[PATCH v4 0/2] Samsung Exynos 7870 DECON driver support

[PATCH v4 0/2] Samsung Exynos 7870 DECON driver support

[Kaustabh Chakraborty]

This patch series aims at adding support for Exynos7870's DECON in the
Exynos7 DECON driver. It introduces a driver data struct so that support
for DECON on other SoCs can be added to it in the future.

It also fixes a few bugs in the driver, such as functions receiving bad
pointers.

Tested on Samsung Galaxy J7 Prime (samsung-on7xelte), Samsung Galaxy A2
Core (samsung-a2corelte), and Samsung Galaxy J6 (samsung-j6lte).

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
Changes in v4:
- Drop applied patch [v2 3/3].
- Correct documentation of port dt property.
- Add documentation of memory-region.
- Remove redundant ctx->suspended completely.
- Link to v3: https://lore.kernel.org/r/20250627-exynosdrm-decon-v3-0-5b456f88cfea@disroot.org

Changes in v3:
- Add a new commit documenting iommus and ports dt properties.
- Link to v2: https://lore.kernel.org/r/20250612-exynosdrm-decon-v2-0-d6c1d21c8057@disroot.org

Changes in v2:
- Add a new commit to prevent an occasional panic under circumstances.
- Rewrite and redo [v1 2/6] to be a more sensible commit.
- Link to v1: https://lore.kernel.org/r/20240919-exynosdrm-decon-v1-0-6c5861c1cb04@disroot.org

---
Kaustabh Chakraborty (2):
      dt-bindings: display: samsung,exynos7-decon: document iommus, memory-region, and ports
      drm/exynos: exynos7_drm_decon: remove ctx->suspended

 .../display/samsung/samsung,exynos7-decon.yaml     | 21 +++++++++++++
 drivers/gpu/drm/exynos/exynos7_drm_decon.c         | 36 ----------------------
 2 files changed, 21 insertions(+), 36 deletions(-)
---
base-commit: 26ffb3d6f02cd0935fb9fa3db897767beee1cb2a
change-id: 20240917-exynosdrm-decon-4c228dd1d2bf

Best regards,
-- 
Kaustabh Chakraborty <kauschluss@disroot.org>

[PATCH v4 1/2] dt-bindings: display: samsung,exynos7-decon: document iommus, memory-region, and ports

[Kaustabh Chakraborty]

Similar to FIMD and Exynos5433's DECON, the Exynos7 DECON hardware:
- May optionally require an IOMMU to initialize a display region.
- Outputs image data to another block, say an MIC or a DSI master.

If an IOMMU is present, it may also require to access the reserved
framebuffer region.

Document these bindings in the devicetree schema.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
 .../display/samsung/samsung,exynos7-decon.yaml      | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/samsung/samsung,exynos7-decon.yaml b/Documentation/devicetree/bindings/display/samsung/samsung,exynos7-decon.yaml
index 53916e4c95d8c0369138941a556c23f5d42fbd39..14b954718008e06aa1627fcd116a61927ce29e99 100644
--- a/Documentation/devicetree/bindings/display/samsung/samsung,exynos7-decon.yaml
+++ b/Documentation/devicetree/bindings/display/samsung/samsung,exynos7-decon.yaml
@@ -80,6 +80,21 @@ properties:
       - const: vsync
       - const: lcd_sys
 
+  iommus:
+    maxItems: 1
+
+  memory-region:
+    maxItems: 1
+    description:
+      A phandle to a node describing a reserved framebuffer memory region.
+      For example, the splash memory region set up by the bootloader.
+
+  port:
+    $ref: /schemas/graph.yaml#/properties/port
+    description:
+      Output port which is connected to either a Mobile Image Compressor
+      (MIC) or a DSI Master device.
+
   power-domains:
     maxItems: 1
 
@@ -92,6 +107,7 @@ required:
   - clock-names
   - interrupts
   - interrupt-names
+  - port
   - reg
 
 additionalProperties: false
@@ -118,4 +134,9 @@ examples:
                       "decon0_vclk";
         pinctrl-0 = <&lcd_clk &pwm1_out>;
         pinctrl-names = "default";
+        port {
+            decon_to_dsi: endpoint {
+                remote-endpoint = <&dsi_to_decon>;
+            };
+        };
     };

-- 
2.49.0

[PATCH v4 2/2] drm/exynos: exynos7_drm_decon: remove ctx->suspended

[Kaustabh Chakraborty]

Condition guards are found to be redundant, as the call flow is properly
managed now, as also observed in the Exynos5433 DECON driver. Since
state checking is no longer necessary, remove it.

This also fixes an issue which prevented decon_commit() from
decon_atomic_enable() due to an incorrect state change setting.

Fixes: 96976c3d9aff ("drm/exynos: Add DECON driver")
Cc: stable@vger.kernel.org
Suggested-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
---
 drivers/gpu/drm/exynos/exynos7_drm_decon.c | 36 ------------------------------
 1 file changed, 36 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos7_drm_decon.c b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
index f91daefa9d2bc5e314c279822047e60ee0d7ca99..aec6ed5ee356586865c266b0bb2becaa897a8e7c 100644
--- a/drivers/gpu/drm/exynos/exynos7_drm_decon.c
+++ b/drivers/gpu/drm/exynos/exynos7_drm_decon.c
@@ -69,7 +69,6 @@ struct decon_context {
 	void __iomem			*regs;
 	unsigned long			irq_flags;
 	bool				i80_if;
-	bool				suspended;
 	wait_queue_head_t		wait_vsync_queue;
 	atomic_t			wait_vsync_event;
 
@@ -132,9 +131,6 @@ static void decon_shadow_protect_win(struct decon_context *ctx,
 
 static void decon_wait_for_vblank(struct decon_context *ctx)
 {
-	if (ctx->suspended)
-		return;
-
 	atomic_set(&ctx->wait_vsync_event, 1);
 
 	/*
@@ -210,9 +206,6 @@ static void decon_commit(struct exynos_drm_crtc *crtc)
 	struct drm_display_mode *mode = &crtc->base.state->adjusted_mode;
 	u32 val, clkdiv;
 
-	if (ctx->suspended)
-		return;
-
 	/* nothing to do if we haven't set the mode yet */
 	if (mode->htotal == 0 || mode->vtotal == 0)
 		return;
@@ -274,9 +267,6 @@ static int decon_enable_vblank(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	u32 val;
 
-	if (ctx->suspended)
-		return -EPERM;
-
 	if (!test_and_set_bit(0, &ctx->irq_flags)) {
 		val = readl(ctx->regs + VIDINTCON0);
 
@@ -299,9 +289,6 @@ static void decon_disable_vblank(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	u32 val;
 
-	if (ctx->suspended)
-		return;
-
 	if (test_and_clear_bit(0, &ctx->irq_flags)) {
 		val = readl(ctx->regs + VIDINTCON0);
 
@@ -404,9 +391,6 @@ static void decon_atomic_begin(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	int i;
 
-	if (ctx->suspended)
-		return;
-
 	for (i = 0; i < WINDOWS_NR; i++)
 		decon_shadow_protect_win(ctx, i, true);
 }
@@ -427,9 +411,6 @@ static void decon_update_plane(struct exynos_drm_crtc *crtc,
 	unsigned int pitch = fb->pitches[0];
 	unsigned int vidw_addr0_base = ctx->data->vidw_buf_start_base;
 
-	if (ctx->suspended)
-		return;
-
 	/*
 	 * SHADOWCON/PRTCON register is used for enabling timing.
 	 *
@@ -517,9 +498,6 @@ static void decon_disable_plane(struct exynos_drm_crtc *crtc,
 	unsigned int win = plane->index;
 	u32 val;
 
-	if (ctx->suspended)
-		return;
-
 	/* protect windows */
 	decon_shadow_protect_win(ctx, win, true);
 
@@ -538,9 +516,6 @@ static void decon_atomic_flush(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	int i;
 
-	if (ctx->suspended)
-		return;
-
 	for (i = 0; i < WINDOWS_NR; i++)
 		decon_shadow_protect_win(ctx, i, false);
 	exynos_crtc_handle_event(crtc);
@@ -568,9 +543,6 @@ static void decon_atomic_enable(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	int ret;
 
-	if (!ctx->suspended)
-		return;
-
 	ret = pm_runtime_resume_and_get(ctx->dev);
 	if (ret < 0) {
 		DRM_DEV_ERROR(ctx->dev, "failed to enable DECON device.\n");
@@ -584,8 +556,6 @@ static void decon_atomic_enable(struct exynos_drm_crtc *crtc)
 		decon_enable_vblank(ctx->crtc);
 
 	decon_commit(ctx->crtc);
-
-	ctx->suspended = false;
 }
 
 static void decon_atomic_disable(struct exynos_drm_crtc *crtc)
@@ -593,9 +563,6 @@ static void decon_atomic_disable(struct exynos_drm_crtc *crtc)
 	struct decon_context *ctx = crtc->ctx;
 	int i;
 
-	if (ctx->suspended)
-		return;
-
 	/*
 	 * We need to make sure that all windows are disabled before we
 	 * suspend that connector. Otherwise we might try to scan from
@@ -605,8 +572,6 @@ static void decon_atomic_disable(struct exynos_drm_crtc *crtc)
 		decon_disable_plane(crtc, &ctx->planes[i]);
 
 	pm_runtime_put_sync(ctx->dev);
-
-	ctx->suspended = true;
 }
 
 static const struct exynos_drm_crtc_ops decon_crtc_ops = {
@@ -723,7 +688,6 @@ static int decon_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ctx->dev = dev;
-	ctx->suspended = true;
 	ctx->data = of_device_get_match_data(dev);
 
 	i80_if_timings = of_get_child_by_name(dev->of_node, "i80-if-timings");

-- 
2.49.0

Re: [PATCH v4 1/2] dt-bindings: display: samsung,exynos7-decon: document iommus, memory-region, and ports

[Krzysztof Kozlowski]

On Sun, Jul 06, 2025 at 10:59:45PM +0530, Kaustabh Chakraborty wrote:
> Similar to FIMD and Exynos5433's DECON, the Exynos7 DECON hardware:
> - May optionally require an IOMMU to initialize a display region.
> - Outputs image data to another block, say an MIC or a DSI master.
> 
> If an IOMMU is present, it may also require to access the reserved
> framebuffer region.
> 
> Document these bindings in the devicetree schema.
> 
> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
>  .../display/samsung/samsung,exynos7-decon.yaml      | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v4 0/2] Samsung Exynos 7870 DECON driver support

[Inki Dae]

Hi  Kaustabh Chakraborty,

This patch series has been merged into the exynos-drm-next branch.

Thanks,
Inki Dae

2025년 7월 7일 (월) 오전 2:30, Kaustabh Chakraborty <kauschluss@disroot.org>님이 작성:
>
> This patch series aims at adding support for Exynos7870's DECON in the
> Exynos7 DECON driver. It introduces a driver data struct so that support
> for DECON on other SoCs can be added to it in the future.
>
> It also fixes a few bugs in the driver, such as functions receiving bad
> pointers.
>
> Tested on Samsung Galaxy J7 Prime (samsung-on7xelte), Samsung Galaxy A2
> Core (samsung-a2corelte), and Samsung Galaxy J6 (samsung-j6lte).
>
> Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> ---
> Changes in v4:
> - Drop applied patch [v2 3/3].
> - Correct documentation of port dt property.
> - Add documentation of memory-region.
> - Remove redundant ctx->suspended completely.
> - Link to v3: https://lore.kernel.org/r/20250627-exynosdrm-decon-v3-0-5b456f88cfea@disroot.org
>
> Changes in v3:
> - Add a new commit documenting iommus and ports dt properties.
> - Link to v2: https://lore.kernel.org/r/20250612-exynosdrm-decon-v2-0-d6c1d21c8057@disroot.org
>
> Changes in v2:
> - Add a new commit to prevent an occasional panic under circumstances.
> - Rewrite and redo [v1 2/6] to be a more sensible commit.
> - Link to v1: https://lore.kernel.org/r/20240919-exynosdrm-decon-v1-0-6c5861c1cb04@disroot.org
>
> ---
> Kaustabh Chakraborty (2):
>       dt-bindings: display: samsung,exynos7-decon: document iommus, memory-region, and ports
>       drm/exynos: exynos7_drm_decon: remove ctx->suspended
>
>  .../display/samsung/samsung,exynos7-decon.yaml     | 21 +++++++++++++
>  drivers/gpu/drm/exynos/exynos7_drm_decon.c         | 36 ----------------------
>  2 files changed, 21 insertions(+), 36 deletions(-)
> ---
> base-commit: 26ffb3d6f02cd0935fb9fa3db897767beee1cb2a
> change-id: 20240917-exynosdrm-decon-4c228dd1d2bf
>
> Best regards,
> --
> Kaustabh Chakraborty <kauschluss@disroot.org>
>
>