drivers/nfc/bcm2079x-i2c.c

/*
 * Copyright (C) 2012 Broadcom Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/jiffies.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/poll.h>
#include <linux/version.h>

#include <linux/nfc/bcm2079x.h>

/* do not change below */
#define MAX_BUFFER_SIZE		780

/* Read data */
#define PACKET_HEADER_SIZE_NCI	(4)
#define PACKET_HEADER_SIZE_HCI	(3)
#define PACKET_TYPE_NCI		(16)
#define PACKET_TYPE_HCIEV	(4)
#define MAX_PACKET_SIZE		(PACKET_HEADER_SIZE_NCI + 255)

struct bcm2079x_dev {
	wait_queue_head_t read_wq;
	struct mutex read_mutex;
	struct i2c_client *client;
	struct miscdevice bcm2079x_device;
	unsigned int wake_gpio;
	unsigned int en_gpio;
	unsigned int irq_gpio;
	bool irq_enabled;
	spinlock_t irq_enabled_lock;
	unsigned int count_irq;
};

static void bcm2079x_init_stat(struct bcm2079x_dev *bcm2079x_dev)
{
	bcm2079x_dev->count_irq = 0;
}

static void bcm2079x_disable_irq(struct bcm2079x_dev *bcm2079x_dev)
{
	unsigned long flags;
	spin_lock_irqsave(&bcm2079x_dev->irq_enabled_lock, flags);
	if (bcm2079x_dev->irq_enabled) {
		disable_irq_nosync(bcm2079x_dev->client->irq);
		bcm2079x_dev->irq_enabled = false;
	}
	spin_unlock_irqrestore(&bcm2079x_dev->irq_enabled_lock, flags);
}

static void bcm2079x_enable_irq(struct bcm2079x_dev *bcm2079x_dev)
{
	unsigned long flags;
	spin_lock_irqsave(&bcm2079x_dev->irq_enabled_lock, flags);
	if (!bcm2079x_dev->irq_enabled) {
		bcm2079x_dev->irq_enabled = true;
		enable_irq(bcm2079x_dev->client->irq);
	}
	spin_unlock_irqrestore(&bcm2079x_dev->irq_enabled_lock, flags);
}

/*
 The alias address 0x79, when sent as a 7-bit address from the host processor
 will match the first byte (highest 2 bits) of the default client address
 (0x1FA) that is programmed in bcm20791.
 When used together with the first byte (0xFA) of the byte sequence below,
 it can be used to address the bcm20791 in a system that does not support
 10-bit address and change the default address to 0x38.
 the new address can be changed by changing the CLIENT_ADDRESS below if 0x38
 conflicts with other device on the same i2c bus.
 */
#define ALIAS_ADDRESS	  0x79

static int change_client_addr(struct bcm2079x_dev *bcm2079x_dev, int addr)
{
	struct i2c_client *client;
	int ret;
	int i;
	char addr_data[] = {
		0xFA, 0xF2, 0x00, 0x00, 0x00, 0x38, 0x00, 0x00, 0x00, 0x2A
	};
	client = bcm2079x_dev->client;
	client->addr = ALIAS_ADDRESS;
	client->flags &= ~I2C_CLIENT_TEN;

	addr_data[5] = addr & 0xFF;
	ret = 0;
	for (i = 1; i < sizeof(addr_data) - 1; ++i)
		ret += addr_data[i];
	addr_data[sizeof(addr_data) - 1] = (ret & 0xFF);
	dev_info(&client->dev,
		 "Change client device from (0x%04X) flag = "\
		 "%04x, addr_data[%d] = %02x\n",
		 client->addr, client->flags, sizeof(addr_data) - 1,
		 addr_data[sizeof(addr_data) - 1]);
	ret = i2c_master_send(client, addr_data, sizeof(addr_data));
	if (ret != sizeof(addr_data)) {
		client->addr = ALIAS_ADDRESS;
		client->flags &= ~I2C_CLIENT_TEN;
		dev_info(&client->dev,
			 "Change client device from (0x%04X) flag = "\
			 "%04x, addr_data[%d] = %02x\n",
			 client->addr, client->flags, sizeof(addr_data) - 1,
			 addr_data[sizeof(addr_data) - 1]);
		ret = i2c_master_send(client, addr_data, sizeof(addr_data));
	}
	client->addr = addr_data[5];

	dev_info(&client->dev,
		 "Change client device changed to (0x%04X) flag = %04x, ret = %d\n",
		 client->addr, client->flags, ret);

    return (ret == sizeof(addr_data) ? 0 : -EIO);
}

static irqreturn_t bcm2079x_dev_irq_handler(int irq, void *dev_id)
{
	struct bcm2079x_dev *bcm2079x_dev = dev_id;
	unsigned long flags;

	spin_lock_irqsave(&bcm2079x_dev->irq_enabled_lock, flags);
	bcm2079x_dev->count_irq++;
	spin_unlock_irqrestore(&bcm2079x_dev->irq_enabled_lock, flags);
	wake_up(&bcm2079x_dev->read_wq);

	return IRQ_HANDLED;
}

static unsigned int bcm2079x_dev_poll(struct file *filp, poll_table *wait)
{
	struct bcm2079x_dev *bcm2079x_dev = filp->private_data;
	unsigned int mask = 0;
	unsigned long flags;

	poll_wait(filp, &bcm2079x_dev->read_wq, wait);

	spin_lock_irqsave(&bcm2079x_dev->irq_enabled_lock, flags);
	if (bcm2079x_dev->count_irq > 0)
	{
		bcm2079x_dev->count_irq--;
		mask |= POLLIN | POLLRDNORM;
	}
	spin_unlock_irqrestore(&bcm2079x_dev->irq_enabled_lock, flags);

	return mask;
}

static ssize_t bcm2079x_dev_read(struct file *filp, char __user *buf,
				  size_t count, loff_t *offset)
{
	struct bcm2079x_dev *bcm2079x_dev = filp->private_data;
	unsigned char tmp[MAX_BUFFER_SIZE];
	int total, len, ret;

	total = 0;
	len = 0;

	if (count > MAX_BUFFER_SIZE)
		count = MAX_BUFFER_SIZE;

	mutex_lock(&bcm2079x_dev->read_mutex);

	/** Read the first 4 bytes to include the length of the NCI or HCI packet.
	**/
	ret = i2c_master_recv(bcm2079x_dev->client, tmp, 4);
	if (ret == 4) {
		total = ret;
		/** First byte is the packet type
		**/
		switch(tmp[0]) {
			case PACKET_TYPE_NCI:
				len = tmp[PACKET_HEADER_SIZE_NCI-1];
				break;

			case PACKET_TYPE_HCIEV:
				len = tmp[PACKET_HEADER_SIZE_HCI-1];
				if (len == 0)
					total--;/*Since payload is 0, decrement total size (from 4 to 3) */
				else
					len--;/*First byte of payload is in tmp[3] already */
				break;

			default:
				len = 0;/*Unknown packet byte */
				break;
		} /* switch*/

		/** make sure full packet fits in the buffer
		**/
		if (len > 0 && (len + total) <= count) {
			/** read the remainder of the packet.
			**/
			ret = i2c_master_recv(bcm2079x_dev->client, tmp+total, len);
			if (ret == len)
				total += len;
		} /* if */
	} /* if */

	mutex_unlock(&bcm2079x_dev->read_mutex);

	if (total > count || copy_to_user(buf, tmp, total)) {
		dev_err(&bcm2079x_dev->client->dev,
			"failed to copy to user space, total = %d\n", total);
		total = -EFAULT;
	}

	return total;
}

static ssize_t bcm2079x_dev_write(struct file *filp, const char __user *buf,
				   size_t count, loff_t *offset)
{
	struct bcm2079x_dev *bcm2079x_dev = filp->private_data;
	char tmp[MAX_BUFFER_SIZE];
	int ret;

	if (count > MAX_BUFFER_SIZE) {
		dev_err(&bcm2079x_dev->client->dev, "out of memory\n");
		return -ENOMEM;
	}

	if (copy_from_user(tmp, buf, count)) {
		dev_err(&bcm2079x_dev->client->dev,
			"failed to copy from user space\n");
		return -EFAULT;
	}

	mutex_lock(&bcm2079x_dev->read_mutex);
	/* Write data */

	ret = i2c_master_send(bcm2079x_dev->client, tmp, count);
	if (ret != count) {
		dev_err(&bcm2079x_dev->client->dev,
			"failed to write %d\n", ret);
		ret = -EIO;
	}
	mutex_unlock(&bcm2079x_dev->read_mutex);

	return ret;
}

static int bcm2079x_dev_open(struct inode *inode, struct file *filp)
{
	int ret = 0;

	struct bcm2079x_dev *bcm2079x_dev = container_of(filp->private_data,
							   struct bcm2079x_dev,
							   bcm2079x_device);
	filp->private_data = bcm2079x_dev;
	bcm2079x_init_stat(bcm2079x_dev);
	bcm2079x_enable_irq(bcm2079x_dev);
	dev_info(&bcm2079x_dev->client->dev,
		 "%d,%d\n", imajor(inode), iminor(inode));

	return ret;
}

static long bcm2079x_dev_unlocked_ioctl(struct file *filp,
					 unsigned int cmd, unsigned long arg)
{
	struct bcm2079x_dev *bcm2079x_dev = filp->private_data;

	switch (cmd) {
	case BCMNFC_READ_FULL_PACKET:
		break;
	case BCMNFC_READ_MULTI_PACKETS:
		break;
	case BCMNFC_CHANGE_ADDR:
		dev_info(&bcm2079x_dev->client->dev,
			 "%s, BCMNFC_CHANGE_ADDR (%x, %lx):\n", __func__, cmd,
			 arg);
		return change_client_addr(bcm2079x_dev, arg);
	case BCMNFC_POWER_CTL:
		gpio_set_value(bcm2079x_dev->en_gpio, arg);
		break;
	case BCMNFC_WAKE_CTL:
		gpio_set_value(bcm2079x_dev->wake_gpio, arg);
		break;
	default:
		dev_err(&bcm2079x_dev->client->dev,
			"%s, unknown cmd (%x, %lx)\n", __func__, cmd, arg);
		return 0;
	}

	return 0;
}

static const struct file_operations bcm2079x_dev_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.poll = bcm2079x_dev_poll,
	.read = bcm2079x_dev_read,
	.write = bcm2079x_dev_write,
	.open = bcm2079x_dev_open,
	.unlocked_ioctl = bcm2079x_dev_unlocked_ioctl
};

static int bcm2079x_probe(struct i2c_client *client,
			   const struct i2c_device_id *id)
{
	int ret;
	struct bcm2079x_platform_data *platform_data;
	struct bcm2079x_dev *bcm2079x_dev;

	platform_data = client->dev.platform_data;

	dev_info(&client->dev, "%s, probing bcm2079x driver flags = %x\n", __func__, client->flags);
	if (platform_data == NULL) {
		dev_err(&client->dev, "nfc probe fail\n");
		return -ENODEV;
	}

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

	ret = gpio_request_one(platform_data->irq_gpio, GPIOF_IN, "nfc_int");
	if (ret)
		return -ENODEV;
	ret = gpio_request_one(platform_data->en_gpio, GPIOF_OUT_INIT_LOW, "nfc_ven");
	if (ret)
		goto err_en;
	ret = gpio_request_one(platform_data->wake_gpio, GPIOF_OUT_INIT_LOW,"nfc_firm");
	if (ret)
		goto err_firm;

	gpio_set_value(platform_data->en_gpio, 0);
	gpio_set_value(platform_data->wake_gpio, 0);

	bcm2079x_dev = kzalloc(sizeof(*bcm2079x_dev), GFP_KERNEL);
	if (bcm2079x_dev == NULL) {
		dev_err(&client->dev,
			"failed to allocate memory for module data\n");
		ret = -ENOMEM;
		goto err_exit;
	}

	bcm2079x_dev->wake_gpio = platform_data->wake_gpio;
	bcm2079x_dev->irq_gpio = platform_data->irq_gpio;
	bcm2079x_dev->en_gpio = platform_data->en_gpio;
	bcm2079x_dev->client = client;

	/* init mutex and queues */
	init_waitqueue_head(&bcm2079x_dev->read_wq);
	mutex_init(&bcm2079x_dev->read_mutex);
	spin_lock_init(&bcm2079x_dev->irq_enabled_lock);

	bcm2079x_dev->bcm2079x_device.minor = MISC_DYNAMIC_MINOR;
	bcm2079x_dev->bcm2079x_device.name = "bcm2079x-i2c";
	bcm2079x_dev->bcm2079x_device.fops = &bcm2079x_dev_fops;

	ret = misc_register(&bcm2079x_dev->bcm2079x_device);
	if (ret) {
		dev_err(&client->dev, "misc_register failed\n");
		goto err_misc_register;
	}

	/* request irq.  the irq is set whenever the chip has data available
	 * for reading.  it is cleared when all data has been read.
	 */
	dev_info(&client->dev, "requesting IRQ %d\n", client->irq);
	bcm2079x_dev->irq_enabled = true;
	ret = request_irq(client->irq, bcm2079x_dev_irq_handler,
			  IRQF_TRIGGER_RISING, client->name, bcm2079x_dev);
	if (ret) {
		dev_err(&client->dev, "request_irq failed\n");
		goto err_request_irq_failed;
	}
	bcm2079x_disable_irq(bcm2079x_dev);
	i2c_set_clientdata(client, bcm2079x_dev);
	dev_info(&client->dev,
		 "%s, probing bcm2079x driver exited successfully\n",
		 __func__);
	return 0;

err_request_irq_failed:
	misc_deregister(&bcm2079x_dev->bcm2079x_device);
err_misc_register:
	mutex_destroy(&bcm2079x_dev->read_mutex);
	kfree(bcm2079x_dev);
err_exit:
	gpio_free(platform_data->wake_gpio);
err_firm:
	gpio_free(platform_data->en_gpio);
err_en:
	gpio_free(platform_data->irq_gpio);
	return ret;
}

static int bcm2079x_remove(struct i2c_client *client)
{
	struct bcm2079x_dev *bcm2079x_dev;

	bcm2079x_dev = i2c_get_clientdata(client);
	free_irq(client->irq, bcm2079x_dev);
	misc_deregister(&bcm2079x_dev->bcm2079x_device);
	mutex_destroy(&bcm2079x_dev->read_mutex);
	gpio_free(bcm2079x_dev->irq_gpio);
	gpio_free(bcm2079x_dev->en_gpio);
	gpio_free(bcm2079x_dev->wake_gpio);
	kfree(bcm2079x_dev);

	return 0;
}

static const struct i2c_device_id bcm2079x_id[] = {
	{"bcm2079x-i2c", 0},
	{}
};

static struct i2c_driver bcm2079x_driver = {
	.id_table = bcm2079x_id,
	.probe = bcm2079x_probe,
	.remove = bcm2079x_remove,
	.driver = {
		.owner = THIS_MODULE,
		.name = "bcm2079x-i2c",
	},
};

/*
 * module load/unload record keeping
 */

static int __init bcm2079x_dev_init(void)
{
	return i2c_add_driver(&bcm2079x_driver);
}
module_init(bcm2079x_dev_init);

static void __exit bcm2079x_dev_exit(void)
{
	i2c_del_driver(&bcm2079x_driver);
}
module_exit(bcm2079x_dev_exit);

MODULE_AUTHOR("Broadcom");
MODULE_DESCRIPTION("NFC bcm2079x driver");
MODULE_LICENSE("GPL");