[PATCH v3 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[PATCH v3 0/2] Add SMI reset and clamp for MediaTek MT8188 SoC

[Friday Yang]

Based on tag: next-20250120, linux-next/master

When we enable/disable power domain, the SMI LARBs linked to this power
domain could be affected by the bus glitch. To avoid this issue, SMI
need to apply clamp and reset opereations.

This patch mainly add these functions:
1) Register genpd callback for SMI LARBs and handle this power domain
   status change in SMI driver.
2) Add bindings to support SMI Sub Common for MT8188.
3) Add bindings to support SMI larbs reset opearation.

Changes 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'

v2:
https://lore.kernel.org/lkml/20241120063701.8194-2-friday.yang@mediatek.com/
https://lore.kernel.org/lkml/20241120063701.8194-3-friday.yang@mediatek.com/

friday.yang (2):
  dt-bindings: memory: mediatek: Add support for SMI reset and clamp
  memory: mtk-smi: mt8188: Add support for SMI reset and clamp

 .../mediatek,smi-common.yaml                  |   2 +
 .../memory-controllers/mediatek,smi-larb.yaml |  20 +++
 drivers/memory/mtk-smi.c                      | 141 +++++++++++++++++-
 3 files changed, 159 insertions(+), 4 deletions(-)

--
2.46.0

[PATCH v3 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang]

From: "friday.yang" <friday.yang@mediatek.com>

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>
---
 .../mediatek,smi-common.yaml                  |  2 ++
 .../memory-controllers/mediatek,smi-larb.yaml | 20 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
index 2f36ac23604c..4392d349878c 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
@@ -39,6 +39,7 @@ 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
@@ -107,6 +108,7 @@ 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 2381660b324c..2e86bb3455f9 100644
--- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-larb.yaml
@@ -69,6 +69,12 @@ 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
@@ -125,6 +131,20 @@ allOf:
       required:
         - mediatek,larb-id

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

 examples:
--
2.46.0

Re: [PATCH v3 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Krzysztof Kozlowski]

On Tue, Jan 21, 2025 at 02:49:26PM +0800, Friday Yang wrote:
> From: "friday.yang" <friday.yang@mediatek.com>
> 
> 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>

SoB/From mismatch.

Please run scripts/checkpatch.pl and fix reported warnings. After that,
run also 'scripts/checkpatch.pl --strict' and (probably) fix more
warnings. Some warnings can be ignored, especially from --strict run,
but the code here looks like it needs a fix. Feel free to get in touch
if the warning is not clear.

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: memory: mediatek: Add SMI reset and clamp for MT8188

[Friday Yang (杨阳)]

On Tue, 2025-01-21 at 11:14 +0100, Krzysztof Kozlowski wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On Tue, Jan 21, 2025 at 02:49:26PM +0800, Friday Yang wrote:
> > From: "friday.yang" <friday.yang@mediatek.com>
> > 
> > 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>
> 
> SoB/From mismatch.
> 
> Please run scripts/checkpatch.pl and fix reported warnings. After
> that,
> run also 'scripts/checkpatch.pl --strict' and (probably) fix more
> warnings. Some warnings can be ignored, especially from --strict run,
> but the code here looks like it needs a fix. Feel free to get in
> touch
> if the warning is not clear.
> 

Thanks for kindly remind, I will fix the signed name mismatch error and
check the patch again.

> Best regards,
> Krzysztof
> 

[PATCH v3 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Friday Yang]

From: "friday.yang" <friday.yang@mediatek.com>

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 | 141 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 137 insertions(+), 4 deletions(-)

diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
index 5710348f72f6..aaeb80379ec1 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>
@@ -36,6 +40,12 @@
 #define SMI_DCM				0x300
 #define SMI_DUMMY			0x444

+#define SMI_COMMON_CLAMP_EN		0x3c0
+#define SMI_COMMON_CLAMP_EN_SET		0x3c4
+#define SMI_COMMON_CLAMP_EN_CLR		0x3c8
+
+#define SMI_SUB_COMM_INPORT_NR		(8)
+
 /* SMI LARB */
 #define SMI_LARB_SLP_CON                0xc
 #define SLP_PROT_EN                     BIT(0)
@@ -134,6 +144,7 @@ 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 +161,7 @@ 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 +169,10 @@ struct mtk_smi_larb { /* larb: local arbiter */
 	int				larbid;
 	u32				*mmu;
 	unsigned char			*bank;
+	struct regmap			*sub_comm_syscon;
+	u8				sub_comm_inport;
+	struct notifier_block		nb;
+	struct reset_control		*rst_con;
 };

 static int
@@ -377,6 +393,19 @@ 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,
@@ -423,6 +452,7 @@ 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 = {
@@ -472,6 +502,46 @@ 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;
+
+	/* sub_comm_syscon could be NULL if larb directly linked to SMI common */
+	if (!larb->sub_comm_syscon)
+		return -EINVAL;
+
+	reg = enable ? SMI_COMMON_CLAMP_EN_SET : SMI_COMMON_CLAMP_EN_CLR;
+
+	ret = regmap_write(larb->sub_comm_syscon, reg,
+			   larb->sub_comm_inport);
+	if (ret)
+		dev_err(dev, "Unable to %s clamp for input port %d: %d\n",
+			enable ? "enable" : "disable",
+			larb->sub_comm_inport, ret);
+
+	return ret;
+}
+
+static int mtk_smi_genpd_callback(struct notifier_block *nb,
+				  unsigned long flags, void *data)
+{
+	struct mtk_smi_larb *larb = container_of(nb, struct mtk_smi_larb, nb);
+	struct device *dev = larb->dev;
+
+	if (flags == GENPD_NOTIFY_PRE_ON || flags == GENPD_NOTIFY_PRE_OFF) {
+		/* disable related SMI sub-common port */
+		mtk_smi_larb_clamp_protect_enable(dev, true);
+	} else if (flags == GENPD_NOTIFY_ON) {
+		/* enable related SMI sub-common port */
+		reset_control_reset(larb->rst_con);
+		mtk_smi_larb_clamp_protect_enable(dev, false);
+	}
+
+	return NOTIFY_OK;
+}
+
 static int mtk_smi_device_link_common(struct device *dev, struct device **com_dev)
 {
 	struct platform_device *smi_com_pdev;
@@ -528,6 +598,53 @@ static int mtk_smi_dts_clk_init(struct device *dev, struct mtk_smi *smi,
 	return ret;
 }

+static int mtk_smi_larb_parse_clamp_optional(struct mtk_smi_larb *larb)
+{
+	struct device *dev = larb->dev;
+	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
+	u32 larb_id;
+	int ret;
+
+	/**
+	 * Only SMI LARBs in camera, image and IPE subsys need to
+	 * apply clamp and reset operations, others can be skipped.
+	 */
+	ret = of_property_read_u32(dev->of_node, "mediatek,larb-id", &larb_id);
+	if (ret)
+		return -EINVAL;
+	if (!larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
+		return 0;
+
+	larb->sub_comm_inport = larb_gen->clamp_port[larb_id];
+	larb->sub_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "mediatek,smi");
+	if (IS_ERR(larb->sub_comm_syscon)) {
+		larb->sub_comm_syscon = NULL;
+		return dev_err_probe(dev, -EINVAL,
+				     "Unknown clamp port for larb %d\n", larb_id);
+	}
+
+	return 0;
+}
+
+static int mtk_smi_larb_parse_reset_optional(struct mtk_smi_larb *larb)
+{
+	struct device *dev = larb->dev;
+	int ret;
+
+	larb->rst_con = devm_reset_control_get(dev, "larb");
+	if (IS_ERR(larb->rst_con))
+		return dev_err_probe(dev, PTR_ERR(larb->rst_con),
+				     "Failed to get larb reset controller\n");
+
+	larb->nb.notifier_call = mtk_smi_genpd_callback;
+	ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
+	if (ret)
+		return dev_err_probe(dev, -EINVAL,
+				     "Failed to add genpd callback %d\n", ret);
+
+	return 0;
+}
+
 static int mtk_smi_larb_probe(struct platform_device *pdev)
 {
 	struct mtk_smi_larb *larb;
@@ -538,6 +655,7 @@ 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))
@@ -554,15 +672,24 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;

-	pm_runtime_enable(dev);
+	ret = mtk_smi_larb_parse_clamp_optional(larb);
+	if (ret)
+		goto err_link_remove;
+
+	ret = mtk_smi_larb_parse_reset_optional(larb);
+	if (ret && ret != -ENOENT)
+		goto err_link_remove;
+
 	platform_set_drvdata(pdev, larb);
 	ret = component_add(dev, &mtk_smi_larb_component_ops);
 	if (ret)
-		goto err_pm_disable;
+		goto err_link_remove;
+
+	pm_runtime_enable(dev);
+
 	return 0;

-err_pm_disable:
-	pm_runtime_disable(dev);
+err_link_remove:
 	device_link_remove(dev, larb->smi_common_dev);
 	return ret;
 }
@@ -686,6 +813,11 @@ 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,
@@ -729,6 +861,7 @@ 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 v3 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Philipp Zabel]

On Di, 2025-01-21 at 14:49 +0800, Friday Yang wrote:
> From: "friday.yang" <friday.yang@mediatek.com>
> 
> 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 | 141 +++++++++++++++++++++++++++++++++++++--
>  1 file changed, 137 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index 5710348f72f6..aaeb80379ec1 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
[...]
> @@ -528,6 +598,53 @@ static int mtk_smi_dts_clk_init(struct device *dev, struct mtk_smi *smi,
>  	return ret;
>  }
> 
> +static int mtk_smi_larb_parse_clamp_optional(struct mtk_smi_larb *larb)
> +{
> +	struct device *dev = larb->dev;
> +	const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> +	u32 larb_id;
> +	int ret;
> +
> +	/**
> +	 * Only SMI LARBs in camera, image and IPE subsys need to
> +	 * apply clamp and reset operations, others can be skipped.
> +	 */
> +	ret = of_property_read_u32(dev->of_node, "mediatek,larb-id", &larb_id);
> +	if (ret)
> +		return -EINVAL;
> +	if (!larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
> +		return 0;
> +
> +	larb->sub_comm_inport = larb_gen->clamp_port[larb_id];
> +	larb->sub_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node, "mediatek,smi");
> +	if (IS_ERR(larb->sub_comm_syscon)) {
> +		larb->sub_comm_syscon = NULL;
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Unknown clamp port for larb %d\n", larb_id);
> +	}
> +
> +	return 0;
> +}
> +
> +static int mtk_smi_larb_parse_reset_optional(struct mtk_smi_larb *larb)
> +{
> +	struct device *dev = larb->dev;
> +	int ret;
> +
> +	larb->rst_con = devm_reset_control_get(dev, "larb");

Please use devm_reset_control_get_exclusive() directly.
Or use devm_reset_control_get_optional_exclusive(), which returns NULL
instead of -ENOENT. That way you can ...

> +	if (IS_ERR(larb->rst_con))
> +		return dev_err_probe(dev, PTR_ERR(larb->rst_con),
> +				     "Failed to get larb reset controller\n");

... suppress this error message in case of -ENOENT and return with:

	if (!larb->rst_con)
		return 0;

here.

> +
> +	larb->nb.notifier_call = mtk_smi_genpd_callback;
> +	ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
> +	if (ret)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Failed to add genpd callback %d\n", ret);
> +
> +	return 0;
> +}
> +
>  static int mtk_smi_larb_probe(struct platform_device *pdev)
>  {
>  	struct mtk_smi_larb *larb;
> @@ -538,6 +655,7 @@ 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))
> @@ -554,15 +672,24 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		return ret;
> 
> -	pm_runtime_enable(dev);
> +	ret = mtk_smi_larb_parse_clamp_optional(larb);
> +	if (ret)
> +		goto err_link_remove;
> +
> +	ret = mtk_smi_larb_parse_reset_optional(larb);
> +	if (ret && ret != -ENOENT)

The ret != -ENOENT check could be dropped if you use
devm_reset_control_get_optional_exclusive() above.


regards
Philipp

Re: [PATCH v3 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

[Friday Yang (杨阳)]

On Tue, 2025-01-21 at 09:53 +0100, Philipp Zabel wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On Di, 2025-01-21 at 14:49 +0800, Friday Yang wrote:
> > From: "friday.yang" <friday.yang@mediatek.com>
> > 
> > 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 | 141
> > +++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 137 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index 5710348f72f6..aaeb80379ec1 100644
> > --- a/drivers/memory/mtk-smi.c
> > +++ b/drivers/memory/mtk-smi.c
> 
> [...]
> > @@ -528,6 +598,53 @@ static int mtk_smi_dts_clk_init(struct device
> > *dev, struct mtk_smi *smi,
> >       return ret;
> >  }
> > 
> > +static int mtk_smi_larb_parse_clamp_optional(struct mtk_smi_larb
> > *larb)
> > +{
> > +     struct device *dev = larb->dev;
> > +     const struct mtk_smi_larb_gen *larb_gen = larb->larb_gen;
> > +     u32 larb_id;
> > +     int ret;
> > +
> > +     /**
> > +      * Only SMI LARBs in camera, image and IPE subsys need to
> > +      * apply clamp and reset operations, others can be skipped.
> > +      */
> > +     ret = of_property_read_u32(dev->of_node, "mediatek,larb-id",
> > &larb_id);
> > +     if (ret)
> > +             return -EINVAL;
> > +     if (!larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
> > +             return 0;
> > +
> > +     larb->sub_comm_inport = larb_gen->clamp_port[larb_id];
> > +     larb->sub_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> > >of_node, "mediatek,smi");
> > +     if (IS_ERR(larb->sub_comm_syscon)) {
> > +             larb->sub_comm_syscon = NULL;
> > +             return dev_err_probe(dev, -EINVAL,
> > +                                  "Unknown clamp port for larb
> > %d\n", larb_id);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int mtk_smi_larb_parse_reset_optional(struct mtk_smi_larb
> > *larb)
> > +{
> > +     struct device *dev = larb->dev;
> > +     int ret;
> > +
> > +     larb->rst_con = devm_reset_control_get(dev, "larb");
> 
> Please use devm_reset_control_get_exclusive() directly.
> Or use devm_reset_control_get_optional_exclusive(), which returns
> NULL
> instead of -ENOENT. That way you can ...

Thanks for your comment, I will fix it in this way.

> 
> > +     if (IS_ERR(larb->rst_con))
> > +             return dev_err_probe(dev, PTR_ERR(larb->rst_con),
> > +                                  "Failed to get larb reset
> > controller\n");
> 
> ... suppress this error message in case of -ENOENT and return with:
> 
>         if (!larb->rst_con)
>                 return 0;
> 
> here.
> 
> > +
> > +     larb->nb.notifier_call = mtk_smi_genpd_callback;
> > +     ret = dev_pm_genpd_add_notifier(dev, &larb->nb);
> > +     if (ret)
> > +             return dev_err_probe(dev, -EINVAL,
> > +                                  "Failed to add genpd callback
> > %d\n", ret);
> > +
> > +     return 0;
> > +}
> > +
> >  static int mtk_smi_larb_probe(struct platform_device *pdev)
> >  {
> >       struct mtk_smi_larb *larb;
> > @@ -538,6 +655,7 @@ 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))
> > @@ -554,15 +672,24 @@ static int mtk_smi_larb_probe(struct
> > platform_device *pdev)
> >       if (ret < 0)
> >               return ret;
> > 
> > -     pm_runtime_enable(dev);
> > +     ret = mtk_smi_larb_parse_clamp_optional(larb);
> > +     if (ret)
> > +             goto err_link_remove;
> > +
> > +     ret = mtk_smi_larb_parse_reset_optional(larb);
> > +     if (ret && ret != -ENOENT)
> 
> The ret != -ENOENT check could be dropped if you use
> devm_reset_control_get_optional_exclusive() above.
> 

OK, I will fix it.

> 
> regards
> Philipp