[PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188

Friday Yang posted 2 patches 2 months ago
There is a newer version of this series
[PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188
Posted by Friday Yang 2 months ago
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 | 129 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)

diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
index 733e22f695ab..acc8904dd117 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 +608,45 @@ 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;
+
+	/* smi_comm_syscon may be NULL if the subsys doesn't have bus glitch issues */
+	if (!larb->smi_comm_syscon)
+		return -EINVAL;
+
+	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 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;
@@ -638,6 +703,51 @@ 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 || !larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
+		return 0;
+
+	larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
+	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node,
+								"mediatek,smi");
+	if (IS_ERR(larb->smi_comm_syscon)) {
+		larb->smi_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_optional_exclusive(dev, "larb");
+	if (!larb->rst_con)
+		return 0;
+
+	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;
@@ -648,6 +758,7 @@ 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 +775,14 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 	if (ret < 0)
 		return ret;
 
+	ret = mtk_smi_larb_parse_clamp_optional(larb);
+	if (ret)
+		goto err_link_remove;
+
+	ret = mtk_smi_larb_parse_reset_optional(larb);
+	if (ret)
+		goto err_link_remove;
+
 	pm_runtime_enable(dev);
 	platform_set_drvdata(pdev, larb);
 	ret = component_add(dev, &mtk_smi_larb_component_ops);
@@ -673,6 +792,7 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
 
 err_pm_disable:
 	pm_runtime_disable(dev);
+err_link_remove:
 	device_link_remove(dev, larb->smi_common_dev);
 	return ret;
 }
@@ -681,6 +801,9 @@ 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 +926,11 @@ 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 +975,7 @@ 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 v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188
Posted by Philipp Zabel 1 month, 3 weeks ago
On Mi, 2025-08-06 at 16:59 +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 | 129 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 129 insertions(+)
> 
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index 733e22f695ab..acc8904dd117 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 +608,45 @@ 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;
> +
> +	/* smi_comm_syscon may be NULL if the subsys doesn't have bus glitch issues */
> +	if (!larb->smi_comm_syscon)
> +		return -EINVAL;
> +
> +	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 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;
> @@ -638,6 +703,51 @@ 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 || !larb_gen->clamp_port || !larb_gen->clamp_port[larb_id])
> +		return 0;
> +
> +	larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
> +	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev->of_node,
> +								"mediatek,smi");
> +	if (IS_ERR(larb->smi_comm_syscon)) {
> +		larb->smi_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_optional_exclusive(dev, "larb");
> +	if (!larb->rst_con)
> +		return 0;

Please don't ignore errors.

regards
Philipp
Re: [PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188
Posted by Friday Yang (杨阳) 2 weeks, 5 days ago
On Tue, 2025-08-12 at 13:52 +0200, Philipp Zabel wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> On Mi, 2025-08-06 at 16:59 +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 | 129
> > +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 129 insertions(+)
> > 
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index 733e22f695ab..acc8904dd117 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 +608,45 @@ 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;
> > +
> > +     /* smi_comm_syscon may be NULL if the subsys doesn't have bus
> > glitch issues */
> > +     if (!larb->smi_comm_syscon)
> > +             return -EINVAL;
> > +
> > +     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 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;
> > @@ -638,6 +703,51 @@ 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 || !larb_gen->clamp_port || !larb_gen-
> > >clamp_port[larb_id])
> > +             return 0;
> > +
> > +     larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
> > +     larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> > >of_node,
> > +                                                             "medi
> > atek,smi");
> > +     if (IS_ERR(larb->smi_comm_syscon)) {
> > +             larb->smi_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_optional_exclusive(dev, "larb");
> > +     if (!larb->rst_con)
> > +             return 0;
> 
> Please don't ignore errors.
> 
> regards
> Philipp

Thanks for comments.
As described before, we need to return the error in
'mtk_smi_larb_parse_reset' when it fails to get reset controller,
because it is not optional now. What's more,
'devm_reset_control_get_optional_exclusive' should be replaced with
'devm_reset_control_get_exclusive' in this case.
Re: [PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188
Posted by Yong Wu (吴勇) 1 month, 3 weeks ago
On Wed, 2025-08-06 at 16:59 +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 | 129
> +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 129 insertions(+)
> 
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index 733e22f695ab..acc8904dd117 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 +608,45 @@ 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;
> +
> +	/* smi_comm_syscon may be NULL if the subsys doesn't have bus
> glitch issues */
> +	if (!larb->smi_comm_syscon)
> +		return -EINVAL;
> +
> +	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 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;
> @@ -638,6 +703,51 @@ 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 || !larb_gen->clamp_port || !larb_gen-
> >clamp_port[larb_id])
> +		return 0;
> +
> +	larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
> +	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> >of_node,
> +								"mediat
> ek,smi");
> +	if (IS_ERR(larb->smi_comm_syscon)) {
> +		larb->smi_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_optional_exclusive(dev,
> "larb");
> +	if (!larb->rst_con)
> +		return 0;
> +
> +	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;
> @@ -648,6 +758,7 @@ 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 +775,14 @@ static int mtk_smi_larb_probe(struct
> platform_device *pdev)
>  	if (ret < 0)
>  		return ret;
>  
> +	ret = mtk_smi_larb_parse_clamp_optional(larb);
> +	if (ret)
> +		goto err_link_remove;
> +
> +	ret = mtk_smi_larb_parse_reset_optional(larb);
> +	if (ret)
> +		goto err_link_remove;


If we have "larb_gen->clamp_port[larb_id]", we must have the reset
function, is this right? if yes,

if (larb->smi_comm_syscon && larb_gen->clamp_port[larb_id]) {
   ret = mtk_smi_larb_parse_reset(larb);  // Not optional.
}

and then we could remove the checking of larb->smi_comm_syscon in 
mtk_smi_larb_clamp_protect_enable, it will be simpler.

Thanks.

> +
>  	pm_runtime_enable(dev);
>  	platform_set_drvdata(pdev, larb);
>  	ret = component_add(dev, &mtk_smi_larb_component_ops);
> @@ -673,6 +792,7 @@ static int mtk_smi_larb_probe(struct
> platform_device *pdev)
>  
>  err_pm_disable:
>  	pm_runtime_disable(dev);
> +err_link_remove:
>  	device_link_remove(dev, larb->smi_common_dev);
>  	return ret;
>  }
> @@ -681,6 +801,9 @@ 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 +926,11 @@ 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 +975,7 @@ 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},
Re: [PATCH v10 2/2] memory: mtk-smi: mt8188: Add SMI reset and clamp for MT8188
Posted by Friday Yang (杨阳) 2 weeks, 5 days ago
On Tue, 2025-08-12 at 11:43 +0000, Yong Wu (吴勇) wrote:
> On Wed, 2025-08-06 at 16:59 +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 | 129
> > +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 129 insertions(+)
> > 
> > diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> > index 733e22f695ab..acc8904dd117 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 +608,45 @@ 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;
> > +
> > +	/* smi_comm_syscon may be NULL if the subsys doesn't have bus
> > glitch issues */
> > +	if (!larb->smi_comm_syscon)
> > +		return -EINVAL;
> > +
> > +	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 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;
> > @@ -638,6 +703,51 @@ 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 || !larb_gen->clamp_port || !larb_gen-
> > > clamp_port[larb_id])
> > 
> > +		return 0;
> > +
> > +	larb->smi_comm_in_port_id = larb_gen->clamp_port[larb_id];
> > +	larb->smi_comm_syscon = syscon_regmap_lookup_by_phandle(dev-
> > > of_node,
> > 
> > +								"mediat
> > ek,smi");
> > +	if (IS_ERR(larb->smi_comm_syscon)) {
> > +		larb->smi_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_optional_exclusive(dev,
> > "larb");
> > +	if (!larb->rst_con)
> > +		return 0;
> > +
> > +	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;
> > @@ -648,6 +758,7 @@ 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 +775,14 @@ static int mtk_smi_larb_probe(struct
> > platform_device *pdev)
> >  	if (ret < 0)
> >  		return ret;
> >  
> > +	ret = mtk_smi_larb_parse_clamp_optional(larb);
> > +	if (ret)
> > +		goto err_link_remove;
> > +
> > +	ret = mtk_smi_larb_parse_reset_optional(larb);
> > +	if (ret)
> > +		goto err_link_remove;
> 
> 
> If we have "larb_gen->clamp_port[larb_id]", we must have the reset
> function, is this right? if yes,
> 
> if (larb->smi_comm_syscon && larb_gen->clamp_port[larb_id]) {
>    ret = mtk_smi_larb_parse_reset(larb);  // Not optional.
> }
> 
> and then we could remove the checking of larb->smi_comm_syscon in 
> mtk_smi_larb_clamp_protect_enable, it will be simpler.
> 
> Thanks.
> 

Thanks for comments.
You are right. We can fix it like this. Just determine whether
clamp and reset are required in 'mtk_smi_larb_probe'. If we
have "larb_gen->clamp_port[larb_id]", then clamp and reset operations
are required. And the '_optional' suffix should be removed from the
function name in this case.

in mtk_smi_larb_probe:
...
if (larb->larb_gen->clamp_port && larb->larb_gen->clamp_port[larb-
>larbid]) {
		ret = mtk_smi_larb_parse_clamp(larb, larb->larbid);
		if (ret)
			goto err_link_remove;

		ret = mtk_smi_larb_parse_reset(larb);
		if (ret)
			goto err_link_remove;
	}
...