOUT_EN_RDMA0		0x1
-#define OD1_MOUT_EN_RDMA1		BIT(16)
-#define UFOE_MOUT_EN_DSI0		0x1
-#define COLOR0_SEL_IN_OVL0		0x1
-#define OVL1_MOUT_EN_COLOR1		0x1
-#define GAMMA_MOUT_EN_RDMA1		0x1
-#define RDMA0_SOUT_DPI0			0x2
-#define RDMA0_SOUT_DPI1			0x3
-#define RDMA0_SOUT_DSI1			0x1
-#define RDMA0_SOUT_DSI2			0x4
-#define RDMA0_SOUT_DSI3			0x5
-#define RDMA1_SOUT_DPI0			0x2
-#define RDMA1_SOUT_DPI1			0x3
-#define RDMA1_SOUT_DSI1			0x1
-#define RDMA1_SOUT_DSI2			0x4
-#define RDMA1_SOUT_DSI3			0x5
-#define RDMA2_SOUT_DPI0			0x2
-#define RDMA2_SOUT_DPI1			0x3
-#define RDMA2_SOUT_DSI1			0x1
-#define RDMA2_SOUT_DSI2			0x4
-#define RDMA2_SOUT_DSI3			0x5
-#define DPI0_SEL_IN_RDMA1		0x1
-#define DPI0_SEL_IN_RDMA2		0x3
-#define DPI1_SEL_IN_RDMA1		(0x1 << 8)
-#define DPI1_SEL_IN_RDMA2		(0x3 << 8)
-#define DSI0_SEL_IN_RDMA1		0x1
-#define DSI0_SEL_IN_RDMA2		0x4
-#define DSI1_SEL_IN_RDMA1		0x1
-#define DSI1_SEL_IN_RDMA2		0x4
-#define DSI2_SEL_IN_RDMA1		(0x1 << 16)
-#define DSI2_SEL_IN_RDMA2		(0x4 << 16)
-#define DSI3_SEL_IN_RDMA1		(0x1 << 16)
-#define DSI3_SEL_IN_RDMA2		(0x4 << 16)
-#define COLOR1_SEL_IN_OVL1		0x1
-
-#define OVL_MOUT_EN_RDMA		0x1
-#define BLS_TO_DSI_RDMA1_TO_DPI1	0x8
-#define BLS_TO_DPI_RDMA1_TO_DSI		0x2
-#define DSI_SEL_IN_BLS			0x0
-#define DPI_SEL_IN_BLS			0x0
-#define DSI_SEL_IN_RDMA			0x1
 
 struct mtk_disp_mutex {
 	int id;
@@ -246,200 +184,6 @@ static const struct mtk_ddp_data mt8173_ddp_driver_data = {
 	.mutex_sof_reg = MT2701_DISP_MUTEX0_SOF0,
 };
 
-static unsigned int mtk_ddp_mout_en(enum mtk_ddp_comp_id cur,
-				    enum mtk_ddp_comp_id next,
-				    unsigned int *addr)
-{
-	unsigned int value;
-
-	if (cur == DDP_COMPONENT_OVL0 && next == DDP_COMPONENT_COLOR0) {
-		*addr = DISP_REG_CONFIG_DISP_OVL0_MOUT_EN;
-		value = OVL0_MOUT_EN_COLOR0;
-	} else if (cur == DDP_COMPONENT_OVL0 && next == DDP_COMPONENT_RDMA0) {
-		*addr = DISP_REG_CONFIG_DISP_OVL_MOUT_EN;
-		value = OVL_MOUT_EN_RDMA;
-	} else if (cur == DDP_COMPONENT_OD0 && next == DDP_COMPONENT_RDMA0) {
-		*addr = DISP_REG_CONFIG_DISP_OD_MOUT_EN;
-		value = OD_MOUT_EN_RDMA0;
-	} else if (cur == DDP_COMPONENT_UFOE && next == DDP_COMPONENT_DSI0) {
-		*addr = DISP_REG_CONFIG_DISP_UFOE_MOUT_EN;
-		value = UFOE_MOUT_EN_DSI0;
-	} else if (cur == DDP_COMPONENT_OVL1 && next == DDP_COMPONENT_COLOR1) {
-		*addr = DISP_REG_CONFIG_DISP_OVL1_MOUT_EN;
-		value = OVL1_MOUT_EN_COLOR1;
-	} else if (cur == DDP_COMPONENT_GAMMA && next == DDP_COMPONENT_RDMA1) {
-		*addr = DISP_REG_CONFIG_DISP_GAMMA_MOUT_EN;
-		value = GAMMA_MOUT_EN_RDMA1;
-	} else if (cur == DDP_COMPONENT_OD1 && next == DDP_COMPONENT_RDMA1) {
-		*addr = DISP_REG_CONFIG_DISP_OD_MOUT_EN;
-		value = OD1_MOUT_EN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DPI0) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
-		value = RDMA0_SOUT_DPI0;
-	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DPI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
-		value = RDMA0_SOUT_DPI1;
-	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DSI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
-		value = RDMA0_SOUT_DSI1;
-	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DSI2) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
-		value = RDMA0_SOUT_DSI2;
-	} else if (cur == DDP_COMPONENT_RDMA0 && next == DDP_COMPONENT_DSI3) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA0_SOUT_EN;
-		value = RDMA0_SOUT_DSI3;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
-		value = RDMA1_SOUT_DSI1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI2) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
-		value = RDMA1_SOUT_DSI2;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI3) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
-		value = RDMA1_SOUT_DSI3;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DPI0) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
-		value = RDMA1_SOUT_DPI0;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DPI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA1_SOUT_EN;
-		value = RDMA1_SOUT_DPI1;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DPI0) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA2_SOUT;
-		value = RDMA2_SOUT_DPI0;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DPI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA2_SOUT;
-		value = RDMA2_SOUT_DPI1;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI1) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA2_SOUT;
-		value = RDMA2_SOUT_DSI1;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI2) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA2_SOUT;
-		value = RDMA2_SOUT_DSI2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI3) {
-		*addr = DISP_REG_CONFIG_DISP_RDMA2_SOUT;
-		value = RDMA2_SOUT_DSI3;
-	} else {
-		value = 0;
-	}
-
-	return value;
-}
-
-static unsigned int mtk_ddp_sel_in(enum mtk_ddp_comp_id cur,
-				   enum mtk_ddp_comp_id next,
-				   unsigned int *addr)
-{
-	unsigned int value;
-
-	if (cur == DDP_COMPONENT_OVL0 && next == DDP_COMPONENT_COLOR0) {
-		*addr = DISP_REG_CONFIG_DISP_COLOR0_SEL_IN;
-		value = COLOR0_SEL_IN_OVL0;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DPI0) {
-		*addr = DISP_REG_CONFIG_DPI_SEL_IN;
-		value = DPI0_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DPI1) {
-		*addr = DISP_REG_CONFIG_DPI_SEL_IN;
-		value = DPI1_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI0) {
-		*addr = DISP_REG_CONFIG_DSIE_SEL_IN;
-		value = DSI0_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI1) {
-		*addr = DISP_REG_CONFIG_DSIO_SEL_IN;
-		value = DSI1_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI2) {
-		*addr = DISP_REG_CONFIG_DSIE_SEL_IN;
-		value = DSI2_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA1 && next == DDP_COMPONENT_DSI3) {
-		*addr = DISP_REG_CONFIG_DSIO_SEL_IN;
-		value = DSI3_SEL_IN_RDMA1;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DPI0) {
-		*addr = DISP_REG_CONFIG_DPI_SEL_IN;
-		value = DPI0_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DPI1) {
-		*addr = DISP_REG_CONFIG_DPI_SEL_IN;
-		value = DPI1_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI0) {
-		*addr = DISP_REG_CONFIG_DSIE_SEL_IN;
-		value = DSI0_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI1) {
-		*addr = DISP_REG_CONFIG_DSIO_SEL_IN;
-		value = DSI1_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI2) {
-		*addr = DISP_REG_CONFIG_DSIE_SEL_IN;
-		value = DSI2_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_RDMA2 && next == DDP_COMPONENT_DSI3) {
-		*addr = DISP_REG_CONFIG_DSIE_SEL_IN;
-		value = DSI3_SEL_IN_RDMA2;
-	} else if (cur == DDP_COMPONENT_OVL1 && next == DDP_COMPONENT_COLOR1) {
-		*addr = DISP_REG_CONFIG_DISP_COLOR1_SEL_IN;
-		value = COLOR1_SEL_IN_OVL1;
-	} else if (cur == DDP_COMPONENT_BLS && next == DDP_COMPONENT_DSI0) {
-		*addr = DISP_REG_CONFIG_DSI_SEL;
-		value = DSI_SEL_IN_BLS;
-	} else {
-		value = 0;
-	}
-
-	return value;
-}
-
-static void mtk_ddp_sout_sel(void __iomem *config_regs,
-			     enum mtk_ddp_comp_id cur,
-			     enum mtk_ddp_comp_id next)
-{
-	if (cur == DDP_COMPONENT_BLS && next == DDP_COMPONENT_DSI0) {
-		writel_relaxed(BLS_TO_DSI_RDMA1_TO_DPI1,
-			       config_regs + DISP_REG_CONFIG_OUT_SEL);
-	} else if (cur == DDP_COMPONENT_BLS && next == DDP_COMPONENT_DPI0) {
-		writel_relaxed(BLS_TO_DPI_RDMA1_TO_DSI,
-			       config_regs + DISP_REG_CONFIG_OUT_SEL);
-		writel_relaxed(DSI_SEL_IN_RDMA,
-			       config_regs + DISP_REG_CONFIG_DSI_SEL);
-		writel_relaxed(DPI_SEL_IN_BLS,
-			       config_regs + DISP_REG_CONFIG_DPI_SEL);
-	}
-}
-
-void mtk_ddp_add_comp_to_path(void __iomem *config_regs,
-			      enum mtk_ddp_comp_id cur,
-			      enum mtk_ddp_comp_id next)
-{
-	unsigned int addr, value, reg;
-
-	value = mtk_ddp_mout_en(cur, next, &addr);
-	if (value) {
-		reg = readl_relaxed(config_regs + addr) | value;
-		writel_relaxed(reg, config_regs + addr);
-	}
-
-	mtk_ddp_sout_sel(config_regs, cur, next);
-
-	value = mtk_ddp_sel_in(cur, next, &addr);
-	if (value) {
-		reg = readl_relaxed(config_regs + addr) | value;
-		writel_relaxed(reg, config_regs + addr);
-	}
-}
-
-void mtk_ddp_remove_comp_from_path(void __iomem *config_regs,
-				   enum mtk_ddp_comp_id cur,
-				   enum mtk_ddp_comp_id next)
-{
-	unsigned int addr, value, reg;
-
-	value = mtk_ddp_mout_en(cur, next, &addr);
-	if (value) {
-		reg = readl_relaxed(config_regs + addr) & ~value;
-		writel_relaxed(reg, config_regs + addr);
-	}
-
-	value = mtk_ddp_sel_in(cur, next, &addr);
-	if (value) {
-		reg = readl_relaxed(config_regs + addr) & ~value;
-		writel_relaxed(reg, config_regs + addr);
-	}
-}
-
 struct mtk_disp_mutex *mtk_disp_mutex_get(struct device *dev, unsigned int id)
 {
 	struct mtk_ddp *ddp = dev_get_drvdata(dev);
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
index 827be424a148..6b691a57be4a 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
@@ -12,13 +12,6 @@ struct regmap;
 struct device;
 struct mtk_disp_mutex;
 
-void mtk_ddp_add_comp_to_path(void __iomem *config_regs,
-			      enum mtk_ddp_comp_id cur,
-			      enum mtk_ddp_comp_id next);
-void mtk_ddp_remove_comp_from_path(void __iomem *config_regs,
-				   enum mtk_ddp_comp_id cur,
-				   enum mtk_ddp_comp_id next);
-
 struct mtk_disp_mutex *mtk_disp_mutex_get(struct device *dev, unsigned int id);
 int mtk_disp_mutex_prepare(struct mtk_disp_mutex *mutex);
 void mtk_disp_mutex_add_comp(struct mtk_disp_mutex *mutex,
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 0563c6813333..f2f07098265d 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -10,6 +10,7 @@
 #include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
+#include <linux/soc/mediatek/mtk-mmsys.h>
 #include <linux/dma-mapping.h>
 
 #include <drm/drm_atomic.h>
@@ -425,7 +426,6 @@ static int mtk_drm_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct mtk_drm_private *private;
-	struct resource *mem;
 	struct device_node *node;
 	struct component_match *match = NULL;
 	int ret;
@@ -436,14 +436,10 @@ static int mtk_drm_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	private->data = of_device_get_match_data(dev);
-
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	private->config_regs = devm_ioremap_resource(dev, mem);
-	if (IS_ERR(private->config_regs)) {
-		ret = PTR_ERR(private->config_regs);
-		dev_err(dev, "Failed to ioremap mmsys-config resource: %d\n",
-			ret);
-		return ret;
+	private->mmsys_dev = dev->parent;
+	if (!private->mmsys_dev) {
+		dev_err(dev, "Failed to get MMSYS device\n");
+		return -ENODEV;
 	}
 
 	/* Iterate over sibling DISP function blocks */
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
index 17bc99b9f5d4..b5be63e53176 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
@@ -39,7 +39,7 @@ struct mtk_drm_private {
 
 	struct device_node *mutex_node;
 	struct device *mutex_dev;
-	void __iomem *config_regs;
+	struct device *mmsys_dev;
 	struct device_node *comp_node[DDP_COMPONENT_ID_MAX];
 	struct mtk_ddp_comp *ddp_comp[DDP_COMPONENT_ID_MAX];
 	const struct mtk_mmsys_driver_data *data;