/*
 * SuperH Pin Function Controller pinmux support.
 *
 * Copyright (C) 2012  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#define DRV_NAME "pinctrl-sh_pfc"

#define pr_fmt(fmt) DRV_NAME " " KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/sh_pfc.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinmux.h>
#include <linux/pinctrl/pinconf-generic.h>

struct sh_pfc_pinctrl {
        struct pinctrl_dev *pctl;
        struct sh_pfc *pfc;

        struct pinmux_gpio **functions;
        unsigned int nr_functions;

        struct pinctrl_pin_desc *pads;
        unsigned int nr_pads;

        spinlock_t lock;
};

static struct sh_pfc_pinctrl *sh_pfc_pmx;

static int sh_pfc_get_groups_count(struct pinctrl_dev *pctldev)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        return pmx->nr_pads;
}

static const char *sh_pfc_get_group_name(struct pinctrl_dev *pctldev,
                                         unsigned selector)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        return pmx->pads[selector].name;
}

static int sh_pfc_get_group_pins(struct pinctrl_dev *pctldev, unsigned group,
                                 const unsigned **pins, unsigned *num_pins)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        *pins = &pmx->pads[group].number;
        *num_pins = 1;

        return 0;
}

static void sh_pfc_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
                                unsigned offset)
{
        seq_printf(s, "%s", DRV_NAME);
}

static struct pinctrl_ops sh_pfc_pinctrl_ops = {
        .get_groups_count       = sh_pfc_get_groups_count,
        .get_group_name         = sh_pfc_get_group_name,
        .get_group_pins         = sh_pfc_get_group_pins,
        .pin_dbg_show           = sh_pfc_pin_dbg_show,
};

static int sh_pfc_get_functions_count(struct pinctrl_dev *pctldev)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        return pmx->nr_functions;
}

static const char *sh_pfc_get_function_name(struct pinctrl_dev *pctldev,
                                            unsigned selector)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        return pmx->functions[selector]->name;
}

static int sh_pfc_get_function_groups(struct pinctrl_dev *pctldev, unsigned func,
                                      const char * const **groups,
                                      unsigned * const num_groups)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        *groups = &pmx->functions[func]->name;
        *num_groups = 1;

        return 0;
}

static int sh_pfc_noop_enable(struct pinctrl_dev *pctldev, unsigned func,
                              unsigned group)
{
        return 0;
}

static void sh_pfc_noop_disable(struct pinctrl_dev *pctldev, unsigned func,
                                unsigned group)
{
}

static inline int sh_pfc_config_function(struct sh_pfc *pfc, unsigned offset)
{
        if (sh_pfc_config_gpio(pfc, offset,
                               PINMUX_TYPE_FUNCTION,
                               GPIO_CFG_DRYRUN) != 0)
                return -EINVAL;

        if (sh_pfc_config_gpio(pfc, offset,
                               PINMUX_TYPE_FUNCTION,
                               GPIO_CFG_REQ) != 0)
                return -EINVAL;

        return 0;
}

static int sh_pfc_reconfig_pin(struct sh_pfc *pfc, unsigned offset,
                               int new_type)
{
        unsigned long flags;
        int pinmux_type;
        int ret = -EINVAL;

        spin_lock_irqsave(&pfc->lock, flags);

        pinmux_type = pfc->gpios[offset].flags & PINMUX_FLAG_TYPE;

        /*
         * See if the present config needs to first be de-configured.
         */
        switch (pinmux_type) {
        case PINMUX_TYPE_GPIO:
                break;
        case PINMUX_TYPE_OUTPUT:
        case PINMUX_TYPE_INPUT:
        case PINMUX_TYPE_INPUT_PULLUP:
        case PINMUX_TYPE_INPUT_PULLDOWN:
                sh_pfc_config_gpio(pfc, offset, pinmux_type, GPIO_CFG_FREE);
                break;
        default:
                goto err;
        }

        /*
         * Dry run
         */
        if (sh_pfc_config_gpio(pfc, offset, new_type,
                               GPIO_CFG_DRYRUN) != 0)
                goto err;

        /*
         * Request
         */
        if (sh_pfc_config_gpio(pfc, offset, new_type,
                               GPIO_CFG_REQ) != 0)
                goto err;

        pfc->gpios[offset].flags &= ~PINMUX_FLAG_TYPE;
        pfc->gpios[offset].flags |= new_type;

        ret = 0;

err:
        spin_unlock_irqrestore(&pfc->lock, flags);

        return ret;
}


static int sh_pfc_gpio_request_enable(struct pinctrl_dev *pctldev,
                                      struct pinctrl_gpio_range *range,
                                      unsigned offset)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
        struct sh_pfc *pfc = pmx->pfc;
        unsigned long flags;
        int ret, pinmux_type;

        spin_lock_irqsave(&pfc->lock, flags);

        pinmux_type = pfc->gpios[offset].flags & PINMUX_FLAG_TYPE;

        switch (pinmux_type) {
        case PINMUX_TYPE_FUNCTION:
                pr_notice_once("Use of GPIO API for function requests is "
                               "deprecated, convert to pinctrl\n");
                /* handle for now */
                ret = sh_pfc_config_function(pfc, offset);
                if (unlikely(ret < 0))
                        goto err;

                break;
        case PINMUX_TYPE_GPIO:
        case PINMUX_TYPE_INPUT:
        case PINMUX_TYPE_OUTPUT:
                break;
        default:
                pr_err("Unsupported mux type (%d), bailing...\n", pinmux_type);
                ret = -ENOTSUPP;
                goto err;
        }

        ret = 0;

err:
        spin_unlock_irqrestore(&pfc->lock, flags);

        return ret;
}

static void sh_pfc_gpio_disable_free(struct pinctrl_dev *pctldev,
                                     struct pinctrl_gpio_range *range,
                                     unsigned offset)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
        struct sh_pfc *pfc = pmx->pfc;
        unsigned long flags;
        int pinmux_type;

        spin_lock_irqsave(&pfc->lock, flags);

        pinmux_type = pfc->gpios[offset].flags & PINMUX_FLAG_TYPE;

        sh_pfc_config_gpio(pfc, offset, pinmux_type, GPIO_CFG_FREE);

        spin_unlock_irqrestore(&pfc->lock, flags);
}

static int sh_pfc_gpio_set_direction(struct pinctrl_dev *pctldev,
                                     struct pinctrl_gpio_range *range,
                                     unsigned offset, bool input)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
        int type = input ? PINMUX_TYPE_INPUT : PINMUX_TYPE_OUTPUT;

        return sh_pfc_reconfig_pin(pmx->pfc, offset, type);
}

static struct pinmux_ops sh_pfc_pinmux_ops = {
        .get_functions_count    = sh_pfc_get_functions_count,
        .get_function_name      = sh_pfc_get_function_name,
        .get_function_groups    = sh_pfc_get_function_groups,
        .enable                 = sh_pfc_noop_enable,
        .disable                = sh_pfc_noop_disable,
        .gpio_request_enable    = sh_pfc_gpio_request_enable,
        .gpio_disable_free      = sh_pfc_gpio_disable_free,
        .gpio_set_direction     = sh_pfc_gpio_set_direction,
};

static int sh_pfc_pinconf_get(struct pinctrl_dev *pctldev, unsigned pin,
                              unsigned long *config)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);
        struct sh_pfc *pfc = pmx->pfc;

        *config = pfc->gpios[pin].flags & PINMUX_FLAG_TYPE;

        return 0;
}

static int sh_pfc_pinconf_set(struct pinctrl_dev *pctldev, unsigned pin,
                              unsigned long config)
{
        struct sh_pfc_pinctrl *pmx = pinctrl_dev_get_drvdata(pctldev);

        /* Validate the new type */
        if (config >= PINMUX_FLAG_TYPE)
                return -EINVAL;

        return sh_pfc_reconfig_pin(pmx->pfc, pin, config);
}

static void sh_pfc_pinconf_dbg_show(struct pinctrl_dev *pctldev,
                                    struct seq_file *s, unsigned pin)
{
        const char *pinmux_type_str[] = {
                [PINMUX_TYPE_NONE]              = "none",
                [PINMUX_TYPE_FUNCTION]          = "function",
                [PINMUX_TYPE_GPIO]              = "gpio",
                [PINMUX_TYPE_OUTPUT]            = "output",
                [PINMUX_TYPE_INPUT]             = "input",
                [PINMUX_TYPE_INPUT_PULLUP]      = "input bias pull up",
                [PINMUX_TYPE_INPUT_PULLDOWN]    = "input bias pull down",
        };
        unsigned long config;
        int rc;

        rc = sh_pfc_pinconf_get(pctldev, pin, &config);
        if (unlikely(rc != 0))
                return;

        seq_printf(s, " %s", pinmux_type_str[config]);
}

static struct pinconf_ops sh_pfc_pinconf_ops = {
        .pin_config_get         = sh_pfc_pinconf_get,
        .pin_config_set         = sh_pfc_pinconf_set,
        .pin_config_dbg_show    = sh_pfc_pinconf_dbg_show,
};

static struct pinctrl_gpio_range sh_pfc_gpio_range = {
        .name           = DRV_NAME,
        .id             = 0,
};

static struct pinctrl_desc sh_pfc_pinctrl_desc = {
        .name           = DRV_NAME,
        .owner          = THIS_MODULE,
        .pctlops        = &sh_pfc_pinctrl_ops,
        .pmxops         = &sh_pfc_pinmux_ops,
        .confops        = &sh_pfc_pinconf_ops,
};

static inline void sh_pfc_map_one_gpio(struct sh_pfc *pfc,
                                       struct sh_pfc_pinctrl *pmx,
                                       struct pinmux_gpio *gpio,
                                       unsigned offset)
{
        struct pinmux_data_reg *dummy;
        unsigned long flags;
        int bit;

        gpio->flags &= ~PINMUX_FLAG_TYPE;

        if (sh_pfc_get_data_reg(pfc, offset, &dummy, &bit) == 0)
                gpio->flags |= PINMUX_TYPE_GPIO;
        else {
                gpio->flags |= PINMUX_TYPE_FUNCTION;

                spin_lock_irqsave(&pmx->lock, flags);
                pmx->nr_functions++;
                spin_unlock_irqrestore(&pmx->lock, flags);
        }
}

/* pinmux ranges -> pinctrl pin descs */
static int sh_pfc_map_gpios(struct sh_pfc *pfc, struct sh_pfc_pinctrl *pmx)
{
        unsigned long flags;
        int i;

        pmx->nr_pads = pfc->last_gpio - pfc->first_gpio + 1;

        pmx->pads = kmalloc(sizeof(struct pinctrl_pin_desc) * pmx->nr_pads,
                            GFP_KERNEL);
        if (unlikely(!pmx->pads)) {
                pmx->nr_pads = 0;
                return -ENOMEM;
        }

        spin_lock_irqsave(&pfc->lock, flags);

        /*
         * We don't necessarily have a 1:1 mapping between pin and linux
         * GPIO number, as the latter maps to the associated enum_id.
         * Care needs to be taken to translate back to pin space when
         * dealing with any pin configurations.
         */
        for (i = 0; i < pmx->nr_pads; i++) {
                struct pinctrl_pin_desc *pin = pmx->pads + i;
                struct pinmux_gpio *gpio = pfc->gpios + i;

                pin->number = pfc->first_gpio + i;
                pin->name = gpio->name;

                /* XXX */
                if (unlikely(!gpio->enum_id))
                        continue;

                sh_pfc_map_one_gpio(pfc, pmx, gpio, i);
        }

        spin_unlock_irqrestore(&pfc->lock, flags);

        sh_pfc_pinctrl_desc.pins = pmx->pads;
        sh_pfc_pinctrl_desc.npins = pmx->nr_pads;

        return 0;
}

static int sh_pfc_map_functions(struct sh_pfc *pfc, struct sh_pfc_pinctrl *pmx)
{
        unsigned long flags;
        int i, fn;

        pmx->functions = kzalloc(pmx->nr_functions * sizeof(void *),
                                 GFP_KERNEL);
        if (unlikely(!pmx->functions))
                return -ENOMEM;

        spin_lock_irqsave(&pmx->lock, flags);

        for (i = fn = 0; i < pmx->nr_pads; i++) {
                struct pinmux_gpio *gpio = pfc->gpios + i;

                if ((gpio->flags & PINMUX_FLAG_TYPE) == PINMUX_TYPE_FUNCTION)
                        pmx->functions[fn++] = gpio;
        }

        spin_unlock_irqrestore(&pmx->lock, flags);

        return 0;
}

static int sh_pfc_pinctrl_probe(struct platform_device *pdev)
{
        struct sh_pfc *pfc;
        int ret;

        if (unlikely(!sh_pfc_pmx))
                return -ENODEV;

        pfc = sh_pfc_pmx->pfc;

        ret = sh_pfc_map_gpios(pfc, sh_pfc_pmx);
        if (unlikely(ret != 0))
                return ret;

        ret = sh_pfc_map_functions(pfc, sh_pfc_pmx);
        if (unlikely(ret != 0))
                goto free_pads;

        sh_pfc_pmx->pctl = pinctrl_register(&sh_pfc_pinctrl_desc, &pdev->dev,
                                            sh_pfc_pmx);
        if (IS_ERR(sh_pfc_pmx->pctl)) {
                ret = PTR_ERR(sh_pfc_pmx->pctl);
                goto free_functions;
        }

        sh_pfc_gpio_range.npins = pfc->last_gpio - pfc->first_gpio + 1;
        sh_pfc_gpio_range.base = pfc->first_gpio;
        sh_pfc_gpio_range.pin_base = pfc->first_gpio;

        pinctrl_add_gpio_range(sh_pfc_pmx->pctl, &sh_pfc_gpio_range);

        platform_set_drvdata(pdev, sh_pfc_pmx);

        return 0;

free_functions:
        kfree(sh_pfc_pmx->functions);
free_pads:
        kfree(sh_pfc_pmx->pads);
        kfree(sh_pfc_pmx);

        return ret;
}

static int sh_pfc_pinctrl_remove(struct platform_device *pdev)
{
        struct sh_pfc_pinctrl *pmx = platform_get_drvdata(pdev);

        pinctrl_unregister(pmx->pctl);

        platform_set_drvdata(pdev, NULL);

        kfree(sh_pfc_pmx->functions);
        kfree(sh_pfc_pmx->pads);
        kfree(sh_pfc_pmx);

        return 0;
}

static struct platform_driver sh_pfc_pinctrl_driver = {
        .probe          = sh_pfc_pinctrl_probe,
        .remove         = sh_pfc_pinctrl_remove,
        .driver         = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
};

static struct platform_device sh_pfc_pinctrl_device = {
        .name           = DRV_NAME,
        .id             = -1,
};

static int sh_pfc_pinctrl_init(void)
{
        int rc;

        rc = platform_driver_register(&sh_pfc_pinctrl_driver);
        if (likely(!rc)) {
                rc = platform_device_register(&sh_pfc_pinctrl_device);
                if (unlikely(rc))
                        platform_driver_unregister(&sh_pfc_pinctrl_driver);
        }

        return rc;
}

int sh_pfc_register_pinctrl(struct sh_pfc *pfc)
{
        sh_pfc_pmx = kzalloc(sizeof(struct sh_pfc_pinctrl), GFP_KERNEL);
        if (unlikely(!sh_pfc_pmx))
                return -ENOMEM;

        spin_lock_init(&sh_pfc_pmx->lock);

        sh_pfc_pmx->pfc = pfc;

        return sh_pfc_pinctrl_init();
}
EXPORT_SYMBOL_GPL(sh_pfc_register_pinctrl);

static void __exit sh_pfc_pinctrl_exit(void)
{
        platform_driver_unregister(&sh_pfc_pinctrl_driver);
}
module_exit(sh_pfc_pinctrl_exit);