/*
 * Marvell Berlin SoC pinctrl core driver
 *
 * Copyright (C) 2014 Marvell Technology Group Ltd.
 *
 * Antoine Ténart <antoine.tenart@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#include "../core.h"
#include "../pinctrl-utils.h"
#include "berlin.h"

struct berlin_pinctrl {
        struct regmap *regmap;
        struct device *dev;
        const struct berlin_pinctrl_desc *desc;
        struct berlin_pinctrl_function *functions;
        unsigned nfunctions;
        struct pinctrl_dev *pctrl_dev;
};

static int berlin_pinctrl_get_group_count(struct pinctrl_dev *pctrl_dev)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);

        return pctrl->desc->ngroups;
}

static const char *berlin_pinctrl_get_group_name(struct pinctrl_dev *pctrl_dev,
                                                 unsigned group)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);

        return pctrl->desc->groups[group].name;
}

static int berlin_pinctrl_dt_node_to_map(struct pinctrl_dev *pctrl_dev,
                                         struct device_node *node,
                                         struct pinctrl_map **map,
                                         unsigned *num_maps)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
        struct property *prop;
        const char *function_name, *group_name;
        unsigned reserved_maps = 0;
        int ret, ngroups;

        *map = NULL;
        *num_maps = 0;

        ret = of_property_read_string(node, "function", &function_name);
        if (ret) {
                dev_err(pctrl->dev,
                        "missing function property in node %s\n",
                        node->name);
                return -EINVAL;
        }

        ngroups = of_property_count_strings(node, "groups");
        if (ngroups < 0) {
                dev_err(pctrl->dev,
                        "missing groups property in node %s\n",
                        node->name);
                return -EINVAL;
        }

        ret = pinctrl_utils_reserve_map(pctrl_dev, map, &reserved_maps,
                                        num_maps, ngroups);
        if (ret) {
                dev_err(pctrl->dev, "can't reserve map: %d\n", ret);
                return ret;
        }

        of_property_for_each_string(node, "groups", prop, group_name) {
                ret = pinctrl_utils_add_map_mux(pctrl_dev, map, &reserved_maps,
                                                num_maps, group_name,
                                                function_name);
                if (ret) {
                        dev_err(pctrl->dev, "can't add map: %d\n", ret);
                        return ret;
                }
        }

        return 0;
}

static void berlin_pinctrl_dt_free_map(struct pinctrl_dev *pctrl_dev,
                                       struct pinctrl_map *map,
                                       unsigned nmaps)
{
        int i;

        for (i = 0; i < nmaps; i++) {
                if (map[i].type == PIN_MAP_TYPE_MUX_GROUP) {
                        kfree(map[i].data.mux.group);

                        /* a function can be applied to multiple groups */
                        if (i == 0)
                                kfree(map[i].data.mux.function);
                }
        }

        kfree(map);
}

static const struct pinctrl_ops berlin_pinctrl_ops = {
        .get_groups_count       = &berlin_pinctrl_get_group_count,
        .get_group_name         = &berlin_pinctrl_get_group_name,
        .dt_node_to_map         = &berlin_pinctrl_dt_node_to_map,
        .dt_free_map            = &berlin_pinctrl_dt_free_map,
};

static int berlin_pinmux_get_functions_count(struct pinctrl_dev *pctrl_dev)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);

        return pctrl->nfunctions;
}

static const char *berlin_pinmux_get_function_name(struct pinctrl_dev *pctrl_dev,
                                                   unsigned function)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);

        return pctrl->functions[function].name;
}

static int berlin_pinmux_get_function_groups(struct pinctrl_dev *pctrl_dev,
                                             unsigned function,
                                             const char * const **groups,
                                             unsigned * const num_groups)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);

        *groups = pctrl->functions[function].groups;
        *num_groups = pctrl->functions[function].ngroups;

        return 0;
}

static struct berlin_desc_function *
berlin_pinctrl_find_function_by_name(struct berlin_pinctrl *pctrl,
                                     const struct berlin_desc_group *group,
                                     const char *fname)
{
        struct berlin_desc_function *function = group->functions;

        while (function->name) {
                if (!strcmp(function->name, fname))
                        return function;

                function++;
        }

        return NULL;
}

static int berlin_pinmux_enable(struct pinctrl_dev *pctrl_dev,
                                unsigned function,
                                unsigned group)
{
        struct berlin_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctrl_dev);
        const struct berlin_desc_group *group_desc = pctrl->desc->groups + group;
        struct berlin_pinctrl_function *func = pctrl->functions + function;
        struct berlin_desc_function *function_desc =
                berlin_pinctrl_find_function_by_name(pctrl, group_desc,
                                                     func->name);
        u32 mask, val;

        if (!function_desc)
                return -EINVAL;

        mask = GENMASK(group_desc->lsb + group_desc->bit_width - 1,
                       group_desc->lsb);
        val = function_desc->muxval << group_desc->lsb;
        regmap_update_bits(pctrl->regmap, group_desc->offset, mask, val);

        return 0;
}

static const struct pinmux_ops berlin_pinmux_ops = {
        .get_functions_count    = &berlin_pinmux_get_functions_count,
        .get_function_name      = &berlin_pinmux_get_function_name,
        .get_function_groups    = &berlin_pinmux_get_function_groups,
        .enable                 = &berlin_pinmux_enable,
};

static int berlin_pinctrl_add_function(struct berlin_pinctrl *pctrl,
                                       const char *name)
{
        struct berlin_pinctrl_function *function = pctrl->functions;

        while (function->name) {
                if (!strcmp(function->name, name)) {
                        function->ngroups++;
                        return -EEXIST;
                }
                function++;
        }

        function->name = name;
        function->ngroups = 1;

        pctrl->nfunctions++;

        return 0;
}

static int berlin_pinctrl_build_state(struct platform_device *pdev)
{
        struct berlin_pinctrl *pctrl = platform_get_drvdata(pdev);
        struct berlin_desc_group const *desc_group;
        struct berlin_desc_function const *desc_function;
        int i, max_functions = 0;

        pctrl->nfunctions = 0;

        for (i = 0; i < pctrl->desc->ngroups; i++) {
                desc_group = pctrl->desc->groups + i;
                /* compute the maxiumum number of functions a group can have */
                max_functions += 1 << (desc_group->bit_width + 1);
        }

        /* we will reallocate later */
        pctrl->functions = devm_kzalloc(&pdev->dev,
                                        max_functions * sizeof(*pctrl->functions),
                                        GFP_KERNEL);
        if (!pctrl->functions)
                return -ENOMEM;

        /* register all functions */
        for (i = 0; i < pctrl->desc->ngroups; i++) {
                desc_group = pctrl->desc->groups + i;
                desc_function = desc_group->functions;

                while (desc_function->name) {
                        berlin_pinctrl_add_function(pctrl, desc_function->name);
                        desc_function++;
                }
        }

        pctrl->functions = krealloc(pctrl->functions,
                                    pctrl->nfunctions * sizeof(*pctrl->functions),
                                    GFP_KERNEL);

        /* map functions to theirs groups */
        for (i = 0; i < pctrl->desc->ngroups; i++) {
                desc_group = pctrl->desc->groups + i;
                desc_function = desc_group->functions;

                while (desc_function->name) {
                        struct berlin_pinctrl_function
                                *function = pctrl->functions;
                        const char **groups;
                        bool found = false;

                        while (function->name) {
                                if (!strcmp(desc_function->name, function->name)) {
                                        found = true;
                                        break;
                                }
                                function++;
                        }

                        if (!found)
                                return -EINVAL;

                        if (!function->groups) {
                                function->groups =
                                        devm_kzalloc(&pdev->dev,
                                                     function->ngroups * sizeof(char *),
                                                     GFP_KERNEL);

                                if (!function->groups)
                                        return -ENOMEM;
                        }

                        groups = function->groups;
                        while (*groups)
                                groups++;

                        *groups = desc_group->name;

                        desc_function++;
                }
        }

        return 0;
}

static struct pinctrl_desc berlin_pctrl_desc = {
        .name           = "berlin-pinctrl",
        .pctlops        = &berlin_pinctrl_ops,
        .pmxops         = &berlin_pinmux_ops,
        .owner          = THIS_MODULE,
};

int berlin_pinctrl_probe(struct platform_device *pdev,
                         const struct berlin_pinctrl_desc *desc)
{
        struct device *dev = &pdev->dev;
        struct berlin_pinctrl *pctrl;
        struct regmap *regmap;
        int ret;

        regmap = dev_get_regmap(&pdev->dev, NULL);
        if (!regmap)
                return -ENODEV;

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

        platform_set_drvdata(pdev, pctrl);

        pctrl->regmap = regmap;
        pctrl->dev = &pdev->dev;
        pctrl->desc = desc;

        ret = berlin_pinctrl_build_state(pdev);
        if (ret) {
                dev_err(dev, "cannot build driver state: %d\n", ret);
                return ret;
        }

        pctrl->pctrl_dev = pinctrl_register(&berlin_pctrl_desc, dev, pctrl);
        if (!pctrl->pctrl_dev) {
                dev_err(dev, "failed to register pinctrl driver\n");
                return -EINVAL;
        }

        return 0;
}