[RFC v2 1/3] firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support

[Oleksii Moisieiev <Oleksii_Moisieiev@xxxxxxxx>]

scmi: Introduce pinctrl SCMI protocol driver

Add basic implementation of the SCMI v3.2 pincontrol protocol
excluding GPIO support. All pinctrl related callbacks and operations
are exposed in the include/linux/scmi_protocol.h

Signed-off-by: Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx>
---
 MAINTAINERS                           |   6 +
 drivers/firmware/arm_scmi/Makefile    |   3 +-
 drivers/firmware/arm_scmi/driver.c    |   2 +
 drivers/firmware/arm_scmi/pinctrl.c   | 932 ++++++++++++++++++++++++++
 drivers/firmware/arm_scmi/protocols.h |   1 +
 include/linux/scmi_protocol.h         |  47 ++
 6 files changed, 990 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/arm_scmi/pinctrl.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 0e64787aace8..0d251ebac437 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20317,6 +20317,12 @@ F:	include/linux/sc[mp]i_protocol.h
 F:	include/trace/events/scmi.h
 F:	include/uapi/linux/virtio_scmi.h
 
+PINCTRL DRIVER FOR SYSTEM CONTROL & POWER/MANAGEMENT INTERFACE (SCPI/SCMI)
+M:	Oleksii Moisieiev <oleksii_moisieiev@xxxxxxxx>
+L:	linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
+S:	Maintained
+F:	drivers/firmware/arm_scmi/pinctrl.c
+
 SYSTEM RESET/SHUTDOWN DRIVERS
 M:	Sebastian Reichel <sre@xxxxxxxxxx>
 L:	linux-pm@xxxxxxxxxxxxxxx
diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index b31d78fa66cc..071ac65f22b9 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -3,6 +3,7 @@ scmi-bus-y = bus.o
 scmi-core-objs := $(scmi-bus-y)
 
 scmi-driver-y = driver.o notify.o
+
 scmi-driver-$(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT) += raw_mode.o
 scmi-transport-$(CONFIG_ARM_SCMI_HAVE_SHMEM) = shmem.o
 scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_MAILBOX) += mailbox.o
@@ -10,7 +11,7 @@ scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_SMC) += smc.o
 scmi-transport-$(CONFIG_ARM_SCMI_HAVE_MSG) += msg.o
 scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_VIRTIO) += virtio.o
 scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_OPTEE) += optee.o
-scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o powercap.o
+scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o powercap.o pinctrl.o
 scmi-module-objs := $(scmi-driver-y) $(scmi-protocols-y) $(scmi-transport-y)
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-core.o
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index dbc474ff62b7..fc7ba587ae6e 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -3021,6 +3021,7 @@ static int __init scmi_driver_init(void)
 	scmi_voltage_register();
 	scmi_system_register();
 	scmi_powercap_register();
+	scmi_pinctrl_register();
 
 	return platform_driver_register(&scmi_driver);
 }
@@ -3038,6 +3039,7 @@ static void __exit scmi_driver_exit(void)
 	scmi_voltage_unregister();
 	scmi_system_unregister();
 	scmi_powercap_unregister();
+	scmi_pinctrl_unregister();
 
 	scmi_transports_exit();
 
diff --git a/drivers/firmware/arm_scmi/pinctrl.c b/drivers/firmware/arm_scmi/pinctrl.c
new file mode 100644
index 000000000000..1c643d21390f
--- /dev/null
+++ b/drivers/firmware/arm_scmi/pinctrl.c
@@ -0,0 +1,932 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Pinctrl Protocol
+ *
+ * Copyright (C) 2023 EPAM
+ */
+
+#include <linux/module.h>
+#include <linux/scmi_protocol.h>
+#include <linux/slab.h>
+
+#include "protocols.h"
+
+#define SET_TYPE(x) FIELD_PREP(GENMASK(1, 0), (x))
+
+#define REG_TYPE_BITS GENMASK(9, 8)
+#define REG_CONFIG GENMASK(7, 0)
+
+#define GET_GROUPS_NR(x) FIELD_GET(GENMASK(31, 16), (x))
+#define GET_PINS_NR(x) FIELD_GET(GENMASK(15, 0), (x))
+#define GET_FUNCTIONS_NR(x) FIELD_GET(GENMASK(15, 0), (x))
+
+#define EXT_NAME_FLAG(x) FIELD_GET(BIT(31), (x))
+#define NUM_ELEMS(x) FIELD_GET(GENMASK(15, 0), (x))
+
+#define REMAINING(x) FIELD_GET(GENMASK(31, 16), (x))
+#define RETURNED(x) FIELD_GET(GENMASK(11, 0), (x))
+
+enum scmi_pinctrl_protocol_cmd {
+	PINCTRL_ATTRIBUTES = 0x3,
+	PINCTRL_LIST_ASSOCIATIONS = 0x4,
+	PINCTRL_CONFIG_GET = 0x5,
+	PINCTRL_CONFIG_SET = 0x6,
+	PINCTRL_FUNCTION_SELECT = 0x7,
+	PINCTRL_REQUEST = 0x8,
+	PINCTRL_RELEASE = 0x9,
+	PINCTRL_NAME_GET = 0xa,
+	PINCTRL_SET_PERMISSIONS = 0xb
+};
+
+struct scmi_msg_conf_set {
+	__le32 identifier;
+	__le32 attributes;
+	__le32 config_value;
+};
+
+struct scmi_msg_conf_get {
+	__le32 identifier;
+	__le32 attributes;
+};
+
+struct scmi_msg_pinctrl_protocol_attributes {
+	__le32 attributes_low;
+	__le32 attributes_high;
+};
+
+struct scmi_msg_ext_name {
+	__le32 identifier;
+	__le32 flags;
+};
+
+struct scmi_resp_ext_name {
+	__le32 flags;
+	u8 name[SCMI_MAX_STR_SIZE];
+};
+
+struct scmi_msg_pinctrl_attributes {
+	__le32 identifier;
+	__le32 flags;
+};
+
+struct scmi_resp_pinctrl_attributes {
+	__le32 attributes;
+	u8 name[SCMI_SHORT_NAME_MAX_SIZE];
+};
+
+struct scmi_msg_pinctrl_list_assoc {
+	__le32 identifier;
+	__le32 flags;
+	__le32 index;
+};
+
+struct scmi_resp_pinctrl_list_assoc {
+	__le32 flags;
+	__le16 array[];
+};
+
+struct scmi_msg_func_set {
+	__le32 identifier;
+	__le32 function_id;
+	__le32 flags;
+};
+
+struct scmi_msg_request {
+	__le32 identifier;
+	__le32 flags;
+};
+
+struct scmi_group_info {
+	bool present;
+	char *name;
+	unsigned int *group_pins;
+	unsigned int nr_pins;
+};
+
+struct scmi_function_info {
+	bool present;
+	char *name;
+	unsigned int *groups;
+	unsigned int nr_groups;
+};
+
+struct scmi_pin_info {
+	bool present;
+	char *name;
+};
+
+struct scmi_pinctrl_info {
+	u32 version;
+	int nr_groups;
+	int nr_functions;
+	int nr_pins;
+	struct scmi_group_info *groups;
+	struct scmi_function_info *functions;
+	struct scmi_pin_info *pins;
+};
+
+static int scmi_pinctrl_attributes_get(const struct scmi_protocol_handle *ph,
+				       struct scmi_pinctrl_info *pi)
+{
+	int ret;
+	struct scmi_xfer *t;
+	struct scmi_msg_pinctrl_protocol_attributes *attr;
+
+	if (!pi)
+		return -EINVAL;
+
+	ret = ph->xops->xfer_get_init(ph, PROTOCOL_ATTRIBUTES,
+				      0, sizeof(*attr), &t);
+	if (ret)
+		return ret;
+
+	attr = t->rx.buf;
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret) {
+		pi->nr_functions =
+			le16_to_cpu(GET_FUNCTIONS_NR(attr->attributes_high));
+		pi->nr_groups = le16_to_cpu(GET_GROUPS_NR(attr->attributes_low));
+		pi->nr_pins = le16_to_cpu(GET_PINS_NR(attr->attributes_low));
+	}
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_pinctrl_get_count(const struct scmi_protocol_handle *ph,
+				  enum scmi_pinctrl_selector_type type)
+{
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph)
+		return -ENODEV;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -ENODEV;
+
+	switch (type) {
+	case PIN_TYPE:
+		return pi->nr_pins;
+	case GROUP_TYPE:
+		return pi->nr_groups;
+	case FUNCTION_TYPE:
+		return pi->nr_functions;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int scmi_pinctrl_validate_id(const struct scmi_protocol_handle *ph,
+				    u32 identifier,
+				    enum scmi_pinctrl_selector_type type)
+{
+	int value;
+
+	if (!ph)
+		return -ENODEV;
+
+	value = scmi_pinctrl_get_count(ph, type);
+	if (value < 0)
+		return value;
+
+	if (identifier >= value)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int scmi_pinctrl_get_ext_name(const struct scmi_protocol_handle *ph,
+				     u32 identifier,
+				     enum scmi_pinctrl_selector_type type,
+				     char **name)
+{
+	struct scmi_xfer *t;
+	int ret = 0;
+	struct scmi_msg_ext_name *tx;
+	struct scmi_resp_ext_name *rx;
+
+	if (!ph || !name)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, identifier, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_NAME_GET, sizeof(*tx),
+				      sizeof(*rx), &t);
+
+	tx = t->tx.buf;
+	rx = t->rx.buf;
+	tx->identifier = identifier;
+	tx->flags = SET_TYPE(cpu_to_le32(type));
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (ret)
+		goto out;
+
+	if (rx->flags) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	*name = kasprintf(GFP_KERNEL, "%s", rx->name);
+	if (!*name)
+		ret = -ENOMEM;
+ out:
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_pinctrl_attributes(const struct scmi_protocol_handle *ph,
+				   enum scmi_pinctrl_selector_type type,
+				   u32 selector, char **name,
+				   unsigned int *n_elems)
+{
+	int ret = 0;
+	struct scmi_xfer *t;
+	struct scmi_msg_pinctrl_attributes *tx;
+	struct scmi_resp_pinctrl_attributes *rx;
+
+	if (!ph || !name)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, selector, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_ATTRIBUTES, sizeof(*tx),
+				      sizeof(*rx), &t);
+	if (ret)
+		return ret;
+
+	tx = t->tx.buf;
+	rx = t->rx.buf;
+	tx->identifier = selector;
+	tx->flags = SET_TYPE(cpu_to_le32(type));
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (ret)
+		goto out;
+
+	*n_elems = NUM_ELEMS(rx->attributes);
+
+	if (!EXT_NAME_FLAG(rx->attributes)) {
+		*name = kasprintf(GFP_KERNEL, "%s", rx->name);
+		if (!*name)
+			ret = -ENOMEM;
+	} else {
+		ret = scmi_pinctrl_get_ext_name(ph, selector, type, name);
+	}
+ out:
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+struct scmi_pinctrl_ipriv {
+	u32 selector;
+	enum scmi_pinctrl_selector_type type;
+	unsigned int *array;
+};
+
+static void iter_pinctrl_assoc_prepare_message(void *message,
+					       unsigned int desc_index,
+					       const void *priv)
+{
+	struct scmi_msg_pinctrl_list_assoc *msg = message;
+	const struct scmi_pinctrl_ipriv *p = priv;
+
+	msg->identifier = cpu_to_le32(p->selector);
+	msg->flags = SET_TYPE(cpu_to_le32(p->type));
+	/* Set the number of OPPs to be skipped/already read */
+	msg->index = cpu_to_le32(desc_index);
+}
+
+static int iter_pinctrl_assoc_update_state(struct scmi_iterator_state *st,
+					   const void *response, void *priv)
+{
+	const struct scmi_resp_pinctrl_list_assoc *r = response;
+
+	st->num_returned = le32_to_cpu(RETURNED(r->flags));
+	st->num_remaining = le32_to_cpu(REMAINING(r->flags));
+
+	return 0;
+}
+
+static int
+iter_pinctrl_assoc_process_response(const struct scmi_protocol_handle *ph,
+				    const void *response,
+				    struct scmi_iterator_state *st, void *priv)
+{
+	const struct scmi_resp_pinctrl_list_assoc *r = response;
+	struct scmi_pinctrl_ipriv *p = priv;
+
+	p->array[st->desc_index + st->loop_idx] =
+		le16_to_cpu(r->array[st->loop_idx]);
+
+	return 0;
+}
+
+static int scmi_pinctrl_list_associations(const struct scmi_protocol_handle *ph,
+					  u32 selector,
+					  enum scmi_pinctrl_selector_type type,
+					  u16 size, unsigned int *array)
+{
+	int ret;
+	void *iter;
+	struct scmi_iterator_ops ops = {
+		.prepare_message = iter_pinctrl_assoc_prepare_message,
+		.update_state = iter_pinctrl_assoc_update_state,
+		.process_response = iter_pinctrl_assoc_process_response,
+	};
+	struct scmi_pinctrl_ipriv ipriv = {
+		.selector = selector,
+		.type = type,
+		.array = array,
+	};
+
+	if (!ph || !array || !size)
+		return -EINVAL;
+
+	if (type == PIN_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, selector, type);
+	if (ret)
+		return ret;
+
+	iter = ph->hops->iter_response_init(ph, &ops, size,
+					    PINCTRL_LIST_ASSOCIATIONS,
+					    sizeof(struct scmi_msg_pinctrl_list_assoc),
+					    &ipriv);
+
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	return ph->hops->iter_response_run(iter);
+}
+
+static int scmi_pinctrl_get_config(const struct scmi_protocol_handle *ph,
+				   u32 selector,
+				   enum scmi_pinctrl_selector_type type,
+				   u8 config_type, u32 *config_value)
+{
+	struct scmi_xfer *t;
+	struct scmi_msg_conf_get *tx;
+	__le32 *le_config;
+	u32 attributes = 0;
+	int ret;
+
+	if (!ph || !config_value || type == FUNCTION_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, selector, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_CONFIG_GET, sizeof(*tx),
+				      sizeof(*le_config), &t);
+	if (ret)
+		return ret;
+
+	tx = t->tx.buf;
+	le_config = t->rx.buf;
+	tx->identifier = cpu_to_le32(selector);
+	attributes = FIELD_PREP(REG_TYPE_BITS, type) |
+		FIELD_PREP(REG_CONFIG, config_type);
+
+	tx->attributes = cpu_to_le32(attributes);
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	if (!ret)
+		*config_value = le32_to_cpu(*le_config);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_pinctrl_set_config(const struct scmi_protocol_handle *ph,
+				   u32 selector,
+				   enum scmi_pinctrl_selector_type type,
+				   u8 config_type, u32 config_value)
+{
+	struct scmi_xfer *t;
+	struct scmi_msg_conf_set *tx;
+	u32 attributes = 0;
+	int ret;
+
+	if (!ph || type == FUNCTION_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, selector, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_CONFIG_SET,
+				      sizeof(*tx), 0, &t);
+	if (ret)
+		return ret;
+
+	tx = t->tx.buf;
+	tx->identifier = cpu_to_le32(selector);
+	attributes = FIELD_PREP(REG_TYPE_BITS, type) |
+		FIELD_PREP(REG_CONFIG, config_type);
+	tx->attributes = cpu_to_le32(attributes);
+	tx->config_value = cpu_to_le32(config_value);
+
+	ret = ph->xops->do_xfer(ph, t);
+
+	ph->xops->xfer_put(ph, t);
+	return ret;
+}
+
+static int scmi_pinctrl_function_select(const struct scmi_protocol_handle *ph,
+					u32 identifier,
+					enum scmi_pinctrl_selector_type type,
+					u32 function_id)
+{
+	struct scmi_xfer *t;
+	struct scmi_msg_func_set *tx;
+	int ret;
+
+	if (!ph || type == FUNCTION_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, identifier, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_FUNCTION_SELECT,
+				      sizeof(*tx), 0, &t);
+	if (ret)
+		return ret;
+
+	tx = t->tx.buf;
+	tx->identifier = cpu_to_le32(identifier);
+	tx->function_id = cpu_to_le32(function_id);
+	tx->flags = SET_TYPE(cpu_to_le32(type));
+
+	ret = ph->xops->do_xfer(ph, t);
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_pinctrl_request(const struct scmi_protocol_handle *ph,
+				u32 identifier,
+				enum scmi_pinctrl_selector_type type)
+{
+	struct scmi_xfer *t;
+	int ret;
+	struct scmi_msg_request *tx;
+
+	if (!ph || type == FUNCTION_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, identifier, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_REQUEST, sizeof(*tx),
+				      0, &t);
+
+	tx = t->tx.buf;
+	tx->identifier = identifier;
+	tx->flags = SET_TYPE(cpu_to_le32(type));
+
+	ret = ph->xops->do_xfer(ph, t);
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_pinctrl_request_pin(const struct scmi_protocol_handle *ph,
+				    u32 pin)
+{
+	return scmi_pinctrl_request(ph, pin, PIN_TYPE);
+}
+
+static int scmi_pinctrl_free(const struct scmi_protocol_handle *ph,
+			     u32 identifier,
+			     enum scmi_pinctrl_selector_type type)
+{
+	struct scmi_xfer *t;
+	int ret;
+	struct scmi_msg_request *tx;
+
+	if (!ph || type == FUNCTION_TYPE)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_validate_id(ph, identifier, type);
+	if (ret)
+		return ret;
+
+	ret = ph->xops->xfer_get_init(ph, PINCTRL_RELEASE,
+				      sizeof(*tx), 0, &t);
+
+	tx = t->tx.buf;
+	tx->identifier = identifier;
+	tx->flags = SET_TYPE(cpu_to_le32(type));
+
+	ret = ph->xops->do_xfer(ph, t);
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
+static int scmi_pinctrl_free_pin(const struct scmi_protocol_handle *ph, u32 pin)
+{
+	return scmi_pinctrl_free(ph, pin, PIN_TYPE);
+}
+
+static int scmi_pinctrl_get_group_info(const struct scmi_protocol_handle *ph,
+				       u32 selector,
+				       struct scmi_group_info *group)
+{
+	int ret = 0;
+
+	if (!ph || !group)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_attributes(ph, GROUP_TYPE, selector,
+				      &group->name,
+				      &group->nr_pins);
+	if (ret)
+		return ret;
+
+	if (!group->nr_pins) {
+		dev_err(ph->dev, "Group %d has 0 elements", selector);
+		return -ENODATA;
+	}
+
+	group->group_pins = devm_kmalloc_array(ph->dev, group->nr_pins,
+					       sizeof(*group->group_pins),
+					       GFP_KERNEL);
+	if (!group->group_pins) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = scmi_pinctrl_list_associations(ph, selector, GROUP_TYPE,
+					     group->nr_pins, group->group_pins);
+	if (ret)
+		goto err_groups;
+
+	group->present = true;
+	return 0;
+
+ err_groups:
+	kfree(group->group_pins);
+ err:
+	kfree(group->name);
+	return ret;
+}
+
+static int scmi_pinctrl_get_group_name(const struct scmi_protocol_handle *ph,
+				       u32 selector, const char **name)
+{
+	int ret;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph || !name)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	if (selector > pi->nr_groups)
+		return -EINVAL;
+
+	if (!pi->groups[selector].present) {
+		ret = scmi_pinctrl_get_group_info(ph, selector,
+						  &pi->groups[selector]);
+		if (ret)
+			return ret;
+	}
+
+	*name = pi->groups[selector].name;
+
+	return 0;
+}
+
+static int scmi_pinctrl_get_group_pins(const struct scmi_protocol_handle *ph,
+				       u32 selector, const unsigned int **pins,
+				       unsigned int *nr_pins)
+{
+	int ret;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph || !pins || !nr_pins)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	if (selector > pi->nr_groups)
+		return -EINVAL;
+
+	if (!pi->groups[selector].present) {
+		ret = scmi_pinctrl_get_group_info(ph, selector,
+						  &pi->groups[selector]);
+		if (ret)
+			return ret;
+	}
+
+	*pins = pi->groups[selector].group_pins;
+	*nr_pins = pi->groups[selector].nr_pins;
+
+	return ret;
+}
+
+static int scmi_pinctrl_get_function_info(const struct scmi_protocol_handle *ph,
+					  u32 selector,
+					  struct scmi_function_info *func)
+{
+	int ret = 0;
+
+	if (!ph || !func)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_attributes(ph, FUNCTION_TYPE, selector,
+				      &func->name,
+				      &func->nr_groups);
+	if (ret)
+		return ret;
+
+	if (!func->nr_groups) {
+		dev_err(ph->dev, "Function %d has 0 elements", selector);
+		return -ENODATA;
+	}
+
+	func->groups = devm_kmalloc_array(ph->dev, func->nr_groups,
+					  sizeof(*func->groups),
+					  GFP_KERNEL);
+	if (!func->groups) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	ret = scmi_pinctrl_list_associations(ph, selector, FUNCTION_TYPE,
+					     func->nr_groups, func->groups);
+	if (ret)
+		goto err_funcs;
+
+	func->present = true;
+	return 0;
+
+ err_funcs:
+	kfree(func->groups);
+ err:
+	kfree(func->name);
+	return ret;
+}
+
+static int scmi_pinctrl_get_function_name(const struct scmi_protocol_handle *ph,
+					  u32 selector, const char **name)
+{
+	int ret;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph || !name)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	if (selector > pi->nr_functions)
+		return -EINVAL;
+
+	if (!pi->functions[selector].present) {
+		ret = scmi_pinctrl_get_function_info(ph, selector,
+						     &pi->functions[selector]);
+		if (ret)
+			return ret;
+	}
+
+	*name = pi->functions[selector].name;
+	return 0;
+}
+
+static int scmi_pinctrl_get_function_groups(const struct scmi_protocol_handle *ph,
+					    u32 selector,
+					    unsigned int *nr_groups,
+					    const unsigned int **groups)
+{
+	int ret;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph || !groups || !nr_groups)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	if (selector > pi->nr_functions)
+		return -EINVAL;
+
+	if (!pi->functions[selector].present) {
+		ret = scmi_pinctrl_get_function_info(ph, selector,
+						     &pi->functions[selector]);
+		if (ret)
+			return ret;
+	}
+
+	*groups = pi->functions[selector].groups;
+	*nr_groups = pi->functions[selector].nr_groups;
+
+	return ret;
+}
+
+static int scmi_pinctrl_set_mux(const struct scmi_protocol_handle *ph,
+				u32 selector, u32 group)
+{
+	return scmi_pinctrl_function_select(ph, group, GROUP_TYPE,
+					    selector);
+}
+
+static int scmi_pinctrl_get_pin_info(const struct scmi_protocol_handle *ph,
+				     u32 selector, struct scmi_pin_info *pin)
+{
+	int ret = 0;
+	struct scmi_pinctrl_info *pi;
+	unsigned int n_elems;
+
+	if (!ph || !pin)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	ret = scmi_pinctrl_attributes(ph, PIN_TYPE, selector,
+				      &pin->name,
+				      &n_elems);
+	if (ret)
+		return ret;
+
+	if (n_elems != pi->nr_pins) {
+		dev_err(ph->dev, "Wrong pin count expected %d has %d",
+			pi->nr_pins, n_elems);
+		return -ENODATA;
+	}
+
+	if (*pin->name == 0) {
+		dev_err(ph->dev, "Pin name is empty");
+		goto err;
+	}
+
+	pin->present = true;
+	return 0;
+
+ err:
+	kfree(pin->name);
+	return ret;
+}
+
+static int scmi_pinctrl_get_pin_name(const struct scmi_protocol_handle *ph,
+				     u32 selector, const char **name)
+{
+	int ret;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph || !name)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	if (selector > pi->nr_pins)
+		return -EINVAL;
+
+	if (!pi->pins[selector].present) {
+		ret = scmi_pinctrl_get_pin_info(ph, selector,
+						&pi->pins[selector]);
+		if (ret)
+			return ret;
+	}
+
+	*name = pi->pins[selector].name;
+
+	return 0;
+}
+
+static int scmi_pinctrl_get_name(const struct scmi_protocol_handle *ph,
+				 u32 selector,
+				 enum scmi_pinctrl_selector_type type,
+				 const char **name)
+{
+	switch (type) {
+	case PIN_TYPE:
+		return scmi_pinctrl_get_pin_name(ph, selector, name);
+	case GROUP_TYPE:
+		return scmi_pinctrl_get_group_name(ph, selector, name);
+	case FUNCTION_TYPE:
+		return scmi_pinctrl_get_function_name(ph, selector, name);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct scmi_pinctrl_proto_ops pinctrl_proto_ops = {
+	.get_count = scmi_pinctrl_get_count,
+	.get_name = scmi_pinctrl_get_name,
+	.get_group_pins = scmi_pinctrl_get_group_pins,
+	.get_function_groups = scmi_pinctrl_get_function_groups,
+	.set_mux = scmi_pinctrl_set_mux,
+	.get_config = scmi_pinctrl_get_config,
+	.set_config = scmi_pinctrl_set_config,
+	.request_pin = scmi_pinctrl_request_pin,
+	.free_pin = scmi_pinctrl_free_pin
+};
+
+static int scmi_pinctrl_protocol_init(const struct scmi_protocol_handle *ph)
+{
+	u32 version;
+	struct scmi_pinctrl_info *pinfo;
+	int ret;
+
+	if (!ph)
+		return -EINVAL;
+
+	ret = ph->xops->version_get(ph, &version);
+	if (ret)
+		return ret;
+
+	dev_dbg(ph->dev, "Pinctrl Version %d.%d\n",
+		PROTOCOL_REV_MAJOR(version), PROTOCOL_REV_MINOR(version));
+
+	pinfo = devm_kzalloc(ph->dev, sizeof(*pinfo), GFP_KERNEL);
+	if (!pinfo)
+		return -ENOMEM;
+
+	ret = scmi_pinctrl_attributes_get(ph, pinfo);
+	if (ret)
+		return ret;
+
+	pinfo->pins = devm_kcalloc(ph->dev, pinfo->nr_pins,
+				   sizeof(*pinfo->pins),
+				   GFP_KERNEL);
+	if (!pinfo->pins)
+		return -ENOMEM;
+
+	pinfo->groups = devm_kcalloc(ph->dev, pinfo->nr_groups,
+				     sizeof(*pinfo->groups),
+				     GFP_KERNEL);
+	if (!pinfo->groups)
+		return -ENOMEM;
+
+	pinfo->functions = devm_kcalloc(ph->dev, pinfo->nr_functions,
+					sizeof(*pinfo->functions),
+					GFP_KERNEL);
+	if (!pinfo->functions)
+		return -ENOMEM;
+
+	pinfo->version = version;
+
+	return ph->set_priv(ph, pinfo);
+}
+
+static int scmi_pinctrl_protocol_deinit(const struct scmi_protocol_handle *ph)
+{
+	int i;
+	struct scmi_pinctrl_info *pi;
+
+	if (!ph)
+		return -EINVAL;
+
+	pi = ph->get_priv(ph);
+	if (!pi)
+		return -EINVAL;
+
+	for (i = 0; i < pi->nr_groups; i++)
+		if (pi->groups[i].present) {
+			devm_kfree(ph->dev, pi->groups[i].group_pins);
+			pi->groups[i].present = false;
+		}
+
+	for (i = 0; i < pi->nr_functions; i++)
+		if (pi->functions[i].present) {
+			devm_kfree(ph->dev, pi->functions[i].groups);
+			pi->functions[i].present = false;
+		}
+
+	return 0;
+}
+
+static const struct scmi_protocol scmi_pinctrl = {
+	.id = SCMI_PROTOCOL_PINCTRL,
+	.owner = THIS_MODULE,
+	.instance_init = &scmi_pinctrl_protocol_init,
+	.instance_deinit = &scmi_pinctrl_protocol_deinit,
+	.ops = &pinctrl_proto_ops,
+};
+
+DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(pinctrl, scmi_pinctrl)
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index 78e1a01eb656..533b94c9a9a7 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -345,5 +345,6 @@ DECLARE_SCMI_REGISTER_UNREGISTER(sensors);
 DECLARE_SCMI_REGISTER_UNREGISTER(voltage);
 DECLARE_SCMI_REGISTER_UNREGISTER(system);
 DECLARE_SCMI_REGISTER_UNREGISTER(powercap);
+DECLARE_SCMI_REGISTER_UNREGISTER(pinctrl);
 
 #endif /* _SCMI_PROTOCOLS_H */
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 0ce5746a4470..8e15d2912045 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -735,6 +735,52 @@ struct scmi_notify_ops {
 					 struct notifier_block *nb);
 };
 
+enum scmi_pinctrl_selector_type {
+	PIN_TYPE = 0,
+	GROUP_TYPE,
+	FUNCTION_TYPE
+};
+
+/**
+ * struct scmi_pinctrl_protocol_ops - represents the various operations provided
+ * by SCMI Pinctrl Protocol
+ *
+ * @get_count: returns count of the registered elements in given type
+ * @get_name: returns name by index of given type
+ * @get_group_pins: returns the set of pins, assigned to the specified group
+ * @get_function_groups: returns the set of groups, assigned to the specified
+ *	function
+ * @set_mux: set muxing function for groups of pins
+ * @get_config: returns configuration parameter for pin or group
+ * @set_config: sets the configuration parameter for pin or group
+ * @request_pin: aquire pin before selecting mux setting
+ * @free_pin: frees pin, acquired by request_pin call
+ */
+struct scmi_pinctrl_proto_ops {
+	int (*get_count)(const struct scmi_protocol_handle *ph,
+			 enum scmi_pinctrl_selector_type type);
+	int (*get_name)(const struct scmi_protocol_handle *ph,
+			u32 selector,
+			enum scmi_pinctrl_selector_type type,
+			const char **name);
+	int (*get_group_pins)(const struct scmi_protocol_handle *ph,
+			      u32 selector,
+			      const unsigned int **pins, unsigned int *nr_pins);
+	int (*get_function_groups)(const struct scmi_protocol_handle *ph,
+				   u32 selector, unsigned int *nr_groups,
+				   const unsigned int **groups);
+	int (*set_mux)(const struct scmi_protocol_handle *ph, u32 selector,
+		       u32 group);
+	int (*get_config)(const struct scmi_protocol_handle *ph, u32 selector,
+			  enum scmi_pinctrl_selector_type type,
+			  u8 config_type, u32 *config_value);
+	int (*set_config)(const struct scmi_protocol_handle *ph, u32 selector,
+			  enum scmi_pinctrl_selector_type type,
+			  u8 config_type, u32 config_value);
+	int (*request_pin)(const struct scmi_protocol_handle *ph, u32 pin);
+	int (*free_pin)(const struct scmi_protocol_handle *ph, u32 pin);
+};
+
 /**
  * struct scmi_handle - Handle returned to ARM SCMI clients for usage.
  *
@@ -783,6 +829,7 @@ enum scmi_std_protocol {
 	SCMI_PROTOCOL_RESET = 0x16,
 	SCMI_PROTOCOL_VOLTAGE = 0x17,
 	SCMI_PROTOCOL_POWERCAP = 0x18,
+	SCMI_PROTOCOL_PINCTRL = 0x19,
 };
 
 enum scmi_system_events {
-- 
2.25.1