// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * I2C Link Layer for Samsung S3FWRN5 NCI based Driver
 *
 * Copyright (C) 2015 Samsung Electronics
 * Robert Baldyga <r.baldyga@samsung.com>
 */

#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/module.h>

#include <net/nfc/nfc.h>

#include "phy_common.h"

#define S3FWRN5_I2C_DRIVER_NAME "s3fwrn5_i2c"

struct s3fwrn5_i2c_phy {
        struct phy_common common;
        struct i2c_client *i2c_dev;
        struct clk *clk;

        unsigned int irq_skip:1;
};

static void s3fwrn5_i2c_set_mode(void *phy_id, enum s3fwrn5_mode mode)
{
        struct s3fwrn5_i2c_phy *phy = phy_id;

        mutex_lock(&phy->common.mutex);

        if (s3fwrn5_phy_power_ctrl(&phy->common, mode) == false)
                goto out;

        phy->irq_skip = true;

out:
        mutex_unlock(&phy->common.mutex);
}

static int s3fwrn5_i2c_write(void *phy_id, struct sk_buff *skb)
{
        struct s3fwrn5_i2c_phy *phy = phy_id;
        int ret;

        mutex_lock(&phy->common.mutex);

        phy->irq_skip = false;

        ret = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
        if (ret == -EREMOTEIO) {
                /* Retry, chip was in standby */
                usleep_range(110000, 120000);
                ret  = i2c_master_send(phy->i2c_dev, skb->data, skb->len);
        }

        mutex_unlock(&phy->common.mutex);

        if (ret < 0)
                return ret;

        if (ret != skb->len)
                return -EREMOTEIO;

        return 0;
}

static const struct s3fwrn5_phy_ops i2c_phy_ops = {
        .set_wake = s3fwrn5_phy_set_wake,
        .set_mode = s3fwrn5_i2c_set_mode,
        .get_mode = s3fwrn5_phy_get_mode,
        .write = s3fwrn5_i2c_write,
};

static int s3fwrn5_i2c_read(struct s3fwrn5_i2c_phy *phy)
{
        struct sk_buff *skb;
        size_t hdr_size;
        size_t data_len;
        char hdr[4];
        int ret;

        hdr_size = (phy->common.mode == S3FWRN5_MODE_NCI) ?
                NCI_CTRL_HDR_SIZE : S3FWRN5_FW_HDR_SIZE;
        ret = i2c_master_recv(phy->i2c_dev, hdr, hdr_size);
        if (ret < 0)
                return ret;

        if (ret < hdr_size)
                return -EBADMSG;

        data_len = (phy->common.mode == S3FWRN5_MODE_NCI) ?
                ((struct nci_ctrl_hdr *)hdr)->plen :
                ((struct s3fwrn5_fw_header *)hdr)->len;

        skb = alloc_skb(hdr_size + data_len, GFP_KERNEL);
        if (!skb)
                return -ENOMEM;

        skb_put_data(skb, hdr, hdr_size);

        if (data_len == 0)
                goto out;

        ret = i2c_master_recv(phy->i2c_dev, skb_put(skb, data_len), data_len);
        if (ret != data_len) {
                kfree_skb(skb);
                return -EBADMSG;
        }

out:
        return s3fwrn5_recv_frame(phy->common.ndev, skb, phy->common.mode);
}

static irqreturn_t s3fwrn5_i2c_irq_thread_fn(int irq, void *phy_id)
{
        struct s3fwrn5_i2c_phy *phy = phy_id;

        if (!phy || !phy->common.ndev) {
                WARN_ON_ONCE(1);
                return IRQ_NONE;
        }

        mutex_lock(&phy->common.mutex);

        if (phy->irq_skip)
                goto out;

        switch (phy->common.mode) {
        case S3FWRN5_MODE_NCI:
        case S3FWRN5_MODE_FW:
                s3fwrn5_i2c_read(phy);
                break;
        case S3FWRN5_MODE_COLD:
                break;
        }

out:
        mutex_unlock(&phy->common.mutex);

        return IRQ_HANDLED;
}

static int s3fwrn5_i2c_parse_dt(struct i2c_client *client)
{
        struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);
        struct device_node *np = client->dev.of_node;

        if (!np)
                return -ENODEV;

        phy->common.gpio_en = of_get_named_gpio(np, "en-gpios", 0);
        if (!gpio_is_valid(phy->common.gpio_en)) {
                /* Support also deprecated property */
                phy->common.gpio_en = of_get_named_gpio(np,
                                                        "s3fwrn5,en-gpios",
                                                        0);
                if (!gpio_is_valid(phy->common.gpio_en))
                        return -ENODEV;
        }

        phy->common.gpio_fw_wake = of_get_named_gpio(np, "wake-gpios", 0);
        if (!gpio_is_valid(phy->common.gpio_fw_wake)) {
                /* Support also deprecated property */
                phy->common.gpio_fw_wake = of_get_named_gpio(np,
                                                             "s3fwrn5,fw-gpios",
                                                             0);
                if (!gpio_is_valid(phy->common.gpio_fw_wake))
                        return -ENODEV;
        }

        return 0;
}

static int s3fwrn5_i2c_probe(struct i2c_client *client)
{
        struct s3fwrn5_i2c_phy *phy;
        int ret;

        phy = devm_kzalloc(&client->dev, sizeof(*phy), GFP_KERNEL);
        if (!phy)
                return -ENOMEM;

        mutex_init(&phy->common.mutex);
        phy->common.mode = S3FWRN5_MODE_COLD;
        phy->irq_skip = true;

        phy->i2c_dev = client;
        i2c_set_clientdata(client, phy);

        ret = s3fwrn5_i2c_parse_dt(client);
        if (ret < 0)
                return ret;

        ret = devm_gpio_request_one(&phy->i2c_dev->dev, phy->common.gpio_en,
                                    GPIOF_OUT_INIT_HIGH, "s3fwrn5_en");
        if (ret < 0)
                return ret;

        ret = devm_gpio_request_one(&phy->i2c_dev->dev,
                                    phy->common.gpio_fw_wake,
                                    GPIOF_OUT_INIT_LOW, "s3fwrn5_fw_wake");
        if (ret < 0)
                return ret;

        /*
         * S3FWRN5 depends on a clock input ("XI" pin) to function properly.
         * Depending on the hardware configuration this could be an always-on
         * oscillator or some external clock that must be explicitly enabled.
         * Make sure the clock is running before starting S3FWRN5.
         */
        phy->clk = devm_clk_get_optional_enabled(&client->dev, NULL);
        if (IS_ERR(phy->clk))
                return dev_err_probe(&client->dev, PTR_ERR(phy->clk),
                                     "failed to get clock\n");

        ret = s3fwrn5_probe(&phy->common.ndev, phy, &phy->i2c_dev->dev,
                            &i2c_phy_ops);
        if (ret < 0)
                return ret;

        ret = devm_request_threaded_irq(&client->dev, phy->i2c_dev->irq, NULL,
                s3fwrn5_i2c_irq_thread_fn, IRQF_ONESHOT,
                S3FWRN5_I2C_DRIVER_NAME, phy);
        if (ret)
                goto s3fwrn5_remove;

        return 0;

s3fwrn5_remove:
        s3fwrn5_remove(phy->common.ndev);
        return ret;
}

static void s3fwrn5_i2c_remove(struct i2c_client *client)
{
        struct s3fwrn5_i2c_phy *phy = i2c_get_clientdata(client);

        s3fwrn5_remove(phy->common.ndev);
}

static const struct i2c_device_id s3fwrn5_i2c_id_table[] = {
        { S3FWRN5_I2C_DRIVER_NAME },
        {}
};
MODULE_DEVICE_TABLE(i2c, s3fwrn5_i2c_id_table);

static const struct of_device_id of_s3fwrn5_i2c_match[] __maybe_unused = {
        { .compatible = "samsung,s3fwrn5-i2c", },
        {}
};
MODULE_DEVICE_TABLE(of, of_s3fwrn5_i2c_match);

static struct i2c_driver s3fwrn5_i2c_driver = {
        .driver = {
                .name = S3FWRN5_I2C_DRIVER_NAME,
                .of_match_table = of_match_ptr(of_s3fwrn5_i2c_match),
        },
        .probe = s3fwrn5_i2c_probe,
        .remove = s3fwrn5_i2c_remove,
        .id_table = s3fwrn5_i2c_id_table,
};

module_i2c_driver(s3fwrn5_i2c_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("I2C driver for Samsung S3FWRN5");
MODULE_AUTHOR("Robert Baldyga <r.baldyga@samsung.com>");