/*
 *  linux/drivers/pinctrl/pinctrl-rt2880.c
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  publishhed by the Free Software Foundation.
 *
 *  Copyright (C) 2013 John Crispin <blogic@openwrt.org>
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/machine.h>

#include <asm/mach-ralink/ralink_regs.h>
#include <asm/mach-ralink/pinmux.h>
#include <asm/mach-ralink/mt7620.h>

#include "core.h"

#define SYSC_REG_GPIO_MODE      0x60
#define SYSC_REG_GPIO_MODE2     0x64

struct rt2880_priv {
        struct device *dev;

        struct pinctrl_pin_desc *pads;
        struct pinctrl_desc *desc;

        struct rt2880_pmx_func **func;
        int func_count;

        struct rt2880_pmx_group *groups;
        const char **group_names;
        int group_count;

        uint8_t *gpio;
        int max_pins;
};

static int rt2880_get_group_count(struct pinctrl_dev *pctrldev)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        return p->group_count;
}

static const char *rt2880_get_group_name(struct pinctrl_dev *pctrldev,
                                         unsigned group)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        if (group >= p->group_count)
                return NULL;

        return p->group_names[group];
}

static int rt2880_get_group_pins(struct pinctrl_dev *pctrldev,
                                 unsigned group,
                                 const unsigned **pins,
                                 unsigned *num_pins)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        if (group >= p->group_count)
                return -EINVAL;

        *pins = p->groups[group].func[0].pins;
        *num_pins = p->groups[group].func[0].pin_count;

        return 0;
}

static void rt2880_pinctrl_dt_free_map(struct pinctrl_dev *pctrldev,
                                    struct pinctrl_map *map, unsigned num_maps)
{
        int i;

        for (i = 0; i < num_maps; i++)
                if (map[i].type == PIN_MAP_TYPE_CONFIGS_PIN ||
                    map[i].type == PIN_MAP_TYPE_CONFIGS_GROUP)
                        kfree(map[i].data.configs.configs);
        kfree(map);
}

static void rt2880_pinctrl_pin_dbg_show(struct pinctrl_dev *pctrldev,
                                        struct seq_file *s,
                                        unsigned offset)
{
        seq_printf(s, "ralink pio");
}

static void rt2880_pinctrl_dt_subnode_to_map(struct pinctrl_dev *pctrldev,
                                struct device_node *np,
                                struct pinctrl_map **map)
{
        const char *function;
        int func = of_property_read_string(np, "ralink,function", &function);
        int grps = of_property_count_strings(np, "ralink,group");
        int i;

        if (func || !grps)
                return;

        for (i = 0; i < grps; i++) {
                const char *group;

                of_property_read_string_index(np, "ralink,group", i, &group);

                (*map)->type = PIN_MAP_TYPE_MUX_GROUP;
                (*map)->name = function;
                (*map)->data.mux.group = group;
                (*map)->data.mux.function = function;
                (*map)++;
        }
}

static int rt2880_pinctrl_dt_node_to_map(struct pinctrl_dev *pctrldev,
                                struct device_node *np_config,
                                struct pinctrl_map **map,
                                unsigned *num_maps)
{
        int max_maps = 0;
        struct pinctrl_map *tmp;
        struct device_node *np;

        for_each_child_of_node(np_config, np) {
                int ret = of_property_count_strings(np, "ralink,group");

                if (ret >= 0)
                        max_maps += ret;
        }

        if (!max_maps)
                return max_maps;

        *map = kzalloc(max_maps * sizeof(struct pinctrl_map), GFP_KERNEL);
        if (!*map)
                return -ENOMEM;

        tmp = *map;

        for_each_child_of_node(np_config, np)
                rt2880_pinctrl_dt_subnode_to_map(pctrldev, np, &tmp);
        *num_maps = max_maps;

        return 0;
}

static const struct pinctrl_ops rt2880_pctrl_ops = {
        .get_groups_count       = rt2880_get_group_count,
        .get_group_name         = rt2880_get_group_name,
        .get_group_pins         = rt2880_get_group_pins,
        .pin_dbg_show           = rt2880_pinctrl_pin_dbg_show,
        .dt_node_to_map         = rt2880_pinctrl_dt_node_to_map,
        .dt_free_map            = rt2880_pinctrl_dt_free_map,
};

static int rt2880_pmx_func_count(struct pinctrl_dev *pctrldev)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        return p->func_count;
}

static const char *rt2880_pmx_func_name(struct pinctrl_dev *pctrldev,
                                         unsigned func)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        return p->func[func]->name;
}

static int rt2880_pmx_group_get_groups(struct pinctrl_dev *pctrldev,
                                unsigned func,
                                const char * const **groups,
                                unsigned * const num_groups)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        if (p->func[func]->group_count == 1)
                *groups = &p->group_names[p->func[func]->groups[0]];
        else
                *groups = p->group_names;

        *num_groups = p->func[func]->group_count;

        return 0;
}

static int rt2880_pmx_group_enable(struct pinctrl_dev *pctrldev,
                                unsigned func,
                                unsigned group)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);
        u32 mode = 0;
        u32 reg = SYSC_REG_GPIO_MODE;
        int i;
        int shift;

        /* dont allow double use */
        if (p->groups[group].enabled) {
                dev_err(p->dev, "%s is already enabled\n", p->groups[group].name);
                return -EBUSY;
        }

        p->groups[group].enabled = 1;
        p->func[func]->enabled = 1;

        shift = p->groups[group].shift;
        if (shift >= 32) {
                shift -= 32;
                reg = SYSC_REG_GPIO_MODE2;
        }
        mode = rt_sysc_r32(reg);
        mode &= ~(p->groups[group].mask << shift);

        /* mark the pins as gpio */
        for (i = 0; i < p->groups[group].func[0].pin_count; i++)
                p->gpio[p->groups[group].func[0].pins[i]] = 1;

        /* function 0 is gpio and needs special handling */
        if (func == 0) {
                mode |= p->groups[group].gpio << shift;
        } else {
                for (i = 0; i < p->func[func]->pin_count; i++)
                        p->gpio[p->func[func]->pins[i]] = 0;
                mode |= p->func[func]->value << shift;
        }
        rt_sysc_w32(mode, reg);

        return 0;
}

static int rt2880_pmx_group_gpio_request_enable(struct pinctrl_dev *pctrldev,
                                struct pinctrl_gpio_range *range,
                                unsigned pin)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        if (!p->gpio[pin]) {
                dev_err(p->dev, "pin %d is not set to gpio mux\n", pin);
                return -EINVAL;
        }

        return 0;
}

static const struct pinmux_ops rt2880_pmx_group_ops = {
        .get_functions_count    = rt2880_pmx_func_count,
        .get_function_name      = rt2880_pmx_func_name,
        .get_function_groups    = rt2880_pmx_group_get_groups,
        .set_mux                = rt2880_pmx_group_enable,
        .gpio_request_enable    = rt2880_pmx_group_gpio_request_enable,
};

static struct pinctrl_desc rt2880_pctrl_desc = {
        .owner          = THIS_MODULE,
        .name           = "rt2880-pinmux",
        .pctlops        = &rt2880_pctrl_ops,
        .pmxops         = &rt2880_pmx_group_ops,
};

static struct rt2880_pmx_func gpio_func = {
        .name = "gpio",
};

static int rt2880_pinmux_index(struct rt2880_priv *p)
{
        struct rt2880_pmx_func **f;
        struct rt2880_pmx_group *mux = p->groups;
        int i, j, c = 0;

        /* count the mux functions */
        while (mux->name) {
                p->group_count++;
                mux++;
        }

        /* allocate the group names array needed by the gpio function */
        p->group_names = devm_kzalloc(p->dev, sizeof(char *) * p->group_count, GFP_KERNEL);
        if (!p->group_names)
                return -1;

        for (i = 0; i < p->group_count; i++) {
                p->group_names[i] = p->groups[i].name;
                p->func_count += p->groups[i].func_count;
        }

        /* we have a dummy function[0] for gpio */
        p->func_count++;

        /* allocate our function and group mapping index buffers */
        f = p->func = devm_kzalloc(p->dev, sizeof(struct rt2880_pmx_func) * p->func_count, GFP_KERNEL);
        gpio_func.groups = devm_kzalloc(p->dev, sizeof(int) * p->group_count, GFP_KERNEL);
        if (!f || !gpio_func.groups)
                return -1;

        /* add a backpointer to the function so it knows its group */
        gpio_func.group_count = p->group_count;
        for (i = 0; i < gpio_func.group_count; i++)
                gpio_func.groups[i] = i;

        f[c] = &gpio_func;
        c++;

        /* add remaining functions */
        for (i = 0; i < p->group_count; i++) {
                for (j = 0; j < p->groups[i].func_count; j++) {
                        f[c] = &p->groups[i].func[j];
                        f[c]->groups = devm_kzalloc(p->dev, sizeof(int), GFP_KERNEL);
                        f[c]->groups[0] = i;
                        f[c]->group_count = 1;
                        c++;
                }
        }
        return 0;
}

static int rt2880_pinmux_pins(struct rt2880_priv *p)
{
        int i, j;

        /* loop over the functions and initialize the pins array. also work out the highest pin used */
        for (i = 0; i < p->func_count; i++) {
                int pin;

                if (!p->func[i]->pin_count)
                        continue;

                p->func[i]->pins = devm_kzalloc(p->dev, sizeof(int) * p->func[i]->pin_count, GFP_KERNEL);
                for (j = 0; j < p->func[i]->pin_count; j++)
                        p->func[i]->pins[j] = p->func[i]->pin_first + j;

                pin = p->func[i]->pin_first + p->func[i]->pin_count;
                if (pin > p->max_pins)
                        p->max_pins = pin;
        }

        /* the buffer that tells us which pins are gpio */
        p->gpio = devm_kzalloc(p->dev,sizeof(uint8_t) * p->max_pins,
                GFP_KERNEL);
        /* the pads needed to tell pinctrl about our pins */
        p->pads = devm_kzalloc(p->dev,
                sizeof(struct pinctrl_pin_desc) * p->max_pins,
                GFP_KERNEL);
        if (!p->pads || !p->gpio ) {
                dev_err(p->dev, "Failed to allocate gpio data\n");
                return -ENOMEM;
        }

        memset(p->gpio, 1, sizeof(uint8_t) * p->max_pins);
        for (i = 0; i < p->func_count; i++) {
                if (!p->func[i]->pin_count)
                        continue;

                for (j = 0; j < p->func[i]->pin_count; j++)
                        p->gpio[p->func[i]->pins[j]] = 0;
        }

        /* pin 0 is always a gpio */
        p->gpio[0] = 1;

        /* set the pads */
        for (i = 0; i < p->max_pins; i++) {
                /* strlen("ioXY") + 1 = 5 */
                char *name = devm_kzalloc(p->dev, 5, GFP_KERNEL);

                if (!name) {
                        dev_err(p->dev, "Failed to allocate pad name\n");
                        return -ENOMEM;
                }
                snprintf(name, 5, "io%d", i);
                p->pads[i].number = i;
                p->pads[i].name = name;
        }
        p->desc->pins = p->pads;
        p->desc->npins = p->max_pins;

        return 0;
}

static int rt2880_pinmux_probe(struct platform_device *pdev)
{
        struct rt2880_priv *p;
        struct pinctrl_dev *dev;
        struct device_node *np;

        if (!rt2880_pinmux_data)
                return -ENOSYS;

        /* setup the private data */
        p = devm_kzalloc(&pdev->dev, sizeof(struct rt2880_priv), GFP_KERNEL);
        if (!p)
                return -ENOMEM;

        p->dev = &pdev->dev;
        p->desc = &rt2880_pctrl_desc;
        p->groups = rt2880_pinmux_data;
        platform_set_drvdata(pdev, p);

        /* init the device */
        if (rt2880_pinmux_index(p)) {
                dev_err(&pdev->dev, "failed to load index\n");
                return -EINVAL;
        }
        if (rt2880_pinmux_pins(p)) {
                dev_err(&pdev->dev, "failed to load pins\n");
                return -EINVAL;
        }
        dev = pinctrl_register(p->desc, &pdev->dev, p);
        if (IS_ERR(dev))
                return PTR_ERR(dev);

        /* finalize by adding gpio ranges for enables gpio controllers */
        for_each_compatible_node(np, NULL, "ralink,rt2880-gpio") {
                const __be32 *ngpio, *gpiobase;
                struct pinctrl_gpio_range *range;
                char *name;

                if (!of_device_is_available(np))
                        continue;

                ngpio = of_get_property(np, "ralink,num-gpios", NULL);
                gpiobase = of_get_property(np, "ralink,gpio-base", NULL);
                if (!ngpio || !gpiobase) {
                        dev_err(&pdev->dev, "failed to load chip info\n");
                        return -EINVAL;
                }

                range = devm_kzalloc(p->dev, sizeof(struct pinctrl_gpio_range) + 4, GFP_KERNEL);
                range->name = name = (char *) &range[1];
                sprintf(name, "pio");
                range->npins = __be32_to_cpu(*ngpio);
                range->base = __be32_to_cpu(*gpiobase);
                range->pin_base = range->base;
                pinctrl_add_gpio_range(dev, range);
        }

        return 0;
}

static const struct of_device_id rt2880_pinmux_match[] = {
        { .compatible = "ralink,rt2880-pinmux" },
        {},
};
MODULE_DEVICE_TABLE(of, rt2880_pinmux_match);

static struct platform_driver rt2880_pinmux_driver = {
        .probe = rt2880_pinmux_probe,
        .driver = {
                .name = "rt2880-pinmux",
                .owner = THIS_MODULE,
                .of_match_table = rt2880_pinmux_match,
        },
};

int __init rt2880_pinmux_init(void)
{
        return platform_driver_register(&rt2880_pinmux_driver);
}

core_initcall_sync(rt2880_pinmux_init);