[RFC,v5,4/5] pinctrl: Implementation of the generic scmi-pinctrl driver

diff --git a/MAINTAINERS b/MAINTAINERS
index 2d81d00e5f4f..c4e36f955e53 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20527,6 +20527,7 @@  M:	Oleksii Moisieiev <oleksii_moisieiev@epam.com>
 L:	linux-arm-kernel@lists.infradead.org
 S:	Maintained
 F:	drivers/firmware/arm_scmi/pinctrl.c
+F:	drivers/pinctrl/pinctrl-scmi.c
 
 SYSTEM RESET/SHUTDOWN DRIVERS
 M:	Sebastian Reichel <sre@kernel.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index 5787c579dcf6..956cfe76fbc6 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -428,6 +428,17 @@  config PINCTRL_ROCKCHIP
 	help
           This support pinctrl and GPIO driver for Rockchip SoCs.
 
+config PINCTRL_SCMI
+	tristate "Pinctrl driver using SCMI protocol interface"
+	depends on ARM_SCMI_PROTOCOL || COMPILE_TEST
+	select PINMUX
+	select GENERIC_PINCONF
+	help
+	  This driver provides support for pinctrl which is controlled
+	  by firmware that implements the SCMI interface.
+	  It uses SCMI Message Protocol to interact with the
+	  firmware providing all the pinctrl controls.
+
 config PINCTRL_SINGLE
 	tristate "One-register-per-pin type device tree based pinctrl driver"
 	depends on OF
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index e196c6e324ad..25d67bac9ee0 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -44,6 +44,7 @@  obj-$(CONFIG_PINCTRL_PIC32)	+= pinctrl-pic32.o
 obj-$(CONFIG_PINCTRL_PISTACHIO)	+= pinctrl-pistachio.o
 obj-$(CONFIG_PINCTRL_RK805)	+= pinctrl-rk805.o
 obj-$(CONFIG_PINCTRL_ROCKCHIP)	+= pinctrl-rockchip.o
+obj-$(CONFIG_PINCTRL_SCMI)	+= pinctrl-scmi.o
 obj-$(CONFIG_PINCTRL_SINGLE)	+= pinctrl-single.o
 obj-$(CONFIG_PINCTRL_ST) 	+= pinctrl-st.o
 obj-$(CONFIG_PINCTRL_STMFX) 	+= pinctrl-stmfx.o
diff --git a/drivers/pinctrl/pinctrl-scmi.c b/drivers/pinctrl/pinctrl-scmi.c
new file mode 100644
index 000000000000..4d16f3c10eef
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-scmi.c
@@ -0,0 +1,445 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Power Interface (SCMI) Protocol based pinctrl driver
+ *
+ * Copyright (C) 2023 EPAM
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/scmi_protocol.h>
+#include <linux/slab.h>
+
+#include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+
+#include "pinctrl-utils.h"
+#include "core.h"
+#include "pinconf.h"
+
+#define DRV_NAME "scmi-pinctrl"
+
+static const struct scmi_pinctrl_proto_ops *pinctrl_ops;
+
+struct scmi_pinctrl_funcs {
+	unsigned int num_groups;
+	const char **groups;
+};
+
+struct scmi_pinctrl {
+	struct device *dev;
+	struct scmi_protocol_handle *ph;
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_desc pctl_desc;
+	struct scmi_pinctrl_funcs *functions;
+	unsigned int nr_functions;
+	char **groups;
+	unsigned int nr_groups;
+	struct pinctrl_pin_desc *pins;
+	unsigned int nr_pins;
+};
+
+static int pinctrl_scmi_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->count_get(pmx->ph, GROUP_TYPE);
+}
+
+static const char *pinctrl_scmi_get_group_name(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	int ret;
+	const char *name;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	ret = pinctrl_ops->name_get(pmx->ph, selector, GROUP_TYPE, &name);
+	if (ret) {
+		dev_err(pmx->dev, "get name failed with err %d", ret);
+		return NULL;
+	}
+
+	return name;
+}
+
+static int pinctrl_scmi_get_group_pins(struct pinctrl_dev *pctldev,
+				       unsigned int selector,
+				       const unsigned int **pins,
+				       unsigned int *num_pins)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->group_pins_get(pmx->ph, selector, pins, num_pins);
+}
+
+#ifdef CONFIG_OF
+static int pinctrl_scmi_dt_node_to_map(struct pinctrl_dev *pctldev,
+				       struct device_node *np_config,
+				       struct pinctrl_map **map,
+				       u32 *num_maps)
+{
+	return pinconf_generic_dt_node_to_map(pctldev, np_config, map, num_maps,
+					      PIN_MAP_TYPE_INVALID);
+}
+
+static void pinctrl_scmi_dt_free_map(struct pinctrl_dev *pctldev, struct pinctrl_map *map,
+				     u32 num_maps)
+{
+	kfree(map);
+}
+
+#endif /* CONFIG_OF */
+
+static const struct pinctrl_ops pinctrl_scmi_pinctrl_ops = {
+	.get_groups_count = pinctrl_scmi_get_groups_count,
+	.get_group_name = pinctrl_scmi_get_group_name,
+	.get_group_pins = pinctrl_scmi_get_group_pins,
+#ifdef CONFIG_OF
+	.dt_node_to_map = pinctrl_scmi_dt_node_to_map,
+	.dt_free_map = pinctrl_scmi_dt_free_map,
+#endif
+};
+
+static int pinctrl_scmi_get_functions_count(struct pinctrl_dev *pctldev)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->count_get(pmx->ph, FUNCTION_TYPE);
+}
+
+static const char *pinctrl_scmi_get_function_name(struct pinctrl_dev *pctldev,
+						  unsigned int selector)
+{
+	int ret;
+	const char *name;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	ret = pinctrl_ops->name_get(pmx->ph, selector, FUNCTION_TYPE, &name);
+	if (ret) {
+		dev_err(pmx->dev, "get name failed with err %d", ret);
+		return NULL;
+	}
+
+	return name;
+}
+
+static int pinctrl_scmi_get_function_groups(struct pinctrl_dev *pctldev,
+					    unsigned int selector,
+					    const char * const **groups,
+					    unsigned int * const num_groups)
+{
+	const unsigned int *group_ids;
+	int ret, i;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	if (!groups || !num_groups)
+		return -EINVAL;
+
+	if (selector < pmx->nr_functions &&
+	    pmx->functions[selector].num_groups) {
+		*groups = (const char * const *)pmx->functions[selector].groups;
+		*num_groups = pmx->functions[selector].num_groups;
+		return 0;
+	}
+
+	ret = pinctrl_ops->function_groups_get(pmx->ph, selector,
+					       &pmx->functions[selector].num_groups,
+					       &group_ids);
+	if (ret) {
+		dev_err(pmx->dev, "Unable to get function groups, err %d", ret);
+		return ret;
+	}
+
+	*num_groups = pmx->functions[selector].num_groups;
+	if (!*num_groups)
+		return -EINVAL;
+
+	pmx->functions[selector].groups =
+		devm_kcalloc(pmx->dev, *num_groups, sizeof(*pmx->functions[selector].groups),
+			     GFP_KERNEL);
+	if (!pmx->functions[selector].groups)
+		return -ENOMEM;
+
+	for (i = 0; i < *num_groups; i++) {
+		pmx->functions[selector].groups[i] =
+			pinctrl_scmi_get_group_name(pmx->pctldev,
+						    group_ids[i]);
+		if (!pmx->functions[selector].groups[i]) {
+			ret = -ENOMEM;
+			goto err_free;
+		}
+	}
+
+	*groups = (const char * const *)pmx->functions[selector].groups;
+
+	return 0;
+
+err_free:
+	devm_kfree(pmx->dev, pmx->functions[selector].groups);
+
+	return ret;
+}
+
+static int pinctrl_scmi_func_set_mux(struct pinctrl_dev *pctldev, unsigned int selector,
+				     unsigned int group)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->mux_set(pmx->ph, selector, group);
+}
+
+static int pinctrl_scmi_request(struct pinctrl_dev *pctldev, unsigned int offset)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->pin_request(pmx->ph, offset);
+}
+
+static int pinctrl_scmi_free(struct pinctrl_dev *pctldev, unsigned int offset)
+{
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+
+	return pinctrl_ops->pin_free(pmx->ph, offset);
+}
+
+static const struct pinmux_ops pinctrl_scmi_pinmux_ops = {
+	.request = pinctrl_scmi_request,
+	.free = pinctrl_scmi_free,
+	.get_functions_count = pinctrl_scmi_get_functions_count,
+	.get_function_name = pinctrl_scmi_get_function_name,
+	.get_function_groups = pinctrl_scmi_get_function_groups,
+	.set_mux = pinctrl_scmi_func_set_mux,
+};
+
+static int pinctrl_scmi_pinconf_get(struct pinctrl_dev *pctldev, unsigned int _pin,
+				    unsigned long *config)
+{
+	int ret;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param config_type;
+	unsigned long config_value;
+
+	if (!config)
+		return -EINVAL;
+
+	config_type = pinconf_to_config_param(*config);
+
+	ret = pinctrl_ops->config_get(pmx->ph, _pin, PIN_TYPE, config_type, &config_value);
+	if (ret)
+		return ret;
+
+	*config = pinconf_to_config_packed(config_type, config_value);
+
+	return 0;
+}
+
+static int pinctrl_scmi_pinconf_set(struct pinctrl_dev *pctldev,
+				    unsigned int _pin,
+				    unsigned long *configs,
+				    unsigned int num_configs)
+{
+	int i, ret;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param config_type;
+	unsigned long config_value;
+
+	if (!configs || num_configs == 0)
+		return -EINVAL;
+
+	for (i = 0; i < num_configs; i++) {
+		config_type = pinconf_to_config_param(configs[i]);
+		config_value = pinconf_to_config_argument(configs[i]);
+
+		ret = pinctrl_ops->config_set(pmx->ph, _pin, PIN_TYPE,
+					      num_configs, (u8 *)&config_type,
+					      &config_value);
+		if (ret) {
+			dev_err(pmx->dev, "Error parsing config %ld\n",
+				configs[i]);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int pinctrl_scmi_pinconf_group_set(struct pinctrl_dev *pctldev,
+					  unsigned int group,
+					  unsigned long *configs,
+					  unsigned int num_configs)
+{
+	int i, ret;
+	struct scmi_pinctrl *pmx =  pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param config_type;
+	unsigned long config_value;
+
+	if (!configs || num_configs == 0)
+		return -EINVAL;
+
+	for (i = 0; i < num_configs; i++) {
+		config_type = pinconf_to_config_param(configs[i]);
+		config_value = pinconf_to_config_argument(configs[i]);
+
+		ret = pinctrl_ops->config_set(pmx->ph, group, GROUP_TYPE,
+					      num_configs, (u8 *)&config_type,
+					      &config_value);
+		if (ret) {
+			dev_err(pmx->dev, "Error parsing config = %ld",
+				configs[i]);
+			break;
+		}
+	}
+
+	return ret;
+};
+
+static int pinctrl_scmi_pinconf_group_get(struct pinctrl_dev *pctldev,
+					  unsigned int group,
+					  unsigned long *config)
+{
+	int ret;
+	struct scmi_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param config_type;
+	unsigned long config_value;
+
+	if (!config)
+		return -EINVAL;
+
+	config_type = pinconf_to_config_param(*config);
+
+	ret = pinctrl_ops->config_get(pmx->ph, group, GROUP_TYPE, config_type, &config_value);
+	if (ret)
+		return ret;
+
+	*config = pinconf_to_config_packed(config_type, config_value);
+
+	return 0;
+}
+
+static const struct pinconf_ops pinctrl_scmi_pinconf_ops = {
+	.is_generic = true,
+	.pin_config_get = pinctrl_scmi_pinconf_get,
+	.pin_config_set = pinctrl_scmi_pinconf_set,
+	.pin_config_group_set = pinctrl_scmi_pinconf_group_set,
+	.pin_config_group_get = pinctrl_scmi_pinconf_group_get,
+	.pin_config_config_dbg_show = pinconf_generic_dump_config,
+};
+
+static int pinctrl_scmi_get_pins(struct scmi_pinctrl *pmx,
+				 unsigned int *nr_pins,
+				 const struct pinctrl_pin_desc **pins)
+{
+	int ret, i;
+
+	if (!pins || !nr_pins)
+		return -EINVAL;
+
+	if (pmx->nr_pins) {
+		*pins = pmx->pins;
+		*nr_pins = pmx->nr_pins;
+		return 0;
+	}
+
+	*nr_pins = pinctrl_ops->count_get(pmx->ph, PIN_TYPE);
+
+	pmx->nr_pins = *nr_pins;
+	pmx->pins = devm_kmalloc_array(pmx->dev, *nr_pins, sizeof(*pmx->pins), GFP_KERNEL);
+	if (!pmx->pins)
+		return -ENOMEM;
+
+	for (i = 0; i < *nr_pins; i++) {
+		pmx->pins[i].number = i;
+		ret = pinctrl_ops->name_get(pmx->ph, i, PIN_TYPE, &pmx->pins[i].name);
+		if (ret) {
+			dev_err(pmx->dev, "Can't get name for pin %d: rc %d", i, ret);
+			pmx->nr_pins = 0;
+			return ret;
+		}
+	}
+
+	*pins = pmx->pins;
+	dev_dbg(pmx->dev, "got pins %d", *nr_pins);
+
+	return 0;
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+	{ SCMI_PROTOCOL_PINCTRL, "pinctrl" },
+	{ }
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static int scmi_pinctrl_probe(struct scmi_device *sdev)
+{
+	int ret;
+	struct device *dev = &sdev->dev;
+	struct scmi_pinctrl *pmx;
+	const struct scmi_handle *handle;
+	struct scmi_protocol_handle *ph;
+
+	if (!sdev || !sdev->handle)
+		return -EINVAL;
+
+	handle = sdev->handle;
+
+	pinctrl_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PINCTRL, &ph);
+	if (IS_ERR(pinctrl_ops))
+		return PTR_ERR(pinctrl_ops);
+
+	pmx = devm_kzalloc(dev, sizeof(*pmx), GFP_KERNEL);
+	if (!pmx)
+		return -ENOMEM;
+
+	pmx->ph = ph;
+
+	pmx->dev = dev;
+	pmx->pctl_desc.name = DRV_NAME;
+	pmx->pctl_desc.owner = THIS_MODULE;
+	pmx->pctl_desc.pctlops = &pinctrl_scmi_pinctrl_ops;
+	pmx->pctl_desc.pmxops = &pinctrl_scmi_pinmux_ops;
+	pmx->pctl_desc.confops = &pinctrl_scmi_pinconf_ops;
+
+	ret = pinctrl_scmi_get_pins(pmx, &pmx->pctl_desc.npins,
+				    &pmx->pctl_desc.pins);
+	if (ret)
+		return ret;
+
+	ret = devm_pinctrl_register_and_init(dev, &pmx->pctl_desc, pmx, &pmx->pctldev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register pinctrl\n");
+
+	pmx->nr_functions = pinctrl_scmi_get_functions_count(pmx->pctldev);
+	pmx->nr_groups = pinctrl_scmi_get_groups_count(pmx->pctldev);
+
+	if (pmx->nr_functions) {
+		pmx->functions =
+			devm_kcalloc(dev, pmx->nr_functions, sizeof(*pmx->functions),
+				     GFP_KERNEL);
+		if (!pmx->functions)
+			return -ENOMEM;
+	}
+
+	if (pmx->nr_groups) {
+		pmx->groups =
+			devm_kcalloc(dev, pmx->nr_groups, sizeof(*pmx->groups), GFP_KERNEL);
+		if (!pmx->groups)
+			return -ENOMEM;
+	}
+
+	return pinctrl_enable(pmx->pctldev);
+}
+
+static struct scmi_driver scmi_pinctrl_driver = {
+	.name = DRV_NAME,
+	.probe = scmi_pinctrl_probe,
+	.id_table = scmi_id_table,
+};
+module_scmi_driver(scmi_pinctrl_driver);
+
+MODULE_AUTHOR("Oleksii Moisieiev <oleksii_moisieiev@epam.com>");
+MODULE_DESCRIPTION("ARM SCMI pin controller driver");
+MODULE_LICENSE("GPL");