[PATCH v11 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[PATCH v11 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[Friday Yang]

Based on tag: next-20250916, linux-next/master

On the MediaTek MT8188 SoC platform, we encountered power-off failures
and SMI bus hang issues during camera stress tests. The issue arises
because bus glitches are sometimes produced when MTCMOS powers on or
off. While this is fairly normal, the software must handle these
glitches to avoid mistaking them for transaction signals. What's
more, this issue emerged only after the initial upstreaming of SMI
driver.

The software solutions can be summarized as follows:

1. Use CLAMP to disable the SMI sub-common port after turning off the
   LARB CG and before turning off the LARB MTCMOS.
2. Use CLAMP to disable/enable the SMI sub-common port.
3. Implement an AXI reset for SMI LARBs.

---
Changes in v11:
- Add error checking in the 'mtk_smi_genpd_callback' function and use
  'switch-case' statement instead of 'if-else'.
- Use 'larb->larb_gen->clamp_port[larb->larbid]' to determine
  whether smi larb requires clamp and reset operations or not in
  'mtk_smi_larb_probe'. Remove the '_optional' suffix from the
  function name.
- Replace 'devm_reset_control_get_optional_exclusive' with
  'devm_reset_control_get_exclusive' in 'mtk_smi_larb_parse_reset',
  return the error code if it fails to get the reset controller.
- Remove genpd callback when smi larb probe fails.

Changes in v10:
- Rename 'smi_comm_inport_id' to 'smi_comm_in_port_id'.
- Return 0 when it fails to get 'larb_id' in
  'mtk_smi_larb_parse_clamp_optional'.
- Link to v10:
  https://lore.kernel.org/lkml/20250806085946.11383-1-friday.yang@mediatek.com/

Changes in v9:
- Add 'dev_pm_genpd_remove_notifier' in 'mtk_smi_larb_remove'.
- Remove unused macros.
- Rename 'sub_comm_syscon' to 'smi_comm_syscon'.
- Rename 'sub_comm_inport_id' to 'smi_comm_inport_id'.
- Add more detailed descriptions in change log.
- Fix incorrect tags.
- Link to v9:
  https://lore.kernel.org/lkml/20250804125215.23076-1-friday.yang@mediatek.com/

Changes in v8:
- Fix incorrect tags.
- Link to v8:
  https://lore.kernel.org/lkml/20250521063347.31578-1-friday.yang@mediatek.com/

Changes in v7:
- We replaced 'pm_runtime_enable' with 'devm_pm_runtime_enable' in the
  v6 patch. This changed the order of cleanup, and reviewers expressed
  concerns that it could introduce unexpected issues. So v7 discard this
  change and continue using 'pm_runtime_enable'. We need to conduct
  further investigation to determine if there are any issues related
  to the cleanup order. This might be resolved in the future, but for
  now, we just maintain the current status.
- Link to v7:
  https://lore.kernel.org/lkml/20250430094545.23932-1-friday.yang@mediatek.com/

Changes in v6:
- Fix coding style.
- Add another patch to replace 'pm_runtime_enable' with
  'devm_pm_runtime_enable'.
- Link to v6:
  https://lore.kernel.org/lkml/20250408033206.12176-1-friday.yang@mediatek.com/

Changes in v5:
- Use 'devm_pm_runtime_enable' instead of 'pm_runtime_enable'.
- Remove 'pm_runtime_disable' in 'mtk_smi_common_remove' and
  'mtk_smi_larb_remove'.
- Link to v5:
  https://lore.kernel.org/lkml/20250311122327.20685-1-friday.yang@mediatek.com/

Changes in v4:
- Use 'devm_reset_control_get_optional_exclusive' instead of
  'devm_reset_control_get'.
- Link to v4:
  https://lore.kernel.org/lkml/20250221074846.14105-1-friday.yang@mediatek.com/

Changes in v3:
- Remove redundant descriptions for 'resets' and 'reset-names'.
- Modify the requirements for 'resets' and 'reset-names'.
- Rename 'mtk_smi_larb_parse_clamp' to 'mtk_smi_larb_parse_clamp_optional'.
- Rename 'mtk_smi_larb_parse_reset' to 'mtk_smi_larb_parse_reset_optional'.
- Merge 'mtk_smi_larb_clamp_protect_enable' and
  'mtk_smi_larb_clamp_protect_disble' into one function.
- Modify the definition for mtk_smi_larb_clamp_port_mt8188,
  use 'larbid' as the index of the array.
- Use 'syscon_regmap_lookup_by_phandle' instead of 'device_node_to_regmap'.
- Do Not parse 'resets', just check the return value of
  'devm_reset_control_get'.
- Add 'has_gals' flag for 'mtk_smi_sub_common_mt8188'.
- Link to v3:
  https://lore.kernel.org/lkml/20250121064934.13482-1-friday.yang@mediatek.com/

Changes in v2:
- According to previous discussions in v1, divided these four
  patches into two topic separately.
- Modify the description for 'resets' in binding.
- Add const value 'larb' for 'reset-names' in binding.
- Modify requirement for 'resets' and 'reset-names' in binding.
- Delete 'mediatek,smi-sub-comm' in binding.
- Delete 'mediatek,smi-sub-comm-in-portid' in binding.
- Modify the example in binding.
- Add 'mtk_smi_larb_clamp_port_mt8188' definition in SMI driver.
- Change the way to parse the 'resets' in driver.
- Change label from 'err_pm_disable' to 'err_link_remove'.
- Link to v2:
  https://lore.kernel.org/lkml/20241120063701.8194-1-friday.yang@mediatek.com/

Friday Yang (2):
  dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188
  memory: mtk-smi: mt8188: Add SMI reset and clamp

 .../mediatek,smi-common.yaml                  |   2 +
 .../memory-controllers/mediatek,smi-larb.yaml |  19 +++
 drivers/memory/mtk-smi.c                      | 151 ++++++++++++++++++
 3 files changed, 172 insertions(+)

--
2.46.0

[PATCH v11 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang]

Add 'resets' and 'reset-names' properties for SMI LARBs to support
SMI reset operations.
On the MediaTek platform, some SMI LARBs are directly connected to
the SMI Common, while others are connected to the SMI Sub-Common,
which in turn is connected to the SMI Common. The hardware block
diagram can be described as follows.

             SMI-Common(Smart Multimedia Interface Common)
                 |
         +----------------+------------------+
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
         |                |                  |
       larb0       SMI-Sub-Common0     SMI-Sub-Common1
                   |      |     |      |             |
                  larb1  larb2 larb3  larb7       larb9

Signed-off-by: Friday Yang <friday.yang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../mediatek,smi-common.yaml                  |  2 ++
 .../memory-controllers/mediatek,smi-larb.yaml | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
index 0762e0ff66ef..3d98c08b2149 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
@@ -40,6 +40,7 @@ properties:
           - mediatek,mt8186-smi-common
           - mediatek,mt8188-smi-common-vdo
           - mediatek,mt8188-smi-common-vpp
+          - mediatek,mt8188-smi-sub-common
           - mediatek,mt8192-smi-common
           - mediatek,mt8195-smi-common-vdo
           - mediatek,mt8195-smi-common-vpp
@@ -108,6 +109,7 @@ allOf:
         compatible:
           contains:
             enum:
+              - mediatek,mt8188-smi-sub-common
               - mediatek,mt8195-smi-sub-common
     then:
       required:
diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
index 2e7fac4b5094..fc5feb2eac1f 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
@@ -70,6 +70,12 @@ properties:
     description: the hardware id of this larb. It's only required when this
       hardware id is not consecutive from its M4U point of view.

+  resets:
+    maxItems: 1
+
+  reset-names:
+    const: larb
+
 required:
   - compatible
   - reg
@@ -126,6 +132,19 @@ allOf:
       required:
         - mediatek,larb-id

+  - if:  # only for image, camera and ipe subsys
+      properties:
+        compatible:
+          const: mediatek,mt8188-smi-larb
+        mediatek,larb-id:
+          enum:
+            [ 9, 10, 11, 12, 13, 16, 17, 18, 19, 20 ]
+
+    then:
+      required:
+        - resets
+        - reset-names
+
 additionalProperties: false

 examples:
--
2.46.0

[PATCH v11 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp

[Friday Yang]

To prevent handling glitch signals during MTCMOS on/off transitions,
SMI requires clamp and reset operations. Parse the reset settings for
SMI LARBs and the clamp settings for the SMI Sub-Common. Register
genpd callback for the SMI LARBs located in image, camera and IPE
subsystems, and apply reset and clamp operations within the callback.

Signed-off-by: Friday Yang <friday.yang@mediatek.com>
---
 drivers/memory/mtk-smi.c | 151 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)

diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
index 733e22f695ab..117ff528db01 100644
--- a/drivers/memory/mtk-smi.c
+++ b/drivers/memory/mtk-smi.c
@@ -10,11 +10,15 @@
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
 #include <linux/soc/mediatek/mtk_sip_svc.h>
 #include <soc/mediatek/smi.h>
 #include <dt-bindings/memory/mt2701-larb-port.h>
@@ -34,6 +38,8 @@
 #define SMI_FIFO_TH1			0x238
 #define SMI_FIFO_TH2			0x23c
 #define SMI_DCM				0x300
+#define SMI_COMMON_CLAMP_EN_SET		0x3c4
+#define SMI_COMMON_CLAMP_EN_CLR		0x3c8
 #define SMI_DUMMY			0x444

 /* SMI LARB */
@@ -134,6 +140,7 @@ struct mtk_smi_larb_gen {
 	unsigned int			larb_direct_to_common_mask;
 	unsigned int			flags_general;
 	const u8			(*ostd)[SMI_LARB_PORT_NR_MAX];
+	const u8			*clamp_port;
 };

 struct mtk_smi {
@@ -150,6 +157,7 @@ struct mtk_smi {
 };

 struct mtk_smi_larb { /* larb: local arbiter */
+	struct device			*dev;
 	struct mtk_smi			smi;
 	void __iomem			*base;
 	struct device			*smi_common_dev; /* common or sub-common dev */
@@ -157,6 +165,10 @@ struct mtk_smi_larb { /* larb: local arbiter */
 	int				larbid;
 	u32				*mmu;
 	unsigned char			*bank;
+	struct regmap			*smi_comm_syscon; /* smi-comm or sub-comm */
+	u8				smi_comm_in_port_id; /* smi-comm or sub-comm */
+	struct notifier_block		nb;
+	struct reset_control		*rst_con;
 };

 static int
@@ -478,6 +490,19 @@ static const u8 mtk_smi_larb_mt8195_ostd[][SMI_LARB_PORT_NR_MAX] = {
 	[28] = {0x1a, 0x0e, 0x0a, 0x0a, 0x0c, 0x0e, 0x10,},
 };

+static const u8 mtk_smi_larb_clamp_port_mt8188[MTK_LARB_NR_MAX] = {
+	[9]	= BIT(1), /* larb10 */
+	[10]	= BIT(2), /* larb11a */
+	[11]	= BIT(2), /* larb11b */
+	[12]	= BIT(3), /* larb11c */
+	[13]	= BIT(0), /* larb12 */
+	[16]	= BIT(1), /* larb15 */
+	[17]	= BIT(2), /* larb16a */
+	[18]	= BIT(2), /* larb16b */
+	[19]	= BIT(3), /* larb17a */
+	[20]	= BIT(3), /* larb17b */
+};
+
 static const struct mtk_smi_larb_gen mtk_smi_larb_mt2701 = {
 	.port_in_larb = {
 		LARB0_PORT_OFFSET, LARB1_PORT_OFFSET,
@@ -531,6 +556,7 @@ static const struct mtk_smi_larb_gen mtk_smi_larb_mt8188 = {
 	.flags_general	            = MTK_SMI_FLAG_THRT_UPDATE | MTK_SMI_FLAG_SW_FLAG |
 				      MTK_SMI_FLAG_SLEEP_CTL | MTK_SMI_FLAG_CFG_PORT_SEC_CTL,
 	.ostd		            = mtk_smi_larb_mt8188_ostd,
+	.clamp_port                 = mtk_smi_larb_clamp_port_mt8188,
 };

 static const struct mtk_smi_larb_gen mtk_smi_larb_mt8192 = {
@@ -582,6 +608,53 @@ static void mtk_smi_larb_sleep_ctrl_disable(struct mtk_smi_larb *larb)
 	writel_relaxed(0, larb->base + SMI_LARB_SLP_CON);
 }

+static int mtk_smi_larb_clamp_protect_enable(struct device *dev, bool enable)
+{
+	struct mtk_smi_larb *larb = dev_get_drvdata(dev);
+	u32 reg;
+	int ret;
+
+	reg = enable ? SMI_COMMON_CLAMP_EN_SET : SMI_COMMON_CLAMP_EN_CLR;
+	ret = regmap_write(larb->smi_comm_syscon, reg, larb->smi_comm_in_port_id);
+	if (ret)
+		dev_err(dev, "Unable to %s clamp for input port %d: %d\n",
+			enable ? "enable" : "disable",
+			larb->smi_comm_in_port_id, ret);
+
+	return ret;
+}
+
+static int mtk_smi_genpd_callback(struct notifier_block *nb,
+				  unsigned long event, void *data)
+{
+	struct mtk_smi_larb *larb = container_of(nb, struct mtk_smi_larb, nb);
+	struct device *dev = larb->dev;
+	int ret = 0;
+
+	switch (event) {
+	case GENPD_NOTIFY_PRE_ON:
+	case GENPD_NOTIFY_PRE_OFF:
+		/* Clamp this larb to avoid the redundant commands */
+		ret = mtk_smi_larb_clamp_protect_enable(dev, true);
+		break;
+	case GENPD_NOTIFY_ON:
+		ret = reset_control_reset(larb->rst_con);
+		if (ret) {
+			dev_err(dev, "Failed to reset smi larb %d\n", ret);
+			break;
+		}
+
+		ret = mtk_smi_larb_clamp_protect_enable(dev, false);
+		break;
+	default:
+		break;
+	}
+	if (ret)
+		return NOTIFY_BAD;
+
+	return NOTIFY_OK;
+}
+
 static int mtk_smi_device_link_common(struct device *dev, struct device **com_dev)
 {
 	struct platform_device *smi_com_pdev;
@@ -638,6 +711,46 @@ static int mtk_smi_dts_clk_init(struct device *dev, struct mtk_smi *smi,
 	return ret;
 }

+static int mtk_smi_larb_parse_syscon(struct mtk_smi_larb *larb, int larbid)
+{
+	struct device *dev = larb->dev;
+	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
+	int ret;
+
+	larb->smi_comm_in_port_id = larb_gen->clamp_port[larbid];
+	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node,
+								"mediatek,smi");
+	if (IS_ERR(larb->smi_comm_syscon)) {
+		ret = PTR_ERR(larb->smi_comm_syscon);
+		larb->smi_comm_syscon = NULL;
+		return dev_err_probe(dev, ret,
+				     "Failed to get smi syscon for larb %d\n", larbid);
+	}
+
+	return 0;
+}
+
+static int mtk_smi_larb_parse_reset(struct mtk_smi_larb *larb)
+{
+	struct device *dev = larb->dev;
+	int ret;
+
+	larb->rst_con = devm_reset_control_get_exclusive(dev, "larb");
+	if (IS_ERR(larb->rst_con))
+		return dev_err_probe(dev, PTR_ERR(larb->rst_con),
+				     "Failed to get reset controller\n");
+
+	larb->nb.notifier_call = mtk_smi_genpd_callback;
+	ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
+	if (ret) {
+		larb->nb.notifier_call = NULL;
+		return dev_err_probe(dev, ret,
+				     "Failed to add genpd callback\n");
+	}
+
+	return 0;
+}
+
 static int mtk_smi_larb_probe(struct platform_device *pdev)
 {
 	struct mtk_smi_larb *larb;
@@ -648,6 +761,7 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 	if (!larb)
 		return -ENOMEM;

+	larb->dev = dev;
 	larb->larb_gen = of_device_get_match_data(dev);
 	larb->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(larb->base))
@@ -664,6 +778,30 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;

+	/* The larbid are sequential for IOMMU if this property is not present */
+	if (!of_property_present(dev->of_node, "mediatek,larb-id"))
+		goto pm_runtime_en;
+	ret = of_property_read_s32(dev->of_node, "mediatek,larb-id", &larb->larbid);
+	if (ret || larb->larbid >= MTK_LARB_NR_MAX) {
+		ret = -EINVAL;
+		goto err_link_remove;
+	}
+
+	/*
+	 * Only SMI LARBs in camera, image and IPE subsys need to
+	 * apply clamp and reset operations, others can be skipped.
+	 */
+	if (larb->larb_gen->clamp_port && larb->larb_gen->clamp_port[larb->larbid]) {
+		ret = mtk_smi_larb_parse_syscon(larb, larb->larbid);
+		if (ret)
+			goto err_link_remove;
+
+		ret = mtk_smi_larb_parse_reset(larb);
+		if (ret)
+			goto err_link_remove;
+	}
+
+pm_runtime_en:
 	pm_runtime_enable(dev);
 	platform_set_drvdata(pdev, larb);
 	ret = component_add(dev, &mtk_smi_larb_component_ops);
@@ -672,7 +810,11 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 	return 0;

 err_pm_disable:
+	if (larb->nb.notifier_call)
+		dev_pm_genpd_remove_notifier(&pdev->dev);
+
 	pm_runtime_disable(dev);
+err_link_remove:
 	device_link_remove(dev, larb->smi_common_dev);
 	return ret;
 }
@@ -681,6 +823,9 @@ static void mtk_smi_larb_remove(struct platform_device *pdev)
 {
 	struct mtk_smi_larb *larb = platform_get_drvdata(pdev);

+	if (larb->nb.notifier_call)
+		dev_pm_genpd_remove_notifier(&pdev->dev);
+
 	device_link_remove(&pdev->dev, larb->smi_common_dev);
 	pm_runtime_disable(&pdev->dev);
 	component_del(&pdev->dev, &mtk_smi_larb_component_ops);
@@ -803,6 +948,11 @@ static const struct mtk_smi_common_plat mtk_smi_common_mt8188_vpp = {
 	.init     = mtk_smi_common_mt8195_init,
 };

+static const struct mtk_smi_common_plat mtk_smi_sub_common_mt8188 = {
+	.type     = MTK_SMI_GEN2_SUB_COMM,
+	.has_gals = true,
+};
+
 static const struct mtk_smi_common_plat mtk_smi_common_mt8192 = {
 	.type     = MTK_SMI_GEN2,
 	.has_gals = true,
@@ -847,6 +997,7 @@ static const struct of_device_id mtk_smi_common_of_ids[] = {
 	{.compatible = "mediatek,mt8186-smi-common", .data = &mtk_smi_common_mt8186},
 	{.compatible = "mediatek,mt8188-smi-common-vdo", .data = &mtk_smi_common_mt8188_vdo},
 	{.compatible = "mediatek,mt8188-smi-common-vpp", .data = &mtk_smi_common_mt8188_vpp},
+	{.compatible = "mediatek,mt8188-smi-sub-common", .data = &mtk_smi_sub_common_mt8188},
 	{.compatible = "mediatek,mt8192-smi-common", .data = &mtk_smi_common_mt8192},
 	{.compatible = "mediatek,mt8195-smi-common-vdo", .data = &mtk_smi_common_mt8195_vdo},
 	{.compatible = "mediatek,mt8195-smi-common-vpp", .data = &mtk_smi_common_mt8195_vpp},
--
2.46.0

Re: [PATCH v11 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp

[AngeloGioacchino Del Regno]

Il 17/09/25 14:07, Friday Yang ha scritto:
> To prevent handling glitch signals during MTCMOS on/off transitions,
> SMI requires clamp and reset operations. Parse the reset settings for
> SMI LARBs and the clamp settings for the SMI Sub-Common. Register
> genpd callback for the SMI LARBs located in image, camera and IPE
> subsystems, and apply reset and clamp operations within the callback.
> 
> Signed-off-by: Friday Yang <friday.yang@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Re: [PATCH v11 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp

[Yong Wu (吴勇)]

On Wed, 2025-09-17 at 20:07 +0800, Friday Yang wrote:
> To prevent handling glitch signals during MTCMOS on/off transitions,
> SMI requires clamp and reset operations. Parse the reset settings for
> SMI LARBs and the clamp settings for the SMI Sub-Common. Register
> genpd callback for the SMI LARBs located in image, camera and IPE
> subsystems, and apply reset and clamp operations within the callback.
> 
> Signed-off-by: Friday Yang <friday.yang@mediatek.com>
> ---
>  drivers/memory/mtk-smi.c | 151
> +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 151 insertions(+)

Reviewed-by: Yong Wu <yong.wu@mediatek.com>

Re: [PATCH v11 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp

[Krzysztof Kozlowski]

On 17/09/2025 14:07, Friday Yang wrote:
>  static int mtk_smi_device_link_common(struct device *dev, struct device **com_dev)
>  {
>  	struct platform_device *smi_com_pdev;
> @@ -638,6 +711,46 @@ static int mtk_smi_dts_clk_init(struct device *dev, struct mtk_smi *smi,
>  	return ret;
>  }
> 
> +static int mtk_smi_larb_parse_syscon(struct mtk_smi_larb *larb, int larbid)
> +{
> +	struct device *dev = larb->dev;
> +	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> +	int ret;
> +
> +	larb->smi_comm_in_port_id = larb_gen->clamp_port[larbid];
> +	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node,
> +								"mediatek,smi");

The code already parses this phandle (in other place). Why do you need
second time?

> +	if (IS_ERR(larb->smi_comm_syscon)) {
> +		ret = PTR_ERR(larb->smi_comm_syscon);
> +		larb->smi_comm_syscon = NULL;
> +		return dev_err_probe(dev, ret,
> +				     "Failed to get smi syscon for larb %d\n", larbid);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mtk_smi_larb_parse_reset(struct mtk_smi_larb *larb)
> +{
> +	struct device *dev = larb->dev;
> +	int ret;
> +
> +	larb->rst_con = devm_reset_control_get_exclusive(dev, "larb");
> +	if (IS_ERR(larb->rst_con))
> +		return dev_err_probe(dev, PTR_ERR(larb->rst_con),
> +				     "Failed to get reset controller\n");


This looks like ABI break. Aren't all devices affected?

> +
> +	larb->nb.notifier_call = mtk_smi_genpd_callback;
> +	ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
> +	if (ret) {
> +		larb->nb.notifier_call = NULL;
> +		return dev_err_probe(dev, ret,
> +				     "Failed to add genpd callback\n");
> +	}
> +
> +	return 0;
> +}
> +
Best regards,
Krzysztof

Re: [PATCH v11 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Krzysztof Kozlowski]

On 17/09/2025 14:07, Friday Yang wrote:
> Add 'resets' and 'reset-names' properties for SMI LARBs to support
> SMI reset operations.

Not informative...

> diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
> index 2e7fac4b5094..fc5feb2eac1f 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
> +++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
> @@ -70,6 +70,12 @@ properties:
>      description: the hardware id of this larb. It's only required when this
>        hardware id is not consecutive from its M4U point of view.
> 
> +  resets:
> +    maxItems: 1
> +
> +  reset-names:
> +    const: larb

Is the reset valid for all existing devices as well? Commit msg does not
explain that... it is pretty useless - you say what you did. We see that
from the diff. Explain something not obvious.



Best regards,
Krzysztof

Re: [PATCH v11 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp

[Friday Yang (杨阳)]

On Sat, 2025-10-18 at 18:41 +0200, Krzysztof Kozlowski wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On 17/09/2025 14:07, Friday Yang wrote:
> >  static int mtk_smi_device_link_common(struct device *dev, struct
> > device **com_dev)
> >  {
> >       struct platform_device *smi_com_pdev;
> > @@ -638,6 +711,46 @@ static int mtk_smi_dts_clk_init(struct device
> > *dev, struct mtk_smi *smi,
> >       return ret;
> >  }
> > 
> > +static int mtk_smi_larb_parse_syscon(struct mtk_smi_larb *larb,
> > int larbid)
> > +{
> > +     struct device *dev = larb->dev;
> > +     const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> > +     int ret;
> > +
> > +     larb->smi_comm_in_port_id = larb_gen->clamp_port[larbid];
> > +     larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> > >of_node,
> > +                                                             "medi
> > atek,smi");
> 
> The code already parses this phandle (in other place). Why do you
> need
> second time?
> 

Thanks for comments. We did parse the 'mediatek,smi' property in
mtk_smi_device_link_common. We need to modify
'mtk_smi_device_link_common' function if this need to be fixed.
Below is the modification, is this acceptable for you?

static int mtk_smi_device_link_common(struct device *dev, struct device
**com_dev,bool require_clamp)
{
...
	struct mtk_smi_larb *larb;
	struct mtk_smi_larb_gen *larb_gen;
	int larbid, ret;

	smi_com_node = of_parse_phandle(dev->of_node, "mediatek,smi",
0);
	if (!smi_com_node)
		return -EINVAL;
	smi_com_pdev = of_find_device_by_node(smi_com_node);
...
	if (require_clamp) {
		larb = container_of(com_dev, struct mtk_smi_larb,
smi_common_dev);
		larb_gen = larb->larb_gen;
		larbid = larb->larb_id;
		larb->smi_comm_in_port_id = larb_gen-
>clamp_port[larbid];
		larb->smi_comm_syscon =
syscon_node_to_regmap(smi_com_node);
		if (IS_ERR(larb->smi_comm_syscon)) {
			dev_err(dev, "Failed to get smi syscon for larb %d\n", larbid);
			ret = PTR_ERR(larb->smi_comm_syscon);
			larb->smi_comm_syscon = NULL;
			goto err_remove_link;
		}
	}
	of_node_put(smi_com_node);
	return 0;

err_remove_link:
	device_link_remove(dev, smi_com_dev);
err_put_device:
	put_device(&smi_com_pdev->dev);
err_put_node:
	of_node_put(smi_com_node);
	return ret;
}

static int mtk_smi_larb_probe(struct platform_device *pdev)
{
	bool require_clamp;
...

	/* The larbid are sequential for IOMMU if this property is not
present */
	ret = of_property_read_s32(dev->of_node, "mediatek,larb-id",
&larb->larbid);
	if (ret == -EINVAL)
		goto add_dev_link;
	else if (ret || larb->larbid >= MTK_LARB_NR_MAX)
		return dev_err_probe(dev, -EINVAL, "Invalid
larbid:%d\n", larb->larbid);

	if (larb->larb_gen->clamp_port && larb->larb_gen-
>clamp_port[larb->larbid])
		require_clamp = true;

add_dev_link:
	ret = mtk_smi_device_link_common(dev, &larb->smi_common_dev,
require_clamp);
	if (ret < 0)
		return ret;

	/*
	 * Only SMI LARBs in camera, image and IPE subsys need to
	 * apply clamp and reset operations, others can be skipped.
	 */
	if (require_clamp) {
		ret = mtk_smi_larb_parse_reset(larb);
		if (ret)
			goto err_link_remove;
	}

pm_runtime_en:
	pm_runtime_enable(dev);
...
}

static int mtk_smi_common_probe(struct platform_device *pdev)
{
...
	if (common->plat->type == MTK_SMI_GEN2_SUB_COMM) {
		ret = mtk_smi_device_link_common(dev, &common-
>smi_common_dev, false);
		if (ret < 0)
			return ret;
	}
...
}

> > +     if (IS_ERR(larb->smi_comm_syscon)) {
> > +             ret = PTR_ERR(larb->smi_comm_syscon);
> > +             larb->smi_comm_syscon = NULL;
> > +             return dev_err_probe(dev, ret,
> > +                                  "Failed to get smi syscon for
> > larb %d\n", larbid);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int mtk_smi_larb_parse_reset(struct mtk_smi_larb *larb)
> > +{
> > +     struct device *dev = larb->dev;
> > +     int ret;
> > +
> > +     larb->rst_con = devm_reset_control_get_exclusive(dev,
> > "larb");
> > +     if (IS_ERR(larb->rst_con))
> > +             return dev_err_probe(dev, PTR_ERR(larb->rst_con),
> > +                                  "Failed to get reset
> > controller\n");
> 
> 
> This looks like ABI break. Aren't all devices affected?
> 

This does not affect other devices, we use this 'clamp_port' to
judge whether to apply clamp or not in 'mtk_smi_larb_probe', 
like below:
	if (larb->larb_gen->clamp_port && larb->larb_gen-
>clamp_port[larb->larbid])
		require_clamp = true;


static const struct mtk_smi_larb_gen mtk_smi_larb_mt8188 = {
	...
	.clamp_port                 = mtk_smi_larb_clamp_port_mt8188,
};

> > +     larb->nb.notifier_call = mtk_smi_genpd_callback;
> > +     ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
> > +     if (ret) {
> > +             larb->nb.notifier_call = NULL;
> > +             return dev_err_probe(dev, ret,
> > +                                  "Failed to add genpd
> > callback\n");
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> 
> Best regards,
> Krzysztof

Re: [PATCH v11 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang (杨阳)]

On Sat, 2025-10-18 at 18:42 +0200, Krzysztof Kozlowski wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On 17/09/2025 14:07, Friday Yang wrote:
> > Add 'resets' and 'reset-names' properties for SMI LARBs to support
> > SMI reset operations.
> 
> Not informative...
> 
> > diff --git a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > b/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > index 2e7fac4b5094..fc5feb2eac1f 100644
> > --- a/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > +++ b/Documentation/devicetree/bindings/memory-
> > controllers/mediatek,smi-larb.yaml
> > @@ -70,6 +70,12 @@ properties:
> >      description: the hardware id of this larb. It's only required
> > when this
> >        hardware id is not consecutive from its M4U point of view.
> > 
> > +  resets:
> > +    maxItems: 1
> > +
> > +  reset-names:
> > +    const: larb
> 
> Is the reset valid for all existing devices as well? Commit msg does
> not
> explain that... it is pretty useless - you say what you did. We see
> that
> from the diff. Explain something not obvious.
> 

Thanks, I could add more descriptions here, like below:

On the MediaTek MT8188 SoC, bus glitches may occur during MTCMOS
on/off transitions. To prevent these glitches from causing errors,
SMI requires clamp and reset operations. This issue specifically
affects the image, camera, and IPE subsystems. This change adds the
'resets' and 'reset-names' properties to the SMI LARBs within
these subsystems to support the necessary reset operations.
...

Can I still remain the 'Reviewed-by' and 'Acked-by' tags if I only
change the commit mesg in v12? I will not change the bindings.



> 
> 
> Best regards,
> Krzysztof

Re: [PATCH v11 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Krzysztof Kozlowski]

On 31/10/2025 07:10, Friday Yang (杨阳) wrote:
> On Sat, 2025-10-18 at 18:42 +0200, Krzysztof Kozlowski wrote:
>> External email : Please do not click links or open attachments until
>> you have verified the sender or the content.
>>
>>
>> On 17/09/2025 14:07, Friday Yang wrote:
>>> Add 'resets' and 'reset-names' properties for SMI LARBs to support
>>> SMI reset operations.
>>
>> Not informative...
>>
>>> diff --git a/Documentation/devicetree/bindings/memory-
>>> controllers/mediatek,smi-larb.yaml
>>> b/Documentation/devicetree/bindings/memory-
>>> controllers/mediatek,smi-larb.yaml
>>> index 2e7fac4b5094..fc5feb2eac1f 100644
>>> --- a/Documentation/devicetree/bindings/memory-
>>> controllers/mediatek,smi-larb.yaml
>>> +++ b/Documentation/devicetree/bindings/memory-
>>> controllers/mediatek,smi-larb.yaml
>>> @@ -70,6 +70,12 @@ properties:
>>>      description: the hardware id of this larb. It's only required
>>> when this
>>>        hardware id is not consecutive from its M4U point of view.
>>>
>>> +  resets:
>>> +    maxItems: 1
>>> +
>>> +  reset-names:
>>> +    const: larb
>>
>> Is the reset valid for all existing devices as well? Commit msg does
>> not
>> explain that... it is pretty useless - you say what you did. We see
>> that
>> from the diff. Explain something not obvious.
>>
> 
> Thanks, I could add more descriptions here, like below:
> 
> On the MediaTek MT8188 SoC, bus glitches may occur during MTCMOS
> on/off transitions. To prevent these glitches from causing errors,
> SMI requires clamp and reset operations. This issue specifically
> affects the image, camera, and IPE subsystems. 

This explains why you need it. But I asked more questions than only "whY".

Read the question:
"Is the reset valid for all existing devices as well?"
Where is the answer for that? I still do not know...

Do not reply to only pieces of review.

> This change adds the
> 'resets' and 'reset-names' properties to the SMI LARBs within
> these subsystems to support the necessary reset operations.

Read again my message:
" it is pretty useless - you say what you did"
That's the same, drop.

So again you just cared to implement only piece of review.

Best regards,
Krzysztof