Merge branch 'ib-mux-pinctrl' into devel

Documentation/devicetree/bindings/pinctrl/pinctrl-multiplexer.yaml

@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/pinctrl-multiplexer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic pinctrl device for on-board MUX Chips
+
+maintainers:
+  - Frank Li <Frank.Li@nxp.com>
+
+description:
+  Generic pinctrl device for on-board MUX Chips, which switch SoC signals
+  between different peripherals (e.g. MMC and UART).
+
+  The MUX select lines are often driven by a I2C GPIO expander.
+
+properties:
+  compatible:
+    const: pinctrl-multiplexer
+
+patternProperties:
+  '-grp$':
+    type: object
+    additionalProperties: false
+    properties:
+      mux-states:
+        maxItems: 1
+
+    required:
+      - mux-states
+
+required:
+  - compatible
+
+allOf:
+  - $ref: pinctrl.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    pinctrl-mux {
+        compatible = "pinctrl-multiplexer";
+
+        uart-grp {
+            mux-states = <&mux 0>;
+        };
+
+        spi-grp {
+            mux-states = <&mux 1>;
+        };
+
+        i2c-grp {
+            mux-states = <&mux 2>;
+        };
+    };

Documentation/devicetree/bindings/pinctrl/pinctrl.yaml

@@ -27,7 +27,7 @@ description: |
 
 properties:
   $nodename:
-    pattern: "^(pinctrl|pinmux)(@[0-9a-f]+)?$"
+    pattern: "^(pinctrl|pinmux)(@[0-9a-f]+|-[a-z0-9]+)?$"
 
   "#pinctrl-cells":
     description: >

drivers/mux/core.c

@@ -533,14 +533,16 @@ static struct mux_chip *of_find_mux_chip_by_node(struct device_node *np)
  * @state: Pointer to where the requested state is returned, or NULL when
  *         the required multiplexer states are handled by other means.
  * @optional: Whether to return NULL and silence errors when mux doesn't exist.
+ * @node: the device nodes, use dev->of_node if it is NULL.
  *
  * Return: Pointer to the mux-control on success, an ERR_PTR with a negative
  * errno on error, or NULL if optional is true and mux doesn't exist.
  */
 static struct mux_control *mux_get(struct device *dev, const char *mux_name,
-				   unsigned int *state, bool optional)
+				   unsigned int *state, bool optional,
+				   struct device_node *node)
 {
-	struct device_node *np = dev->of_node;
+	struct device_node *np = node ? node : dev->of_node;
 	struct of_phandle_args args;
 	struct mux_chip *mux_chip;
 	unsigned int controller;
@@ -635,7 +637,7 @@ static struct mux_control *mux_get(struct device *dev, const char *mux_name,
  */
 struct mux_control *mux_control_get(struct device *dev, const char *mux_name)
 {
-	struct mux_control *mux = mux_get(dev, mux_name, NULL, false);
+	struct mux_control *mux = mux_get(dev, mux_name, NULL, false, NULL);
 
 	if (!mux)
 		return ERR_PTR(-ENOENT);
@@ -654,7 +656,7 @@ EXPORT_SYMBOL_GPL(mux_control_get);
  */
 struct mux_control *mux_control_get_optional(struct device *dev, const char *mux_name)
 {
-	return mux_get(dev, mux_name, NULL, true);
+	return mux_get(dev, mux_name, NULL, true, NULL);
 }
 EXPORT_SYMBOL_GPL(mux_control_get_optional);
 
@@ -712,11 +714,14 @@ EXPORT_SYMBOL_GPL(devm_mux_control_get);
  * @dev: The device that needs a mux-state.
  * @mux_name: The name identifying the mux-state.
  * @optional: Whether to return NULL and silence errors when mux doesn't exist.
+ * @np: the device nodes, use dev->of_node if it is NULL.
  *
  * Return: Pointer to the mux-state on success, an ERR_PTR with a negative
  * errno on error, or NULL if optional is true and mux doesn't exist.
  */
-static struct mux_state *mux_state_get(struct device *dev, const char *mux_name, bool optional)
+static struct mux_state *
+mux_state_get(struct device *dev, const char *mux_name, bool optional,
+	      struct device_node *np)
 {
 	struct mux_state *mstate;
 
@@ -724,7 +729,7 @@ static struct mux_state *mux_state_get(struct device *dev, const char *mux_name,
 	if (!mstate)
 		return ERR_PTR(-ENOMEM);
 
-	mstate->mux = mux_get(dev, mux_name, &mstate->state, optional);
+	mstate->mux = mux_get(dev, mux_name, &mstate->state, optional, np);
 	if (IS_ERR(mstate->mux)) {
 		int err = PTR_ERR(mstate->mux);
 
@@ -766,6 +771,7 @@ static void devm_mux_state_release(struct device *dev, void *res)
  * @dev: The device that needs a mux-state.
  * @mux_name: The name identifying the mux-state.
  * @optional: Whether to return NULL and silence errors when mux doesn't exist.
+ * @np: The device nodes, use dev->of_node if it is NULL.
  * @init: Optional function pointer for mux-state object initialisation.
  * @exit: Optional function pointer for mux-state object cleanup on release.
  *
@@ -773,7 +779,7 @@ static void devm_mux_state_release(struct device *dev, void *res)
  * errno on error, or NULL if optional is true and mux doesn't exist.
  */
 static struct mux_state *__devm_mux_state_get(struct device *dev, const char *mux_name,
-					      bool optional,
+					      bool optional, struct device_node *np,
 					      int (*init)(struct mux_state *mstate),
 					      int (*exit)(struct mux_state *mstate))
 {
@@ -781,7 +787,7 @@ static struct mux_state *__devm_mux_state_get(struct device *dev, const char *mu
 	struct mux_state *mstate;
 	int ret;
 
-	mstate = mux_state_get(dev, mux_name, optional);
+	mstate = mux_state_get(dev, mux_name, optional, np);
 	if (IS_ERR(mstate))
 		return ERR_CAST(mstate);
 	else if (optional && !mstate)
@@ -815,20 +821,23 @@ static struct mux_state *__devm_mux_state_get(struct device *dev, const char *mu
 }
 
 /**
- * devm_mux_state_get() - Get the mux-state for a device, with resource
- *			  management.
+ * devm_mux_state_get_from_np() - Get the mux-state for a device, with resource
+ *				  management.
  * @dev: The device that needs a mux-control.
  * @mux_name: The name identifying the mux-control.
+ * @np: the device nodes, use dev->of_node if it is NULL.
  *
  * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
  *
  * The mux-state will automatically be freed on release.
  */
-struct mux_state *devm_mux_state_get(struct device *dev, const char *mux_name)
+struct mux_state *
+devm_mux_state_get_from_np(struct device *dev, const char *mux_name,
+			   struct device_node *np)
 {
-	return __devm_mux_state_get(dev, mux_name, false, NULL, NULL);
+	return __devm_mux_state_get(dev, mux_name, false, np, NULL, NULL);
 }
-EXPORT_SYMBOL_GPL(devm_mux_state_get);
+EXPORT_SYMBOL_GPL(devm_mux_state_get_from_np);
 
 /**
  * devm_mux_state_get_optional() - Get the optional mux-state for a device,
@@ -843,7 +852,7 @@ EXPORT_SYMBOL_GPL(devm_mux_state_get);
  */
 struct mux_state *devm_mux_state_get_optional(struct device *dev, const char *mux_name)
 {
-	return __devm_mux_state_get(dev, mux_name, true, NULL, NULL);
+	return __devm_mux_state_get(dev, mux_name, true, NULL, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(devm_mux_state_get_optional);
 
@@ -861,7 +870,8 @@ EXPORT_SYMBOL_GPL(devm_mux_state_get_optional);
  */
 struct mux_state *devm_mux_state_get_selected(struct device *dev, const char *mux_name)
 {
-	return __devm_mux_state_get(dev, mux_name, false, mux_state_select, mux_state_deselect);
+	return __devm_mux_state_get(dev, mux_name, false, NULL,
+				    mux_state_select, mux_state_deselect);
 }
 EXPORT_SYMBOL_GPL(devm_mux_state_get_selected);
 
@@ -881,7 +891,8 @@ EXPORT_SYMBOL_GPL(devm_mux_state_get_selected);
 struct mux_state *devm_mux_state_get_optional_selected(struct device *dev,
 						       const char *mux_name)
 {
-	return __devm_mux_state_get(dev, mux_name, true, mux_state_select, mux_state_deselect);
+	return __devm_mux_state_get(dev, mux_name, true, NULL,
+				    mux_state_select, mux_state_deselect);
 }
 EXPORT_SYMBOL_GPL(devm_mux_state_get_optional_selected);
 

drivers/pinctrl/Kconfig

@@ -272,6 +272,15 @@ config PINCTRL_GEMINI
 	select GENERIC_PINCONF
 	select MFD_SYSCON
 
+config PINCTRL_GENERIC_MUX
+	tristate "Generic Pinctrl driver by using multiplexer"
+	depends on MULTIPLEXER
+	select PINMUX
+	select GENERIC_PINCTRL
+	help
+          Generic pinctrl driver by MULTIPLEXER framework to control on
+          board pin selection.
+
 config PINCTRL_INGENIC
 	bool "Pinctrl driver for the Ingenic JZ47xx SoCs"
 	default MACH_INGENIC

drivers/pinctrl/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_PINCTRL_EQUILIBRIUM)   += pinctrl-equilibrium.o
 obj-$(CONFIG_PINCTRL_EP93XX)	+= pinctrl-ep93xx.o
 obj-$(CONFIG_PINCTRL_EYEQ5)	+= pinctrl-eyeq5.o
 obj-$(CONFIG_PINCTRL_GEMINI)	+= pinctrl-gemini.o
+obj-$(CONFIG_PINCTRL_GENERIC_MUX) += pinctrl-generic-mux.o
 obj-$(CONFIG_PINCTRL_INGENIC)	+= pinctrl-ingenic.o
 obj-$(CONFIG_PINCTRL_K210)	+= pinctrl-k210.o
 obj-$(CONFIG_PINCTRL_K230)	+= pinctrl-k230.o

drivers/pinctrl/pinconf.h

@@ -172,6 +172,13 @@ int pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
 						 struct device_node *np,
 						 struct pinctrl_map **maps,
 						 unsigned int *num_maps);
+
+int pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+			   struct device_node *np, struct pinctrl_map **maps,
+			   unsigned int *num_maps, unsigned int *num_reserved_maps,
+			   const char **group_name, unsigned int ngroups,
+			   const char **functions, unsigned int *pins,
+			   unsigned int npins);
 #else
 static inline int
 pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
@@ -181,4 +188,15 @@ pinctrl_generic_pins_function_dt_node_to_map(struct pinctrl_dev *pctldev,
 {
 	return -ENOTSUPP;
 }
+
+static inline int
+pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+		       struct device_node *np, struct pinctrl_map **maps,
+		       unsigned int *num_maps, unsigned int *num_reserved_maps,
+		       const char **group_name, unsigned int ngroups,
+		       const char **functions, unsigned int *pins,
+		       void *function_data)
+{
+	return -ENOTSUPP;
+}
 #endif

drivers/pinctrl/pinctrl-generic-mux.c

@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic Pin Control Driver for Board-Level Mux Chips
+ * Copyright 2026 NXP
+ */
+
+#include <linux/cleanup.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/mutex.h>
+#include <linux/mux/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+#include <linux/slab.h>
+
+#include "core.h"
+#include "pinconf.h"
+#include "pinmux.h"
+#include "pinctrl-utils.h"
+
+struct mux_pin_function {
+	struct mux_state *mux_state;
+};
+
+struct mux_pinctrl {
+	struct device *dev;
+	struct pinctrl_dev *pctl;
+
+	/* mutex protect [pinctrl|pinmux]_generic functions */
+	struct mutex lock;
+};
+
+static int
+mux_pinmux_dt_node_to_map(struct pinctrl_dev *pctldev,
+			  struct device_node *np_config,
+			  struct pinctrl_map **maps, unsigned int *num_maps)
+{
+	unsigned int num_reserved_maps = 0;
+	struct mux_pin_function *function;
+	const char **group_names;
+	int ret;
+
+	function = devm_kzalloc(pctldev->dev, sizeof(*function), GFP_KERNEL);
+	if (!function)
+		return -ENOMEM;
+
+	group_names = devm_kcalloc(pctldev->dev, 1, sizeof(*group_names), GFP_KERNEL);
+	if (!group_names)
+		return -ENOMEM;
+
+	function->mux_state = devm_mux_state_get_from_np(pctldev->dev, NULL, np_config);
+	if (IS_ERR(function->mux_state))
+		return PTR_ERR(function->mux_state);
+
+	ret = pinctrl_generic_to_map(pctldev, np_config, np_config, maps,
+				     num_maps, &num_reserved_maps, group_names,
+				     0, &np_config->name, NULL, 0);
+
+	if (ret)
+		return ret;
+
+	ret = pinmux_generic_add_function(pctldev, np_config->name, group_names,
+					  1, function);
+	if (ret < 0) {
+		pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct pinctrl_ops mux_pinctrl_ops = {
+	.get_groups_count = pinctrl_generic_get_group_count,
+	.get_group_name = pinctrl_generic_get_group_name,
+	.get_group_pins = pinctrl_generic_get_group_pins,
+	.dt_node_to_map = mux_pinmux_dt_node_to_map,
+	.dt_free_map = pinctrl_utils_free_map,
+};
+
+static int mux_pinmux_set_mux(struct pinctrl_dev *pctldev,
+			      unsigned int func_selector,
+			      unsigned int group_selector)
+{
+	struct mux_pinctrl *mpctl = pinctrl_dev_get_drvdata(pctldev);
+	const struct function_desc *function;
+	struct mux_pin_function *func;
+	int ret;
+
+	guard(mutex)(&mpctl->lock);
+
+	function = pinmux_generic_get_function(pctldev, func_selector);
+	func = function->data;
+
+	ret = mux_state_select(func->mux_state);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void mux_pinmux_release_mux(struct pinctrl_dev *pctldev,
+				   unsigned int func_selector,
+				   unsigned int group_selector)
+{
+	struct mux_pinctrl *mpctl = pinctrl_dev_get_drvdata(pctldev);
+	const struct function_desc *function;
+	struct mux_pin_function *func;
+
+	guard(mutex)(&mpctl->lock);
+
+	function = pinmux_generic_get_function(pctldev, func_selector);
+	func = function->data;
+
+	mux_state_deselect(func->mux_state);
+}
+
+static const struct pinmux_ops mux_pinmux_ops = {
+	.get_functions_count = pinmux_generic_get_function_count,
+	.get_function_name = pinmux_generic_get_function_name,
+	.get_function_groups = pinmux_generic_get_function_groups,
+	.set_mux = mux_pinmux_set_mux,
+	.release_mux = mux_pinmux_release_mux,
+};
+
+static int mux_pinctrl_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mux_pinctrl *mpctl;
+	struct pinctrl_desc *pctl_desc;
+	int ret;
+
+	mpctl = devm_kzalloc(dev, sizeof(*mpctl), GFP_KERNEL);
+	if (!mpctl)
+		return -ENOMEM;
+
+	mpctl->dev = dev;
+
+	platform_set_drvdata(pdev, mpctl);
+
+	pctl_desc = devm_kzalloc(dev, sizeof(*pctl_desc), GFP_KERNEL);
+	if (!pctl_desc)
+		return -ENOMEM;
+
+	ret = devm_mutex_init(dev, &mpctl->lock);
+	if (ret)
+		return ret;
+
+	pctl_desc->name = dev_name(dev);
+	pctl_desc->owner = THIS_MODULE;
+	pctl_desc->pctlops = &mux_pinctrl_ops;
+	pctl_desc->pmxops = &mux_pinmux_ops;
+
+	ret = devm_pinctrl_register_and_init(dev, pctl_desc, mpctl,
+					     &mpctl->pctl);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register pinctrl.\n");
+
+	ret = pinctrl_enable(mpctl->pctl);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable pinctrl.\n");
+
+	return 0;
+}
+
+static const struct of_device_id mux_pinctrl_of_match[] = {
+	{ .compatible = "pinctrl-multiplexer" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mux_pinctrl_of_match);
+
+static struct platform_driver mux_pinctrl_driver = {
+	.driver = {
+		.name = "generic-pinctrl-mux",
+		.of_match_table = mux_pinctrl_of_match,
+	},
+	.probe = mux_pinctrl_probe,
+};
+module_platform_driver(mux_pinctrl_driver);
+
+MODULE_AUTHOR("Frank Li <Frank.Li@nxp.com>");
+MODULE_DESCRIPTION("Generic Pin Control Driver for Board-Level Mux Chips");
+MODULE_LICENSE("GPL");

drivers/pinctrl/pinctrl-generic.c

@@ -17,29 +17,18 @@
 #include "pinctrl-utils.h"
 #include "pinmux.h"
 
-static int pinctrl_generic_pins_function_dt_subnode_to_map(struct pinctrl_dev *pctldev,
-							   struct device_node *parent,
-							   struct device_node *np,
-							   struct pinctrl_map **maps,
-							   unsigned int *num_maps,
-							   unsigned int *num_reserved_maps,
-							   const char **group_names,
-							   unsigned int ngroups)
+int pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *parent,
+			   struct device_node *np, struct pinctrl_map **maps,
+			   unsigned int *num_maps, unsigned int *num_reserved_maps,
+			   const char **group_names, unsigned int ngroups,
+			   const char **functions, unsigned int *pins,
+			   unsigned int npins)
 {
 	struct device *dev = pctldev->dev;
-	const char **functions;
+	unsigned int num_configs;
 	const char *group_name;
 	unsigned long *configs;
-	unsigned int num_configs, pin, *pins;
-	int npins, ret, reserve = 1;
-
-	npins = of_property_count_u32_elems(np, "pins");
-
-	if (npins < 1) {
-		dev_err(dev, "invalid pinctrl group %pOFn.%pOFn %d\n",
-			parent, np, npins);
-		return npins;
-	}
+	int ret, reserve = 1;
 
 	group_name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn.%pOFn", parent, np);
 	if (!group_name)
@@ -47,26 +36,6 @@ static int pinctrl_generic_pins_function_dt_subnode_to_map(struct pinctrl_dev *p
 
 	group_names[ngroups] = group_name;
 
-	pins = devm_kcalloc(dev, npins, sizeof(*pins), GFP_KERNEL);
-	if (!pins)
-		return -ENOMEM;
-
-	functions = devm_kcalloc(dev, npins, sizeof(*functions), GFP_KERNEL);
-	if (!functions)
-		return -ENOMEM;
-
-	for (int i = 0; i < npins; i++) {
-		ret = of_property_read_u32_index(np, "pins", i, &pin);
-		if (ret)
-			return ret;
-
-		pins[i] = pin;
-
-		ret = of_property_read_string(np, "function", &functions[i]);
-		if (ret)
-			return ret;
-	}
-
 	ret = pinctrl_utils_reserve_map(pctldev, maps, num_reserved_maps, num_maps, reserve);
 	if (ret)
 		return ret;
@@ -102,6 +71,54 @@ static int pinctrl_generic_pins_function_dt_subnode_to_map(struct pinctrl_dev *p
 
 	return 0;
 };
+EXPORT_SYMBOL_GPL(pinctrl_generic_to_map);
+
+static int pinctrl_generic_pins_function_dt_subnode_to_map(struct pinctrl_dev *pctldev,
+							   struct device_node *parent,
+							   struct device_node *np,
+							   struct pinctrl_map **maps,
+							   unsigned int *num_maps,
+							   unsigned int *num_reserved_maps,
+							   const char **group_names,
+							   unsigned int ngroups)
+{
+	struct device *dev = pctldev->dev;
+	unsigned int pin, *pins;
+	const char **functions;
+	int npins, ret;
+
+	npins = of_property_count_u32_elems(np, "pins");
+
+	if (npins < 1) {
+		dev_err(dev, "invalid pinctrl group %pOFn.%pOFn %d\n",
+			parent, np, npins);
+		return npins;
+	}
+
+	pins = devm_kcalloc(dev, npins, sizeof(*pins), GFP_KERNEL);
+	if (!pins)
+		return -ENOMEM;
+
+	functions = devm_kcalloc(dev, npins, sizeof(*functions), GFP_KERNEL);
+	if (!functions)
+		return -ENOMEM;
+
+	for (int i = 0; i < npins; i++) {
+		ret = of_property_read_u32_index(np, "pins", i, &pin);
+		if (ret)
+			return ret;
+
+		pins[i] = pin;
+
+		ret = of_property_read_string(np, "function", &functions[i]);
+		if (ret)
+			return ret;
+	}
+
+	return pinctrl_generic_to_map(pctldev, parent, np, maps, num_maps,
+				      num_reserved_maps, group_names, ngroups,
+				      functions, pins, npins);
+}
 
 /*
  * For platforms that do not define groups or functions in the driver, but

drivers/pinctrl/pinmux.c

@@ -517,6 +517,7 @@ void pinmux_disable_setting(const struct pinctrl_setting *setting)
 {
 	struct pinctrl_dev *pctldev = setting->pctldev;
 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
+	const struct pinmux_ops *ops = pctldev->desc->pmxops;
 	int ret = 0;
 	const unsigned int *pins = NULL;
 	unsigned int num_pins = 0;
@@ -563,6 +564,10 @@ void pinmux_disable_setting(const struct pinctrl_setting *setting)
 				 pins[i], desc->name, gname);
 		}
 	}
+
+	if (ops->release_mux)
+		ops->release_mux(pctldev, setting->data.mux.func,
+				 setting->data.mux.group);
 }
 
 #ifdef CONFIG_DEBUG_FS

include/linux/mux/consumer.h

@@ -60,7 +60,10 @@ struct mux_control *mux_control_get_optional(struct device *dev, const char *mux
 void mux_control_put(struct mux_control *mux);
 
 struct mux_control *devm_mux_control_get(struct device *dev, const char *mux_name);
-struct mux_state *devm_mux_state_get(struct device *dev, const char *mux_name);
+
+struct mux_state *
+devm_mux_state_get_from_np(struct device *dev, const char *mux_name, struct device_node *np);
+
 struct mux_state *devm_mux_state_get_optional(struct device *dev, const char *mux_name);
 struct mux_state *devm_mux_state_get_selected(struct device *dev, const char *mux_name);
 struct mux_state *devm_mux_state_get_optional_selected(struct device *dev, const char *mux_name);
@@ -161,4 +164,7 @@ static inline struct mux_state *devm_mux_state_get_optional_selected(struct devi
 
 #endif /* CONFIG_MULTIPLEXER */
 
+#define devm_mux_state_get(dev, mux_name)		\
+	devm_mux_state_get_from_np(dev, mux_name, NULL)
+
 #endif /* _LINUX_MUX_CONSUMER_H */

include/linux/pinctrl/pinmux.h

@@ -51,6 +51,8 @@ struct pinctrl_gpio_range;
  *	are handled by the pinmux subsystem. The @func_selector selects a
  *	certain function whereas @group_selector selects a certain set of pins
  *	to be used. On simple controllers the latter argument may be ignored
+ * @release_mux: Release software resources acquired by @set_mux. This callback
+ *	must not change hardware state to avoid glitches when switching mux.
  * @gpio_request_enable: requests and enables GPIO on a certain pin.
  *	Implement this only if you can mux every pin individually as GPIO. The
  *	affected GPIO range is passed along with an offset(pin number) into that
@@ -80,6 +82,9 @@ struct pinmux_ops {
 				  unsigned int selector);
 	int (*set_mux) (struct pinctrl_dev *pctldev, unsigned int func_selector,
 			unsigned int group_selector);
+	void (*release_mux) (struct pinctrl_dev *pctldev,
+			     unsigned int func_selector,
+			     unsigned int group_selector);
 	int (*gpio_request_enable) (struct pinctrl_dev *pctldev,
 				    struct pinctrl_gpio_range *range,
 				    unsigned int offset);