/*
 * 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/mfd/syscon.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 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		= &pinctrl_utils_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_set(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,
	.set_mux		= &berlin_pinmux_set,
};

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 device_node *parent_np = of_get_parent(dev->of_node);
	struct berlin_pinctrl *pctrl;
	struct regmap *regmap;
	int ret;

	regmap = dev_get_regmap(&pdev->dev, NULL);
	if (!regmap)
		regmap = syscon_node_to_regmap(parent_np);
	of_node_put(parent_np);
	if (IS_ERR(regmap))
		return PTR_ERR(regmap);

	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;
}