Merge tag 'drm-misc-fixes-2017-08-08' of git://anongit.freedesktop.org/git/drm-misc...

[mirror_ubuntu-bionic-kernel.git] / drivers / pinctrl / samsung / pinctrl-exynos5440.c

/*
 * pin-controller/pin-mux/pin-config/gpio-driver for Samsung's EXYNOS5440 SoC.
 *
 * Author: Thomas Abraham <thomas.ab@samsung.com>
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/gpio/driver.h>
#include <linux/device.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/of_irq.h>
#include "../core.h"

/* EXYNOS5440 GPIO and Pinctrl register offsets */
#define GPIO_MUX                0x00
#define GPIO_IE                 0x04
#define GPIO_INT                0x08
#define GPIO_TYPE               0x0C
#define GPIO_VAL                0x10
#define GPIO_OE                 0x14
#define GPIO_IN                 0x18
#define GPIO_PE                 0x1C
#define GPIO_PS                 0x20
#define GPIO_SR                 0x24
#define GPIO_DS0                0x28
#define GPIO_DS1                0x2C

#define EXYNOS5440_MAX_PINS             23
#define EXYNOS5440_MAX_GPIO_INT 8
#define PIN_NAME_LENGTH         10

#define GROUP_SUFFIX            "-grp"
#define FUNCTION_SUFFIX         "-mux"

/*
 * pin configuration type and its value are packed together into a 16-bits.
 * The upper 8-bits represent the configuration type and the lower 8-bits
 * hold the value of the configuration type.
 */
#define PINCFG_TYPE_MASK                0xFF
#define PINCFG_VALUE_SHIFT              8
#define PINCFG_VALUE_MASK               (0xFF << PINCFG_VALUE_SHIFT)
#define PINCFG_PACK(type, value)        (((value) << PINCFG_VALUE_SHIFT) | type)
#define PINCFG_UNPACK_TYPE(cfg)         ((cfg) & PINCFG_TYPE_MASK)
#define PINCFG_UNPACK_VALUE(cfg)        (((cfg) & PINCFG_VALUE_MASK) >> \
                                                PINCFG_VALUE_SHIFT)

/**
 * enum pincfg_type - possible pin configuration types supported.
 * @PINCFG_TYPE_PUD: Pull up/down configuration.
 * @PINCFG_TYPE_DRV: Drive strength configuration.
 * @PINCFG_TYPE_SKEW_RATE: Skew rate configuration.
 * @PINCFG_TYPE_INPUT_TYPE: Pin input type configuration.
 */
enum pincfg_type {
        PINCFG_TYPE_PUD,
        PINCFG_TYPE_DRV,
        PINCFG_TYPE_SKEW_RATE,
        PINCFG_TYPE_INPUT_TYPE
};

/**
 * struct exynos5440_pin_group: represent group of pins for pincfg setting.
 * @name: name of the pin group, used to lookup the group.
 * @pins: the pins included in this group.
 * @num_pins: number of pins included in this group.
 */
struct exynos5440_pin_group {
        const char              *name;
        const unsigned int      *pins;
        u8                      num_pins;
};

/**
 * struct exynos5440_pmx_func: represent a pin function.
 * @name: name of the pin function, used to lookup the function.
 * @groups: one or more names of pin groups that provide this function.
 * @num_groups: number of groups included in @groups.
 * @function: the function number to be programmed when selected.
 */
struct exynos5440_pmx_func {
        const char              *name;
        const char              **groups;
        u8                      num_groups;
        unsigned long           function;
};

/**
 * struct exynos5440_pinctrl_priv_data: driver's private runtime data.
 * @reg_base: ioremapped based address of the register space.
 * @gc: gpio chip registered with gpiolib.
 * @pin_groups: list of pin groups parsed from device tree.
 * @nr_groups: number of pin groups available.
 * @pmx_functions: list of pin functions parsed from device tree.
 * @nr_functions: number of pin functions available.
 * @range: gpio range to register with pinctrl
 */
struct exynos5440_pinctrl_priv_data {
        void __iomem                    *reg_base;
        struct gpio_chip                *gc;
        struct irq_domain               *irq_domain;

        const struct exynos5440_pin_group       *pin_groups;
        unsigned int                    nr_groups;
        const struct exynos5440_pmx_func        *pmx_functions;
        unsigned int                    nr_functions;
        struct pinctrl_gpio_range       range;
};

/**
 * struct exynos5440_gpio_intr_data: private data for gpio interrupts.
 * @priv: driver's private runtime data.
 * @gpio_int: gpio interrupt number.
 */
struct exynos5440_gpio_intr_data {
        struct exynos5440_pinctrl_priv_data     *priv;
        unsigned int                            gpio_int;
};

/* list of all possible config options supported */
static struct pin_config {
        char            *prop_cfg;
        unsigned int    cfg_type;
} pcfgs[] = {
        { "samsung,exynos5440-pin-pud", PINCFG_TYPE_PUD },
        { "samsung,exynos5440-pin-drv", PINCFG_TYPE_DRV },
        { "samsung,exynos5440-pin-skew-rate", PINCFG_TYPE_SKEW_RATE },
        { "samsung,exynos5440-pin-input-type", PINCFG_TYPE_INPUT_TYPE },
};

/* check if the selector is a valid pin group selector */
static int exynos5440_get_group_count(struct pinctrl_dev *pctldev)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        return priv->nr_groups;
}

/* return the name of the group selected by the group selector */
static const char *exynos5440_get_group_name(struct pinctrl_dev *pctldev,
                                                unsigned selector)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        return priv->pin_groups[selector].name;
}

/* return the pin numbers associated with the specified group */
static int exynos5440_get_group_pins(struct pinctrl_dev *pctldev,
                unsigned selector, const unsigned **pins, unsigned *num_pins)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        *pins = priv->pin_groups[selector].pins;
        *num_pins = priv->pin_groups[selector].num_pins;
        return 0;
}

/* create pinctrl_map entries by parsing device tree nodes */
static int exynos5440_dt_node_to_map(struct pinctrl_dev *pctldev,
                        struct device_node *np, struct pinctrl_map **maps,
                        unsigned *nmaps)
{
        struct device *dev = pctldev->dev;
        struct pinctrl_map *map;
        unsigned long *cfg = NULL;
        char *gname, *fname;
        int cfg_cnt = 0, map_cnt = 0, idx = 0;

        /* count the number of config options specfied in the node */
        for (idx = 0; idx < ARRAY_SIZE(pcfgs); idx++)
                if (of_find_property(np, pcfgs[idx].prop_cfg, NULL))
                        cfg_cnt++;

        /*
         * Find out the number of map entries to create. All the config options
         * can be accomadated into a single config map entry.
         */
        if (cfg_cnt)
                map_cnt = 1;
        if (of_find_property(np, "samsung,exynos5440-pin-function", NULL))
                map_cnt++;
        if (!map_cnt) {
                dev_err(dev, "node %s does not have either config or function "
                                "configurations\n", np->name);
                return -EINVAL;
        }

        /* Allocate memory for pin-map entries */
        map = kzalloc(sizeof(*map) * map_cnt, GFP_KERNEL);
        if (!map)
                return -ENOMEM;
        *nmaps = 0;

        /*
         * Allocate memory for pin group name. The pin group name is derived
         * from the node name from which these map entries are be created.
         */
        gname = kasprintf(GFP_KERNEL, "%s%s", np->name, GROUP_SUFFIX);
        if (!gname)
                goto free_map;

        /*
         * don't have config options? then skip over to creating function
         * map entries.
         */
        if (!cfg_cnt)
                goto skip_cfgs;

        /* Allocate memory for config entries */
        cfg = kzalloc(sizeof(*cfg) * cfg_cnt, GFP_KERNEL);
        if (!cfg)
                goto free_gname;

        /* Prepare a list of config settings */
        for (idx = 0, cfg_cnt = 0; idx < ARRAY_SIZE(pcfgs); idx++) {
                u32 value;
                if (!of_property_read_u32(np, pcfgs[idx].prop_cfg, &value))
                        cfg[cfg_cnt++] =
                                PINCFG_PACK(pcfgs[idx].cfg_type, value);
        }

        /* create the config map entry */
        map[*nmaps].data.configs.group_or_pin = gname;
        map[*nmaps].data.configs.configs = cfg;
        map[*nmaps].data.configs.num_configs = cfg_cnt;
        map[*nmaps].type = PIN_MAP_TYPE_CONFIGS_GROUP;
        *nmaps += 1;

skip_cfgs:
        /* create the function map entry */
        if (of_find_property(np, "samsung,exynos5440-pin-function", NULL)) {
                fname = kasprintf(GFP_KERNEL,
                                  "%s%s", np->name, FUNCTION_SUFFIX);
                if (!fname)
                        goto free_cfg;

                map[*nmaps].data.mux.group = gname;
                map[*nmaps].data.mux.function = fname;
                map[*nmaps].type = PIN_MAP_TYPE_MUX_GROUP;
                *nmaps += 1;
        }

        *maps = map;
        return 0;

free_cfg:
        kfree(cfg);
free_gname:
        kfree(gname);
free_map:
        kfree(map);
        return -ENOMEM;
}

/* free the memory allocated to hold the pin-map table */
static void exynos5440_dt_free_map(struct pinctrl_dev *pctldev,
                             struct pinctrl_map *map, unsigned num_maps)
{
        int idx;

        for (idx = 0; idx < num_maps; idx++) {
                if (map[idx].type == PIN_MAP_TYPE_MUX_GROUP) {
                        kfree(map[idx].data.mux.function);
                        if (!idx)
                                kfree(map[idx].data.mux.group);
                } else if (map->type == PIN_MAP_TYPE_CONFIGS_GROUP) {
                        kfree(map[idx].data.configs.configs);
                        if (!idx)
                                kfree(map[idx].data.configs.group_or_pin);
                }
        }

        kfree(map);
}

/* list of pinctrl callbacks for the pinctrl core */
static const struct pinctrl_ops exynos5440_pctrl_ops = {
        .get_groups_count       = exynos5440_get_group_count,
        .get_group_name         = exynos5440_get_group_name,
        .get_group_pins         = exynos5440_get_group_pins,
        .dt_node_to_map         = exynos5440_dt_node_to_map,
        .dt_free_map            = exynos5440_dt_free_map,
};

/* check if the selector is a valid pin function selector */
static int exynos5440_get_functions_count(struct pinctrl_dev *pctldev)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        return priv->nr_functions;
}

/* return the name of the pin function specified */
static const char *exynos5440_pinmux_get_fname(struct pinctrl_dev *pctldev,
                                                unsigned selector)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        return priv->pmx_functions[selector].name;
}

/* return the groups associated for the specified function selector */
static int exynos5440_pinmux_get_groups(struct pinctrl_dev *pctldev,
                unsigned selector, const char * const **groups,
                unsigned * const num_groups)
{
        struct exynos5440_pinctrl_priv_data *priv;

        priv = pinctrl_dev_get_drvdata(pctldev);
        *groups = priv->pmx_functions[selector].groups;
        *num_groups = priv->pmx_functions[selector].num_groups;
        return 0;
}

/* enable or disable a pinmux function */
static void exynos5440_pinmux_setup(struct pinctrl_dev *pctldev, unsigned selector,
                                        unsigned group, bool enable)
{
        struct exynos5440_pinctrl_priv_data *priv;
        void __iomem *base;
        u32 function;
        u32 data;

        priv = pinctrl_dev_get_drvdata(pctldev);
        base = priv->reg_base;
        function = priv->pmx_functions[selector].function;

        data = readl(base + GPIO_MUX);
        if (enable)
                data |= (1 << function);
        else
                data &= ~(1 << function);
        writel(data, base + GPIO_MUX);
}

/* enable a specified pinmux by writing to registers */
static int exynos5440_pinmux_set_mux(struct pinctrl_dev *pctldev,
                                     unsigned selector,
                                     unsigned group)
{
        exynos5440_pinmux_setup(pctldev, selector, group, true);
        return 0;
}

/*
 * The calls to gpio_direction_output() and gpio_direction_input()
 * leads to this function call (via the pinctrl_gpio_direction_{input|output}()
 * function called from the gpiolib interface).
 */
static int exynos5440_pinmux_gpio_set_direction(struct pinctrl_dev *pctldev,
                struct pinctrl_gpio_range *range, unsigned offset, bool input)
{
        return 0;
}

/* list of pinmux callbacks for the pinmux vertical in pinctrl core */
static const struct pinmux_ops exynos5440_pinmux_ops = {
        .get_functions_count    = exynos5440_get_functions_count,
        .get_function_name      = exynos5440_pinmux_get_fname,
        .get_function_groups    = exynos5440_pinmux_get_groups,
        .set_mux                = exynos5440_pinmux_set_mux,
        .gpio_set_direction     = exynos5440_pinmux_gpio_set_direction,
};

/* set the pin config settings for a specified pin */
static int exynos5440_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
                                unsigned long *configs,
                                unsigned num_configs)
{
        struct exynos5440_pinctrl_priv_data *priv;
        void __iomem *base;
        enum pincfg_type cfg_type;
        u32 cfg_value;
        u32 data;
        int i;

        priv = pinctrl_dev_get_drvdata(pctldev);
        base = priv->reg_base;

        for (i = 0; i < num_configs; i++) {
                cfg_type = PINCFG_UNPACK_TYPE(configs[i]);
                cfg_value = PINCFG_UNPACK_VALUE(configs[i]);

                switch (cfg_type) {
                case PINCFG_TYPE_PUD:
                        /* first set pull enable/disable bit */
                        data = readl(base + GPIO_PE);
                        data &= ~(1 << pin);
                        if (cfg_value)
                                data |= (1 << pin);
                        writel(data, base + GPIO_PE);

                        /* then set pull up/down bit */
                        data = readl(base + GPIO_PS);
                        data &= ~(1 << pin);
                        if (cfg_value == 2)
                                data |= (1 << pin);
                        writel(data, base + GPIO_PS);
                        break;

                case PINCFG_TYPE_DRV:
                        /* set the first bit of the drive strength */
                        data = readl(base + GPIO_DS0);
                        data &= ~(1 << pin);
                        data |= ((cfg_value & 1) << pin);
                        writel(data, base + GPIO_DS0);
                        cfg_value >>= 1;

                        /* set the second bit of the driver strength */
                        data = readl(base + GPIO_DS1);
                        data &= ~(1 << pin);
                        data |= ((cfg_value & 1) << pin);
                        writel(data, base + GPIO_DS1);
                        break;
                case PINCFG_TYPE_SKEW_RATE:
                        data = readl(base + GPIO_SR);
                        data &= ~(1 << pin);
                        data |= ((cfg_value & 1) << pin);
                        writel(data, base + GPIO_SR);
                        break;
                case PINCFG_TYPE_INPUT_TYPE:
                        data = readl(base + GPIO_TYPE);
                        data &= ~(1 << pin);
                        data |= ((cfg_value & 1) << pin);
                        writel(data, base + GPIO_TYPE);
                        break;
                default:
                        WARN_ON(1);
                        return -EINVAL;
                }
        } /* for each config */

        return 0;
}

/* get the pin config settings for a specified pin */
static int exynos5440_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
                                        unsigned long *config)
{
        struct exynos5440_pinctrl_priv_data *priv;
        void __iomem *base;
        enum pincfg_type cfg_type = PINCFG_UNPACK_TYPE(*config);
        u32 data;

        priv = pinctrl_dev_get_drvdata(pctldev);
        base = priv->reg_base;

        switch (cfg_type) {
        case PINCFG_TYPE_PUD:
                data = readl(base + GPIO_PE);
                data = (data >> pin) & 1;
                if (!data)
                        *config = 0;
                else
                        *config = ((readl(base + GPIO_PS) >> pin) & 1) + 1;
                break;
        case PINCFG_TYPE_DRV:
                data = readl(base + GPIO_DS0);
                data = (data >> pin) & 1;
                *config = data;
                data = readl(base + GPIO_DS1);
                data = (data >> pin) & 1;
                *config |= (data << 1);
                break;
        case PINCFG_TYPE_SKEW_RATE:
                data = readl(base + GPIO_SR);
                *config = (data >> pin) & 1;
                break;
        case PINCFG_TYPE_INPUT_TYPE:
                data = readl(base + GPIO_TYPE);
                *config = (data >> pin) & 1;
                break;
        default:
                WARN_ON(1);
                return -EINVAL;
        }

        return 0;
}

/* set the pin config settings for a specified pin group */
static int exynos5440_pinconf_group_set(struct pinctrl_dev *pctldev,
                        unsigned group, unsigned long *configs,
                        unsigned num_configs)
{
        struct exynos5440_pinctrl_priv_data *priv;
        const unsigned int *pins;
        unsigned int cnt;

        priv = pinctrl_dev_get_drvdata(pctldev);
        pins = priv->pin_groups[group].pins;

        for (cnt = 0; cnt < priv->pin_groups[group].num_pins; cnt++)
                exynos5440_pinconf_set(pctldev, pins[cnt], configs,
                                       num_configs);

        return 0;
}

/* get the pin config settings for a specified pin group */
static int exynos5440_pinconf_group_get(struct pinctrl_dev *pctldev,
                                unsigned int group, unsigned long *config)
{
        struct exynos5440_pinctrl_priv_data *priv;
        const unsigned int *pins;

        priv = pinctrl_dev_get_drvdata(pctldev);
        pins = priv->pin_groups[group].pins;
        exynos5440_pinconf_get(pctldev, pins[0], config);
        return 0;
}

/* list of pinconfig callbacks for pinconfig vertical in the pinctrl code */
static const struct pinconf_ops exynos5440_pinconf_ops = {
        .pin_config_get         = exynos5440_pinconf_get,
        .pin_config_set         = exynos5440_pinconf_set,
        .pin_config_group_get   = exynos5440_pinconf_group_get,
        .pin_config_group_set   = exynos5440_pinconf_group_set,
};

/* gpiolib gpio_set callback function */
static void exynos5440_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
{
        struct exynos5440_pinctrl_priv_data *priv = gpiochip_get_data(gc);
        void __iomem *base = priv->reg_base;
        u32 data;

        data = readl(base + GPIO_VAL);
        data &= ~(1 << offset);
        if (value)
                data |= 1 << offset;
        writel(data, base + GPIO_VAL);
}

/* gpiolib gpio_get callback function */
static int exynos5440_gpio_get(struct gpio_chip *gc, unsigned offset)
{
        struct exynos5440_pinctrl_priv_data *priv = gpiochip_get_data(gc);
        void __iomem *base = priv->reg_base;
        u32 data;

        data = readl(base + GPIO_IN);
        data >>= offset;
        data &= 1;
        return data;
}

/* gpiolib gpio_direction_input callback function */
static int exynos5440_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
        struct exynos5440_pinctrl_priv_data *priv = gpiochip_get_data(gc);
        void __iomem *base = priv->reg_base;
        u32 data;

        /* first disable the data output enable on this pin */
        data = readl(base + GPIO_OE);
        data &= ~(1 << offset);
        writel(data, base + GPIO_OE);

        /* now enable input on this pin */
        data =  readl(base + GPIO_IE);
        data |= 1 << offset;
        writel(data, base + GPIO_IE);
        return 0;
}

/* gpiolib gpio_direction_output callback function */
static int exynos5440_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
                                                        int value)
{
        struct exynos5440_pinctrl_priv_data *priv = gpiochip_get_data(gc);
        void __iomem *base = priv->reg_base;
        u32 data;

        exynos5440_gpio_set(gc, offset, value);

        /* first disable the data input enable on this pin */
        data = readl(base + GPIO_IE);
        data &= ~(1 << offset);
        writel(data, base + GPIO_IE);

        /* now enable output on this pin */
        data =  readl(base + GPIO_OE);
        data |= 1 << offset;
        writel(data, base + GPIO_OE);
        return 0;
}

/* gpiolib gpio_to_irq callback function */
static int exynos5440_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
        struct exynos5440_pinctrl_priv_data *priv = gpiochip_get_data(gc);
        unsigned int virq;

        if (offset < 16 || offset > 23)
                return -ENXIO;

        if (!priv->irq_domain)
                return -ENXIO;

        virq = irq_create_mapping(priv->irq_domain, offset - 16);
        return virq ? : -ENXIO;
}

/* parse the pin numbers listed in the 'samsung,exynos5440-pins' property */
static int exynos5440_pinctrl_parse_dt_pins(struct platform_device *pdev,
                        struct device_node *cfg_np, unsigned int **pin_list,
                        unsigned int *npins)
{
        struct device *dev = &pdev->dev;
        struct property *prop;

        prop = of_find_property(cfg_np, "samsung,exynos5440-pins", NULL);
        if (!prop)
                return -ENOENT;

        *npins = prop->length / sizeof(unsigned long);
        if (!*npins) {
                dev_err(dev, "invalid pin list in %s node", cfg_np->name);
                return -EINVAL;
        }

        *pin_list = devm_kzalloc(dev, *npins * sizeof(**pin_list), GFP_KERNEL);
        if (!*pin_list)
                return -ENOMEM;

        return of_property_read_u32_array(cfg_np, "samsung,exynos5440-pins",
                        *pin_list, *npins);
}

/*
 * Parse the information about all the available pin groups and pin functions
 * from device node of the pin-controller.
 */
static int exynos5440_pinctrl_parse_dt(struct platform_device *pdev,
                                struct exynos5440_pinctrl_priv_data *priv)
{
        struct device *dev = &pdev->dev;
        struct device_node *dev_np = dev->of_node;
        struct device_node *cfg_np;
        struct exynos5440_pin_group *groups, *grp;
        struct exynos5440_pmx_func *functions, *func;
        unsigned *pin_list;
        unsigned int npins, grp_cnt, func_idx = 0;
        char *gname, *fname;
        int ret;

        grp_cnt = of_get_child_count(dev_np);
        if (!grp_cnt)
                return -EINVAL;

        groups = devm_kzalloc(dev, grp_cnt * sizeof(*groups), GFP_KERNEL);
        if (!groups)
                return -EINVAL;

        grp = groups;

        functions = devm_kzalloc(dev, grp_cnt * sizeof(*functions), GFP_KERNEL);
        if (!functions)
                return -EINVAL;

        func = functions;

        /*
         * Iterate over all the child nodes of the pin controller node
         * and create pin groups and pin function lists.
         */
        for_each_child_of_node(dev_np, cfg_np) {
                u32 function;

                ret = exynos5440_pinctrl_parse_dt_pins(pdev, cfg_np,
                                        &pin_list, &npins);
                if (ret) {
                        gname = NULL;
                        goto skip_to_pin_function;
                }

                /* derive pin group name from the node name */
                gname = devm_kasprintf(dev, GFP_KERNEL,
                                       "%s%s", cfg_np->name, GROUP_SUFFIX);
                if (!gname)
                        return -ENOMEM;

                grp->name = gname;
                grp->pins = pin_list;
                grp->num_pins = npins;
                grp++;

skip_to_pin_function:
                ret = of_property_read_u32(cfg_np, "samsung,exynos5440-pin-function",
                                                &function);
                if (ret)
                        continue;

                /* derive function name from the node name */
                fname = devm_kasprintf(dev, GFP_KERNEL,
                                       "%s%s", cfg_np->name, FUNCTION_SUFFIX);
                if (!fname)
                        return -ENOMEM;

                func->name = fname;
                func->groups = devm_kzalloc(dev, sizeof(char *), GFP_KERNEL);
                if (!func->groups)
                        return -ENOMEM;
                func->groups[0] = gname;
                func->num_groups = gname ? 1 : 0;
                func->function = function;
                func++;
                func_idx++;
        }

        priv->pin_groups = groups;
        priv->nr_groups = grp_cnt;
        priv->pmx_functions = functions;
        priv->nr_functions = func_idx;
        return 0;
}

/* register the pinctrl interface with the pinctrl subsystem */
static int exynos5440_pinctrl_register(struct platform_device *pdev,
                                struct exynos5440_pinctrl_priv_data *priv)
{
        struct device *dev = &pdev->dev;
        struct pinctrl_desc *ctrldesc;
        struct pinctrl_dev *pctl_dev;
        struct pinctrl_pin_desc *pindesc, *pdesc;
        char *pin_names;
        int pin, ret;

        ctrldesc = devm_kzalloc(dev, sizeof(*ctrldesc), GFP_KERNEL);
        if (!ctrldesc)
                return -ENOMEM;

        ctrldesc->name = "exynos5440-pinctrl";
        ctrldesc->owner = THIS_MODULE;
        ctrldesc->pctlops = &exynos5440_pctrl_ops;
        ctrldesc->pmxops = &exynos5440_pinmux_ops;
        ctrldesc->confops = &exynos5440_pinconf_ops;

        pindesc = devm_kzalloc(&pdev->dev, sizeof(*pindesc) *
                                EXYNOS5440_MAX_PINS, GFP_KERNEL);
        if (!pindesc)
                return -ENOMEM;
        ctrldesc->pins = pindesc;
        ctrldesc->npins = EXYNOS5440_MAX_PINS;

        /* dynamically populate the pin number and pin name for pindesc */
        for (pin = 0, pdesc = pindesc; pin < ctrldesc->npins; pin++, pdesc++)
                pdesc->number = pin;

        /*
         * allocate space for storing the dynamically generated names for all
         * the pins which belong to this pin-controller.
         */
        pin_names = devm_kzalloc(&pdev->dev, sizeof(char) * PIN_NAME_LENGTH *
                                        ctrldesc->npins, GFP_KERNEL);
        if (!pin_names)
                return -ENOMEM;

        /* for each pin, set the name of the pin */
        for (pin = 0; pin < ctrldesc->npins; pin++) {
                snprintf(pin_names, 6, "gpio%02d", pin);
                pdesc = pindesc + pin;
                pdesc->name = pin_names;
                pin_names += PIN_NAME_LENGTH;
        }

        ret = exynos5440_pinctrl_parse_dt(pdev, priv);
        if (ret)
                return ret;

        pctl_dev = devm_pinctrl_register(&pdev->dev, ctrldesc, priv);
        if (IS_ERR(pctl_dev)) {
                dev_err(&pdev->dev, "could not register pinctrl driver\n");
                return PTR_ERR(pctl_dev);
        }

        priv->range.name = "exynos5440-pctrl-gpio-range";
        priv->range.id = 0;
        priv->range.base = 0;
        priv->range.npins = EXYNOS5440_MAX_PINS;
        priv->range.gc = priv->gc;
        pinctrl_add_gpio_range(pctl_dev, &priv->range);
        return 0;
}

/* register the gpiolib interface with the gpiolib subsystem */
static int exynos5440_gpiolib_register(struct platform_device *pdev,
                                struct exynos5440_pinctrl_priv_data *priv)
{
        struct gpio_chip *gc;
        int ret;

        gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
        if (!gc)
                return -ENOMEM;

        priv->gc = gc;
        gc->base = 0;
        gc->ngpio = EXYNOS5440_MAX_PINS;
        gc->parent = &pdev->dev;
        gc->set = exynos5440_gpio_set;
        gc->get = exynos5440_gpio_get;
        gc->direction_input = exynos5440_gpio_direction_input;
        gc->direction_output = exynos5440_gpio_direction_output;
        gc->to_irq = exynos5440_gpio_to_irq;
        gc->label = "gpiolib-exynos5440";
        gc->owner = THIS_MODULE;
        ret = gpiochip_add_data(gc, priv);
        if (ret) {
                dev_err(&pdev->dev, "failed to register gpio_chip %s, error "
                                        "code: %d\n", gc->label, ret);
                return ret;
        }

        return 0;
}

/* unregister the gpiolib interface with the gpiolib subsystem */
static int exynos5440_gpiolib_unregister(struct platform_device *pdev,
                                struct exynos5440_pinctrl_priv_data *priv)
{
        gpiochip_remove(priv->gc);
        return 0;
}

static void exynos5440_gpio_irq_unmask(struct irq_data *irqd)
{
        struct exynos5440_pinctrl_priv_data *d;
        unsigned long gpio_int;

        d = irq_data_get_irq_chip_data(irqd);
        gpio_int = readl(d->reg_base + GPIO_INT);
        gpio_int |= 1 << irqd->hwirq;
        writel(gpio_int, d->reg_base + GPIO_INT);
}

static void exynos5440_gpio_irq_mask(struct irq_data *irqd)
{
        struct exynos5440_pinctrl_priv_data *d;
        unsigned long gpio_int;

        d = irq_data_get_irq_chip_data(irqd);
        gpio_int = readl(d->reg_base + GPIO_INT);
        gpio_int &= ~(1 << irqd->hwirq);
        writel(gpio_int, d->reg_base + GPIO_INT);
}

/* irq_chip for gpio interrupts */
static struct irq_chip exynos5440_gpio_irq_chip = {
        .name           = "exynos5440_gpio_irq_chip",
        .irq_unmask     = exynos5440_gpio_irq_unmask,
        .irq_mask       = exynos5440_gpio_irq_mask,
};

/* interrupt handler for GPIO interrupts 0..7 */
static irqreturn_t exynos5440_gpio_irq(int irq, void *data)
{
        struct exynos5440_gpio_intr_data *intd = data;
        struct exynos5440_pinctrl_priv_data *d = intd->priv;
        int virq;

        virq = irq_linear_revmap(d->irq_domain, intd->gpio_int);
        if (!virq)
                return IRQ_NONE;
        generic_handle_irq(virq);
        return IRQ_HANDLED;
}

static int exynos5440_gpio_irq_map(struct irq_domain *h, unsigned int virq,
                                        irq_hw_number_t hw)
{
        struct exynos5440_pinctrl_priv_data *d = h->host_data;

        irq_set_chip_data(virq, d);
        irq_set_chip_and_handler(virq, &exynos5440_gpio_irq_chip,
                                        handle_level_irq);
        return 0;
}

/* irq domain callbacks for gpio interrupt controller */
static const struct irq_domain_ops exynos5440_gpio_irqd_ops = {
        .map    = exynos5440_gpio_irq_map,
        .xlate  = irq_domain_xlate_twocell,
};

/* setup handling of gpio interrupts */
static int exynos5440_gpio_irq_init(struct platform_device *pdev,
                                struct exynos5440_pinctrl_priv_data *priv)
{
        struct device *dev = &pdev->dev;
        struct exynos5440_gpio_intr_data *intd;
        int i, irq, ret;

        intd = devm_kzalloc(dev, sizeof(*intd) * EXYNOS5440_MAX_GPIO_INT,
                                        GFP_KERNEL);
        if (!intd)
                return -ENOMEM;

        for (i = 0; i < EXYNOS5440_MAX_GPIO_INT; i++) {
                irq = irq_of_parse_and_map(dev->of_node, i);
                if (irq <= 0) {
                        dev_err(dev, "irq parsing failed\n");
                        return -EINVAL;
                }

                intd->gpio_int = i;
                intd->priv = priv;
                ret = devm_request_irq(dev, irq, exynos5440_gpio_irq,
                                        0, dev_name(dev), intd++);
                if (ret) {
                        dev_err(dev, "irq request failed\n");
                        return -ENXIO;
                }
        }

        priv->irq_domain = irq_domain_add_linear(dev->of_node,
                                EXYNOS5440_MAX_GPIO_INT,
                                &exynos5440_gpio_irqd_ops, priv);
        if (!priv->irq_domain) {
                dev_err(dev, "failed to create irq domain\n");
                return -ENXIO;
        }

        return 0;
}

static int exynos5440_pinctrl_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct exynos5440_pinctrl_priv_data *priv;
        struct resource *res;
        int ret;

        if (!dev->of_node) {
                dev_err(dev, "device tree node not found\n");
                return -ENODEV;
        }

        priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        priv->reg_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(priv->reg_base))
                return PTR_ERR(priv->reg_base);

        ret = exynos5440_gpiolib_register(pdev, priv);
        if (ret)
                return ret;

        ret = exynos5440_pinctrl_register(pdev, priv);
        if (ret) {
                exynos5440_gpiolib_unregister(pdev, priv);
                return ret;
        }

        ret = exynos5440_gpio_irq_init(pdev, priv);
        if (ret) {
                dev_err(dev, "failed to setup gpio interrupts\n");
                return ret;
        }

        platform_set_drvdata(pdev, priv);
        dev_info(dev, "EXYNOS5440 pinctrl driver registered\n");
        return 0;
}

static const struct of_device_id exynos5440_pinctrl_dt_match[] = {
        { .compatible = "samsung,exynos5440-pinctrl" },
        {},
};

static struct platform_driver exynos5440_pinctrl_driver = {
        .probe          = exynos5440_pinctrl_probe,
        .driver = {
                .name   = "exynos5440-pinctrl",
                .of_match_table = exynos5440_pinctrl_dt_match,
                .suppress_bind_attrs = true,
        },
};

static int __init exynos5440_pinctrl_drv_register(void)
{
        return platform_driver_register(&exynos5440_pinctrl_driver);
}
postcore_initcall(exynos5440_pinctrl_drv_register);