pinctrl: samsung: Protect bank registers with a spinlock

[linux-2.6.git] / drivers / pinctrl / pinctrl-samsung.c

/*
 * pin-controller/pin-mux/pin-config/gpio-driver for Samsung's SoC's.
 *
 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 * Copyright (c) 2012 Linaro Ltd
 *              http://www.linaro.org
 *
 * Author: Thomas Abraham <thomas.ab@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.
 *
 * This driver implements the Samsung pinctrl driver. It supports setting up of
 * pinmux and pinconf configurations. The gpiolib interface is also included.
 * External interrupt (gpio and wakeup) support are not included in this driver
 * but provides extensions to which platform specific implementation of the gpio
 * and wakeup interrupts can be hooked to.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/irqdomain.h>
#include <linux/spinlock.h>

#include "core.h"
#include "pinctrl-samsung.h"

#define GROUP_SUFFIX            "-grp"
#define GSUFFIX_LEN             sizeof(GROUP_SUFFIX)
#define FUNCTION_SUFFIX         "-mux"
#define FSUFFIX_LEN             sizeof(FUNCTION_SUFFIX)

/* list of all possible config options supported */
static struct pin_config {
        char            *prop_cfg;
        unsigned int    cfg_type;
} pcfgs[] = {
        { "samsung,pin-pud", PINCFG_TYPE_PUD },
        { "samsung,pin-drv", PINCFG_TYPE_DRV },
        { "samsung,pin-con-pdn", PINCFG_TYPE_CON_PDN },
        { "samsung,pin-pud-pdn", PINCFG_TYPE_PUD_PDN },
};

static unsigned int pin_base;

static inline struct samsung_pin_bank *gc_to_pin_bank(struct gpio_chip *gc)
{
        return container_of(gc, struct samsung_pin_bank, gpio_chip);
}

/* check if the selector is a valid pin group selector */
static int samsung_get_group_count(struct pinctrl_dev *pctldev)
{
        struct samsung_pinctrl_drv_data *drvdata;

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

/* return the name of the group selected by the group selector */
static const char *samsung_get_group_name(struct pinctrl_dev *pctldev,
                                                unsigned selector)
{
        struct samsung_pinctrl_drv_data *drvdata;

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

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

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

/* create pinctrl_map entries by parsing device tree nodes */
static int samsung_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,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) {
                dev_err(dev, "could not alloc memory for pin-maps\n");
                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 = kzalloc(strlen(np->name) + GSUFFIX_LEN, GFP_KERNEL);
        if (!gname) {
                dev_err(dev, "failed to alloc memory for group name\n");
                goto free_map;
        }
        sprintf(gname, "%s%s", np->name, GROUP_SUFFIX);

        /*
         * 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) {
                dev_err(dev, "failed to alloc memory for configs\n");
                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,pin-function", NULL)) {
                fname = kzalloc(strlen(np->name) + FSUFFIX_LEN, GFP_KERNEL);
                if (!fname) {
                        dev_err(dev, "failed to alloc memory for func name\n");
                        goto free_cfg;
                }
                sprintf(fname, "%s%s", np->name, FUNCTION_SUFFIX);

                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 samsung_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 samsung_pctrl_ops = {
        .get_groups_count       = samsung_get_group_count,
        .get_group_name         = samsung_get_group_name,
        .get_group_pins         = samsung_get_group_pins,
        .dt_node_to_map         = samsung_dt_node_to_map,
        .dt_free_map            = samsung_dt_free_map,
};

/* check if the selector is a valid pin function selector */
static int samsung_get_functions_count(struct pinctrl_dev *pctldev)
{
        struct samsung_pinctrl_drv_data *drvdata;

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

/* return the name of the pin function specified */
static const char *samsung_pinmux_get_fname(struct pinctrl_dev *pctldev,
                                                unsigned selector)
{
        struct samsung_pinctrl_drv_data *drvdata;

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

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

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

/*
 * given a pin number that is local to a pin controller, find out the pin bank
 * and the register base of the pin bank.
 */
static void pin_to_reg_bank(struct samsung_pinctrl_drv_data *drvdata,
                        unsigned pin, void __iomem **reg, u32 *offset,
                        struct samsung_pin_bank **bank)
{
        struct samsung_pin_bank *b;

        b = drvdata->ctrl->pin_banks;

        while ((pin >= b->pin_base) &&
                        ((b->pin_base + b->nr_pins - 1) < pin))
                b++;

        *reg = drvdata->virt_base + b->pctl_offset;
        *offset = pin - b->pin_base;
        if (bank)
                *bank = b;

        /* some banks have two config registers in a single bank */
        if (*offset * b->func_width > BITS_PER_LONG)
                *reg += 4;
}

/* enable or disable a pinmux function */
static void samsung_pinmux_setup(struct pinctrl_dev *pctldev, unsigned selector,
                                        unsigned group, bool enable)
{
        struct samsung_pinctrl_drv_data *drvdata;
        const unsigned int *pins;
        struct samsung_pin_bank *bank;
        void __iomem *reg;
        u32 mask, shift, data, pin_offset, cnt;
        unsigned long flags;

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

        /*
         * for each pin in the pin group selected, program the correspoding pin
         * pin function number in the config register.
         */
        for (cnt = 0; cnt < drvdata->pin_groups[group].num_pins; cnt++) {
                pin_to_reg_bank(drvdata, pins[cnt] - drvdata->ctrl->base,
                                &reg, &pin_offset, &bank);
                mask = (1 << bank->func_width) - 1;
                shift = pin_offset * bank->func_width;

                spin_lock_irqsave(&bank->slock, flags);

                data = readl(reg);
                data &= ~(mask << shift);
                if (enable)
                        data |= drvdata->pin_groups[group].func << shift;
                writel(data, reg);

                spin_unlock_irqrestore(&bank->slock, flags);
        }
}

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

/* disable a specified pinmux by writing to registers */
static void samsung_pinmux_disable(struct pinctrl_dev *pctldev,
                                        unsigned selector, unsigned group)
{
        samsung_pinmux_setup(pctldev, selector, group, false);
}

/*
 * 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 samsung_pinmux_gpio_set_direction(struct pinctrl_dev *pctldev,
                struct pinctrl_gpio_range *range, unsigned offset, bool input)
{
        struct samsung_pin_bank *bank;
        struct samsung_pinctrl_drv_data *drvdata;
        void __iomem *reg;
        u32 data, pin_offset, mask, shift;
        unsigned long flags;

        bank = gc_to_pin_bank(range->gc);
        drvdata = pinctrl_dev_get_drvdata(pctldev);

        pin_offset = offset - bank->pin_base;
        reg = drvdata->virt_base + bank->pctl_offset;

        mask = (1 << bank->func_width) - 1;
        shift = pin_offset * bank->func_width;

        spin_lock_irqsave(&bank->slock, flags);

        data = readl(reg);
        data &= ~(mask << shift);
        if (!input)
                data |= FUNC_OUTPUT << shift;
        writel(data, reg);

        spin_unlock_irqrestore(&bank->slock, flags);

        return 0;
}

/* list of pinmux callbacks for the pinmux vertical in pinctrl core */
static const struct pinmux_ops samsung_pinmux_ops = {
        .get_functions_count    = samsung_get_functions_count,
        .get_function_name      = samsung_pinmux_get_fname,
        .get_function_groups    = samsung_pinmux_get_groups,
        .enable                 = samsung_pinmux_enable,
        .disable                = samsung_pinmux_disable,
        .gpio_set_direction     = samsung_pinmux_gpio_set_direction,
};

/* set or get the pin config settings for a specified pin */
static int samsung_pinconf_rw(struct pinctrl_dev *pctldev, unsigned int pin,
                                unsigned long *config, bool set)
{
        struct samsung_pinctrl_drv_data *drvdata;
        struct samsung_pin_bank *bank;
        void __iomem *reg_base;
        enum pincfg_type cfg_type = PINCFG_UNPACK_TYPE(*config);
        u32 data, width, pin_offset, mask, shift;
        u32 cfg_value, cfg_reg;
        unsigned long flags;

        drvdata = pinctrl_dev_get_drvdata(pctldev);
        pin_to_reg_bank(drvdata, pin - drvdata->ctrl->base, &reg_base,
                                        &pin_offset, &bank);

        switch (cfg_type) {
        case PINCFG_TYPE_PUD:
                width = bank->pud_width;
                cfg_reg = PUD_REG;
                break;
        case PINCFG_TYPE_DRV:
                width = bank->drv_width;
                cfg_reg = DRV_REG;
                break;
        case PINCFG_TYPE_CON_PDN:
                width = bank->conpdn_width;
                cfg_reg = CONPDN_REG;
                break;
        case PINCFG_TYPE_PUD_PDN:
                width = bank->pudpdn_width;
                cfg_reg = PUDPDN_REG;
                break;
        default:
                WARN_ON(1);
                return -EINVAL;
        }

        if (!width)
                return -EINVAL;

        spin_lock_irqsave(&bank->slock, flags);

        mask = (1 << width) - 1;
        shift = pin_offset * width;
        data = readl(reg_base + cfg_reg);

        if (set) {
                cfg_value = PINCFG_UNPACK_VALUE(*config);
                data &= ~(mask << shift);
                data |= (cfg_value << shift);
                writel(data, reg_base + cfg_reg);
        } else {
                data >>= shift;
                data &= mask;
                *config = PINCFG_PACK(cfg_type, data);
        }

        spin_unlock_irqrestore(&bank->slock, flags);

        return 0;
}

/* set the pin config settings for a specified pin */
static int samsung_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
                                unsigned long config)
{
        return samsung_pinconf_rw(pctldev, pin, &config, true);
}

/* get the pin config settings for a specified pin */
static int samsung_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
                                        unsigned long *config)
{
        return samsung_pinconf_rw(pctldev, pin, config, false);
}

/* set the pin config settings for a specified pin group */
static int samsung_pinconf_group_set(struct pinctrl_dev *pctldev,
                        unsigned group, unsigned long config)
{
        struct samsung_pinctrl_drv_data *drvdata;
        const unsigned int *pins;
        unsigned int cnt;

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

        for (cnt = 0; cnt < drvdata->pin_groups[group].num_pins; cnt++)
                samsung_pinconf_set(pctldev, pins[cnt], config);

        return 0;
}

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

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

/* list of pinconfig callbacks for pinconfig vertical in the pinctrl code */
static const struct pinconf_ops samsung_pinconf_ops = {
        .pin_config_get         = samsung_pinconf_get,
        .pin_config_set         = samsung_pinconf_set,
        .pin_config_group_get   = samsung_pinconf_group_get,
        .pin_config_group_set   = samsung_pinconf_group_set,
};

/* gpiolib gpio_set callback function */
static void samsung_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
{
        struct samsung_pin_bank *bank = gc_to_pin_bank(gc);
        unsigned long flags;
        void __iomem *reg;
        u32 data;

        reg = bank->drvdata->virt_base + bank->pctl_offset;

        spin_lock_irqsave(&bank->slock, flags);

        data = readl(reg + DAT_REG);
        data &= ~(1 << offset);
        if (value)
                data |= 1 << offset;
        writel(data, reg + DAT_REG);

        spin_unlock_irqrestore(&bank->slock, flags);
}

/* gpiolib gpio_get callback function */
static int samsung_gpio_get(struct gpio_chip *gc, unsigned offset)
{
        void __iomem *reg;
        u32 data;
        struct samsung_pin_bank *bank = gc_to_pin_bank(gc);

        reg = bank->drvdata->virt_base + bank->pctl_offset;

        data = readl(reg + DAT_REG);
        data >>= offset;
        data &= 1;
        return data;
}

/*
 * gpiolib gpio_direction_input callback function. The setting of the pin
 * mux function as 'gpio input' will be handled by the pinctrl susbsystem
 * interface.
 */
static int samsung_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
        return pinctrl_gpio_direction_input(gc->base + offset);
}

/*
 * gpiolib gpio_direction_output callback function. The setting of the pin
 * mux function as 'gpio output' will be handled by the pinctrl susbsystem
 * interface.
 */
static int samsung_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
                                                        int value)
{
        samsung_gpio_set(gc, offset, value);
        return pinctrl_gpio_direction_output(gc->base + offset);
}

/*
 * gpiolib gpio_to_irq callback function. Creates a mapping between a GPIO pin
 * and a virtual IRQ, if not already present.
 */
static int samsung_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
        struct samsung_pin_bank *bank = gc_to_pin_bank(gc);
        unsigned int virq;

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

        virq = irq_create_mapping(bank->irq_domain, offset);

        return (virq) ? : -ENXIO;
}

/*
 * Parse the pin names listed in the 'samsung,pins' property and convert it
 * into a list of gpio numbers are create a pin group from it.
 */
static int samsung_pinctrl_parse_dt_pins(struct platform_device *pdev,
                                         struct device_node *cfg_np,
                                         struct pinctrl_desc *pctl,
                                         unsigned int **pin_list,
                                         unsigned int *npins)
{
        struct device *dev = &pdev->dev;
        struct property *prop;
        struct pinctrl_pin_desc const *pdesc = pctl->pins;
        unsigned int idx = 0, cnt;
        const char *pin_name;

        *npins = of_property_count_strings(cfg_np, "samsung,pins");
        if (IS_ERR_VALUE(*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) {
                dev_err(dev, "failed to allocate memory for pin list\n");
                return -ENOMEM;
        }

        of_property_for_each_string(cfg_np, "samsung,pins", prop, pin_name) {
                for (cnt = 0; cnt < pctl->npins; cnt++) {
                        if (pdesc[cnt].name) {
                                if (!strcmp(pin_name, pdesc[cnt].name)) {
                                        (*pin_list)[idx++] = pdesc[cnt].number;
                                        break;
                                }
                        }
                }
                if (cnt == pctl->npins) {
                        dev_err(dev, "pin %s not valid in %s node\n",
                                        pin_name, cfg_np->name);
                        devm_kfree(dev, *pin_list);
                        return -EINVAL;
                }
        }

        return 0;
}

/*
 * Parse the information about all the available pin groups and pin functions
 * from device node of the pin-controller. A pin group is formed with all
 * the pins listed in the "samsung,pins" property.
 */
static int samsung_pinctrl_parse_dt(struct platform_device *pdev,
                                    struct samsung_pinctrl_drv_data *drvdata)
{
        struct device *dev = &pdev->dev;
        struct device_node *dev_np = dev->of_node;
        struct device_node *cfg_np;
        struct samsung_pin_group *groups, *grp;
        struct samsung_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) {
                dev_err(dev, "failed allocate memory for ping group list\n");
                return -EINVAL;
        }
        grp = groups;

        functions = devm_kzalloc(dev, grp_cnt * sizeof(*functions), GFP_KERNEL);
        if (!functions) {
                dev_err(dev, "failed to allocate memory for function list\n");
                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;
                if (!of_find_property(cfg_np, "samsung,pins", NULL))
                        continue;

                ret = samsung_pinctrl_parse_dt_pins(pdev, cfg_np,
                                        &drvdata->pctl, &pin_list, &npins);
                if (ret)
                        return ret;

                /* derive pin group name from the node name */
                gname = devm_kzalloc(dev, strlen(cfg_np->name) + GSUFFIX_LEN,
                                        GFP_KERNEL);
                if (!gname) {
                        dev_err(dev, "failed to alloc memory for group name\n");
                        return -ENOMEM;
                }
                sprintf(gname, "%s%s", cfg_np->name, GROUP_SUFFIX);

                grp->name = gname;
                grp->pins = pin_list;
                grp->num_pins = npins;
                of_property_read_u32(cfg_np, "samsung,pin-function", &function);
                grp->func = function;
                grp++;

                if (!of_find_property(cfg_np, "samsung,pin-function", NULL))
                        continue;

                /* derive function name from the node name */
                fname = devm_kzalloc(dev, strlen(cfg_np->name) + FSUFFIX_LEN,
                                        GFP_KERNEL);
                if (!fname) {
                        dev_err(dev, "failed to alloc memory for func name\n");
                        return -ENOMEM;
                }
                sprintf(fname, "%s%s", cfg_np->name, FUNCTION_SUFFIX);

                func->name = fname;
                func->groups = devm_kzalloc(dev, sizeof(char *), GFP_KERNEL);
                if (!func->groups) {
                        dev_err(dev, "failed to alloc memory for group list "
                                        "in pin function");
                        return -ENOMEM;
                }
                func->groups[0] = gname;
                func->num_groups = 1;
                func++;
                func_idx++;
        }

        drvdata->pin_groups = groups;
        drvdata->nr_groups = grp_cnt;
        drvdata->pmx_functions = functions;
        drvdata->nr_functions = func_idx;

        return 0;
}

/* register the pinctrl interface with the pinctrl subsystem */
static int samsung_pinctrl_register(struct platform_device *pdev,
                                    struct samsung_pinctrl_drv_data *drvdata)
{
        struct pinctrl_desc *ctrldesc = &drvdata->pctl;
        struct pinctrl_pin_desc *pindesc, *pdesc;
        struct samsung_pin_bank *pin_bank;
        char *pin_names;
        int pin, bank, ret;

        ctrldesc->name = "samsung-pinctrl";
        ctrldesc->owner = THIS_MODULE;
        ctrldesc->pctlops = &samsung_pctrl_ops;
        ctrldesc->pmxops = &samsung_pinmux_ops;
        ctrldesc->confops = &samsung_pinconf_ops;

        pindesc = devm_kzalloc(&pdev->dev, sizeof(*pindesc) *
                        drvdata->ctrl->nr_pins, GFP_KERNEL);
        if (!pindesc) {
                dev_err(&pdev->dev, "mem alloc for pin descriptors failed\n");
                return -ENOMEM;
        }
        ctrldesc->pins = pindesc;
        ctrldesc->npins = drvdata->ctrl->nr_pins;

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

        /*
         * 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 *
                                        drvdata->ctrl->nr_pins, GFP_KERNEL);
        if (!pin_names) {
                dev_err(&pdev->dev, "mem alloc for pin names failed\n");
                return -ENOMEM;
        }

        /* for each pin, the name of the pin is pin-bank name + pin number */
        for (bank = 0; bank < drvdata->ctrl->nr_banks; bank++) {
                pin_bank = &drvdata->ctrl->pin_banks[bank];
                for (pin = 0; pin < pin_bank->nr_pins; pin++) {
                        sprintf(pin_names, "%s-%d", pin_bank->name, pin);
                        pdesc = pindesc + pin_bank->pin_base + pin;
                        pdesc->name = pin_names;
                        pin_names += PIN_NAME_LENGTH;
                }
        }

        drvdata->pctl_dev = pinctrl_register(ctrldesc, &pdev->dev, drvdata);
        if (!drvdata->pctl_dev) {
                dev_err(&pdev->dev, "could not register pinctrl driver\n");
                return -EINVAL;
        }

        for (bank = 0; bank < drvdata->ctrl->nr_banks; ++bank) {
                pin_bank = &drvdata->ctrl->pin_banks[bank];
                pin_bank->grange.name = pin_bank->name;
                pin_bank->grange.id = bank;
                pin_bank->grange.pin_base = pin_bank->pin_base;
                pin_bank->grange.base = pin_bank->gpio_chip.base;
                pin_bank->grange.npins = pin_bank->gpio_chip.ngpio;
                pin_bank->grange.gc = &pin_bank->gpio_chip;
                pinctrl_add_gpio_range(drvdata->pctl_dev, &pin_bank->grange);
        }

        ret = samsung_pinctrl_parse_dt(pdev, drvdata);
        if (ret) {
                pinctrl_unregister(drvdata->pctl_dev);
                return ret;
        }

        return 0;
}

static const struct gpio_chip samsung_gpiolib_chip = {
        .set = samsung_gpio_set,
        .get = samsung_gpio_get,
        .direction_input = samsung_gpio_direction_input,
        .direction_output = samsung_gpio_direction_output,
        .to_irq = samsung_gpio_to_irq,
        .owner = THIS_MODULE,
};

/* register the gpiolib interface with the gpiolib subsystem */
static int samsung_gpiolib_register(struct platform_device *pdev,
                                    struct samsung_pinctrl_drv_data *drvdata)
{
        struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
        struct samsung_pin_bank *bank = ctrl->pin_banks;
        struct gpio_chip *gc;
        int ret;
        int i;

        for (i = 0; i < ctrl->nr_banks; ++i, ++bank) {
                bank->gpio_chip = samsung_gpiolib_chip;

                gc = &bank->gpio_chip;
                gc->base = ctrl->base + bank->pin_base;
                gc->ngpio = bank->nr_pins;
                gc->dev = &pdev->dev;
                gc->of_node = bank->of_node;
                gc->label = bank->name;

                ret = gpiochip_add(gc);
                if (ret) {
                        dev_err(&pdev->dev, "failed to register gpio_chip %s, error code: %d\n",
                                                        gc->label, ret);
                        goto fail;
                }
        }

        return 0;

fail:
        for (--i, --bank; i >= 0; --i, --bank)
                if (gpiochip_remove(&bank->gpio_chip))
                        dev_err(&pdev->dev, "gpio chip %s remove failed\n",
                                                        bank->gpio_chip.label);
        return ret;
}

/* unregister the gpiolib interface with the gpiolib subsystem */
static int samsung_gpiolib_unregister(struct platform_device *pdev,
                                      struct samsung_pinctrl_drv_data *drvdata)
{
        struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
        struct samsung_pin_bank *bank = ctrl->pin_banks;
        int ret = 0;
        int i;

        for (i = 0; !ret && i < ctrl->nr_banks; ++i, ++bank)
                ret = gpiochip_remove(&bank->gpio_chip);

        if (ret)
                dev_err(&pdev->dev, "gpio chip remove failed\n");

        return ret;
}

static const struct of_device_id samsung_pinctrl_dt_match[];

/* retrieve the soc specific data */
static struct samsung_pin_ctrl *samsung_pinctrl_get_soc_data(
                                struct samsung_pinctrl_drv_data *d,
                                struct platform_device *pdev)
{
        int id;
        const struct of_device_id *match;
        struct device_node *node = pdev->dev.of_node;
        struct device_node *np;
        struct samsung_pin_ctrl *ctrl;
        struct samsung_pin_bank *bank;
        int i;

        id = of_alias_get_id(node, "pinctrl");
        if (id < 0) {
                dev_err(&pdev->dev, "failed to get alias id\n");
                return NULL;
        }
        match = of_match_node(samsung_pinctrl_dt_match, node);
        ctrl = (struct samsung_pin_ctrl *)match->data + id;

        bank = ctrl->pin_banks;
        for (i = 0; i < ctrl->nr_banks; ++i, ++bank) {
                spin_lock_init(&bank->slock);
                bank->drvdata = d;
                bank->pin_base = ctrl->nr_pins;
                ctrl->nr_pins += bank->nr_pins;
        }

        for_each_child_of_node(node, np) {
                if (!of_find_property(np, "gpio-controller", NULL))
                        continue;
                bank = ctrl->pin_banks;
                for (i = 0; i < ctrl->nr_banks; ++i, ++bank) {
                        if (!strcmp(bank->name, np->name)) {
                                bank->of_node = np;
                                break;
                        }
                }
        }

        ctrl->base = pin_base;
        pin_base += ctrl->nr_pins;

        return ctrl;
}

static int samsung_pinctrl_probe(struct platform_device *pdev)
{
        struct samsung_pinctrl_drv_data *drvdata;
        struct device *dev = &pdev->dev;
        struct samsung_pin_ctrl *ctrl;
        struct resource *res;
        int ret;

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

        drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata) {
                dev_err(dev, "failed to allocate memory for driver's "
                                "private data\n");
                return -ENOMEM;
        }

        ctrl = samsung_pinctrl_get_soc_data(drvdata, pdev);
        if (!ctrl) {
                dev_err(&pdev->dev, "driver data not available\n");
                return -EINVAL;
        }
        drvdata->ctrl = ctrl;
        drvdata->dev = dev;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev, "cannot find IO resource\n");
                return -ENOENT;
        }

        drvdata->virt_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(drvdata->virt_base))
                return PTR_ERR(drvdata->virt_base);

        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
        if (res)
                drvdata->irq = res->start;

        ret = samsung_gpiolib_register(pdev, drvdata);
        if (ret)
                return ret;

        ret = samsung_pinctrl_register(pdev, drvdata);
        if (ret) {
                samsung_gpiolib_unregister(pdev, drvdata);
                return ret;
        }

        if (ctrl->eint_gpio_init)
                ctrl->eint_gpio_init(drvdata);
        if (ctrl->eint_wkup_init)
                ctrl->eint_wkup_init(drvdata);

        platform_set_drvdata(pdev, drvdata);
        return 0;
}

static const struct of_device_id samsung_pinctrl_dt_match[] = {
        { .compatible = "samsung,exynos4210-pinctrl",
                .data = (void *)exynos4210_pin_ctrl },
        { .compatible = "samsung,exynos4x12-pinctrl",
                .data = (void *)exynos4x12_pin_ctrl },
        {},
};
MODULE_DEVICE_TABLE(of, samsung_pinctrl_dt_match);

static struct platform_driver samsung_pinctrl_driver = {
        .probe          = samsung_pinctrl_probe,
        .driver = {
                .name   = "samsung-pinctrl",
                .owner  = THIS_MODULE,
                .of_match_table = of_match_ptr(samsung_pinctrl_dt_match),
        },
};

static int __init samsung_pinctrl_drv_register(void)
{
        return platform_driver_register(&samsung_pinctrl_driver);
}
postcore_initcall(samsung_pinctrl_drv_register);

static void __exit samsung_pinctrl_drv_unregister(void)
{
        platform_driver_unregister(&samsung_pinctrl_driver);
}
module_exit(samsung_pinctrl_drv_unregister);

MODULE_AUTHOR("Thomas Abraham <thomas.ab@samsung.com>");
MODULE_DESCRIPTION("Samsung pinctrl driver");
MODULE_LICENSE("GPL v2");