text: /**
   * Marvell NFC-over-I2C driver: I2C interface related functions
   *
   * Copyright (C) 2015, Marvell International Ltd.
   *
   * This software file (the "File") is distributed by Marvell International
   * Ltd. under the terms of the GNU General Public License Version 2, June 1991
   * (the "License").  You may use, redistribute and/or modify this File in
   * accordance with the terms and conditions of the License, a copy of which
   * is available on the worldwide web at
   * http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
   *
   * THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
   * ARE EXPRESSLY DISCLAIMED.  The License provides additional details about
   * this warranty disclaimer.
   **/
  
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/i2c.h>
  #include <linux/pm_runtime.h>
  #include <linux/nfc.h>
  #include <linux/gpio.h>
  #include <linux/delay.h>
  #include <linux/of_irq.h>
  #include <linux/of_gpio.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;
  	}
  
  	if (nci_hdr.plen > NCI_MAX_PAYLOAD_SIZE) {
  		nfc_err(&drv_data->i2c->dev, "invalid packet payload size\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))
  		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;
  		kfree_skb(skb);
  	}
  
  	return ret;
  }
  
  static void nfcmrvl_i2c_nci_update_config(struct nfcmrvl_private *priv,
  					  const void *param)
  {
  }
  
  static 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_find_property(node, "i2c-int-falling", NULL))
  		pdata->irq_polarity = IRQF_TRIGGER_FALLING;
  	else
  		pdata->irq_polarity = IRQF_TRIGGER_RISING;
  
  	ret = irq_of_parse_and_map(node, 0);
  	if (ret < 0) {
  		pr_err("Unable to get irq, error: %d\n", ret);
  		return ret;
  	}
  	pdata->irq = ret;
  
  	return 0;
  }
  
  static int nfcmrvl_i2c_probe(struct i2c_client *client,
  			     const struct i2c_device_id *id)
  {
  	struct nfcmrvl_i2c_drv_data *drv_data;
  	struct nfcmrvl_platform_data *pdata;
  	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 int 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);
  
  	return 0;
  }
  
  
  static const struct of_device_id of_nfcmrvl_i2c_match[] = {
  	{ .compatible = "marvell,nfc-i2c", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, of_nfcmrvl_i2c_match);
  
  static const struct i2c_device_id nfcmrvl_i2c_id_table[] = {
  	{ "nfcmrvl_i2c", 0 },
  	{}
  };
  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",
  		.owner		= THIS_MODULE,
  		.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");
  