1 files changed, 531 insertions, 162 deletions

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index 88cc5095d0c9..3a8dd184ba3d 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Core driver for the pin muxing portions of the pin control subsystem
  *
@@ -8,40 +9,42 @@
  * Author: Linus Walleij <linus.walleij@linaro.org>
  *
  * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
- *
- * License terms: GNU General Public License (GPL) version 2
  */
 #define pr_fmt(fmt) "pinmux core: " fmt
 
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
+#include <linux/array_size.h>
+#include <linux/ctype.h>
+#include <linux/cleanup.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
-#include <linux/slab.h>
-#include <linux/radix-tree.h>
 #include <linux/err.h>
+#include <linux/init.h>
 #include <linux/list.h>
-#include <linux/string.h>
-#include <linux/sysfs.h>
-#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/radix-tree.h>
 #include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
 #include <linux/pinctrl/machine.h>
+#include <linux/pinctrl/pinctrl.h>
 #include <linux/pinctrl/pinmux.h>
+
 #include "core.h"
 #include "pinmux.h"
 
 int pinmux_check_ops(struct pinctrl_dev *pctldev)
 {
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
-	unsigned nfuncs;
-	unsigned selector = 0;
+	unsigned int nfuncs;
+	unsigned int selector = 0;
 
 	/* Check that we implement required operations */
 	if (!ops ||
 	    !ops->get_functions_count ||
 	    !ops->get_function_name ||
 	    !ops->get_function_groups ||
-	    !ops->enable) {
+	    !ops->set_mux) {
 		dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
 		return -EINVAL;
 	}
@@ -61,7 +64,7 @@ int pinmux_check_ops(struct pinctrl_dev *pctldev)
 	return 0;
 }
 
-int pinmux_validate_map(struct pinctrl_map const *map, int i)
+int pinmux_validate_map(const struct pinctrl_map *map, int i)
 {
 	if (!map->data.mux.function) {
 		pr_err("failed to register map %s (%d): no function given\n",
@@ -73,7 +76,41 @@ int pinmux_validate_map(struct pinctrl_map const *map, int i)
 }
 
 /**
+ * pinmux_can_be_used_for_gpio() - check if a specific pin
+ *	is either muxed to a different function or used as gpio.
+ *
+ * @pctldev: the associated pin controller device
+ * @pin: the pin number in the global pin space
+ *
+ * Controllers not defined as strict will always return true,
+ * menaning that the gpio can be used.
+ */
+bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned int pin)
+{
+	struct pin_desc *desc = pin_desc_get(pctldev, pin);
+	const struct pinmux_ops *ops = pctldev->desc->pmxops;
+	const struct pinctrl_setting_mux *mux_setting;
+	bool func_is_gpio = false;
+
+	/* Can't inspect pin, assume it can be used */
+	if (!desc || !ops)
+		return true;
+
+	mux_setting = desc->mux_setting;
+
+	guard(mutex)(&desc->mux_lock);
+	if (mux_setting && ops->function_is_gpio)
+		func_is_gpio = ops->function_is_gpio(pctldev, mux_setting->func);
+
+	if (ops->strict && desc->mux_usecount && !func_is_gpio)
+		return false;
+
+	return !(ops->strict && !!desc->gpio_owner);
+}
+
+/**
  * pin_request() - request a single pin to be muxed in, typically for GPIO
+ * @pctldev: the associated pin controller device
  * @pin: the pin number in the global pin space
  * @owner: a representation of the owner of this pin; typically the device
  *	name that controls its mux function, or the requested GPIO name
@@ -86,7 +123,9 @@ static int pin_request(struct pinctrl_dev *pctldev,
 {
 	struct pin_desc *desc;
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
+	const struct pinctrl_setting_mux *mux_setting;
 	int status = -EINVAL;
+	bool gpio_ok = false;
 
 	desc = pin_desc_get(pctldev, pin);
 	if (desc == NULL) {
@@ -96,32 +135,44 @@ static int pin_request(struct pinctrl_dev *pctldev,
 		goto out;
 	}
 
+	mux_setting = desc->mux_setting;
+
 	dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
 		pin, desc->name, owner);
 
-	if (gpio_range) {
-		/* There's no need to support multiple GPIO requests */
-		if (desc->gpio_owner) {
+	scoped_guard(mutex, &desc->mux_lock) {
+		if (mux_setting) {
+			if (ops->function_is_gpio)
+				gpio_ok = ops->function_is_gpio(pctldev,
+								mux_setting->func);
+		} else {
+			gpio_ok = true;
+		}
+
+		if ((!gpio_range || ops->strict) && !gpio_ok &&
+		    desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
 			dev_err(pctldev->dev,
 				"pin %s already requested by %s; cannot claim for %s\n",
-				desc->name, desc->gpio_owner, owner);
+				desc->name, desc->mux_owner, owner);
 			goto out;
 		}
 
-		desc->gpio_owner = owner;
-	} else {
-		if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
+		if ((gpio_range || ops->strict) && !gpio_ok && desc->gpio_owner) {
 			dev_err(pctldev->dev,
 				"pin %s already requested by %s; cannot claim for %s\n",
-				desc->name, desc->mux_owner, owner);
+				desc->name, desc->gpio_owner, owner);
 			goto out;
 		}
 
-		desc->mux_usecount++;
-		if (desc->mux_usecount > 1)
-			return 0;
+		if (gpio_range) {
+			desc->gpio_owner = owner;
+		} else {
+			desc->mux_usecount++;
+			if (desc->mux_usecount > 1)
+				return 0;
 
-		desc->mux_owner = owner;
+			desc->mux_owner = owner;
+		}
 	}
 
 	/* Let each pin increase references to this module */
@@ -145,25 +196,25 @@ static int pin_request(struct pinctrl_dev *pctldev,
 	else
 		status = 0;
 
-	if (status) {
-		dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
+	if (status)
 		module_put(pctldev->owner);
-	}
 
 out_free_pin:
 	if (status) {
-		if (gpio_range) {
-			desc->gpio_owner = NULL;
-		} else {
-			desc->mux_usecount--;
-			if (!desc->mux_usecount)
-				desc->mux_owner = NULL;
+		scoped_guard(mutex, &desc->mux_lock) {
+			if (gpio_range) {
+				desc->gpio_owner = NULL;
+			} else {
+				desc->mux_usecount--;
+				if (!desc->mux_usecount)
+					desc->mux_owner = NULL;
+			}
 		}
 	}
 out:
 	if (status)
-		dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
-			pin, owner, status);
+		dev_err_probe(pctldev->dev, status, "pin-%d (%s)\n",
+			      pin, owner);
 
 	return status;
 }
@@ -193,15 +244,26 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 		return NULL;
 	}
 
-	if (!gpio_range) {
-		/*
-		 * A pin should not be freed more times than allocated.
-		 */
-		if (WARN_ON(!desc->mux_usecount))
-			return NULL;
-		desc->mux_usecount--;
-		if (desc->mux_usecount)
-			return NULL;
+	scoped_guard(mutex, &desc->mux_lock) {
+		if (!gpio_range) {
+			/*
+			 * A pin should not be freed more times than allocated.
+			 */
+			if (WARN_ON(!desc->mux_usecount))
+				return NULL;
+			desc->mux_usecount--;
+			if (desc->mux_usecount)
+				return NULL;
+		}
+
+		if (gpio_range) {
+			owner = desc->gpio_owner;
+			desc->gpio_owner = NULL;
+		} else {
+			owner = desc->mux_owner;
+			desc->mux_owner = NULL;
+			desc->mux_setting = NULL;
+		}
 	}
 
 	/*
@@ -213,15 +275,6 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
 	else if (ops->free)
 		ops->free(pctldev, pin);
 
-	if (gpio_range) {
-		owner = desc->gpio_owner;
-		desc->gpio_owner = NULL;
-	} else {
-		owner = desc->mux_owner;
-		desc->mux_owner = NULL;
-		desc->mux_setting = NULL;
-	}
-
 	module_put(pctldev->owner);
 
 	return owner;
@@ -232,10 +285,11 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
  * @pctldev: pin controller device affected
  * @pin: the pin to mux in for GPIO
  * @range: the applicable GPIO range
+ * @gpio: number of requested GPIO
  */
 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 			struct pinctrl_gpio_range *range,
-			unsigned pin, unsigned gpio)
+			unsigned int pin, unsigned int gpio)
 {
 	const char *owner;
 	int ret;
@@ -243,7 +297,7 @@ int pinmux_request_gpio(struct pinctrl_dev *pctldev,
 	/* Conjure some name stating what chip and pin this is taken by */
 	owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
 	if (!owner)
-		return -EINVAL;
+		return -ENOMEM;
 
 	ret = pin_request(pctldev, pin, owner, range);
 	if (ret < 0)
@@ -258,7 +312,7 @@ int pinmux_request_gpio(struct pinctrl_dev *pctldev,
  * @pin: the affected currently GPIO-muxed in pin
  * @range: applicable GPIO range
  */
-void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
+void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned int pin,
 		      struct pinctrl_gpio_range *range)
 {
 	const char *owner;
@@ -276,7 +330,7 @@ void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
  */
 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
 			  struct pinctrl_gpio_range *range,
-			  unsigned pin, bool input)
+			  unsigned int pin, bool input)
 {
 	const struct pinmux_ops *ops;
 	int ret;
@@ -295,35 +349,31 @@ static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
 					const char *function)
 {
 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
-	unsigned nfuncs = ops->get_functions_count(pctldev);
-	unsigned selector = 0;
+	unsigned int nfuncs = ops->get_functions_count(pctldev);
+	unsigned int selector = 0;
 
 	/* See if this pctldev has this function */
 	while (selector < nfuncs) {
-		const char *fname = ops->get_function_name(pctldev,
-							   selector);
+		const char *fname = ops->get_function_name(pctldev, selector);
 
-		if (!strcmp(function, fname))
+		if (fname && !strcmp(function, fname))
 			return selector;
 
 		selector++;
 	}
 
-	pr_err("%s does not support function %s\n",
-	       pinctrl_dev_get_name(pctldev), function);
 	return -EINVAL;
 }
 
-int pinmux_map_to_setting(struct pinctrl_map const *map,
+int pinmux_map_to_setting(const struct pinctrl_map *map,
 			  struct pinctrl_setting *setting)
 {
 	struct pinctrl_dev *pctldev = setting->pctldev;
 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
 	char const * const *groups;
-	unsigned num_groups;
+	unsigned int num_groups;
 	int ret;
 	const char *group;
-	int i;
 
 	if (!pmxops) {
 		dev_err(pctldev->dev, "does not support mux function\n");
@@ -352,19 +402,13 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 		return -EINVAL;
 	}
 	if (map->data.mux.group) {
-		bool found = false;
 		group = map->data.mux.group;
-		for (i = 0; i < num_groups; i++) {
-			if (!strcmp(group, groups[i])) {
-				found = true;
-				break;
-			}
-		}
-		if (!found) {
+		ret = match_string(groups, num_groups, group);
+		if (ret < 0) {
 			dev_err(pctldev->dev,
 				"invalid group \"%s\" for function \"%s\"\n",
 				group, map->data.mux.function);
-			return -EINVAL;
+			return ret;
 		}
 	} else {
 		group = groups[0];
@@ -381,29 +425,35 @@ int pinmux_map_to_setting(struct pinctrl_map const *map,
 	return 0;
 }
 
-void pinmux_free_setting(struct pinctrl_setting const *setting)
+void pinmux_free_setting(const struct pinctrl_setting *setting)
 {
 	/* This function is currently unused */
 }
 
-int pinmux_enable_setting(struct pinctrl_setting const *setting)
+int pinmux_enable_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;
-	const unsigned *pins;
-	unsigned num_pins;
+	int ret = 0;
+	const unsigned int *pins = NULL;
+	unsigned int num_pins = 0;
 	int i;
 	struct pin_desc *desc;
 
-	ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
-				      &pins, &num_pins);
+	if (pctlops->get_group_pins)
+		ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
+					      &pins, &num_pins);
+
 	if (ret) {
+		const char *gname;
+
 		/* errors only affect debug data, so just warn */
+		gname = pctlops->get_group_name(pctldev,
+						setting->data.mux.group);
 		dev_warn(pctldev->dev,
-			 "could not get pins for group selector %d\n",
-			 setting->data.mux.group);
+			 "could not get pins for group %s\n",
+			 gname);
 		num_pins = 0;
 	}
 
@@ -411,9 +461,17 @@ int pinmux_enable_setting(struct pinctrl_setting const *setting)
 	for (i = 0; i < num_pins; i++) {
 		ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
 		if (ret) {
-			dev_err(pctldev->dev,
-				"could not request pin %d on device %s\n",
-				pins[i], pinctrl_dev_get_name(pctldev));
+			const char *gname;
+			const char *pname;
+
+			desc = pin_desc_get(pctldev, pins[i]);
+			pname = desc ? desc->name : "non-existing";
+			gname = pctlops->get_group_name(pctldev,
+						setting->data.mux.group);
+			dev_err_probe(pctldev->dev, ret,
+				"could not request pin %d (%s) from group %s on device %s\n",
+				pins[i], pname, gname,
+				pinctrl_dev_get_name(pctldev));
 			goto err_pin_request;
 		}
 	}
@@ -427,22 +485,25 @@ int pinmux_enable_setting(struct pinctrl_setting const *setting)
 				 pins[i]);
 			continue;
 		}
-		desc->mux_setting = &(setting->data.mux);
+		scoped_guard(mutex, &desc->mux_lock)
+			desc->mux_setting = &(setting->data.mux);
 	}
 
-	ret = ops->enable(pctldev, setting->data.mux.func,
-			  setting->data.mux.group);
+	ret = ops->set_mux(pctldev, setting->data.mux.func,
+			   setting->data.mux.group);
 
 	if (ret)
-		goto err_enable;
+		goto err_set_mux;
 
 	return 0;
 
-err_enable:
+err_set_mux:
 	for (i = 0; i < num_pins; i++) {
 		desc = pin_desc_get(pctldev, pins[i]);
-		if (desc)
-			desc->mux_setting = NULL;
+		if (desc) {
+			scoped_guard(mutex, &desc->mux_lock)
+				desc->mux_setting = NULL;
+		}
 	}
 err_pin_request:
 	/* On error release all taken pins */
@@ -452,24 +513,29 @@ err_pin_request:
 	return ret;
 }
 
-void pinmux_disable_setting(struct pinctrl_setting const *setting)
+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;
-	const unsigned *pins;
-	unsigned num_pins;
+	int ret = 0;
+	const unsigned int *pins = NULL;
+	unsigned int num_pins = 0;
 	int i;
 	struct pin_desc *desc;
+	bool is_equal;
 
-	ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
-				      &pins, &num_pins);
+	if (pctlops->get_group_pins)
+		ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
+					      &pins, &num_pins);
 	if (ret) {
+		const char *gname;
+
 		/* errors only affect debug data, so just warn */
+		gname = pctlops->get_group_name(pctldev,
+						setting->data.mux.group);
 		dev_warn(pctldev->dev,
-			 "could not get pins for group selector %d\n",
-			 setting->data.mux.group);
+			 "could not get pins for group %s\n",
+			 gname);
 		num_pins = 0;
 	}
 
@@ -482,15 +548,21 @@ void pinmux_disable_setting(struct pinctrl_setting const *setting)
 				 pins[i]);
 			continue;
 		}
-		desc->mux_setting = NULL;
-	}
+		scoped_guard(mutex, &desc->mux_lock)
+			is_equal = (desc->mux_setting == &(setting->data.mux));
 
-	/* And release the pins */
-	for (i = 0; i < num_pins; i++)
-		pin_free(pctldev, pins[i], NULL);
+		if (is_equal) {
+			pin_free(pctldev, pins[i], NULL);
+		} else {
+			const char *gname;
 
-	if (ops->disable)
-		ops->disable(pctldev, setting->data.mux.func, setting->data.mux.group);
+			gname = pctlops->get_group_name(pctldev,
+						setting->data.mux.group);
+			dev_warn(pctldev->dev,
+				 "not freeing pin %d (%s) as part of deactivating group %s - it is already used for some other setting",
+				 pins[i], desc->name, gname);
+		}
+	}
 }
 
 #ifdef CONFIG_DEBUG_FS
@@ -500,8 +572,8 @@ static int pinmux_functions_show(struct seq_file *s, void *what)
 {
 	struct pinctrl_dev *pctldev = s->private;
 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
-	unsigned nfuncs;
-	unsigned func_selector = 0;
+	unsigned int nfuncs;
+	unsigned int func_selector = 0;
 
 	if (!pmxops)
 		return 0;
@@ -512,17 +584,20 @@ static int pinmux_functions_show(struct seq_file *s, void *what)
 		const char *func = pmxops->get_function_name(pctldev,
 							  func_selector);
 		const char * const *groups;
-		unsigned num_groups;
+		unsigned int num_groups;
 		int ret;
 		int i;
 
 		ret = pmxops->get_function_groups(pctldev, func_selector,
 						  &groups, &num_groups);
-		if (ret)
+		if (ret) {
 			seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
 				   func);
+			func_selector++;
+			continue;
+		}
 
-		seq_printf(s, "function: %s, groups = [ ", func);
+		seq_printf(s, "function %d: %s, groups = [ ", func_selector, func);
 		for (i = 0; i < num_groups; i++)
 			seq_printf(s, "%s ", groups[i]);
 		seq_puts(s, "]\n");
@@ -534,19 +609,25 @@ static int pinmux_functions_show(struct seq_file *s, void *what)
 
 	return 0;
 }
+DEFINE_SHOW_ATTRIBUTE(pinmux_functions);
 
 static int pinmux_pins_show(struct seq_file *s, void *what)
 {
 	struct pinctrl_dev *pctldev = s->private;
 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
-	unsigned i, pin;
+	unsigned int i, pin;
 
 	if (!pmxops)
 		return 0;
 
 	seq_puts(s, "Pinmux settings per pin\n");
-	seq_puts(s, "Format: pin (name): mux_owner gpio_owner hog?\n");
+	if (pmxops->strict)
+		seq_puts(s,
+		 "Format: pin (name): mux_owner|gpio_owner (strict) hog?\n");
+	else
+		seq_puts(s,
+		"Format: pin (name): mux_owner gpio_owner hog?\n");
 
 	mutex_lock(&pctldev->mutex);
 
@@ -561,34 +642,51 @@ static int pinmux_pins_show(struct seq_file *s, void *what)
 		if (desc == NULL)
 			continue;
 
-		if (desc->mux_owner &&
-		    !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
-			is_hog = true;
-
-		seq_printf(s, "pin %d (%s): %s %s%s", pin,
-			   desc->name ? desc->name : "unnamed",
-			   desc->mux_owner ? desc->mux_owner
-				: "(MUX UNCLAIMED)",
-			   desc->gpio_owner ? desc->gpio_owner
-				: "(GPIO UNCLAIMED)",
-			   is_hog ? " (HOG)" : "");
+		scoped_guard(mutex, &desc->mux_lock) {
+			if (desc->mux_owner &&
+			    !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
+				is_hog = true;
+
+			if (pmxops->strict) {
+				if (desc->mux_owner)
+					seq_printf(s, "pin %d (%s): device %s%s",
+						   pin, desc->name, desc->mux_owner,
+						   is_hog ? " (HOG)" : "");
+				else if (desc->gpio_owner)
+					seq_printf(s, "pin %d (%s): GPIO %s",
+						   pin, desc->name, desc->gpio_owner);
+				else
+					seq_printf(s, "pin %d (%s): UNCLAIMED",
+						   pin, desc->name);
+			} else {
+				/* For non-strict controllers */
+				seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name,
+					   desc->mux_owner ? desc->mux_owner
+					   : "(MUX UNCLAIMED)",
+					   desc->gpio_owner ? desc->gpio_owner
+					   : "(GPIO UNCLAIMED)",
+					   is_hog ? " (HOG)" : "");
+			}
 
-		if (desc->mux_setting)
-			seq_printf(s, " function %s group %s\n",
-				   pmxops->get_function_name(pctldev,
-					desc->mux_setting->func),
-				   pctlops->get_group_name(pctldev,
-					desc->mux_setting->group));
-		else
-			seq_printf(s, "\n");
+			/* If mux: print function+group claiming the pin */
+			if (desc->mux_setting)
+				seq_printf(s, " function %s group %s\n",
+					   pmxops->get_function_name(pctldev,
+						desc->mux_setting->func),
+					   pctlops->get_group_name(pctldev,
+						desc->mux_setting->group));
+			else
+				seq_putc(s, '\n');
+		}
 	}
 
 	mutex_unlock(&pctldev->mutex);
 
 	return 0;
 }
+DEFINE_SHOW_ATTRIBUTE(pinmux_pins);
 
-void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
+void pinmux_show_map(struct seq_file *s, const struct pinctrl_map *map)
 {
 	seq_printf(s, "group %s\nfunction %s\n",
 		map->data.mux.group ? map->data.mux.group : "(default)",
@@ -596,7 +694,7 @@ void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
 }
 
 void pinmux_show_setting(struct seq_file *s,
-			 struct pinctrl_setting const *setting)
+			 const struct pinctrl_setting *setting)
 {
 	struct pinctrl_dev *pctldev = setting->pctldev;
 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
@@ -609,37 +707,308 @@ void pinmux_show_setting(struct seq_file *s,
 		   setting->data.mux.func);
 }
 
-static int pinmux_functions_open(struct inode *inode, struct file *file)
+static int pinmux_select_show(struct seq_file *s, void *unused)
 {
-	return single_open(file, pinmux_functions_show, inode->i_private);
+	return -EPERM;
 }
 
-static int pinmux_pins_open(struct inode *inode, struct file *file)
+static ssize_t pinmux_select_write(struct file *file, const char __user *user_buf,
+				   size_t len, loff_t *ppos)
 {
-	return single_open(file, pinmux_pins_show, inode->i_private);
-}
+	struct seq_file *sfile = file->private_data;
+	struct pinctrl_dev *pctldev = sfile->private;
+	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
+	const char *const *groups;
+	char *buf, *gname, *fname;
+	unsigned int num_groups;
+	int fsel, gsel, ret;
+
+	buf = memdup_user_nul(user_buf, len);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	/* remove leading and trailing spaces of input buffer */
+	gname = strstrip(buf);
+	if (*gname == '\0') {
+		ret = -EINVAL;
+		goto exit_free_buf;
+	}
+
+	/* find a separator which is a spacelike character */
+	for (fname = gname; !isspace(*fname); fname++) {
+		if (*fname == '\0') {
+			ret = -EINVAL;
+			goto exit_free_buf;
+		}
+	}
+	*fname = '\0';
+
+	/* drop extra spaces between function and group names */
+	fname = skip_spaces(fname + 1);
+	if (*fname == '\0') {
+		ret = -EINVAL;
+		goto exit_free_buf;
+	}
 
-static const struct file_operations pinmux_functions_ops = {
-	.open		= pinmux_functions_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+	ret = pinmux_func_name_to_selector(pctldev, fname);
+	if (ret < 0) {
+		dev_err(pctldev->dev, "invalid function %s in map table\n", fname);
+		goto exit_free_buf;
+	}
+	fsel = ret;
+
+	ret = pmxops->get_function_groups(pctldev, fsel, &groups, &num_groups);
+	if (ret) {
+		dev_err(pctldev->dev, "no groups for function %d (%s)", fsel, fname);
+		goto exit_free_buf;
+	}
+
+	ret = match_string(groups, num_groups, gname);
+	if (ret < 0) {
+		dev_err(pctldev->dev, "invalid group %s", gname);
+		goto exit_free_buf;
+	}
+
+	ret = pinctrl_get_group_selector(pctldev, gname);
+	if (ret < 0)
+		goto exit_free_buf;
+	gsel = ret;
+
+	ret = pmxops->set_mux(pctldev, fsel, gsel);
+	if (ret) {
+		dev_err(pctldev->dev, "set_mux() failed: %d", ret);
+		goto exit_free_buf;
+	}
+	ret = len;
 
-static const struct file_operations pinmux_pins_ops = {
-	.open		= pinmux_pins_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+exit_free_buf:
+	kfree(buf);
+
+	return ret;
+}
+DEFINE_SHOW_STORE_ATTRIBUTE(pinmux_select);
 
 void pinmux_init_device_debugfs(struct dentry *devroot,
 			 struct pinctrl_dev *pctldev)
 {
-	debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
-			    devroot, pctldev, &pinmux_functions_ops);
-	debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
-			    devroot, pctldev, &pinmux_pins_ops);
+	debugfs_create_file("pinmux-functions", 0444,
+			    devroot, pctldev, &pinmux_functions_fops);
+	debugfs_create_file("pinmux-pins", 0444,
+			    devroot, pctldev, &pinmux_pins_fops);
+	debugfs_create_file("pinmux-select", 0200,
+			    devroot, pctldev, &pinmux_select_fops);
 }
 
 #endif /* CONFIG_DEBUG_FS */
+
+#ifdef CONFIG_GENERIC_PINMUX_FUNCTIONS
+
+/**
+ * pinmux_generic_get_function_count() - returns number of functions
+ * @pctldev: pin controller device
+ */
+int pinmux_generic_get_function_count(struct pinctrl_dev *pctldev)
+{
+	return pctldev->num_functions;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_get_function_count);
+
+/**
+ * pinmux_generic_get_function_name() - returns the function name
+ * @pctldev: pin controller device
+ * @selector: function number
+ */
+const char *
+pinmux_generic_get_function_name(struct pinctrl_dev *pctldev,
+				 unsigned int selector)
+{
+	struct function_desc *function;
+
+	function = radix_tree_lookup(&pctldev->pin_function_tree,
+				     selector);
+	if (!function)
+		return NULL;
+
+	return function->func->name;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_get_function_name);
+
+/**
+ * pinmux_generic_get_function_groups() - gets the function groups
+ * @pctldev: pin controller device
+ * @selector: function number
+ * @groups: array of pin groups
+ * @ngroups: number of pin groups
+ */
+int pinmux_generic_get_function_groups(struct pinctrl_dev *pctldev,
+				       unsigned int selector,
+				       const char * const **groups,
+				       unsigned int * const ngroups)
+{
+	struct function_desc *function;
+
+	function = radix_tree_lookup(&pctldev->pin_function_tree,
+				     selector);
+	if (!function) {
+		dev_err(pctldev->dev, "%s could not find function%i\n",
+			__func__, selector);
+		return -EINVAL;
+	}
+	*groups = function->func->groups;
+	*ngroups = function->func->ngroups;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_get_function_groups);
+
+/**
+ * pinmux_generic_get_function() - returns a function based on the number
+ * @pctldev: pin controller device
+ * @selector: function number
+ */
+const struct function_desc *
+pinmux_generic_get_function(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	struct function_desc *function;
+
+	function = radix_tree_lookup(&pctldev->pin_function_tree,
+				     selector);
+	if (!function)
+		return NULL;
+
+	return function;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_get_function);
+
+/**
+ * pinmux_generic_function_is_gpio() - returns true if given function is a GPIO
+ * @pctldev: pin controller device
+ * @selector: function number
+ *
+ * Returns:
+ * True if given function is a GPIO, false otherwise.
+ */
+bool pinmux_generic_function_is_gpio(struct pinctrl_dev *pctldev,
+				     unsigned int selector)
+{
+	struct function_desc *function;
+
+	function = radix_tree_lookup(&pctldev->pin_function_tree, selector);
+	if (!function)
+		return false;
+
+	return function->func->flags & PINFUNCTION_FLAG_GPIO;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_function_is_gpio);
+
+/**
+ * pinmux_generic_add_function() - adds a function group
+ * @pctldev: pin controller device
+ * @name: name of the function
+ * @groups: array of pin groups
+ * @ngroups: number of pin groups
+ * @data: pin controller driver specific data
+ */
+int pinmux_generic_add_function(struct pinctrl_dev *pctldev,
+				const char *name,
+				const char * const *groups,
+				const unsigned int ngroups,
+				void *data)
+{
+	struct pinfunction func = PINCTRL_PINFUNCTION(name, groups, ngroups);
+
+	return pinmux_generic_add_pinfunction(pctldev, &func, data);
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_add_function);
+
+/**
+ * pinmux_generic_add_pinfunction() - adds a function group
+ * @pctldev: pin controller device
+ * @func: pinfunction structure describing the function group
+ * @data: pin controller driver specific data
+ */
+int pinmux_generic_add_pinfunction(struct pinctrl_dev *pctldev,
+				   const struct pinfunction *func, void *data)
+{
+	struct function_desc *function;
+	int selector, error;
+
+	selector = pinmux_func_name_to_selector(pctldev, func->name);
+	if (selector >= 0)
+		return selector;
+
+	selector = pctldev->num_functions;
+
+	function = devm_kzalloc(pctldev->dev, sizeof(*function), GFP_KERNEL);
+	if (!function)
+		return -ENOMEM;
+
+	/*
+	 * FIXME: It's generally a bad idea to use devres in subsystem core
+	 * code - managed interfaces are aimed at drivers - but pinctrl already
+	 * uses it all over the place so it's a larger piece of technical debt
+	 * to fix.
+	 */
+	function->func = devm_kmemdup_const(pctldev->dev, func,
+					    sizeof(*func), GFP_KERNEL);
+	if (!function->func)
+		return -ENOMEM;
+
+	function->data = data;
+
+	error = radix_tree_insert(&pctldev->pin_function_tree, selector, function);
+	if (error)
+		return error;
+
+	pctldev->num_functions++;
+
+	return selector;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_add_pinfunction);
+
+/**
+ * pinmux_generic_remove_function() - removes a numbered function
+ * @pctldev: pin controller device
+ * @selector: function number
+ *
+ * Note that the caller must take care of locking.
+ */
+int pinmux_generic_remove_function(struct pinctrl_dev *pctldev,
+				   unsigned int selector)
+{
+	struct function_desc *function;
+
+	function = radix_tree_lookup(&pctldev->pin_function_tree,
+				     selector);
+	if (!function)
+		return -ENOENT;
+
+	radix_tree_delete(&pctldev->pin_function_tree, selector);
+	devm_kfree(pctldev->dev, function);
+
+	pctldev->num_functions--;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinmux_generic_remove_function);
+
+/**
+ * pinmux_generic_free_functions() - removes all functions
+ * @pctldev: pin controller device
+ *
+ * Note that the caller must take care of locking. The pinctrl
+ * functions are allocated with devm_kzalloc() so no need to free
+ * them here.
+ */
+void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
+{
+	struct radix_tree_iter iter;
+	void __rcu **slot;
+
+	radix_tree_for_each_slot(slot, &pctldev->pin_function_tree, &iter, 0)
+		radix_tree_delete(&pctldev->pin_function_tree, iter.index);
+
+	pctldev->num_functions = 0;
+}
+
+#endif /* CONFIG_GENERIC_PINMUX_FUNCTIONS */