// SPDX-License-Identifier: GPL-2.0
/*
 *  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/pinconf-generic.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/mt7620.h>

#include "pinmux.h"
#include "../core.h"
#include "../pinctrl-utils.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;

        u8 *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 int group)
{
        struct rt2880_priv *p = pinctrl_dev_get_drvdata(pctrldev);

        return (group >= p->group_count) ? NULL : p->group_names[group];
}

static int rt2880_get_group_pins(struct pinctrl_dev *pctrldev,
                                 unsigned int group,
                                 const unsigned int **pins,
                                 unsigned int *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 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,
        .dt_node_to_map         = pinconf_generic_dt_node_to_map_all,
        .dt_free_map            = pinconf_generic_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 int 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 int func,
                                       const char * const **groups,
                                       unsigned int * 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 int func, unsigned int 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 0;
        }

        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 int 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_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_kcalloc(p->dev, p->group_count,
                                      sizeof(char *), GFP_KERNEL);
        if (!p->group_names)
                return -ENOMEM;

        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 */
        p->func = devm_kcalloc(p->dev, p->func_count,
                               sizeof(*p->func), GFP_KERNEL);
        gpio_func.groups = devm_kcalloc(p->dev, p->group_count, sizeof(int),
                                        GFP_KERNEL);
        if (!p->func || !gpio_func.groups)
                return -ENOMEM;

        /* 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;

        p->func[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++) {
                        p->func[c] = &p->groups[i].func[j];
                        p->func[c]->groups = devm_kzalloc(p->dev, sizeof(int),
                                                    GFP_KERNEL);
                        if (!p->func[c]->groups)
                                return -ENOMEM;
                        p->func[c]->groups[0] = i;
                        p->func[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_kcalloc(p->dev,
                                                p->func[i]->pin_count,
                                                sizeof(int),
                                                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_kcalloc(p->dev, p->max_pins, sizeof(u8), GFP_KERNEL);
        /* the pads needed to tell pinctrl about our pins */
        p->pads = devm_kcalloc(p->dev, p->max_pins,
                               sizeof(struct pinctrl_pin_desc), GFP_KERNEL);
        if (!p->pads || !p->gpio)
                return -ENOMEM;

        memset(p->gpio, 1, sizeof(u8) * 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)
                        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;
}

int rt2880_pinmux_init(struct platform_device *pdev,
                       struct rt2880_pmx_group *data)
{
        struct rt2880_priv *p;
        struct pinctrl_dev *dev;
        int err;

        if (!data)
                return -ENOTSUPP;

        /* 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 = data;
        platform_set_drvdata(pdev, p);

        /* init the device */
        err = rt2880_pinmux_index(p);
        if (err) {
                dev_err(&pdev->dev, "failed to load index\n");
                return err;
        }

        err = rt2880_pinmux_pins(p);
        if (err) {
                dev_err(&pdev->dev, "failed to load pins\n");
                return err;
        }
        dev = pinctrl_register(p->desc, &pdev->dev, p);

        return PTR_ERR_OR_ZERO(dev);
}