Merge tag 'scmi-updates-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/drivers

ARM SCMI updates for v5.11

Two main additions this time:
1. Support for SCMI v3.0 sensor extensions
2. Support for voltage domain management protocol added newly to SCMI v3.0

* tag 'scmi-updates-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  firmware: arm_scmi: Remove residual _le structs naming
  firmware: arm_scmi: Add SCMI v3.0 sensor notifications
  firmware: arm_scmi: Add SCMI v3.0 sensor configuration support
  firmware: arm_scmi: Add SCMI v3.0 sensors timestamped reads
  hwmon: (scmi) Update hwmon internal scale data type
  firmware: arm_scmi: Add support to enumerated SCMI voltage domain device
  firmware: arm_scmi: Add voltage domain management protocol support
  dt-bindings: arm: Add support for SCMI Regulators
  firmware: arm_scmi: Add SCMI v3.0 sensors descriptors extensions
  firmware: arm_scmi: Add full list of sensor type enumeration
  firmware: arm_scmi: Rework scmi_sensors_protocol_init
  firmware: arm_scmi: Fix missing destroy_workqueue()

Link: https://lore.kernel.org/r/20201124122412.22386-1-sudeep.holla@arm.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

6 files changed, 1058 insertions, 58 deletions

diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index bc0d54f8e861..6a2ef63306d6 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -4,7 +4,7 @@ scmi-driver-y = driver.o notify.o
 scmi-transport-y = shmem.o
 scmi-transport-$(CONFIG_MAILBOX) += mailbox.o
 scmi-transport-$(CONFIG_HAVE_ARM_SMCCC_DISCOVERY) += smc.o
-scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o
+scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o
 scmi-module-objs := $(scmi-bus-y) $(scmi-driver-y) $(scmi-protocols-y) \
 		    $(scmi-transport-y)
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 65063fa948d4..c0fb45e7c3e8 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -169,6 +169,7 @@ DECLARE_SCMI_REGISTER_UNREGISTER(perf);
 DECLARE_SCMI_REGISTER_UNREGISTER(power);
 DECLARE_SCMI_REGISTER_UNREGISTER(reset);
 DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
+DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
 DECLARE_SCMI_REGISTER_UNREGISTER(system);
 
 #define DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(id, name) \
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3dfd8b6a0ebf..5392e1fc6b4e 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -743,6 +743,7 @@ static struct scmi_prot_devnames devnames[] = {
 	{ SCMI_PROTOCOL_CLOCK,  { "clocks" },},
 	{ SCMI_PROTOCOL_SENSOR, { "hwmon" },},
 	{ SCMI_PROTOCOL_RESET,  { "reset" },},
+	{ SCMI_PROTOCOL_VOLTAGE,  { "regulator" },},
 };
 
 static inline void
@@ -946,6 +947,7 @@ static int __init scmi_driver_init(void)
 	scmi_power_register();
 	scmi_reset_register();
 	scmi_sensors_register();
+	scmi_voltage_register();
 	scmi_system_register();
 
 	return platform_driver_register(&scmi_driver);
@@ -961,6 +963,7 @@ static void __exit scmi_driver_exit(void)
 	scmi_power_unregister();
 	scmi_reset_unregister();
 	scmi_sensors_unregister();
+	scmi_voltage_unregister();
 	scmi_system_unregister();
 
 	platform_driver_unregister(&scmi_driver);
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index ce336899d636..66196b293b6c 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -1474,17 +1474,17 @@ int scmi_notification_init(struct scmi_handle *handle)
 	ni->gid = gid;
 	ni->handle = handle;
 
+	ni->registered_protocols = devm_kcalloc(handle->dev, SCMI_MAX_PROTO,
+						sizeof(char *), GFP_KERNEL);
+	if (!ni->registered_protocols)
+		goto err;
+
 	ni->notify_wq = alloc_workqueue(dev_name(handle->dev),
 					WQ_UNBOUND | WQ_FREEZABLE | WQ_SYSFS,
 					0);
 	if (!ni->notify_wq)
 		goto err;
 
-	ni->registered_protocols = devm_kcalloc(handle->dev, SCMI_MAX_PROTO,
-						sizeof(char *), GFP_KERNEL);
-	if (!ni->registered_protocols)
-		goto err;
-
 	mutex_init(&ni->pending_mtx);
 	hash_init(ni->pending_events_handlers);
 
diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
index b4232d611033..4541b891b733 100644
--- a/drivers/firmware/arm_scmi/sensors.c
+++ b/drivers/firmware/arm_scmi/sensors.c
@@ -2,21 +2,30 @@
 /*
  * System Control and Management Interface (SCMI) Sensor Protocol
  *
- * Copyright (C) 2018 ARM Ltd.
+ * Copyright (C) 2018-2020 ARM Ltd.
  */
 
 #define pr_fmt(fmt) "SCMI Notifications SENSOR - " fmt
 
+#include <linux/bitfield.h>
 #include <linux/scmi_protocol.h>
 
 #include "common.h"
 #include "notify.h"
 
+#define SCMI_MAX_NUM_SENSOR_AXIS	63
+#define	SCMIv2_SENSOR_PROTOCOL		0x10000
+
 enum scmi_sensor_protocol_cmd {
 	SENSOR_DESCRIPTION_GET = 0x3,
 	SENSOR_TRIP_POINT_NOTIFY = 0x4,
 	SENSOR_TRIP_POINT_CONFIG = 0x5,
 	SENSOR_READING_GET = 0x6,
+	SENSOR_AXIS_DESCRIPTION_GET = 0x7,
+	SENSOR_LIST_UPDATE_INTERVALS = 0x8,
+	SENSOR_CONFIG_GET = 0x9,
+	SENSOR_CONFIG_SET = 0xA,
+	SENSOR_CONTINUOUS_UPDATE_NOTIFY = 0xB,
 };
 
 struct scmi_msg_resp_sensor_attributes {
@@ -28,29 +37,106 @@ struct scmi_msg_resp_sensor_attributes {
 	__le32 reg_size;
 };
 
+/* v3 attributes_low macros */
+#define SUPPORTS_UPDATE_NOTIFY(x)	FIELD_GET(BIT(30), (x))
+#define SENSOR_TSTAMP_EXP(x)		FIELD_GET(GENMASK(14, 10), (x))
+#define SUPPORTS_TIMESTAMP(x)		FIELD_GET(BIT(9), (x))
+#define SUPPORTS_EXTEND_ATTRS(x)	FIELD_GET(BIT(8), (x))
+
+/* v2 attributes_high macros */
+#define SENSOR_UPDATE_BASE(x)		FIELD_GET(GENMASK(31, 27), (x))
+#define SENSOR_UPDATE_SCALE(x)		FIELD_GET(GENMASK(26, 22), (x))
+
+/* v3 attributes_high macros */
+#define SENSOR_AXIS_NUMBER(x)		FIELD_GET(GENMASK(21, 16), (x))
+#define SUPPORTS_AXIS(x)		FIELD_GET(BIT(8), (x))
+
+/* v3 resolution macros */
+#define SENSOR_RES(x)			FIELD_GET(GENMASK(26, 0), (x))
+#define SENSOR_RES_EXP(x)		FIELD_GET(GENMASK(31, 27), (x))
+
+struct scmi_msg_resp_attrs {
+	__le32 min_range_low;
+	__le32 min_range_high;
+	__le32 max_range_low;
+	__le32 max_range_high;
+};
+
 struct scmi_msg_resp_sensor_description {
 	__le16 num_returned;
 	__le16 num_remaining;
-	struct {
+	struct scmi_sensor_descriptor {
 		__le32 id;
 		__le32 attributes_low;
-#define SUPPORTS_ASYNC_READ(x)	((x) & BIT(31))
-#define NUM_TRIP_POINTS(x)	((x) & 0xff)
+/* Common attributes_low macros */
+#define SUPPORTS_ASYNC_READ(x)		FIELD_GET(BIT(31), (x))
+#define NUM_TRIP_POINTS(x)		FIELD_GET(GENMASK(7, 0), (x))
 		__le32 attributes_high;
-#define SENSOR_TYPE(x)		((x) & 0xff)
-#define SENSOR_SCALE(x)		(((x) >> 11) & 0x1f)
-#define SENSOR_SCALE_SIGN	BIT(4)
-#define SENSOR_SCALE_EXTEND	GENMASK(7, 5)
-#define SENSOR_UPDATE_SCALE(x)	(((x) >> 22) & 0x1f)
-#define SENSOR_UPDATE_BASE(x)	(((x) >> 27) & 0x1f)
-		    u8 name[SCMI_MAX_STR_SIZE];
-	} desc[0];
+/* Common attributes_high macros */
+#define SENSOR_SCALE(x)			FIELD_GET(GENMASK(15, 11), (x))
+#define SENSOR_SCALE_SIGN		BIT(4)
+#define SENSOR_SCALE_EXTEND		GENMASK(31, 5)
+#define SENSOR_TYPE(x)			FIELD_GET(GENMASK(7, 0), (x))
+		u8 name[SCMI_MAX_STR_SIZE];
+		/* only for version > 2.0 */
+		__le32 power;
+		__le32 resolution;
+		struct scmi_msg_resp_attrs scalar_attrs;
+	} desc[];
 };
 
-struct scmi_msg_sensor_trip_point_notify {
+/* Base scmi_sensor_descriptor size excluding extended attrs after name */
+#define SCMI_MSG_RESP_SENS_DESCR_BASE_SZ	28
+
+/* Sign extend to a full s32 */
+#define	S32_EXT(v)							\
+	({								\
+		int __v = (v);						\
+									\
+		if (__v & SENSOR_SCALE_SIGN)				\
+			__v |= SENSOR_SCALE_EXTEND;			\
+		__v;							\
+	})
+
+struct scmi_msg_sensor_axis_description_get {
+	__le32 id;
+	__le32 axis_desc_index;
+};
+
+struct scmi_msg_resp_sensor_axis_description {
+	__le32 num_axis_flags;
+#define NUM_AXIS_RETURNED(x)		FIELD_GET(GENMASK(5, 0), (x))
+#define NUM_AXIS_REMAINING(x)		FIELD_GET(GENMASK(31, 26), (x))
+	struct scmi_axis_descriptor {
+		__le32 id;
+		__le32 attributes_low;
+		__le32 attributes_high;
+		u8 name[SCMI_MAX_STR_SIZE];
+		__le32 resolution;
+		struct scmi_msg_resp_attrs attrs;
+	} desc[];
+};
+
+/* Base scmi_axis_descriptor size excluding extended attrs after name */
+#define SCMI_MSG_RESP_AXIS_DESCR_BASE_SZ	28
+
+struct scmi_msg_sensor_list_update_intervals {
+	__le32 id;
+	__le32 index;
+};
+
+struct scmi_msg_resp_sensor_list_update_intervals {
+	__le32 num_intervals_flags;
+#define NUM_INTERVALS_RETURNED(x)	FIELD_GET(GENMASK(11, 0), (x))
+#define SEGMENTED_INTVL_FORMAT(x)	FIELD_GET(BIT(12), (x))
+#define NUM_INTERVALS_REMAINING(x)	FIELD_GET(GENMASK(31, 16), (x))
+	__le32 intervals[];
+};
+
+struct scmi_msg_sensor_request_notify {
 	__le32 id;
 	__le32 event_control;
-#define SENSOR_TP_NOTIFY_ALL	BIT(0)
+#define SENSOR_NOTIFY_ALL	BIT(0)
 };
 
 struct scmi_msg_set_sensor_trip_point {
@@ -66,18 +152,46 @@ struct scmi_msg_set_sensor_trip_point {
 	__le32 value_high;
 };
 
+struct scmi_msg_sensor_config_set {
+	__le32 id;
+	__le32 sensor_config;
+};
+
 struct scmi_msg_sensor_reading_get {
 	__le32 id;
 	__le32 flags;
 #define SENSOR_READ_ASYNC	BIT(0)
 };
 
+struct scmi_resp_sensor_reading_complete {
+	__le32 id;
+	__le64 readings;
+};
+
+struct scmi_sensor_reading_resp {
+	__le32 sensor_value_low;
+	__le32 sensor_value_high;
+	__le32 timestamp_low;
+	__le32 timestamp_high;
+};
+
+struct scmi_resp_sensor_reading_complete_v3 {
+	__le32 id;
+	struct scmi_sensor_reading_resp readings[];
+};
+
 struct scmi_sensor_trip_notify_payld {
 	__le32 agent_id;
 	__le32 sensor_id;
 	__le32 trip_point_desc;
 };
 
+struct scmi_sensor_update_notify_payld {
+	__le32 agent_id;
+	__le32 sensor_id;
+	struct scmi_sensor_reading_resp readings[];
+};
+
 struct sensors_info {
 	u32 version;
 	int num_sensors;
@@ -114,6 +228,194 @@ static int scmi_sensor_attributes_get(const struct scmi_handle *handle,
 	return ret;
 }
 
+static inline void scmi_parse_range_attrs(struct scmi_range_attrs *out,
+					  struct scmi_msg_resp_attrs *in)
+{
+	out->min_range = get_unaligned_le64((void *)&in->min_range_low);
+	out->max_range = get_unaligned_le64((void *)&in->max_range_low);
+}
+
+static int scmi_sensor_update_intervals(const struct scmi_handle *handle,
+					struct scmi_sensor_info *s)
+{
+	int ret, cnt;
+	u32 desc_index = 0;
+	u16 num_returned, num_remaining;
+	struct scmi_xfer *ti;
+	struct scmi_msg_resp_sensor_list_update_intervals *buf;
+	struct scmi_msg_sensor_list_update_intervals *msg;
+
+	ret = scmi_xfer_get_init(handle, SENSOR_LIST_UPDATE_INTERVALS,
+				 SCMI_PROTOCOL_SENSOR, sizeof(*msg), 0, &ti);
+	if (ret)
+		return ret;
+
+	buf = ti->rx.buf;
+	do {
+		u32 flags;
+
+		msg = ti->tx.buf;
+		/* Set the number of sensors to be skipped/already read */
+		msg->id = cpu_to_le32(s->id);
+		msg->index = cpu_to_le32(desc_index);
+
+		ret = scmi_do_xfer(handle, ti);
+		if (ret)
+			break;
+
+		flags = le32_to_cpu(buf->num_intervals_flags);
+		num_returned = NUM_INTERVALS_RETURNED(flags);
+		num_remaining = NUM_INTERVALS_REMAINING(flags);
+
+		/*
+		 * Max intervals is not declared previously anywhere so we
+		 * assume it's returned+remaining.
+		 */
+		if (!s->intervals.count) {
+			s->intervals.segmented = SEGMENTED_INTVL_FORMAT(flags);
+			s->intervals.count = num_returned + num_remaining;
+			/* segmented intervals are reported in one triplet */
+			if (s->intervals.segmented &&
+			    (num_remaining || num_returned != 3)) {
+				dev_err(handle->dev,
+					"Sensor ID:%d advertises an invalid segmented interval (%d)\n",
+					s->id, s->intervals.count);
+				s->intervals.segmented = false;
+				s->intervals.count = 0;
+				ret = -EINVAL;
+				break;
+			}
+			/* Direct allocation when exceeding pre-allocated */
+			if (s->intervals.count >= SCMI_MAX_PREALLOC_POOL) {
+				s->intervals.desc =
+					devm_kcalloc(handle->dev,
+						     s->intervals.count,
+						     sizeof(*s->intervals.desc),
+						     GFP_KERNEL);
+				if (!s->intervals.desc) {
+					s->intervals.segmented = false;
+					s->intervals.count = 0;
+					ret = -ENOMEM;
+					break;
+				}
+			}
+		} else if (desc_index + num_returned > s->intervals.count) {
+			dev_err(handle->dev,
+				"No. of update intervals can't exceed %d\n",
+				s->intervals.count);
+			ret = -EINVAL;
+			break;
+		}
+
+		for (cnt = 0; cnt < num_returned; cnt++)
+			s->intervals.desc[desc_index + cnt] =
+					le32_to_cpu(buf->intervals[cnt]);
+
+		desc_index += num_returned;
+
+		scmi_reset_rx_to_maxsz(handle, ti);
+		/*
+		 * check for both returned and remaining to avoid infinite
+		 * loop due to buggy firmware
+		 */
+	} while (num_returned && num_remaining);
+
+	scmi_xfer_put(handle, ti);
+	return ret;
+}
+
+static int scmi_sensor_axis_description(const struct scmi_handle *handle,
+					struct scmi_sensor_info *s)
+{
+	int ret, cnt;
+	u32 desc_index = 0;
+	u16 num_returned, num_remaining;
+	struct scmi_xfer *te;
+	struct scmi_msg_resp_sensor_axis_description *buf;
+	struct scmi_msg_sensor_axis_description_get *msg;
+
+	s->axis = devm_kcalloc(handle->dev, s->num_axis,
+			       sizeof(*s->axis), GFP_KERNEL);
+	if (!s->axis)
+		return -ENOMEM;
+
+	ret = scmi_xfer_get_init(handle, SENSOR_AXIS_DESCRIPTION_GET,
+				 SCMI_PROTOCOL_SENSOR, sizeof(*msg), 0, &te);
+	if (ret)
+		return ret;
+
+	buf = te->rx.buf;
+	do {
+		u32 flags;
+		struct scmi_axis_descriptor *adesc;
+
+		msg = te->tx.buf;
+		/* Set the number of sensors to be skipped/already read */
+		msg->id = cpu_to_le32(s->id);
+		msg->axis_desc_index = cpu_to_le32(desc_index);
+
+		ret = scmi_do_xfer(handle, te);
+		if (ret)
+			break;
+
+		flags = le32_to_cpu(buf->num_axis_flags);
+		num_returned = NUM_AXIS_RETURNED(flags);
+		num_remaining = NUM_AXIS_REMAINING(flags);
+
+		if (desc_index + num_returned > s->num_axis) {
+			dev_err(handle->dev, "No. of axis can't exceed %d\n",
+				s->num_axis);
+			break;
+		}
+
+		adesc = &buf->desc[0];
+		for (cnt = 0; cnt < num_returned; cnt++) {
+			u32 attrh, attrl;
+			struct scmi_sensor_axis_info *a;
+			size_t dsize = SCMI_MSG_RESP_AXIS_DESCR_BASE_SZ;
+
+			attrl = le32_to_cpu(adesc->attributes_low);
+
+			a = &s->axis[desc_index + cnt];
+
+			a->id = le32_to_cpu(adesc->id);
+			a->extended_attrs = SUPPORTS_EXTEND_ATTRS(attrl);
+
+			attrh = le32_to_cpu(adesc->attributes_high);
+			a->scale = S32_EXT(SENSOR_SCALE(attrh));
+			a->type = SENSOR_TYPE(attrh);
+			strlcpy(a->name, adesc->name, SCMI_MAX_STR_SIZE);
+
+			if (a->extended_attrs) {
+				unsigned int ares =
+					le32_to_cpu(adesc->resolution);
+
+				a->resolution = SENSOR_RES(ares);
+				a->exponent =
+					S32_EXT(SENSOR_RES_EXP(ares));
+				dsize += sizeof(adesc->resolution);
+
+				scmi_parse_range_attrs(&a->attrs,
+						       &adesc->attrs);
+				dsize += sizeof(adesc->attrs);
+			}
+
+			adesc = (typeof(adesc))((u8 *)adesc + dsize);
+		}
+
+		desc_index += num_returned;
+
+		scmi_reset_rx_to_maxsz(handle, te);
+		/*
+		 * check for both returned and remaining to avoid infinite
+		 * loop due to buggy firmware
+		 */
+	} while (num_returned && num_remaining);
+
+	scmi_xfer_put(handle, te);
+	return ret;
+}
+
 static int scmi_sensor_description_get(const struct scmi_handle *handle,
 				       struct sensors_info *si)
 {
@@ -131,9 +433,10 @@ static int scmi_sensor_description_get(const struct scmi_handle *handle,
 	buf = t->rx.buf;
 
 	do {
+		struct scmi_sensor_descriptor *sdesc;
+
 		/* Set the number of sensors to be skipped/already read */
 		put_unaligned_le32(desc_index, t->tx.buf);
-
 		ret = scmi_do_xfer(handle, t);
 		if (ret)
 			break;
@@ -147,22 +450,97 @@ static int scmi_sensor_description_get(const struct scmi_handle *handle,
 			break;
 		}
 
+		sdesc = &buf->desc[0];
 		for (cnt = 0; cnt < num_returned; cnt++) {
 			u32 attrh, attrl;
 			struct scmi_sensor_info *s;
+			size_t dsize = SCMI_MSG_RESP_SENS_DESCR_BASE_SZ;
 
-			attrl = le32_to_cpu(buf->desc[cnt].attributes_low);
-			attrh = le32_to_cpu(buf->desc[cnt].attributes_high);
 			s = &si->sensors[desc_index + cnt];
-			s->id = le32_to_cpu(buf->desc[cnt].id);
-			s->type = SENSOR_TYPE(attrh);
-			s->scale = SENSOR_SCALE(attrh);
-			/* Sign extend to a full s8 */
-			if (s->scale & SENSOR_SCALE_SIGN)
-				s->scale |= SENSOR_SCALE_EXTEND;
+			s->id = le32_to_cpu(sdesc->id);
+
+			attrl = le32_to_cpu(sdesc->attributes_low);
+			/* common bitfields parsing */
 			s->async = SUPPORTS_ASYNC_READ(attrl);
 			s->num_trip_points = NUM_TRIP_POINTS(attrl);
-			strlcpy(s->name, buf->desc[cnt].name, SCMI_MAX_STR_SIZE);
+			/**
+			 * only SCMIv3.0 specific bitfield below.
+			 * Such bitfields are assumed to be zeroed on non
+			 * relevant fw versions...assuming fw not buggy !
+			 */
+			s->update = SUPPORTS_UPDATE_NOTIFY(attrl);
+			s->timestamped = SUPPORTS_TIMESTAMP(attrl);
+			if (s->timestamped)
+				s->tstamp_scale =
+					S32_EXT(SENSOR_TSTAMP_EXP(attrl));
+			s->extended_scalar_attrs =
+				SUPPORTS_EXTEND_ATTRS(attrl);
+
+			attrh = le32_to_cpu(sdesc->attributes_high);
+			/* common bitfields parsing */
+			s->scale = S32_EXT(SENSOR_SCALE(attrh));
+			s->type = SENSOR_TYPE(attrh);
+			/* Use pre-allocated pool wherever possible */
+			s->intervals.desc = s->intervals.prealloc_pool;
+			if (si->version == SCMIv2_SENSOR_PROTOCOL) {
+				s->intervals.segmented = false;
+				s->intervals.count = 1;
+				/*
+				 * Convert SCMIv2.0 update interval format to
+				 * SCMIv3.0 to be used as the common exposed
+				 * descriptor, accessible via common macros.
+				 */
+				s->intervals.desc[0] =
+					(SENSOR_UPDATE_BASE(attrh) << 5) |
+					 SENSOR_UPDATE_SCALE(attrh);
+			} else {
+				/*
+				 * From SCMIv3.0 update intervals are retrieved
+				 * via a dedicated (optional) command.
+				 * Since the command is optional, on error carry
+				 * on without any update interval.
+				 */
+				if (scmi_sensor_update_intervals(handle, s))
+					dev_dbg(handle->dev,
+						"Update Intervals not available for sensor ID:%d\n",
+						s->id);
+			}
+			/**
+			 * only > SCMIv2.0 specific bitfield below.
+			 * Such bitfields are assumed to be zeroed on non
+			 * relevant fw versions...assuming fw not buggy !
+			 */
+			s->num_axis = min_t(unsigned int,
+					    SUPPORTS_AXIS(attrh) ?
+					    SENSOR_AXIS_NUMBER(attrh) : 0,
+					    SCMI_MAX_NUM_SENSOR_AXIS);
+			strlcpy(s->name, sdesc->name, SCMI_MAX_STR_SIZE);
+
+			if (s->extended_scalar_attrs) {
+				s->sensor_power = le32_to_cpu(sdesc->power);
+				dsize += sizeof(sdesc->power);
+				/* Only for sensors reporting scalar values */
+				if (s->num_axis == 0) {
+					unsigned int sres =
+						le32_to_cpu(sdesc->resolution);
+
+					s->resolution = SENSOR_RES(sres);
+					s->exponent =
+						S32_EXT(SENSOR_RES_EXP(sres));
+					dsize += sizeof(sdesc->resolution);
+
+					scmi_parse_range_attrs(&s->scalar_attrs,
+							       &sdesc->scalar_attrs);
+					dsize += sizeof(sdesc->scalar_attrs);
+				}
+			}
+			if (s->num_axis > 0) {
+				ret = scmi_sensor_axis_description(handle, s);
+				if (ret)
+					goto out;
+			}
+
+			sdesc = (typeof(sdesc))((u8 *)sdesc + dsize);
 		}
 
 		desc_index += num_returned;
@@ -174,19 +552,21 @@ static int scmi_sensor_description_get(const struct scmi_handle *handle,
 		 */
 	} while (num_returned && num_remaining);
 
+out:
 	scmi_xfer_put(handle, t);
 	return ret;
 }
 
-static int scmi_sensor_trip_point_notify(const struct scmi_handle *handle,
-					 u32 sensor_id, bool enable)
+static inline int
+scmi_sensor_request_notify(const struct scmi_handle *handle, u32 sensor_id,
+			   u8 message_id, bool enable)
 {
 	int ret;
-	u32 evt_cntl = enable ? SENSOR_TP_NOTIFY_ALL : 0;
+	u32 evt_cntl = enable ? SENSOR_NOTIFY_ALL : 0;
 	struct scmi_xfer *t;
-	struct scmi_msg_sensor_trip_point_notify *cfg;
+	struct scmi_msg_sensor_request_notify *cfg;
 
-	ret = scmi_xfer_get_init(handle, SENSOR_TRIP_POINT_NOTIFY,
+	ret = scmi_xfer_get_init(handle, message_id,
 				 SCMI_PROTOCOL_SENSOR, sizeof(*cfg), 0, &t);
 	if (ret)
 		return ret;
@@ -201,6 +581,23 @@ static int scmi_sensor_trip_point_notify(const struct scmi_handle *handle,
 	return ret;
 }
 
+static int scmi_sensor_trip_point_notify(const struct scmi_handle *handle,
+					 u32 sensor_id, bool enable)
+{
+	return scmi_sensor_request_notify(handle, sensor_id,
+					  SENSOR_TRIP_POINT_NOTIFY,
+					  enable);
+}
+
+static int
+scmi_sensor_continuous_update_notify(const struct scmi_handle *handle,
+				     u32 sensor_id, bool enable)
+{
+	return scmi_sensor_request_notify(handle, sensor_id,
+					  SENSOR_CONTINUOUS_UPDATE_NOTIFY,
+					  enable);
+}
+
 static int
 scmi_sensor_trip_point_config(const struct scmi_handle *handle, u32 sensor_id,
 			      u8 trip_id, u64 trip_value)
@@ -227,6 +624,75 @@ scmi_sensor_trip_point_config(const struct scmi_handle *handle, u32 sensor_id,
 	return ret;
 }
 
+static int scmi_sensor_config_get(const struct scmi_handle *handle,
+				  u32 sensor_id, u32 *sensor_config)
+{
+	int ret;
+	struct scmi_xfer *t;
+
+	ret = scmi_xfer_get_init(handle, SENSOR_CONFIG_GET,
+				 SCMI_PROTOCOL_SENSOR, sizeof(__le32),
+				 sizeof(__le32), &t);
+	if (ret)
+		return ret;
+
+	put_unaligned_le32(cpu_to_le32(sensor_id), t->tx.buf);
+	ret = scmi_do_xfer(handle, t);
+	if (!ret) {
+		struct sensors_info *si = handle->sensor_priv;
+		struct scmi_sensor_info *s = si->sensors + sensor_id;
+
+		*sensor_config = get_unaligned_le64(t->rx.buf);
+		s->sensor_config = *sensor_config;
+	}
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+static int scmi_sensor_config_set(const struct scmi_handle *handle,
+				  u32 sensor_id, u32 sensor_config)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct scmi_msg_sensor_config_set *msg;
+
+	ret = scmi_xfer_get_init(handle, SENSOR_CONFIG_SET,
+				 SCMI_PROTOCOL_SENSOR, sizeof(*msg), 0, &t);
+	if (ret)
+		return ret;
+
+	msg = t->tx.buf;
+	msg->id = cpu_to_le32(sensor_id);
+	msg->sensor_config = cpu_to_le32(sensor_config);
+
+	ret = scmi_do_xfer(handle, t);
+	if (!ret) {
+		struct sensors_info *si = handle->sensor_priv;
+		struct scmi_sensor_info *s = si->sensors + sensor_id;
+
+		s->sensor_config = sensor_config;
+	}
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+/**
+ * scmi_sensor_reading_get  - Read scalar sensor value
+ * @handle: Platform handle
+ * @sensor_id: Sensor ID
+ * @value: The 64bit value sensor reading
+ *
+ * This function returns a single 64 bit reading value representing the sensor
+ * value; if the platform SCMI Protocol implementation and the sensor support
+ * multiple axis and timestamped-reads, this just returns the first axis while
+ * dropping the timestamp value.
+ * Use instead the @scmi_sensor_reading_get_timestamped to retrieve the array of
+ * timestamped multi-axis values.
+ *
+ * Return: 0 on Success
+ */
 static int scmi_sensor_reading_get(const struct scmi_handle *handle,
 				   u32 sensor_id, u64 *value)
 {
@@ -237,20 +703,24 @@ static int scmi_sensor_reading_get(const struct scmi_handle *handle,
 	struct scmi_sensor_info *s = si->sensors + sensor_id;
 
 	ret = scmi_xfer_get_init(handle, SENSOR_READING_GET,
-				 SCMI_PROTOCOL_SENSOR, sizeof(*sensor),
-				 sizeof(u64), &t);
+				 SCMI_PROTOCOL_SENSOR, sizeof(*sensor), 0, &t);
 	if (ret)
 		return ret;
 
 	sensor = t->tx.buf;
 	sensor->id = cpu_to_le32(sensor_id);
-
 	if (s->async) {
 		sensor->flags = cpu_to_le32(SENSOR_READ_ASYNC);
 		ret = scmi_do_xfer_with_response(handle, t);
-		if (!ret)
-			*value = get_unaligned_le64((void *)
-						    ((__le32 *)t->rx.buf + 1));
+		if (!ret) {
+			struct scmi_resp_sensor_reading_complete *resp;
+
+			resp = t->rx.buf;
+			if (le32_to_cpu(resp->id) == sensor_id)
+				*value = get_unaligned_le64(&resp->readings);
+			else
+				ret = -EPROTO;
+		}
 	} else {
 		sensor->flags = cpu_to_le32(0);
 		ret = scmi_do_xfer(handle, t);
@@ -262,6 +732,84 @@ static int scmi_sensor_reading_get(const struct scmi_handle *handle,
 	return ret;
 }
 
+static inline void
+scmi_parse_sensor_readings(struct scmi_sensor_reading *out,
+			   const struct scmi_sensor_reading_resp *in)
+{
+	out->value = get_unaligned_le64((void *)&in->sensor_value_low);
+	out->timestamp = get_unaligned_le64((void *)&in->timestamp_low);
+}
+
+/**
+ * scmi_sensor_reading_get_timestamped  - Read multiple-axis timestamped values
+ * @handle: Platform handle
+ * @sensor_id: Sensor ID
+ * @count: The length of the provided @readings array
+ * @readings: An array of elements each representing a timestamped per-axis
+ *	      reading of type @struct scmi_sensor_reading.
+ *	      Returned readings are ordered as the @axis descriptors array
+ *	      included in @struct scmi_sensor_info and the max number of
+ *	      returned elements is min(@count, @num_axis); ideally the provided
+ *	      array should be of length @count equal to @num_axis.
+ *
+ * Return: 0 on Success
+ */
+static int
+scmi_sensor_reading_get_timestamped(const struct scmi_handle *handle,
+				    u32 sensor_id, u8 count,
+				    struct scmi_sensor_reading *readings)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct scmi_msg_sensor_reading_get *sensor;
+	struct sensors_info *si = handle->sensor_priv;
+	struct scmi_sensor_info *s = si->sensors + sensor_id;
+
+	if (!count || !readings ||
+	    (!s->num_axis && count > 1) || (s->num_axis && count > s->num_axis))
+		return -EINVAL;
+
+	ret = scmi_xfer_get_init(handle, SENSOR_READING_GET,
+				 SCMI_PROTOCOL_SENSOR, sizeof(*sensor), 0, &t);
+	if (ret)
+		return ret;
+
+	sensor = t->tx.buf;
+	sensor->id = cpu_to_le32(sensor_id);
+	if (s->async) {
+		sensor->flags = cpu_to_le32(SENSOR_READ_ASYNC);
+		ret = scmi_do_xfer_with_response(handle, t);
+		if (!ret) {
+			int i;
+			struct scmi_resp_sensor_reading_complete_v3 *resp;
+
+			resp = t->rx.buf;
+			/* Retrieve only the number of requested axis anyway */
+			if (le32_to_cpu(resp->id) == sensor_id)
+				for (i = 0; i < count; i++)
+					scmi_parse_sensor_readings(&readings[i],
+								   &resp->readings[i]);
+			else
+				ret = -EPROTO;
+		}
+	} else {
+		sensor->flags = cpu_to_le32(0);
+		ret = scmi_do_xfer(handle, t);
+		if (!ret) {
+			int i;
+			struct scmi_sensor_reading_resp *resp_readings;
+
+			resp_readings = t->rx.buf;
+			for (i = 0; i < count; i++)
+				scmi_parse_sensor_readings(&readings[i],
+							   &resp_readings[i]);
+		}
+	}
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
 static const struct scmi_sensor_info *
 scmi_sensor_info_get(const struct scmi_handle *handle, u32 sensor_id)
 {
@@ -282,6 +830,9 @@ static const struct scmi_sensor_ops sensor_ops = {
 	.info_get = scmi_sensor_info_get,
 	.trip_point_config = scmi_sensor_trip_point_config,
 	.reading_get = scmi_sensor_reading_get,
+	.reading_get_timestamped = scmi_sensor_reading_get_timestamped,
+	.config_get = scmi_sensor_config_get,
+	.config_set = scmi_sensor_config_set,
 };
 
 static int scmi_sensor_set_notify_enabled(const struct scmi_handle *handle,
@@ -289,7 +840,19 @@ static int scmi_sensor_set_notify_enabled(const struct scmi_handle *handle,
 {
 	int ret;
 
-	ret = scmi_sensor_trip_point_notify(handle, src_id, enable);
+	switch (evt_id) {
+	case SCMI_EVENT_SENSOR_TRIP_POINT_EVENT:
+		ret = scmi_sensor_trip_point_notify(handle, src_id, enable);
+		break;
+	case SCMI_EVENT_SENSOR_UPDATE:
+		ret = scmi_sensor_continuous_update_notify(handle, src_id,
+							   enable);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
 	if (ret)
 		pr_debug("FAIL_ENABLED - evt[%X] dom[%d] - ret:%d\n",
 			 evt_id, src_id, ret);
@@ -302,20 +865,59 @@ static void *scmi_sensor_fill_custom_report(const struct scmi_handle *handle,
 					    const void *payld, size_t payld_sz,
 					    void *report, u32 *src_id)
 {
-	const struct scmi_sensor_trip_notify_payld *p = payld;
-	struct scmi_sensor_trip_point_report *r = report;
+	void *rep = NULL;
+
+	switch (evt_id) {
+	case SCMI_EVENT_SENSOR_TRIP_POINT_EVENT:
+	{
+		const struct scmi_sensor_trip_notify_payld *p = payld;
+		struct scmi_sensor_trip_point_report *r = report;
 
-	if (evt_id != SCMI_EVENT_SENSOR_TRIP_POINT_EVENT ||
-	    sizeof(*p) != payld_sz)
-		return NULL;
+		if (sizeof(*p) != payld_sz)
+			break;
 
-	r->timestamp = timestamp;
-	r->agent_id = le32_to_cpu(p->agent_id);
-	r->sensor_id = le32_to_cpu(p->sensor_id);
-	r->trip_point_desc = le32_to_cpu(p->trip_point_desc);
-	*src_id = r->sensor_id;
+		r->timestamp = timestamp;
+		r->agent_id = le32_to_cpu(p->agent_id);
+		r->sensor_id = le32_to_cpu(p->sensor_id);
+		r->trip_point_desc = le32_to_cpu(p->trip_point_desc);
+		*src_id = r->sensor_id;
+		rep = r;
+		break;
+	}
+	case SCMI_EVENT_SENSOR_UPDATE:
+	{
+		int i;
+		struct scmi_sensor_info *s;
+		const struct scmi_sensor_update_notify_payld *p = payld;
+		struct scmi_sensor_update_report *r = report;
+		struct sensors_info *sinfo = handle->sensor_priv;
+
+		/* payld_sz is variable for this event */
+		r->sensor_id = le32_to_cpu(p->sensor_id);
+		if (r->sensor_id >= sinfo->num_sensors)
+			break;
+		r->timestamp = timestamp;
+		r->agent_id = le32_to_cpu(p->agent_id);
+		s = &sinfo->sensors[r->sensor_id];
+		/*
+		 * The generated report r (@struct scmi_sensor_update_report)
+		 * was pre-allocated to contain up to SCMI_MAX_NUM_SENSOR_AXIS
+		 * readings: here it is filled with the effective @num_axis
+		 * readings defined for this sensor or 1 for scalar sensors.
+		 */
+		r->readings_count = s->num_axis ?: 1;
+		for (i = 0; i < r->readings_count; i++)
+			scmi_parse_sensor_readings(&r->readings[i],
+						   &p->readings[i]);
+		*src_id = r->sensor_id;
+		rep = r;
+		break;
+	}
+	default:
+		break;
+	}
 
-	return r;
+	return rep;
 }
 
 static const struct scmi_event sensor_events[] = {
@@ -324,6 +926,16 @@ static const struct scmi_event sensor_events[] = {
 		.max_payld_sz = sizeof(struct scmi_sensor_trip_notify_payld),
 		.max_report_sz = sizeof(struct scmi_sensor_trip_point_report),
 	},
+	{
+		.id = SCMI_EVENT_SENSOR_UPDATE,
+		.max_payld_sz =
+			sizeof(struct scmi_sensor_update_notify_payld) +
+			 SCMI_MAX_NUM_SENSOR_AXIS *
+			 sizeof(struct scmi_sensor_reading_resp),
+		.max_report_sz = sizeof(struct scmi_sensor_update_report) +
+				  SCMI_MAX_NUM_SENSOR_AXIS *
+				  sizeof(struct scmi_sensor_reading),
+	},
 };
 
 static const struct scmi_event_ops sensor_event_ops = {
@@ -334,6 +946,7 @@ static const struct scmi_event_ops sensor_event_ops = {
 static int scmi_sensors_protocol_init(struct scmi_handle *handle)
 {
 	u32 version;
+	int ret;
 	struct sensors_info *sinfo;
 
 	scmi_version_get(handle, SCMI_PROTOCOL_SENSOR, &version);
@@ -344,15 +957,19 @@ static int scmi_sensors_protocol_init(struct scmi_handle *handle)
 	sinfo = devm_kzalloc(handle->dev, sizeof(*sinfo), GFP_KERNEL);
 	if (!sinfo)
 		return -ENOMEM;
+	sinfo->version = version;
 
-	scmi_sensor_attributes_get(handle, sinfo);
-
+	ret = scmi_sensor_attributes_get(handle, sinfo);
+	if (ret)
+		return ret;
 	sinfo->sensors = devm_kcalloc(handle->dev, sinfo->num_sensors,
 				      sizeof(*sinfo->sensors), GFP_KERNEL);
 	if (!sinfo->sensors)
 		return -ENOMEM;
 
-	scmi_sensor_description_get(handle, sinfo);
+	ret = scmi_sensor_description_get(handle, sinfo);
+	if (ret)
+		return ret;
 
 	scmi_register_protocol_events(handle,
 				      SCMI_PROTOCOL_SENSOR, SCMI_PROTO_QUEUE_SZ,
@@ -360,9 +977,8 @@ static int scmi_sensors_protocol_init(struct scmi_handle *handle)
 				      ARRAY_SIZE(sensor_events),
 				      sinfo->num_sensors);
 
-	sinfo->version = version;
-	handle->sensor_ops = &sensor_ops;
 	handle->sensor_priv = sinfo;
+	handle->sensor_ops = &sensor_ops;
 
 	return 0;
 }
diff --git a/drivers/firmware/arm_scmi/voltage.c b/drivers/firmware/arm_scmi/voltage.c
new file mode 100644
index 000000000000..e794e4349ae6
--- /dev/null
+++ b/drivers/firmware/arm_scmi/voltage.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Voltage Protocol
+ *
+ * Copyright (C) 2020 ARM Ltd.
+ */
+
+#include <linux/scmi_protocol.h>
+
+#include "common.h"
+
+#define VOLTAGE_DOMS_NUM_MASK		GENMASK(15, 0)
+#define REMAINING_LEVELS_MASK		GENMASK(31, 16)
+#define RETURNED_LEVELS_MASK		GENMASK(11, 0)
+
+enum scmi_voltage_protocol_cmd {
+	VOLTAGE_DOMAIN_ATTRIBUTES = 0x3,
+	VOLTAGE_DESCRIBE_LEVELS = 0x4,
+	VOLTAGE_CONFIG_SET = 0x5,
+	VOLTAGE_CONFIG_GET = 0x6,
+	VOLTAGE_LEVEL_SET = 0x7,
+	VOLTAGE_LEVEL_GET = 0x8,
+};
+
+#define NUM_VOLTAGE_DOMAINS(x)	((u16)(FIELD_GET(VOLTAGE_DOMS_NUM_MASK, (x))))
+
+struct scmi_msg_resp_domain_attributes {
+	__le32 attr;
+	u8 name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_msg_cmd_describe_levels {
+	__le32 domain_id;
+	__le32 level_index;
+};
+
+struct scmi_msg_resp_describe_levels {
+	__le32 flags;
+#define NUM_REMAINING_LEVELS(f)	((u16)(FIELD_GET(REMAINING_LEVELS_MASK, (f))))
+#define NUM_RETURNED_LEVELS(f)	((u16)(FIELD_GET(RETURNED_LEVELS_MASK, (f))))
+#define SUPPORTS_SEGMENTED_LEVELS(f)	((f) & BIT(12))
+	__le32 voltage[];
+};
+
+struct scmi_msg_cmd_config_set {
+	__le32 domain_id;
+	__le32 config;
+};
+
+struct scmi_msg_cmd_level_set {
+	__le32 domain_id;
+	__le32 flags;
+	__le32 voltage_level;
+};
+
+struct voltage_info {
+	unsigned int version;
+	unsigned int num_domains;
+	struct scmi_voltage_info *domains;
+};
+
+static int scmi_protocol_attributes_get(const struct scmi_handle *handle,
+					struct voltage_info *vinfo)
+{
+	int ret;
+	struct scmi_xfer *t;
+
+	ret = scmi_xfer_get_init(handle, PROTOCOL_ATTRIBUTES,
+				 SCMI_PROTOCOL_VOLTAGE, 0, sizeof(__le32), &t);
+	if (ret)
+		return ret;
+
+	ret = scmi_do_xfer(handle, t);
+	if (!ret)
+		vinfo->num_domains =
+			NUM_VOLTAGE_DOMAINS(get_unaligned_le32(t->rx.buf));
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+static int scmi_init_voltage_levels(struct device *dev,
+				    struct scmi_voltage_info *v,
+				    u32 num_returned, u32 num_remaining,
+				    bool segmented)
+{
+	u32 num_levels;
+
+	num_levels = num_returned + num_remaining;
+	/*
+	 * segmented levels entries are represented by a single triplet
+	 * returned all in one go.
+	 */
+	if (!num_levels ||
+	    (segmented && (num_remaining || num_returned != 3))) {
+		dev_err(dev,
+			"Invalid level descriptor(%d/%d/%d) for voltage dom %d\n",
+			num_levels, num_returned, num_remaining, v->id);
+		return -EINVAL;
+	}
+
+	v->levels_uv = devm_kcalloc(dev, num_levels, sizeof(u32), GFP_KERNEL);
+	if (!v->levels_uv)
+		return -ENOMEM;
+
+	v->num_levels = num_levels;
+	v->segmented = segmented;
+
+	return 0;
+}
+
+static int scmi_voltage_descriptors_get(const struct scmi_handle *handle,
+					struct voltage_info *vinfo)
+{
+	int ret, dom;
+	struct scmi_xfer *td, *tl;
+	struct device *dev = handle->dev;
+	struct scmi_msg_resp_domain_attributes *resp_dom;
+	struct scmi_msg_resp_describe_levels *resp_levels;
+
+	ret = scmi_xfer_get_init(handle, VOLTAGE_DOMAIN_ATTRIBUTES,
+				 SCMI_PROTOCOL_VOLTAGE, sizeof(__le32),
+				 sizeof(*resp_dom), &td);
+	if (ret)
+		return ret;
+	resp_dom = td->rx.buf;
+
+	ret = scmi_xfer_get_init(handle, VOLTAGE_DESCRIBE_LEVELS,
+				 SCMI_PROTOCOL_VOLTAGE, sizeof(__le64), 0, &tl);
+	if (ret)
+		goto outd;
+	resp_levels = tl->rx.buf;
+
+	for (dom = 0; dom < vinfo->num_domains; dom++) {
+		u32 desc_index = 0;
+		u16 num_returned = 0, num_remaining = 0;
+		struct scmi_msg_cmd_describe_levels *cmd;
+		struct scmi_voltage_info *v;
+
+		/* Retrieve domain attributes at first ... */
+		put_unaligned_le32(dom, td->tx.buf);
+		ret = scmi_do_xfer(handle, td);
+		/* Skip domain on comms error */
+		if (ret)
+			continue;
+
+		v = vinfo->domains + dom;
+		v->id = dom;
+		v->attributes = le32_to_cpu(resp_dom->attr);
+		strlcpy(v->name, resp_dom->name, SCMI_MAX_STR_SIZE);
+
+		cmd = tl->tx.buf;
+		/* ...then retrieve domain levels descriptions */
+		do {
+			u32 flags;
+			int cnt;
+
+			cmd->domain_id = cpu_to_le32(v->id);
+			cmd->level_index = desc_index;
+			ret = scmi_do_xfer(handle, tl);
+			if (ret)
+				break;
+
+			flags = le32_to_cpu(resp_levels->flags);
+			num_returned = NUM_RETURNED_LEVELS(flags);
+			num_remaining = NUM_REMAINING_LEVELS(flags);
+
+			/* Allocate space for num_levels if not already done */
+			if (!v->num_levels) {
+				ret = scmi_init_voltage_levels(dev, v,
+							       num_returned,
+							       num_remaining,
+					      SUPPORTS_SEGMENTED_LEVELS(flags));
+				if (ret)
+					break;
+			}
+
+			if (desc_index + num_returned > v->num_levels) {
+				dev_err(handle->dev,
+					"No. of voltage levels can't exceed %d\n",
+					v->num_levels);
+				ret = -EINVAL;
+				break;
+			}
+
+			for (cnt = 0; cnt < num_returned; cnt++) {
+				s32 val;
+
+				val =
+				    (s32)le32_to_cpu(resp_levels->voltage[cnt]);
+				v->levels_uv[desc_index + cnt] = val;
+				if (val < 0)
+					v->negative_volts_allowed = true;
+			}
+
+			desc_index += num_returned;
+
+			scmi_reset_rx_to_maxsz(handle, tl);
+			/* check both to avoid infinite loop due to buggy fw */
+		} while (num_returned && num_remaining);
+
+		if (ret) {
+			v->num_levels = 0;
+			devm_kfree(dev, v->levels_uv);
+		}
+
+		scmi_reset_rx_to_maxsz(handle, td);
+	}
+
+	scmi_xfer_put(handle, tl);
+outd:
+	scmi_xfer_put(handle, td);
+
+	return ret;
+}
+
+static int __scmi_voltage_get_u32(const struct scmi_handle *handle,
+				  u8 cmd_id, u32 domain_id, u32 *value)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = handle->voltage_priv;
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = scmi_xfer_get_init(handle, cmd_id,
+				 SCMI_PROTOCOL_VOLTAGE,
+				 sizeof(__le32), 0, &t);
+	if (ret)
+		return ret;
+
+	put_unaligned_le32(domain_id, t->tx.buf);
+	ret = scmi_do_xfer(handle, t);
+	if (!ret)
+		*value = get_unaligned_le32(t->rx.buf);
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+static int scmi_voltage_config_set(const struct scmi_handle *handle,
+				   u32 domain_id, u32 config)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = handle->voltage_priv;
+	struct scmi_msg_cmd_config_set *cmd;
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = scmi_xfer_get_init(handle, VOLTAGE_CONFIG_SET,
+				 SCMI_PROTOCOL_VOLTAGE,
+				 sizeof(*cmd), 0, &t);
+	if (ret)
+		return ret;
+
+	cmd = t->tx.buf;
+	cmd->domain_id = cpu_to_le32(domain_id);
+	cmd->config = cpu_to_le32(config & GENMASK(3, 0));
+
+	ret = scmi_do_xfer(handle, t);
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+static int scmi_voltage_config_get(const struct scmi_handle *handle,
+				   u32 domain_id, u32 *config)
+{
+	return __scmi_voltage_get_u32(handle, VOLTAGE_CONFIG_GET,
+				      domain_id, config);
+}
+
+static int scmi_voltage_level_set(const struct scmi_handle *handle,
+				  u32 domain_id, u32 flags, s32 volt_uV)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct voltage_info *vinfo = handle->voltage_priv;
+	struct scmi_msg_cmd_level_set *cmd;
+
+	if (domain_id >= vinfo->num_domains)
+		return -EINVAL;
+
+	ret = scmi_xfer_get_init(handle, VOLTAGE_LEVEL_SET,
+				 SCMI_PROTOCOL_VOLTAGE,
+				 sizeof(*cmd), 0, &t);
+	if (ret)
+		return ret;
+
+	cmd = t->tx.buf;
+	cmd->domain_id = cpu_to_le32(domain_id);
+	cmd->flags = cpu_to_le32(flags);
+	cmd->voltage_level = cpu_to_le32(volt_uV);
+
+	ret = scmi_do_xfer(handle, t);
+
+	scmi_xfer_put(handle, t);
+	return ret;
+}
+
+static int scmi_voltage_level_get(const struct scmi_handle *handle,
+				  u32 domain_id, s32 *volt_uV)
+{
+	return __scmi_voltage_get_u32(handle, VOLTAGE_LEVEL_GET,
+				      domain_id, (u32 *)volt_uV);
+}
+
+static const struct scmi_voltage_info * __must_check
+scmi_voltage_info_get(const struct scmi_handle *handle, u32 domain_id)
+{
+	struct voltage_info *vinfo = handle->voltage_priv;
+
+	if (domain_id >= vinfo->num_domains ||
+	    !vinfo->domains[domain_id].num_levels)
+		return NULL;
+
+	return vinfo->domains + domain_id;
+}
+
+static int scmi_voltage_domains_num_get(const struct scmi_handle *handle)
+{
+	struct voltage_info *vinfo = handle->voltage_priv;
+
+	return vinfo->num_domains;
+}
+
+static struct scmi_voltage_ops voltage_ops = {
+	.num_domains_get = scmi_voltage_domains_num_get,
+	.info_get = scmi_voltage_info_get,
+	.config_set = scmi_voltage_config_set,
+	.config_get = scmi_voltage_config_get,
+	.level_set = scmi_voltage_level_set,
+	.level_get = scmi_voltage_level_get,
+};
+
+static int scmi_voltage_protocol_init(struct scmi_handle *handle)
+{
+	int ret;
+	u32 version;
+	struct voltage_info *vinfo;
+
+	ret = scmi_version_get(handle, SCMI_PROTOCOL_VOLTAGE, &version);
+	if (ret)
+		return ret;
+
+	dev_dbg(handle->dev, "Voltage Version %d.%d\n",
+		PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+	vinfo = devm_kzalloc(handle->dev, sizeof(*vinfo), GFP_KERNEL);
+	if (!vinfo)
+		return -ENOMEM;
+	vinfo->version = version;
+
+	ret = scmi_protocol_attributes_get(handle, vinfo);
+	if (ret)
+		return ret;
+
+	if (vinfo->num_domains) {
+		vinfo->domains = devm_kcalloc(handle->dev, vinfo->num_domains,
+					      sizeof(*vinfo->domains),
+					      GFP_KERNEL);
+		if (!vinfo->domains)
+			return -ENOMEM;
+		ret = scmi_voltage_descriptors_get(handle, vinfo);
+		if (ret)
+			return ret;
+	} else {
+		dev_warn(handle->dev, "No Voltage domains found.\n");
+	}
+
+	handle->voltage_ops = &voltage_ops;
+	handle->voltage_priv = vinfo;
+
+	return 0;
+}
+
+DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(SCMI_PROTOCOL_VOLTAGE, voltage)