pinctrl-samsung.c

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/*
 * 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 <[email protected]>
 *
 * 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 "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 */
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 },
};

/* 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 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 gpio_chip *gc, unsigned pin,
            void __iomem **reg, u32 *offset,
            struct samsung_pin_bank **bank)
{
    struct samsung_pinctrl_drv_data *drvdata;
    struct samsung_pin_bank *b;

    drvdata = dev_get_drvdata(gc->dev);
    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;

    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->gc, pins[cnt] - drvdata->ctrl->base,
                &reg, &pin_offset, &bank);
        mask = (1 << bank->func_width) - 1;
        shift = pin_offset * bank->func_width;

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

/* 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;
    void __iomem *reg;
    u32 data, pin_offset, mask, shift;

    pin_to_reg_bank(range->gc, offset, &reg, &pin_offset, &bank);
    mask = (1 << bank->func_width) - 1;
    shift = pin_offset * bank->func_width;

    data = readl(reg);
    data &= ~(mask << shift);
    if (!input)
        data |= FUNC_OUTPUT << shift;
    writel(data, reg);
    return 0;
}

/* list of pinmux callbacks for the pinmux vertical in pinctrl core */
static 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;

    drvdata = pinctrl_dev_get_drvdata(pctldev);
    pin_to_reg_bank(drvdata->gc, 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;
    }

    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);
    }
    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 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)
{
    void __iomem *reg;
    u32 pin_offset, data;

    pin_to_reg_bank(gc, offset, &reg, &pin_offset, NULL);
    data = readl(reg + DAT_REG);
    data &= ~(1 << pin_offset);
    if (value)
        data |= 1 << pin_offset;
    writel(data, reg + DAT_REG);
}

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

    pin_to_reg_bank(gc, offset, &reg, &pin_offset, NULL);
    data = readl(reg + DAT_REG);
    data >>= pin_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);
}

/*
 * 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 __devinit 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 (*npins < 0) {
        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 __devinit 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, "interrupt-controller", 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 __devinit 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;
    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;
    }

    drvdata->grange.name = "samsung-pctrl-gpio-range";
    drvdata->grange.id = 0;
    drvdata->grange.base = drvdata->ctrl->base;
    drvdata->grange.npins = drvdata->ctrl->nr_pins;
    drvdata->grange.gc = drvdata->gc;
    pinctrl_add_gpio_range(drvdata->pctl_dev, &drvdata->grange);

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

    return 0;
}

/* register the gpiolib interface with the gpiolib subsystem */
static int __devinit samsung_gpiolib_register(struct platform_device *pdev,
                struct samsung_pinctrl_drv_data *drvdata)
{
    struct gpio_chip *gc;
    int ret;

    gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
    if (!gc) {
        dev_err(&pdev->dev, "mem alloc for gpio_chip failed\n");
        return -ENOMEM;
    }

    drvdata->gc = gc;
    gc->base = drvdata->ctrl->base;
    gc->ngpio = drvdata->ctrl->nr_pins;
    gc->dev = &pdev->dev;
    gc->set = samsung_gpio_set;
    gc->get = samsung_gpio_get;
    gc->direction_input = samsung_gpio_direction_input;
    gc->direction_output = samsung_gpio_direction_output;
    gc->label = drvdata->ctrl->label;
    gc->owner = THIS_MODULE;
    ret = gpiochip_add(gc);
    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 __devinit samsung_gpiolib_unregister(struct platform_device *pdev,
                struct samsung_pinctrl_drv_data *drvdata)
{
    int ret = gpiochip_remove(drvdata->gc);
    if (ret) {
        dev_err(&pdev->dev, "gpio chip remove failed\n");
        return ret;
    }
    return 0;
}

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 platform_device *pdev)
{
    int id;
    const struct of_device_id *match;
    const struct device_node *node = pdev->dev.of_node;

    id = of_alias_get_id(pdev->dev.of_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);
    return (struct samsung_pin_ctrl *)match->data + id;
}

static int __devinit 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;
    }

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

    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;
    }
    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_request_and_ioremap(&pdev->dev, res);
    if (!drvdata->virt_base) {
        dev_err(dev, "ioremap failed\n");
        return -ENODEV;
    }

    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,pinctrl-exynos4210",
        .data = (void *)exynos4210_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 <[email protected]>");
MODULE_DESCRIPTION("Samsung pinctrl driver");
MODULE_LICENSE("GPL v2");