root/drivers/nfc/nfcmrvl/i2c.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Marvell NFC-over-I2C driver: I2C interface related functions
 *
 * Copyright (C) 2015, Marvell International Ltd.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/nfc.h>
#include <linux/delay.h>
#include <linux/of_irq.h>
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include "nfcmrvl.h"

struct nfcmrvl_i2c_drv_data {
        unsigned long flags;
        struct device *dev;
        struct i2c_client *i2c;
        struct nfcmrvl_private *priv;
};

static int nfcmrvl_i2c_read(struct nfcmrvl_i2c_drv_data *drv_data,
                            struct sk_buff **skb)
{
        int ret;
        struct nci_ctrl_hdr nci_hdr;

        /* Read NCI header to know the payload size */
        ret = i2c_master_recv(drv_data->i2c, (u8 *)&nci_hdr, NCI_CTRL_HDR_SIZE);
        if (ret != NCI_CTRL_HDR_SIZE) {
                nfc_err(&drv_data->i2c->dev, "cannot read NCI header\n");
                return -EBADMSG;
        }

        *skb = nci_skb_alloc(drv_data->priv->ndev,
                             nci_hdr.plen + NCI_CTRL_HDR_SIZE, GFP_KERNEL);
        if (!*skb)
                return -ENOMEM;

        /* Copy NCI header into the SKB */
        skb_put_data(*skb, &nci_hdr, NCI_CTRL_HDR_SIZE);

        if (nci_hdr.plen) {
                /* Read the NCI payload */
                ret = i2c_master_recv(drv_data->i2c,
                                      skb_put(*skb, nci_hdr.plen),
                                      nci_hdr.plen);

                if (ret != nci_hdr.plen) {
                        nfc_err(&drv_data->i2c->dev,
                                "Invalid frame payload length: %u (expected %u)\n",
                                ret, nci_hdr.plen);
                        kfree_skb(*skb);
                        return -EBADMSG;
                }
        }

        return 0;
}

static irqreturn_t nfcmrvl_i2c_int_irq_thread_fn(int irq, void *drv_data_ptr)
{
        struct nfcmrvl_i2c_drv_data *drv_data = drv_data_ptr;
        struct sk_buff *skb = NULL;
        int ret;

        if (!drv_data->priv)
                return IRQ_HANDLED;

        if (test_bit(NFCMRVL_PHY_ERROR, &drv_data->priv->flags))
                return IRQ_HANDLED;

        ret = nfcmrvl_i2c_read(drv_data, &skb);

        switch (ret) {
        case -EREMOTEIO:
                set_bit(NFCMRVL_PHY_ERROR, &drv_data->priv->flags);
                break;
        case -ENOMEM:
        case -EBADMSG:
                nfc_err(&drv_data->i2c->dev, "read failed %d\n", ret);
                break;
        default:
                if (nfcmrvl_nci_recv_frame(drv_data->priv, skb) < 0)
                        nfc_err(&drv_data->i2c->dev, "corrupted RX packet\n");
                break;
        }
        return IRQ_HANDLED;
}

static int nfcmrvl_i2c_nci_open(struct nfcmrvl_private *priv)
{
        struct nfcmrvl_i2c_drv_data *drv_data = priv->drv_data;

        if (!drv_data)
                return -ENODEV;

        return 0;
}

static int nfcmrvl_i2c_nci_close(struct nfcmrvl_private *priv)
{
        return 0;
}

static int nfcmrvl_i2c_nci_send(struct nfcmrvl_private *priv,
                                struct sk_buff *skb)
{
        struct nfcmrvl_i2c_drv_data *drv_data = priv->drv_data;
        int ret;

        if (test_bit(NFCMRVL_PHY_ERROR, &priv->flags)) {
                kfree_skb(skb);
                return -EREMOTEIO;
        }

        ret = i2c_master_send(drv_data->i2c, skb->data, skb->len);

        /* Retry if chip was in standby */
        if (ret == -EREMOTEIO) {
                nfc_info(drv_data->dev, "chip may sleep, retry\n");
                usleep_range(6000, 10000);
                ret = i2c_master_send(drv_data->i2c, skb->data, skb->len);
        }

        if (ret >= 0) {
                if (ret != skb->len) {
                        nfc_err(drv_data->dev,
                                "Invalid length sent: %u (expected %u)\n",
                                ret, skb->len);
                        ret = -EREMOTEIO;
                } else
                        ret = 0;
        }

        if (ret) {
                kfree_skb(skb);
                return ret;
        }

        consume_skb(skb);
        return 0;
}

static void nfcmrvl_i2c_nci_update_config(struct nfcmrvl_private *priv,
                                          const void *param)
{
}

static const struct nfcmrvl_if_ops i2c_ops = {
        .nci_open = nfcmrvl_i2c_nci_open,
        .nci_close = nfcmrvl_i2c_nci_close,
        .nci_send = nfcmrvl_i2c_nci_send,
        .nci_update_config = nfcmrvl_i2c_nci_update_config,
};

static int nfcmrvl_i2c_parse_dt(struct device_node *node,
                                struct nfcmrvl_platform_data *pdata)
{
        int ret;

        ret = nfcmrvl_parse_dt(node, pdata);
        if (ret < 0) {
                pr_err("Failed to get generic entries\n");
                return ret;
        }

        if (of_property_read_bool(node, "i2c-int-falling"))
                pdata->irq_polarity = IRQF_TRIGGER_FALLING;
        else
                pdata->irq_polarity = IRQF_TRIGGER_RISING;

        ret = irq_of_parse_and_map(node, 0);
        if (!ret) {
                pr_err("Unable to get irq\n");
                return -EINVAL;
        }
        pdata->irq = ret;

        return 0;
}

static int nfcmrvl_i2c_probe(struct i2c_client *client)
{
        const struct nfcmrvl_platform_data *pdata;
        struct nfcmrvl_i2c_drv_data *drv_data;
        struct nfcmrvl_platform_data config;
        int ret;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
                return -ENODEV;
        }

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

        drv_data->i2c = client;
        drv_data->dev = &client->dev;
        drv_data->priv = NULL;

        i2c_set_clientdata(client, drv_data);

        pdata = client->dev.platform_data;

        if (!pdata && client->dev.of_node)
                if (nfcmrvl_i2c_parse_dt(client->dev.of_node, &config) == 0)
                        pdata = &config;

        if (!pdata)
                return -EINVAL;

        /* Request the read IRQ */
        ret = devm_request_threaded_irq(&drv_data->i2c->dev, pdata->irq,
                                        NULL, nfcmrvl_i2c_int_irq_thread_fn,
                                        pdata->irq_polarity | IRQF_ONESHOT,
                                        "nfcmrvl_i2c_int", drv_data);
        if (ret < 0) {
                nfc_err(&drv_data->i2c->dev,
                        "Unable to register IRQ handler\n");
                return ret;
        }

        drv_data->priv = nfcmrvl_nci_register_dev(NFCMRVL_PHY_I2C,
                                                  drv_data, &i2c_ops,
                                                  &drv_data->i2c->dev, pdata);

        if (IS_ERR(drv_data->priv))
                return PTR_ERR(drv_data->priv);

        drv_data->priv->support_fw_dnld = true;

        return 0;
}

static void nfcmrvl_i2c_remove(struct i2c_client *client)
{
        struct nfcmrvl_i2c_drv_data *drv_data = i2c_get_clientdata(client);

        nfcmrvl_nci_unregister_dev(drv_data->priv);
}


static const struct of_device_id of_nfcmrvl_i2c_match[] __maybe_unused = {
        { .compatible = "marvell,nfc-i2c", },
        {},
};
MODULE_DEVICE_TABLE(of, of_nfcmrvl_i2c_match);

static const struct i2c_device_id nfcmrvl_i2c_id_table[] = {
        { "nfcmrvl_i2c" },
        {}
};
MODULE_DEVICE_TABLE(i2c, nfcmrvl_i2c_id_table);

static struct i2c_driver nfcmrvl_i2c_driver = {
        .probe = nfcmrvl_i2c_probe,
        .id_table = nfcmrvl_i2c_id_table,
        .remove = nfcmrvl_i2c_remove,
        .driver = {
                .name           = "nfcmrvl_i2c",
                .of_match_table = of_match_ptr(of_nfcmrvl_i2c_match),
        },
};

module_i2c_driver(nfcmrvl_i2c_driver);

MODULE_AUTHOR("Marvell International Ltd.");
MODULE_DESCRIPTION("Marvell NFC-over-I2C driver");
MODULE_LICENSE("GPL v2");