// SPDX-License-Identifier: GPL-2.0-only
/*
 * Core driver for the pin muxing portions of the pin control subsystem
 *
 * Copyright (C) 2011-2012 ST-Ericsson SA
 * Written on behalf of Linaro for ST-Ericsson
 * Based on bits of regulator core, gpio core and clk core
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
 */
#define pr_fmt(fmt) "pinmux core: " fmt

#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/radix-tree.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/machine.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;

        /* Check that we implement required operations */
        if (!ops ||
            !ops->get_functions_count ||
            !ops->get_function_name ||
            !ops->get_function_groups ||
            !ops->set_mux) {
                dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
                return -EINVAL;
        }
        /* Check that all functions registered have names */
        nfuncs = ops->get_functions_count(pctldev);
        while (selector < nfuncs) {
                const char *fname = ops->get_function_name(pctldev,
                                                           selector);
                if (!fname) {
                        dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
                                selector);
                        return -EINVAL;
                }
                selector++;
        }

        return 0;
}

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",
                       map->name, i);
                return -EINVAL;
        }

        return 0;
}

/**
 * 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 pin)
{
        struct pin_desc *desc = pin_desc_get(pctldev, pin);
        const struct pinmux_ops *ops = pctldev->desc->pmxops;

        /* Can't inspect pin, assume it can be used */
        if (!desc || !ops)
                return true;

        if (ops->strict && desc->mux_usecount)
                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
 * @gpio_range: the range matching the GPIO pin if this is a request for a
 *      single GPIO pin
 */
static int pin_request(struct pinctrl_dev *pctldev,
                       int pin, const char *owner,
                       struct pinctrl_gpio_range *gpio_range)
{
        struct pin_desc *desc;
        const struct pinmux_ops *ops = pctldev->desc->pmxops;
        int status = -EINVAL;

        desc = pin_desc_get(pctldev, pin);
        if (desc == NULL) {
                dev_err(pctldev->dev,
                        "pin %d is not registered so it cannot be requested\n",
                        pin);
                goto out;
        }

        dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
                pin, desc->name, owner);

        if ((!gpio_range || ops->strict) &&
            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->mux_owner, owner);
                goto out;
        }

        if ((gpio_range || ops->strict) && desc->gpio_owner) {
                dev_err(pctldev->dev,
                        "pin %s already requested by %s; cannot claim for %s\n",
                        desc->name, desc->gpio_owner, owner);
                goto out;
        }

        if (gpio_range) {
                desc->gpio_owner = owner;
        } else {
                desc->mux_usecount++;
                if (desc->mux_usecount > 1)
                        return 0;

                desc->mux_owner = owner;
        }

        /* Let each pin increase references to this module */
        if (!try_module_get(pctldev->owner)) {
                dev_err(pctldev->dev,
                        "could not increase module refcount for pin %d\n",
                        pin);
                status = -EINVAL;
                goto out_free_pin;
        }

        /*
         * If there is no kind of request function for the pin we just assume
         * we got it by default and proceed.
         */
        if (gpio_range && ops->gpio_request_enable)
                /* This requests and enables a single GPIO pin */
                status = ops->gpio_request_enable(pctldev, gpio_range, pin);
        else if (ops->request)
                status = ops->request(pctldev, pin);
        else
                status = 0;

        if (status) {
                dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
                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;
                }
        }
out:
        if (status)
                dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
                        pin, owner, status);

        return status;
}

/**
 * pin_free() - release a single muxed in pin so something else can be muxed
 * @pctldev: pin controller device handling this pin
 * @pin: the pin to free
 * @gpio_range: the range matching the GPIO pin if this is a request for a
 *      single GPIO pin
 *
 * This function returns a pointer to the previous owner. This is used
 * for callers that dynamically allocate an owner name so it can be freed
 * once the pin is free. This is done for GPIO request functions.
 */
static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
                            struct pinctrl_gpio_range *gpio_range)
{
        const struct pinmux_ops *ops = pctldev->desc->pmxops;
        struct pin_desc *desc;
        const char *owner;

        desc = pin_desc_get(pctldev, pin);
        if (desc == NULL) {
                dev_err(pctldev->dev,
                        "pin is not registered so it cannot be freed\n");
                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;
        }

        /*
         * If there is no kind of request function for the pin we just assume
         * we got it by default and proceed.
         */
        if (gpio_range && ops->gpio_disable_free)
                ops->gpio_disable_free(pctldev, gpio_range, 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;
}

/**
 * pinmux_request_gpio() - request pinmuxing for a GPIO 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)
{
        const char *owner;
        int ret;

        /* Conjure some name stating what chip and pin this is taken by */
        owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
        if (!owner)
                return -ENOMEM;

        ret = pin_request(pctldev, pin, owner, range);
        if (ret < 0)
                kfree(owner);

        return ret;
}

/**
 * pinmux_free_gpio() - release a pin from GPIO muxing
 * @pctldev: the pin controller device for the pin
 * @pin: the affected currently GPIO-muxed in pin
 * @range: applicable GPIO range
 */
void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
                      struct pinctrl_gpio_range *range)
{
        const char *owner;

        owner = pin_free(pctldev, pin, range);
        kfree(owner);
}

/**
 * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 * @pctldev: the pin controller handling this pin
 * @range: applicable GPIO range
 * @pin: the affected GPIO pin in this controller
 * @input: true if we set the pin as input, false for output
 */
int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
                          struct pinctrl_gpio_range *range,
                          unsigned pin, bool input)
{
        const struct pinmux_ops *ops;
        int ret;

        ops = pctldev->desc->pmxops;

        if (ops->gpio_set_direction)
                ret = ops->gpio_set_direction(pctldev, range, pin, input);
        else
                ret = 0;

        return ret;
}

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;

        /* See if this pctldev has this function */
        while (selector < nfuncs) {
                const char *fname = ops->get_function_name(pctldev, selector);

                if (!strcmp(function, fname))
                        return selector;

                selector++;
        }

        return -EINVAL;
}

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;
        int ret;
        const char *group;

        if (!pmxops) {
                dev_err(pctldev->dev, "does not support mux function\n");
                return -EINVAL;
        }

        ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
        if (ret < 0) {
                dev_err(pctldev->dev, "invalid function %s in map table\n",
                        map->data.mux.function);
                return ret;
        }
        setting->data.mux.func = ret;

        ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
                                          &groups, &num_groups);
        if (ret < 0) {
                dev_err(pctldev->dev, "can't query groups for function %s\n",
                        map->data.mux.function);
                return ret;
        }
        if (!num_groups) {
                dev_err(pctldev->dev,
                        "function %s can't be selected on any group\n",
                        map->data.mux.function);
                return -EINVAL;
        }
        if (map->data.mux.group) {
                group = map->data.mux.group;
                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 ret;
                }
        } else {
                group = groups[0];
        }

        ret = pinctrl_get_group_selector(pctldev, group);
        if (ret < 0) {
                dev_err(pctldev->dev, "invalid group %s in map table\n",
                        map->data.mux.group);
                return ret;
        }
        setting->data.mux.group = ret;

        return 0;
}

void pinmux_free_setting(const struct pinctrl_setting *setting)
{
        /* This function is currently unused */
}

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 = 0;
        const unsigned *pins = NULL;
        unsigned num_pins = 0;
        int i;
        struct pin_desc *desc;

        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 %s\n",
                         gname);
                num_pins = 0;
        }

        /* Try to allocate all pins in this group, one by one */
        for (i = 0; i < num_pins; i++) {
                ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
                if (ret) {
                        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(pctldev->dev,
                                "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;
                }
        }

        /* Now that we have acquired the pins, encode the mux setting */
        for (i = 0; i < num_pins; i++) {
                desc = pin_desc_get(pctldev, pins[i]);
                if (desc == NULL) {
                        dev_warn(pctldev->dev,
                                 "could not get pin desc for pin %d\n",
                                 pins[i]);
                        continue;
                }
                desc->mux_setting = &(setting->data.mux);
        }

        ret = ops->set_mux(pctldev, setting->data.mux.func,
                           setting->data.mux.group);

        if (ret)
                goto err_set_mux;

        return 0;

err_set_mux:
        for (i = 0; i < num_pins; i++) {
                desc = pin_desc_get(pctldev, pins[i]);
                if (desc)
                        desc->mux_setting = NULL;
        }
err_pin_request:
        /* On error release all taken pins */
        while (--i >= 0)
                pin_free(pctldev, pins[i], NULL);

        return ret;
}

void pinmux_disable_setting(const struct pinctrl_setting *setting)
{
        struct pinctrl_dev *pctldev = setting->pctldev;
        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
        int ret = 0;
        const unsigned *pins = NULL;
        unsigned num_pins = 0;
        int i;
        struct pin_desc *desc;

        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 %s\n",
                         gname);
                num_pins = 0;
        }

        /* Flag the descs that no setting is active */
        for (i = 0; i < num_pins; i++) {
                desc = pin_desc_get(pctldev, pins[i]);
                if (desc == NULL) {
                        dev_warn(pctldev->dev,
                                 "could not get pin desc for pin %d\n",
                                 pins[i]);
                        continue;
                }
                if (desc->mux_setting == &(setting->data.mux)) {
                        pin_free(pctldev, pins[i], NULL);
                } else {
                        const char *gname;

                        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

/* Called from pincontrol core */
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;

        if (!pmxops)
                return 0;

        mutex_lock(&pctldev->mutex);
        nfuncs = pmxops->get_functions_count(pctldev);
        while (func_selector < nfuncs) {
                const char *func = pmxops->get_function_name(pctldev,
                                                          func_selector);
                const char * const *groups;
                unsigned num_groups;
                int ret;
                int i;

                ret = pmxops->get_function_groups(pctldev, func_selector,
                                                  &groups, &num_groups);
                if (ret) {
                        seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
                                   func);
                        func_selector++;
                        continue;
                }

                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");

                func_selector++;
        }

        mutex_unlock(&pctldev->mutex);

        return 0;
}

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;

        if (!pmxops)
                return 0;

        seq_puts(s, "Pinmux settings per pin\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);

        /* The pin number can be retrived from the pin controller descriptor */
        for (i = 0; i < pctldev->desc->npins; i++) {
                struct pin_desc *desc;
                bool is_hog = false;

                pin = pctldev->desc->pins[i].number;
                desc = pin_desc_get(pctldev, pin);
                /* Skip if we cannot search the pin */
                if (desc == NULL)
                        continue;

                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 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;
}

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)",
                map->data.mux.function);
}

void pinmux_show_setting(struct seq_file *s,
                         const struct pinctrl_setting *setting)
{
        struct pinctrl_dev *pctldev = setting->pctldev;
        const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
        const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;

        seq_printf(s, "group: %s (%u) function: %s (%u)\n",
                   pctlops->get_group_name(pctldev, setting->data.mux.group),
                   setting->data.mux.group,
                   pmxops->get_function_name(pctldev, setting->data.mux.func),
                   setting->data.mux.func);
}

DEFINE_SHOW_ATTRIBUTE(pinmux_functions);
DEFINE_SHOW_ATTRIBUTE(pinmux_pins);

#define PINMUX_SELECT_MAX 128
static ssize_t pinmux_select(struct file *file, const char __user *user_buf,
                                   size_t len, loff_t *ppos)
{
        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;

        if (len > PINMUX_SELECT_MAX)
                return -ENOMEM;

        buf = kzalloc(PINMUX_SELECT_MAX, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = strncpy_from_user(buf, user_buf, PINMUX_SELECT_MAX);
        if (ret < 0)
                goto exit_free_buf;
        buf[len-1] = '\0';

        /* 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;
        }

        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) {
                dev_err(pctldev->dev, "failed to get group selector for %s", gname);
                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;

exit_free_buf:
        kfree(buf);

        return ret;
}

static int pinmux_select_open(struct inode *inode, struct file *file)
{
        return single_open(file, NULL, inode->i_private);
}

static const struct file_operations pinmux_select_ops = {
        .owner = THIS_MODULE,
        .open = pinmux_select_open,
        .write = pinmux_select,
        .llseek = no_llseek,
        .release = single_release,
};

void pinmux_init_device_debugfs(struct dentry *devroot,
                         struct pinctrl_dev *pctldev)
{
        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_ops);
}

#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->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
 * @num_groups: number of pin groups
 */
int pinmux_generic_get_function_groups(struct pinctrl_dev *pctldev,
                                       unsigned int selector,
                                       const char * const **groups,
                                       unsigned * const num_groups)
{
        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->group_names;
        *num_groups = function->num_group_names;

        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
 */
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_add_function() - adds a function group
 * @pctldev: pin controller device
 * @name: name of the function
 * @groups: array of pin groups
 * @num_groups: number of pin groups
 * @data: pin controller driver specific data
 */
int pinmux_generic_add_function(struct pinctrl_dev *pctldev,
                                const char *name,
                                const char **groups,
                                const unsigned int num_groups,
                                void *data)
{
        struct function_desc *function;
        int selector;

        if (!name)
                return -EINVAL;

        selector = pinmux_func_name_to_selector(pctldev, name);
        if (selector >= 0)
                return selector;

        selector = pctldev->num_functions;

        function = devm_kzalloc(pctldev->dev, sizeof(*function), GFP_KERNEL);
        if (!function)
                return -ENOMEM;

        function->name = name;
        function->group_names = groups;
        function->num_group_names = num_groups;
        function->data = data;

        radix_tree_insert(&pctldev->pin_function_tree, selector, function);

        pctldev->num_functions++;

        return selector;
}
EXPORT_SYMBOL_GPL(pinmux_generic_add_function);

/**
 * 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 */