diff mbox series

[v3,1/4] firmware: scmi: voltage regulator

Message ID 20210222072747.7514-1-etienne.carriere@linaro.org
State New
Delegated to: Tom Rini
Headers show
Series [v3,1/4] firmware: scmi: voltage regulator | expand

Commit Message

Etienne Carriere Feb. 22, 2021, 7:27 a.m. UTC
Implement voltage regulators interfaced by the SCMI voltage domain
protocol. The DT bindings are defined in the Linux kernel since
SCMI voltage domain and regulators patches [1] and [2] integration
in v5.11-rc7.

Link: [1] https://github.com/torvalds/linux/commit/0f80fcec08e9c50b8d2992cf26495673765ebaba
Link: [2] https://github.com/torvalds/linux/commit/2add5cacff3531e54c50b0832128299faa9f0563
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
---
Changes in v3:
- applied review tags

Changes in v2:
- no change
---
 doc/device-tree-bindings/arm/arm,scmi.txt |  34 +++++
 drivers/firmware/scmi/scmi_agent-uclass.c |  35 ++++-
 drivers/power/regulator/Kconfig           |   8 +
 drivers/power/regulator/Makefile          |   1 +
 drivers/power/regulator/scmi_regulator.c  | 170 ++++++++++++++++++++++
 include/scmi_protocols.h                  | 113 ++++++++++++++
 6 files changed, 359 insertions(+), 2 deletions(-)
 create mode 100644 drivers/power/regulator/scmi_regulator.c

Comments

Patrick Delaunay March 3, 2021, 10:09 a.m. UTC | #1
Hi Etienne,

On 2/22/21 8:27 AM, Etienne Carriere wrote:
> Implement voltage regulators interfaced by the SCMI voltage domain
> protocol. The DT bindings are defined in the Linux kernel since
> SCMI voltage domain and regulators patches [1] and [2] integration
> in v5.11-rc7.
>
> Link: [1] https://github.com/torvalds/linux/commit/0f80fcec08e9c50b8d2992cf26495673765ebaba
> Link: [2] https://github.com/torvalds/linux/commit/2add5cacff3531e54c50b0832128299faa9f0563
> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
> ---
> Changes in v3:
> - applied review tags
>
> Changes in v2:
> - no change
> ---
>   doc/device-tree-bindings/arm/arm,scmi.txt |  34 +++++
>   drivers/firmware/scmi/scmi_agent-uclass.c |  35 ++++-
>   drivers/power/regulator/Kconfig           |   8 +
>   drivers/power/regulator/Makefile          |   1 +
>   drivers/power/regulator/scmi_regulator.c  | 170 ++++++++++++++++++++++
>   include/scmi_protocols.h                  | 113 ++++++++++++++
>   6 files changed, 359 insertions(+), 2 deletions(-)
>   create mode 100644 drivers/power/regulator/scmi_regulator.c
>
> diff --git a/doc/device-tree-bindings/arm/arm,scmi.txt b/doc/device-tree-bindings/arm/arm,scmi.txt
> index 1f293ea24..a76124f4a 100644
> --- a/doc/device-tree-bindings/arm/arm,scmi.txt
> +++ b/doc/device-tree-bindings/arm/arm,scmi.txt
> @@ -62,6 +62,20 @@ Required properties:
>    - #power-domain-cells : Should be 1. Contains the device or the power
>   			 domain ID value used by SCMI commands.
>   
> +Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
> +------------------------------------------------------------
> +An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
> +and should be always positioned as a root regulator.
> +It does not support any current operation.
> +
> +SCMI Regulators are grouped under a 'regulators' node which in turn is a child
> +of the SCMI Voltage protocol node inside the desired SCMI instance node.
> +
> +This binding uses the common regulator binding[6].
> +
> +Required properties:
> + - reg : shall identify an existent SCMI Voltage Domain.
> +
>   Sensor bindings for the sensors based on SCMI Message Protocol
>   --------------------------------------------------------------
>   SCMI provides an API to access the various sensors on the SoC.
> @@ -105,6 +119,7 @@ Required sub-node properties:
>   [3] Documentation/devicetree/bindings/thermal/thermal.txt
>   [4] Documentation/devicetree/bindings/sram/sram.yaml
>   [5] Documentation/devicetree/bindings/reset/reset.txt
> +[6] Documentation/devicetree/bindings/regulator/regulator.yaml
>   
>   Example:
>   
> @@ -169,6 +184,25 @@ firmware {
>   			reg = <0x16>;
>   			#reset-cells = <1>;
>   		};
> +
> +		scmi_voltage: protocol@17 {
> +			reg = <0x17>;
> +
> +			regulators {
> +				regulator_devX: regulator@0 {
> +					reg = <0x0>;
> +					regulator-max-microvolt = <3300000>;
> +				};
> +
> +				regulator_devY: regulator@9 {
> +					reg = <0x9>;
> +					regulator-min-microvolt = <500000>;
> +					regulator-max-microvolt = <4200000>;
> +				};
> +
> +				...
> +			};
> +		};
>   	};
>   };
>   
> diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
> index 516e690ac..03d236426 100644
> --- a/drivers/firmware/scmi/scmi_agent-uclass.c
> +++ b/drivers/firmware/scmi/scmi_agent-uclass.c
> @@ -50,6 +50,29 @@ int scmi_to_linux_errno(s32 scmi_code)
>   	return -EPROTO;
>   }
>   
> +static int regulator_devices_bind(struct udevice *dev, struct driver *drv,
> +				  ofnode protocol_node)
> +{
> +	ofnode regulators_node;
> +	ofnode node;
> +	int ret;
> +
> +	regulators_node = ofnode_find_subnode(protocol_node, "regulators");
> +	if (!ofnode_valid(regulators_node)) {
> +		dev_err(dev, "regulators subnode not found\n");
> +		return -ENXIO;
> +	}
> +
> +	ofnode_for_each_subnode(node, regulators_node) {
> +		ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
> +				  NULL);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +

This parsing function can be moved in

drivers/power/regulator/scmi_regulator.c

By adding the intermediate NOP uclass, binded with "protocol@17" node

for example


U_BOOT_DRIVER(scmi_regulator) = {
     .name = "scmi_regulator",
     .id = UCLASS_REGULATOR,
     .ops = &scmi_voltd_ops,
     .probe = scmi_regulator_probe,
     .ofdata_to_platdata = scmi_regulator_ofdata_to_platdata,
     .platdata_auto_alloc_size = sizeof(struct scmi_regulator_platdata),
};

static int scmi_regulator_bind(struct udevice *dev)
{
     struct driver *drv;
     ofnode node, subnode;
     int ret;

     node = dev_read_subnode(dev, "regulators");
     if (!ofnode_valid(node)) {
         dev_err(dev, "regulators subnode not found\n");
         return -ENXIO;
     }

     drv = DM_GET_DRIVER(scmi_regulator);
     ofnode_for_each_subnode(subnode, node) {
         ret = device_bind_ofnode(dev, drv, ofnode_get_name(subnode),
                      NULL, subnode, NULL);
         if (ret)
             return ret;
     }

     return 0;
}

U_BOOT_DRIVER(scmi_voltage_domain) = {
     .name = "scmi_voltage_domain",
     .id = UCLASS_NOP,
     .bind = scmi_regulator_bind,
};


I think it is more elegant and more alligned with existing behavior

for SCMI clock and SCMI reset.


warning:

in this case the tree of U-Boot class change, SCMI agent become the 
grand-father

of each regulator and  all the call "devm_scmi_process_msg(dev->parent, 
&msg);"

should be replaced by "devm_scmi_process_msg(dev->parent->parent, &msg);"

>   /*
>    * SCMI agent devices binds devices of various uclasses depeding on
>    * the FDT description. scmi_bind_protocol() is a generic bind sequence
> @@ -79,6 +102,10 @@ static int scmi_bind_protocols(struct udevice *dev)
>   			if (IS_ENABLED(CONFIG_RESET_SCMI))
>   				drv = DM_DRIVER_GET(scmi_reset_domain);
>   			break;
> +		case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
> +			if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI))
> +				drv = DM_DRIVER_GET(scmi_voltage_domain);
> +			break;
>   		default:
>   			break;
>   		}
> @@ -89,8 +116,12 @@ static int scmi_bind_protocols(struct udevice *dev)
>   			continue;
>   		}
>   
> -		ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
> -				  NULL);
> +		if (protocol_id == SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN)
> +			ret = regulator_devices_bind(dev, drv, node);
> +		else
> +			ret = device_bind(dev, drv, ofnode_get_name(node),
> +					  NULL, node, NULL);
> +
>   		if (ret)
>   			break;
>   	}

(...)

Regards

Patrick
Etienne Carriere March 4, 2021, 11:37 p.m. UTC | #2
Hello Patrick,

On Wed, 3 Mar 2021 at 11:09, Patrick DELAUNAY
<patrick.delaunay@foss.st.com> wrote:
>
> Hi Etienne,
>
> On 2/22/21 8:27 AM, Etienne Carriere wrote:
> > Implement voltage regulators interfaced by the SCMI voltage domain
> > protocol. The DT bindings are defined in the Linux kernel since
> > SCMI voltage domain and regulators patches [1] and [2] integration
> > in v5.11-rc7.
> >
> > Link: [1] https://github.com/torvalds/linux/commit/0f80fcec08e9c50b8d2992cf26495673765ebaba
> > Link: [2] https://github.com/torvalds/linux/commit/2add5cacff3531e54c50b0832128299faa9f0563
> > Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> > Reviewed-by: Simon Glass <sjg@chromium.org>
> > Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
> > ---
> > Changes in v3:
> > - applied review tags
> >
> > Changes in v2:
> > - no change
> > ---
> >   doc/device-tree-bindings/arm/arm,scmi.txt |  34 +++++
> >   drivers/firmware/scmi/scmi_agent-uclass.c |  35 ++++-
> >   drivers/power/regulator/Kconfig           |   8 +
> >   drivers/power/regulator/Makefile          |   1 +
> >   drivers/power/regulator/scmi_regulator.c  | 170 ++++++++++++++++++++++
> >   include/scmi_protocols.h                  | 113 ++++++++++++++
> >   6 files changed, 359 insertions(+), 2 deletions(-)
> >   create mode 100644 drivers/power/regulator/scmi_regulator.c
> >
> > diff --git a/doc/device-tree-bindings/arm/arm,scmi.txt b/doc/device-tree-bindings/arm/arm,scmi.txt
> > index 1f293ea24..a76124f4a 100644
> > --- a/doc/device-tree-bindings/arm/arm,scmi.txt
> > +++ b/doc/device-tree-bindings/arm/arm,scmi.txt
> > @@ -62,6 +62,20 @@ Required properties:
> >    - #power-domain-cells : Should be 1. Contains the device or the power
> >                        domain ID value used by SCMI commands.
> >
> > +Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
> > +------------------------------------------------------------
> > +An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
> > +and should be always positioned as a root regulator.
> > +It does not support any current operation.
> > +
> > +SCMI Regulators are grouped under a 'regulators' node which in turn is a child
> > +of the SCMI Voltage protocol node inside the desired SCMI instance node.
> > +
> > +This binding uses the common regulator binding[6].
> > +
> > +Required properties:
> > + - reg : shall identify an existent SCMI Voltage Domain.
> > +
> >   Sensor bindings for the sensors based on SCMI Message Protocol
> >   --------------------------------------------------------------
> >   SCMI provides an API to access the various sensors on the SoC.
> > @@ -105,6 +119,7 @@ Required sub-node properties:
> >   [3] Documentation/devicetree/bindings/thermal/thermal.txt
> >   [4] Documentation/devicetree/bindings/sram/sram.yaml
> >   [5] Documentation/devicetree/bindings/reset/reset.txt
> > +[6] Documentation/devicetree/bindings/regulator/regulator.yaml
> >
> >   Example:
> >
> > @@ -169,6 +184,25 @@ firmware {
> >                       reg = <0x16>;
> >                       #reset-cells = <1>;
> >               };
> > +
> > +             scmi_voltage: protocol@17 {
> > +                     reg = <0x17>;
> > +
> > +                     regulators {
> > +                             regulator_devX: regulator@0 {
> > +                                     reg = <0x0>;
> > +                                     regulator-max-microvolt = <3300000>;
> > +                             };
> > +
> > +                             regulator_devY: regulator@9 {
> > +                                     reg = <0x9>;
> > +                                     regulator-min-microvolt = <500000>;
> > +                                     regulator-max-microvolt = <4200000>;
> > +                             };
> > +
> > +                             ...
> > +                     };
> > +             };
> >       };
> >   };
> >
> > diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
> > index 516e690ac..03d236426 100644
> > --- a/drivers/firmware/scmi/scmi_agent-uclass.c
> > +++ b/drivers/firmware/scmi/scmi_agent-uclass.c
> > @@ -50,6 +50,29 @@ int scmi_to_linux_errno(s32 scmi_code)
> >       return -EPROTO;
> >   }
> >
> > +static int regulator_devices_bind(struct udevice *dev, struct driver *drv,
> > +                               ofnode protocol_node)
> > +{
> > +     ofnode regulators_node;
> > +     ofnode node;
> > +     int ret;
> > +
> > +     regulators_node = ofnode_find_subnode(protocol_node, "regulators");
> > +     if (!ofnode_valid(regulators_node)) {
> > +             dev_err(dev, "regulators subnode not found\n");
> > +             return -ENXIO;
> > +     }
> > +
> > +     ofnode_for_each_subnode(node, regulators_node) {
> > +             ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
> > +                               NULL);
> > +             if (ret)
> > +                     return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
>
> This parsing function can be moved in
>
> drivers/power/regulator/scmi_regulator.c

That is a good idea.
I didn't want to export a function from regu/scmi-regu.c to scmi/...
The intermediate device would nicely do the binding job.
At the cost of an additional udevice. Is that worth it?

I agree it would reflect more the DT since scmi regus are in a child
node of the SCMI protocol.
But should the software align with the DT?

That said, if no one argues against your id, i'll make the proposed
changes and post a v4.

Thanks,
etienne

>
> By adding the intermediate NOP uclass, binded with "protocol@17" node
>
> for example
>
>
> U_BOOT_DRIVER(scmi_regulator) = {
>      .name = "scmi_regulator",
>      .id = UCLASS_REGULATOR,
>      .ops = &scmi_voltd_ops,
>      .probe = scmi_regulator_probe,
>      .ofdata_to_platdata = scmi_regulator_ofdata_to_platdata,
>      .platdata_auto_alloc_size = sizeof(struct scmi_regulator_platdata),
> };
>
> static int scmi_regulator_bind(struct udevice *dev)
> {
>      struct driver *drv;
>      ofnode node, subnode;
>      int ret;
>
>      node = dev_read_subnode(dev, "regulators");
>      if (!ofnode_valid(node)) {
>          dev_err(dev, "regulators subnode not found\n");
>          return -ENXIO;
>      }
>
>      drv = DM_GET_DRIVER(scmi_regulator);
>      ofnode_for_each_subnode(subnode, node) {
>          ret = device_bind_ofnode(dev, drv, ofnode_get_name(subnode),
>                       NULL, subnode, NULL);
>          if (ret)
>              return ret;
>      }
>
>      return 0;
> }
>
> U_BOOT_DRIVER(scmi_voltage_domain) = {
>      .name = "scmi_voltage_domain",
>      .id = UCLASS_NOP,
>      .bind = scmi_regulator_bind,
> };
>
>
> I think it is more elegant and more alligned with existing behavior
>
> for SCMI clock and SCMI reset.

SCMI clocks and reset are different in that there is only 1 device per
clock grapes and reset controller series.
For SCMI regulator, there is 1 device per regulator.

>
>
> warning:
>
> in this case the tree of U-Boot class change, SCMI agent become the
> grand-father
>
> of each regulator and  all the call "devm_scmi_process_msg(dev->parent,
> &msg);"
>
> should be replaced by "devm_scmi_process_msg(dev->parent->parent, &msg);"
>
> >   /*
> >    * SCMI agent devices binds devices of various uclasses depeding on
> >    * the FDT description. scmi_bind_protocol() is a generic bind sequence
> > @@ -79,6 +102,10 @@ static int scmi_bind_protocols(struct udevice *dev)
> >                       if (IS_ENABLED(CONFIG_RESET_SCMI))
> >                               drv = DM_DRIVER_GET(scmi_reset_domain);
> >                       break;
> > +             case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
> > +                     if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI))
> > +                             drv = DM_DRIVER_GET(scmi_voltage_domain);
> > +                     break;
> >               default:
> >                       break;
> >               }
> > @@ -89,8 +116,12 @@ static int scmi_bind_protocols(struct udevice *dev)
> >                       continue;
> >               }
> >
> > -             ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
> > -                               NULL);
> > +             if (protocol_id == SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN)
> > +                     ret = regulator_devices_bind(dev, drv, node);
> > +             else
> > +                     ret = device_bind(dev, drv, ofnode_get_name(node),
> > +                                       NULL, node, NULL);
> > +
> >               if (ret)
> >                       break;
> >       }
>
> (...)
>
> Regards
>
> Patrick
>
diff mbox series

Patch

diff --git a/doc/device-tree-bindings/arm/arm,scmi.txt b/doc/device-tree-bindings/arm/arm,scmi.txt
index 1f293ea24..a76124f4a 100644
--- a/doc/device-tree-bindings/arm/arm,scmi.txt
+++ b/doc/device-tree-bindings/arm/arm,scmi.txt
@@ -62,6 +62,20 @@  Required properties:
  - #power-domain-cells : Should be 1. Contains the device or the power
 			 domain ID value used by SCMI commands.
 
+Regulator bindings for the SCMI Regulator based on SCMI Message Protocol
+------------------------------------------------------------
+An SCMI Regulator is permanently bound to a well defined SCMI Voltage Domain,
+and should be always positioned as a root regulator.
+It does not support any current operation.
+
+SCMI Regulators are grouped under a 'regulators' node which in turn is a child
+of the SCMI Voltage protocol node inside the desired SCMI instance node.
+
+This binding uses the common regulator binding[6].
+
+Required properties:
+ - reg : shall identify an existent SCMI Voltage Domain.
+
 Sensor bindings for the sensors based on SCMI Message Protocol
 --------------------------------------------------------------
 SCMI provides an API to access the various sensors on the SoC.
@@ -105,6 +119,7 @@  Required sub-node properties:
 [3] Documentation/devicetree/bindings/thermal/thermal.txt
 [4] Documentation/devicetree/bindings/sram/sram.yaml
 [5] Documentation/devicetree/bindings/reset/reset.txt
+[6] Documentation/devicetree/bindings/regulator/regulator.yaml
 
 Example:
 
@@ -169,6 +184,25 @@  firmware {
 			reg = <0x16>;
 			#reset-cells = <1>;
 		};
+
+		scmi_voltage: protocol@17 {
+			reg = <0x17>;
+
+			regulators {
+				regulator_devX: regulator@0 {
+					reg = <0x0>;
+					regulator-max-microvolt = <3300000>;
+				};
+
+				regulator_devY: regulator@9 {
+					reg = <0x9>;
+					regulator-min-microvolt = <500000>;
+					regulator-max-microvolt = <4200000>;
+				};
+
+				...
+			};
+		};
 	};
 };
 
diff --git a/drivers/firmware/scmi/scmi_agent-uclass.c b/drivers/firmware/scmi/scmi_agent-uclass.c
index 516e690ac..03d236426 100644
--- a/drivers/firmware/scmi/scmi_agent-uclass.c
+++ b/drivers/firmware/scmi/scmi_agent-uclass.c
@@ -50,6 +50,29 @@  int scmi_to_linux_errno(s32 scmi_code)
 	return -EPROTO;
 }
 
+static int regulator_devices_bind(struct udevice *dev, struct driver *drv,
+				  ofnode protocol_node)
+{
+	ofnode regulators_node;
+	ofnode node;
+	int ret;
+
+	regulators_node = ofnode_find_subnode(protocol_node, "regulators");
+	if (!ofnode_valid(regulators_node)) {
+		dev_err(dev, "regulators subnode not found\n");
+		return -ENXIO;
+	}
+
+	ofnode_for_each_subnode(node, regulators_node) {
+		ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
+				  NULL);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 /*
  * SCMI agent devices binds devices of various uclasses depeding on
  * the FDT description. scmi_bind_protocol() is a generic bind sequence
@@ -79,6 +102,10 @@  static int scmi_bind_protocols(struct udevice *dev)
 			if (IS_ENABLED(CONFIG_RESET_SCMI))
 				drv = DM_DRIVER_GET(scmi_reset_domain);
 			break;
+		case SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN:
+			if (IS_ENABLED(CONFIG_DM_REGULATOR_SCMI))
+				drv = DM_DRIVER_GET(scmi_voltage_domain);
+			break;
 		default:
 			break;
 		}
@@ -89,8 +116,12 @@  static int scmi_bind_protocols(struct udevice *dev)
 			continue;
 		}
 
-		ret = device_bind(dev, drv, ofnode_get_name(node), NULL, node,
-				  NULL);
+		if (protocol_id == SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN)
+			ret = regulator_devices_bind(dev, drv, node);
+		else
+			ret = device_bind(dev, drv, ofnode_get_name(node),
+					  NULL, node, NULL);
+
 		if (ret)
 			break;
 	}
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index fbbea18c7..5d6180229 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -353,3 +353,11 @@  config DM_REGULATOR_TPS65941
 	TPS65941 series of PMICs have 5 single phase BUCKs that can also
 	be configured in multi phase modes & 4 LDOs. The driver implements
 	get/set api for value and enable.
+
+config DM_REGULATOR_SCMI
+	bool "Enable driver for SCMI voltage domain regulators"
+	depends on DM_REGULATOR
+	select SCMI_AGENT
+        help
+          Enable this option if you want to support regulators exposed through
+	  the SCMI voltage domain protocol by a SCMI server.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 9d58112dc..b2f5972ea 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -30,3 +30,4 @@  obj-$(CONFIG_DM_REGULATOR_TPS65910) += tps65910_regulator.o
 obj-$(CONFIG_DM_REGULATOR_TPS62360) += tps62360_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_STPMIC1) += stpmic1.o
 obj-$(CONFIG_DM_REGULATOR_TPS65941) += tps65941_regulator.o
+obj-$(CONFIG_DM_REGULATOR_SCMI) += scmi_regulator.o
diff --git a/drivers/power/regulator/scmi_regulator.c b/drivers/power/regulator/scmi_regulator.c
new file mode 100644
index 000000000..072a978a8
--- /dev/null
+++ b/drivers/power/regulator/scmi_regulator.c
@@ -0,0 +1,170 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020-2021 Linaro Limited
+ */
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <scmi_agent.h>
+#include <scmi_protocols.h>
+#include <asm/types.h>
+#include <dm/device.h>
+#include <dm/device_compat.h>
+#include <linux/kernel.h>
+#include <power/regulator.h>
+
+/**
+ * struct scmi_regulator_platdata - Platform data for a scmi voltage domain regulator
+ * @domain_id: ID representing the regulator for the related SCMI agent
+ */
+struct scmi_regulator_platdata {
+	u32 domain_id;
+};
+
+static int scmi_voltd_set_enable(struct udevice *dev, bool enable)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	struct scmi_voltd_config_set_in in = {
+		.domain_id = pdata->domain_id,
+		.config = enable ? SCMI_VOLTD_CONFIG_ON : SCMI_VOLTD_CONFIG_OFF,
+	};
+	struct scmi_voltd_config_set_out out;
+	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
+					  SCMI_VOLTAGE_DOMAIN_CONFIG_SET,
+					  in, out);
+	int ret;
+
+	ret = devm_scmi_process_msg(dev->parent, &msg);
+	if (ret)
+		return ret;
+
+	ret = scmi_to_linux_errno(out.status);
+	if (ret)
+		return ret;
+
+	return ret;
+}
+
+static int scmi_voltd_get_enable(struct udevice *dev)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	struct scmi_voltd_config_get_in in = {
+		.domain_id = pdata->domain_id,
+	};
+	struct scmi_voltd_config_get_out out;
+	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
+					  SCMI_VOLTAGE_DOMAIN_CONFIG_GET,
+					  in, out);
+	int ret;
+
+	ret = devm_scmi_process_msg(dev->parent, &msg);
+	if (ret < 0)
+		return ret;
+
+	ret = scmi_to_linux_errno(out.status);
+	if (ret < 0)
+		return ret;
+
+	return out.config == SCMI_VOLTD_CONFIG_ON;
+}
+
+static int scmi_voltd_set_voltage_level(struct udevice *dev, int uV)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	struct scmi_voltd_level_set_in in = {
+		.domain_id = pdata->domain_id,
+		.voltage_level = uV,
+	};
+	struct scmi_voltd_level_set_out out;
+	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
+					  SCMI_VOLTAGE_DOMAIN_LEVEL_SET,
+					  in, out);
+	int ret;
+
+	ret = devm_scmi_process_msg(dev->parent, &msg);
+	if (ret < 0)
+		return ret;
+
+	return scmi_to_linux_errno(out.status);
+}
+
+static int scmi_voltd_get_voltage_level(struct udevice *dev)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	struct scmi_voltd_level_get_in in = {
+		.domain_id = pdata->domain_id,
+	};
+	struct scmi_voltd_level_get_out out;
+	struct scmi_msg msg = SCMI_MSG_IN(SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
+					  SCMI_VOLTAGE_DOMAIN_LEVEL_GET,
+					  in, out);
+	int ret;
+
+	ret = devm_scmi_process_msg(dev->parent, &msg);
+	if (ret < 0)
+		return ret;
+
+	ret = scmi_to_linux_errno(out.status);
+	if (ret < 0)
+		return ret;
+
+	return out.voltage_level;
+}
+
+static int scmi_regulator_of_to_plat(struct udevice *dev)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	fdt_addr_t reg;
+
+	reg = dev_read_addr(dev);
+	if (reg == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	pdata->domain_id = (u32)reg;
+
+	return 0;
+}
+
+static int scmi_regulator_probe(struct udevice *dev)
+{
+	struct scmi_regulator_platdata *pdata = dev_get_plat(dev);
+	struct scmi_voltd_attr_in in = { 0 };
+	struct scmi_voltd_attr_out out = { 0 };
+	struct scmi_msg scmi_msg = {
+		.protocol_id = SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN,
+		.message_id = SCMI_VOLTAGE_DOMAIN_ATTRIBUTES,
+		.in_msg = (u8 *)&in,
+		.in_msg_sz = sizeof(in),
+		.out_msg = (u8 *)&out,
+		.out_msg_sz = sizeof(out),
+	};
+	int ret;
+
+	/* Check voltage domain is known from SCMI server */
+	in.domain_id = pdata->domain_id;
+
+	ret = devm_scmi_process_msg(dev->parent, &scmi_msg);
+	if (ret) {
+		dev_err(dev, "Failed to query voltage domain %u: %d\n",
+			pdata->domain_id, ret);
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static const struct dm_regulator_ops scmi_voltd_ops = {
+	.get_value  = scmi_voltd_get_voltage_level,
+	.set_value  = scmi_voltd_set_voltage_level,
+	.get_enable = scmi_voltd_get_enable,
+	.set_enable = scmi_voltd_set_enable,
+};
+
+U_BOOT_DRIVER(scmi_voltage_domain) = {
+	.name = "scmi_voltage_domain",
+	.id = UCLASS_REGULATOR,
+	.ops = &scmi_voltd_ops,
+	.probe = scmi_regulator_probe,
+	.of_to_plat = scmi_regulator_of_to_plat,
+	.plat_auto = sizeof(struct scmi_regulator_platdata),
+};
diff --git a/include/scmi_protocols.h b/include/scmi_protocols.h
index ccab97c96..2db71697e 100644
--- a/include/scmi_protocols.h
+++ b/include/scmi_protocols.h
@@ -23,6 +23,7 @@  enum scmi_std_protocol {
 	SCMI_PROTOCOL_ID_CLOCK = 0x14,
 	SCMI_PROTOCOL_ID_SENSOR = 0x15,
 	SCMI_PROTOCOL_ID_RESET_DOMAIN = 0x16,
+	SCMI_PROTOCOL_ID_VOLTAGE_DOMAIN = 0x17,
 };
 
 enum scmi_status_code {
@@ -176,4 +177,116 @@  struct scmi_rd_reset_out {
 	s32 status;
 };
 
+/*
+ * SCMI Voltage Domain Protocol
+ */
+
+enum scmi_voltage_domain_message_id {
+	SCMI_VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
+	SCMI_VOLTAGE_DOMAIN_CONFIG_SET = 0x5,
+	SCMI_VOLTAGE_DOMAIN_CONFIG_GET = 0x6,
+	SCMI_VOLTAGE_DOMAIN_LEVEL_SET = 0x7,
+	SCMI_VOLTAGE_DOMAIN_LEVEL_GET = 0x8,
+};
+
+#define SCMI_VOLTD_NAME_LEN		16
+
+#define SCMI_VOLTD_CONFIG_MASK		GENMASK(3, 0)
+#define SCMI_VOLTD_CONFIG_OFF		0
+#define SCMI_VOLTD_CONFIG_ON		0x7
+
+/**
+ * struct scmi_voltd_attr_in - Payload for VOLTAGE_DOMAIN_ATTRIBUTES message
+ * @domain_id:	SCMI voltage domain ID
+ */
+struct scmi_voltd_attr_in {
+	u32 domain_id;
+};
+
+/**
+ * struct scmi_voltd_attr_out - Payload for VOLTAGE_DOMAIN_ATTRIBUTES response
+ * @status:	SCMI command status
+ * @attributes:	Retrieved attributes of the voltage domain
+ * @name:	Voltage domain name
+ */
+struct scmi_voltd_attr_out {
+	s32 status;
+	u32 attributes;
+	char name[SCMI_VOLTD_NAME_LEN];
+};
+
+/**
+ * struct scmi_voltd_config_set_in - Message payload for VOLTAGE_CONFIG_SET cmd
+ * @domain_id:	SCMI voltage domain ID
+ * @config:	Configuration data of the voltage domain
+ */
+struct scmi_voltd_config_set_in {
+	u32 domain_id;
+	u32 config;
+};
+
+/**
+ * struct scmi_voltd_config_set_out - Response for VOLTAGE_CONFIG_SET command
+ * @status:	SCMI command status
+ */
+struct scmi_voltd_config_set_out {
+	s32 status;
+};
+
+/**
+ * struct scmi_voltd_config_get_in - Message payload for VOLTAGE_CONFIG_GET cmd
+ * @domain_id:	SCMI voltage domain ID
+ */
+struct scmi_voltd_config_get_in {
+	u32 domain_id;
+};
+
+/**
+ * struct scmi_voltd_config_get_out - Response for VOLTAGE_CONFIG_GET command
+ * @status:	SCMI command status
+ * @config:	Configuration data of the voltage domain
+ */
+struct scmi_voltd_config_get_out {
+	s32 status;
+	u32 config;
+};
+
+/**
+ * struct scmi_voltd_level_set_in - Message payload for VOLTAGE_LEVEL_SET cmd
+ * @domain_id:		SCMI voltage domain ID
+ * @flags:		Parameter flags for configuring target level
+ * @voltage_level:	Target voltage level in microvolts (uV)
+ */
+struct scmi_voltd_level_set_in {
+	u32 domain_id;
+	u32 flags;
+	s32 voltage_level;
+};
+
+/**
+ * struct scmi_voltd_level_set_out - Response for VOLTAGE_LEVEL_SET command
+ * @status:	SCMI	command status
+ */
+struct scmi_voltd_level_set_out {
+	s32 status;
+};
+
+/**
+ * struct scmi_voltd_level_get_in - Message payload for VOLTAGE_LEVEL_GET cmd
+ * @domain_id:		SCMI voltage domain ID
+ */
+struct scmi_voltd_level_get_in {
+	u32 domain_id;
+};
+
+/**
+ * struct scmi_voltd_level_get_out - Response for VOLTAGE_LEVEL_GET command
+ * @status:		SCMI command status
+ * @voltage_level:	Voltage level in microvolts (uV)
+ */
+struct scmi_voltd_level_get_out {
+	s32 status;
+	s32 voltage_level;
+};
+
 #endif /* _SCMI_PROTOCOLS_H */