NFC: Driver for NXP Semiconductors PN544 NFC chip.

Creates a new "Near Field Communication" subsystem in drivers/nfc.
http://en.wikipedia.org/wiki/Near_Field_Communication is useful ;)

This is a driver for the pn544 NFC device. The driver transfers
ETSI messages between the device and the user space.

Signed-off-by: Matti J. Aaltonen <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/nfc/nfc-pn544.txt

···
+Kernel driver for the NXP Semiconductors PN544 Near Field
+Communication chip
+
+Author: Jari Vanhala
+Contact: Matti Aaltonen (matti.j.aaltonen at nokia.com)
+
+General
+-------
+
+The PN544 is an integrated transmission module for contactless
+communication. The driver goes under drives/nfc/ and is compiled as a
+module named "pn544". It registers a misc device and creates a device
+file named "/dev/pn544".
+
+Host Interfaces: I2C, SPI and HSU, this driver supports currently only I2C.
+
+The Interface
+-------------
+
+The driver offers a sysfs interface for a hardware test and an IOCTL
+interface for selecting between two operating modes. There are read,
+write and poll functions for transferring messages. The two operating
+modes are the normal (HCI) mode and the firmware update mode.
+
+PN544 is controlled by sending messages from the userspace to the
+chip. The main function of the driver is just to pass those messages
+without caring about the message content.
+
+
+Protocols
+---------
+
+In the normal (HCI) mode and in the firmware update mode read and
+write functions behave a bit differently because the message formats
+or the protocols are different.
+
+In the normal (HCI) mode the protocol used is derived from the ETSI
+HCI specification. The firmware is updated using a specific protocol,
+which is different from HCI.
+
+HCI messages consist of an eight bit header and the message body. The
+header contains the message length. Maximum size for an HCI message is
+33. In HCI mode sent messages are tested for a correct
+checksum. Firmware update messages have the length in the second (MSB)
+and third (LSB) bytes of the message. The maximum FW message length is
+1024 bytes.
+
+For the ETSI HCI specification see
+http://www.etsi.org/WebSite/Technologies/ProtocolSpecification.aspx
+
+The Hardware Test
+-----------------
+
+The idea of the test is that it can performed by reading from the
+corresponding sysfs file. The test is implemented in the board file
+and it should test that PN544 can be put into the firmware update
+mode. If the test is not implemented the sysfs file does not get
+created.
+
+Example:
+> cat /sys/module/pn544/drivers/i2c\:pn544/3-002b/nfc_test
+1
+
+Normal Operation
+----------------
+
+PN544 is powered up when the device file is opened, otherwise it's
+turned off. Only one instance can use the device at a time.
+
+Userspace applications control PN544 with HCI messages. The hardware
+sends an interrupt when data is available for reading. Data is
+physically read when the read function is called by a userspace
+application. Poll() checks the read interrupt state. Configuration and
+self testing are also done from the userspace using read and write.
+
+Example platform data:
+
+static int rx71_pn544_nfc_request_resources(struct i2c_client *client)
+{
+	/* Get and setup the HW resources for the device */
+}
+
+static void rx71_pn544_nfc_free_resources(void)
+{
+	/* Release the HW resources */
+}
+
+static void rx71_pn544_nfc_enable(int fw)
+{
+	/* Turn the device on */
+}
+
+static int rx71_pn544_nfc_test(void)
+{
+	/*
+	 * Put the device into the FW update mode
+	 * and then back to the normal mode.
+	 * Check the behavior and return one on success,
+	 * zero on failure.
+	 */
+}
+
+static void rx71_pn544_nfc_disable(void)
+{
+	/* turn the power off */
+}
+
+static struct pn544_nfc_platform_data rx71_nfc_data = {
+	.request_resources = rx71_pn544_nfc_request_resources,
+	.free_resources = rx71_pn544_nfc_free_resources,
+	.enable = rx71_pn544_nfc_enable,
+	.test = rx71_pn544_nfc_test,
+	.disable = rx71_pn544_nfc_disable,
+};

drivers/Kconfig

···
 
 source "drivers/leds/Kconfig"
 
+source "drivers/nfc/Kconfig"
+
 source "drivers/accessibility/Kconfig"
 
 source "drivers/infiniband/Kconfig"

drivers/Makefile

···
 
 obj-y				+= serial/
 obj-$(CONFIG_PARPORT)		+= parport/
-obj-y				+= base/ block/ misc/ mfd/
+obj-y				+= base/ block/ misc/ mfd/ nfc/
 obj-$(CONFIG_NUBUS)		+= nubus/
 obj-y				+= macintosh/
 obj-$(CONFIG_IDE)		+= ide/

drivers/nfc/Kconfig

···
+#
+# Near Field Communication (NFC) devices
+#
+
+menuconfig NFC_DEVICES
+	bool "NFC devices"
+	default n
+	---help---
+	  You'll have to say Y if your computer contains an NFC device that
+	  you want to use under Linux.
+
+	  You can say N here if you don't have any Near Field Communication
+	  devices connected to your computer.
+
+if NFC_DEVICES
+
+config PN544_NFC
+	tristate "PN544 NFC driver"
+	depends on I2C
+	select CRC_CCITT
+	default n
+	---help---
+	  Say yes if you want PN544 Near Field Communication driver.
+	  This is for i2c connected version. If unsure, say N here.
+
+	  To compile this driver as a module, choose m here. The module will
+	  be called pn544.
+
+
+endif # NFC_DEVICES

drivers/nfc/Makefile

···
+#
+# Makefile for nfc devices
+#
+
+obj-$(CONFIG_PN544_NFC)		+= pn544.o

drivers/nfc/pn544.c

···
+/*
+ * Driver for the PN544 NFC chip.
+ *
+ * Copyright (C) Nokia Corporation
+ *
+ * Author: Jari Vanhala <[e-mail]>
+ * Contact: Matti Aaltonen <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/completion.h>
+#include <linux/crc-ccitt.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nfc/pn544.h>
+#include <linux/poll.h>
+#include <linux/regulator/consumer.h>
+#include <linux/serial_core.h> /* for TCGETS */
+#include <linux/slab.h>
+
+#define DRIVER_CARD	"PN544 NFC"
+#define DRIVER_DESC	"NFC driver for PN544"
+
+static struct i2c_device_id pn544_id_table[] = {
+	{ PN544_DRIVER_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, pn544_id_table);
+
+#define HCI_MODE	0
+#define FW_MODE		1
+
+enum pn544_state {
+	PN544_ST_COLD,
+	PN544_ST_FW_READY,
+	PN544_ST_READY,
+};
+
+enum pn544_irq {
+	PN544_NONE,
+	PN544_INT,
+};
+
+struct pn544_info {
+	struct miscdevice miscdev;
+	struct i2c_client *i2c_dev;
+	struct regulator_bulk_data regs[2];
+
+	enum pn544_state state;
+	wait_queue_head_t read_wait;
+	loff_t read_offset;
+	enum pn544_irq read_irq;
+	struct mutex read_mutex; /* Serialize read_irq access */
+	struct mutex mutex; /* Serialize info struct access */
+	u8 *buf;
+	unsigned int buflen;
+};
+
+static const char reg_vdd_io[]	= "Vdd_IO";
+static const char reg_vbat[]	= "VBat";
+
+/* sysfs interface */
+static ssize_t pn544_test(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct pn544_info *info = dev_get_drvdata(dev);
+	struct i2c_client *client = info->i2c_dev;
+	struct pn544_nfc_platform_data *pdata = client->dev.platform_data;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", pdata->test());
+}
+
+static int pn544_enable(struct pn544_info *info, int mode)
+{
+	struct pn544_nfc_platform_data *pdata;
+	struct i2c_client *client = info->i2c_dev;
+
+	int r;
+
+	r = regulator_bulk_enable(ARRAY_SIZE(info->regs), info->regs);
+	if (r < 0)
+		return r;
+
+	pdata = client->dev.platform_data;
+	info->read_irq = PN544_NONE;
+	if (pdata->enable)
+		pdata->enable(mode);
+
+	if (mode) {
+		info->state = PN544_ST_FW_READY;
+		dev_dbg(&client->dev, "now in FW-mode\n");
+	} else {
+		info->state = PN544_ST_READY;
+		dev_dbg(&client->dev, "now in HCI-mode\n");
+	}
+
+	usleep_range(10000, 15000);
+
+	return 0;
+}
+
+static void pn544_disable(struct pn544_info *info)
+{
+	struct pn544_nfc_platform_data *pdata;
+	struct i2c_client *client = info->i2c_dev;
+
+	pdata = client->dev.platform_data;
+	if (pdata->disable)
+		pdata->disable();
+
+	info->state = PN544_ST_COLD;
+
+	dev_dbg(&client->dev, "Now in OFF-mode\n");
+
+	msleep(PN544_RESETVEN_TIME);
+
+	info->read_irq = PN544_NONE;
+	regulator_bulk_disable(ARRAY_SIZE(info->regs), info->regs);
+}
+
+static int check_crc(u8 *buf, int buflen)
+{
+	u8 len;
+	u16 crc;
+
+	len = buf[0] + 1;
+	if (len < 4 || len != buflen || len > PN544_MSG_MAX_SIZE) {
+		pr_err(PN544_DRIVER_NAME
+		       ": CRC; corrupt packet len %u (%d)\n", len, buflen);
+		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
+			       16, 2, buf, buflen, false);
+		return -EPERM;
+	}
+	crc = crc_ccitt(0xffff, buf, len - 2);
+	crc = ~crc;
+
+	if (buf[len-2] != (crc & 0xff) || buf[len-1] != (crc >> 8)) {
+		pr_err(PN544_DRIVER_NAME ": CRC error 0x%x != 0x%x 0x%x\n",
+		       crc, buf[len-1], buf[len-2]);
+
+		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
+			       16, 2, buf, buflen, false);
+		return -EPERM;
+	}
+	return 0;
+}
+
+static int pn544_i2c_write(struct i2c_client *client, u8 *buf, int len)
+{
+	int r;
+
+	if (len < 4 || len != (buf[0] + 1)) {
+		dev_err(&client->dev, "%s: Illegal message length: %d\n",
+			__func__, len);
+		return -EINVAL;
+	}
+
+	if (check_crc(buf, len))
+		return -EINVAL;
+
+	usleep_range(3000, 6000);
+
+	r = i2c_master_send(client, buf, len);
+	dev_dbg(&client->dev, "send: %d\n", r);
+
+	if (r == -EREMOTEIO) { /* Retry, chip was in standby */
+		usleep_range(6000, 10000);
+		r = i2c_master_send(client, buf, len);
+		dev_dbg(&client->dev, "send2: %d\n", r);
+	}
+
+	if (r != len)
+		return -EREMOTEIO;
+
+	return r;
+}
+
+static int pn544_i2c_read(struct i2c_client *client, u8 *buf, int buflen)
+{
+	int r;
+	u8 len;
+
+	/*
+	 * You could read a packet in one go, but then you'd need to read
+	 * max size and rest would be 0xff fill, so we do split reads.
+	 */
+	r = i2c_master_recv(client, &len, 1);
+	dev_dbg(&client->dev, "recv1: %d\n", r);
+
+	if (r != 1)
+		return -EREMOTEIO;
+
+	if (len < PN544_LLC_HCI_OVERHEAD)
+		len = PN544_LLC_HCI_OVERHEAD;
+	else if (len > (PN544_MSG_MAX_SIZE - 1))
+		len = PN544_MSG_MAX_SIZE - 1;
+
+	if (1 + len > buflen) /* len+(data+crc16) */
+		return -EMSGSIZE;
+
+	buf[0] = len;
+
+	r = i2c_master_recv(client, buf + 1, len);
+	dev_dbg(&client->dev, "recv2: %d\n", r);
+
+	if (r != len)
+		return -EREMOTEIO;
+
+	usleep_range(3000, 6000);
+
+	return r + 1;
+}
+
+static int pn544_fw_write(struct i2c_client *client, u8 *buf, int len)
+{
+	int r;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	if (len < PN544_FW_HEADER_SIZE ||
+	    (PN544_FW_HEADER_SIZE + (buf[1] << 8) + buf[2]) != len)
+		return -EINVAL;
+
+	r = i2c_master_send(client, buf, len);
+	dev_dbg(&client->dev, "fw send: %d\n", r);
+
+	if (r == -EREMOTEIO) { /* Retry, chip was in standby */
+		usleep_range(6000, 10000);
+		r = i2c_master_send(client, buf, len);
+		dev_dbg(&client->dev, "fw send2: %d\n", r);
+	}
+
+	if (r != len)
+		return -EREMOTEIO;
+
+	return r;
+}
+
+static int pn544_fw_read(struct i2c_client *client, u8 *buf, int buflen)
+{
+	int r, len;
+
+	if (buflen < PN544_FW_HEADER_SIZE)
+		return -EINVAL;
+
+	r = i2c_master_recv(client, buf, PN544_FW_HEADER_SIZE);
+	dev_dbg(&client->dev, "FW recv1: %d\n", r);
+
+	if (r < 0)
+		return r;
+
+	if (r < PN544_FW_HEADER_SIZE)
+		return -EINVAL;
+
+	len = (buf[1] << 8) + buf[2];
+	if (len == 0) /* just header, no additional data */
+		return r;
+
+	if (len > buflen - PN544_FW_HEADER_SIZE)
+		return -EMSGSIZE;
+
+	r = i2c_master_recv(client, buf + PN544_FW_HEADER_SIZE, len);
+	dev_dbg(&client->dev, "fw recv2: %d\n", r);
+
+	if (r != len)
+		return -EINVAL;
+
+	return r + PN544_FW_HEADER_SIZE;
+}
+
+static irqreturn_t pn544_irq_thread_fn(int irq, void *dev_id)
+{
+	struct pn544_info *info = dev_id;
+	struct i2c_client *client = info->i2c_dev;
+
+	BUG_ON(!info);
+	BUG_ON(irq != info->i2c_dev->irq);
+
+	dev_dbg(&client->dev, "IRQ\n");
+
+	mutex_lock(&info->read_mutex);
+	info->read_irq = PN544_INT;
+	mutex_unlock(&info->read_mutex);
+
+	wake_up_interruptible(&info->read_wait);
+
+	return IRQ_HANDLED;
+}
+
+static enum pn544_irq pn544_irq_state(struct pn544_info *info)
+{
+	enum pn544_irq irq;
+
+	mutex_lock(&info->read_mutex);
+	irq = info->read_irq;
+	mutex_unlock(&info->read_mutex);
+	/*
+	 * XXX: should we check GPIO-line status directly?
+	 * return pdata->irq_status() ? PN544_INT : PN544_NONE;
+	 */
+
+	return irq;
+}
+
+static ssize_t pn544_read(struct file *file, char __user *buf,
+			  size_t count, loff_t *offset)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+	enum pn544_irq irq;
+	size_t len;
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s: info: %p, count: %zu\n", __func__,
+		info, count);
+
+	mutex_lock(&info->mutex);
+
+	if (info->state == PN544_ST_COLD) {
+		r = -ENODEV;
+		goto out;
+	}
+
+	irq = pn544_irq_state(info);
+	if (irq == PN544_NONE) {
+		if (file->f_flags & O_NONBLOCK) {
+			r = -EAGAIN;
+			goto out;
+		}
+
+		if (wait_event_interruptible(info->read_wait,
+					     (info->read_irq == PN544_INT))) {
+			r = -ERESTARTSYS;
+			goto out;
+		}
+	}
+
+	if (info->state == PN544_ST_FW_READY) {
+		len = min(count, info->buflen);
+
+		mutex_lock(&info->read_mutex);
+		r = pn544_fw_read(info->i2c_dev, info->buf, len);
+		info->read_irq = PN544_NONE;
+		mutex_unlock(&info->read_mutex);
+
+		if (r < 0) {
+			dev_err(&info->i2c_dev->dev, "FW read failed: %d\n", r);
+			goto out;
+		}
+
+		print_hex_dump(KERN_DEBUG, "FW read: ", DUMP_PREFIX_NONE,
+			       16, 2, info->buf, r, false);
+
+		*offset += r;
+		if (copy_to_user(buf, info->buf, r)) {
+			r = -EFAULT;
+			goto out;
+		}
+	} else {
+		len = min(count, info->buflen);
+
+		mutex_lock(&info->read_mutex);
+		r = pn544_i2c_read(info->i2c_dev, info->buf, len);
+		info->read_irq = PN544_NONE;
+		mutex_unlock(&info->read_mutex);
+
+		if (r < 0) {
+			dev_err(&info->i2c_dev->dev, "read failed (%d)\n", r);
+			goto out;
+		}
+		print_hex_dump(KERN_DEBUG, "read: ", DUMP_PREFIX_NONE,
+			       16, 2, info->buf, r, false);
+
+		*offset += r;
+		if (copy_to_user(buf, info->buf, r)) {
+			r = -EFAULT;
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&info->mutex);
+
+	return r;
+}
+
+static unsigned int pn544_poll(struct file *file, poll_table *wait)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s: info: %p\n", __func__, info);
+
+	mutex_lock(&info->mutex);
+
+	if (info->state == PN544_ST_COLD) {
+		r = -ENODEV;
+		goto out;
+	}
+
+	poll_wait(file, &info->read_wait, wait);
+
+	if (pn544_irq_state(info) == PN544_INT) {
+		r = POLLIN | POLLRDNORM;
+		goto out;
+	}
+out:
+	mutex_unlock(&info->mutex);
+
+	return r;
+}
+
+static ssize_t pn544_write(struct file *file, const char __user *buf,
+			   size_t count, loff_t *ppos)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+	ssize_t	len;
+	int r;
+
+	dev_dbg(&client->dev, "%s: info: %p, count %zu\n", __func__,
+		info, count);
+
+	mutex_lock(&info->mutex);
+
+	if (info->state == PN544_ST_COLD) {
+		r = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * XXX: should we detect rset-writes and clean possible
+	 * read_irq state
+	 */
+	if (info->state == PN544_ST_FW_READY) {
+		size_t fw_len;
+
+		if (count < PN544_FW_HEADER_SIZE) {
+			r = -EINVAL;
+			goto out;
+		}
+
+		len = min(count, info->buflen);
+		if (copy_from_user(info->buf, buf, len)) {
+			r = -EFAULT;
+			goto out;
+		}
+
+		print_hex_dump(KERN_DEBUG, "FW write: ", DUMP_PREFIX_NONE,
+			       16, 2, info->buf, len, false);
+
+		fw_len = PN544_FW_HEADER_SIZE + (info->buf[1] << 8) +
+			info->buf[2];
+
+		if (len > fw_len) /* 1 msg at a time */
+			len = fw_len;
+
+		r = pn544_fw_write(info->i2c_dev, info->buf, len);
+	} else {
+		if (count < PN544_LLC_MIN_SIZE) {
+			r = -EINVAL;
+			goto out;
+		}
+
+		len = min(count, info->buflen);
+		if (copy_from_user(info->buf, buf, len)) {
+			r = -EFAULT;
+			goto out;
+		}
+
+		print_hex_dump(KERN_DEBUG, "write: ", DUMP_PREFIX_NONE,
+			       16, 2, info->buf, len, false);
+
+		if (len > (info->buf[0] + 1)) /* 1 msg at a time */
+			len  = info->buf[0] + 1;
+
+		r = pn544_i2c_write(info->i2c_dev, info->buf, len);
+	}
+out:
+	mutex_unlock(&info->mutex);
+
+	return r;
+
+}
+
+static long pn544_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+	struct pn544_nfc_platform_data *pdata;
+	unsigned int val;
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s: info: %p, cmd: 0x%x\n", __func__, info, cmd);
+
+	mutex_lock(&info->mutex);
+
+	if (info->state == PN544_ST_COLD) {
+		r = -ENODEV;
+		goto out;
+	}
+
+	pdata = info->i2c_dev->dev.platform_data;
+	switch (cmd) {
+	case PN544_GET_FW_MODE:
+		dev_dbg(&client->dev, "%s:  PN544_GET_FW_MODE\n", __func__);
+
+		val = (info->state == PN544_ST_FW_READY);
+		if (copy_to_user((void __user *)arg, &val, sizeof(val))) {
+			r = -EFAULT;
+			goto out;
+		}
+
+		break;
+
+	case PN544_SET_FW_MODE:
+		dev_dbg(&client->dev, "%s:  PN544_SET_FW_MODE\n", __func__);
+
+		if (copy_from_user(&val, (void __user *)arg, sizeof(val))) {
+			r = -EFAULT;
+			goto out;
+		}
+
+		if (val) {
+			if (info->state == PN544_ST_FW_READY)
+				break;
+
+			pn544_disable(info);
+			r = pn544_enable(info, FW_MODE);
+			if (r < 0)
+				goto out;
+		} else {
+			if (info->state == PN544_ST_READY)
+				break;
+			pn544_disable(info);
+			r = pn544_enable(info, HCI_MODE);
+			if (r < 0)
+				goto out;
+		}
+		file->f_pos = info->read_offset;
+		break;
+
+	case TCGETS:
+		dev_dbg(&client->dev, "%s:  TCGETS\n", __func__);
+
+		r = -ENOIOCTLCMD;
+		break;
+
+	default:
+		dev_err(&client->dev, "Unknown ioctl 0x%x\n", cmd);
+		r = -ENOIOCTLCMD;
+		break;
+	}
+
+out:
+	mutex_unlock(&info->mutex);
+
+	return r;
+}
+
+static int pn544_open(struct inode *inode, struct file *file)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s: info: %p, client %p\n", __func__,
+		info, info->i2c_dev);
+
+	mutex_lock(&info->mutex);
+
+	/*
+	 * Only 1 at a time.
+	 * XXX: maybe user (counter) would work better
+	 */
+	if (info->state != PN544_ST_COLD) {
+		r = -EBUSY;
+		goto out;
+	}
+
+	file->f_pos = info->read_offset;
+	r = pn544_enable(info, HCI_MODE);
+
+out:
+	mutex_unlock(&info->mutex);
+	return r;
+}
+
+static int pn544_close(struct inode *inode, struct file *file)
+{
+	struct pn544_info *info = container_of(file->private_data,
+					       struct pn544_info, miscdev);
+	struct i2c_client *client = info->i2c_dev;
+
+	dev_dbg(&client->dev, "%s: info: %p, client %p\n",
+		__func__, info, info->i2c_dev);
+
+	mutex_lock(&info->mutex);
+	pn544_disable(info);
+	mutex_unlock(&info->mutex);
+
+	return 0;
+}
+
+static const struct file_operations pn544_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.read		= pn544_read,
+	.write		= pn544_write,
+	.poll		= pn544_poll,
+	.open		= pn544_open,
+	.release	= pn544_close,
+	.unlocked_ioctl	= pn544_ioctl,
+};
+
+#ifdef CONFIG_PM
+static int pn544_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pn544_info *info;
+	int r = 0;
+
+	dev_info(&client->dev, "***\n%s: client %p\n***\n", __func__, client);
+
+	info = i2c_get_clientdata(client);
+	dev_info(&client->dev, "%s: info: %p, client %p\n", __func__,
+		 info, client);
+
+	mutex_lock(&info->mutex);
+
+	switch (info->state) {
+	case PN544_ST_FW_READY:
+		/* Do not suspend while upgrading FW, please! */
+		r = -EPERM;
+		break;
+
+	case PN544_ST_READY:
+		/*
+		 * CHECK: Device should be in standby-mode. No way to check?
+		 * Allowing low power mode for the regulator is potentially
+		 * dangerous if pn544 does not go to suspension.
+		 */
+		break;
+
+	case PN544_ST_COLD:
+		break;
+	};
+
+	mutex_unlock(&info->mutex);
+	return r;
+}
+
+static int pn544_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct pn544_info *info = i2c_get_clientdata(client);
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s: info: %p, client %p\n", __func__,
+		info, client);
+
+	mutex_lock(&info->mutex);
+
+	switch (info->state) {
+	case PN544_ST_READY:
+		/*
+		 * CHECK: If regulator low power mode is allowed in
+		 * pn544_suspend, we should go back to normal mode
+		 * here.
+		 */
+		break;
+
+	case PN544_ST_COLD:
+		break;
+
+	case PN544_ST_FW_READY:
+		break;
+	};
+
+	mutex_unlock(&info->mutex);
+
+	return r;
+}
+
+static SIMPLE_DEV_PM_OPS(pn544_pm_ops, pn544_suspend, pn544_resume);
+#endif
+
+static struct device_attribute pn544_attr =
+	__ATTR(nfc_test, S_IRUGO, pn544_test, NULL);
+
+static int __devinit pn544_probe(struct i2c_client *client,
+				 const struct i2c_device_id *id)
+{
+	struct pn544_info *info;
+	struct pn544_nfc_platform_data *pdata;
+	int r = 0;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
+
+	/* private data allocation */
+	info = kzalloc(sizeof(struct pn544_info), GFP_KERNEL);
+	if (!info) {
+		dev_err(&client->dev,
+			"Cannot allocate memory for pn544_info.\n");
+		r = -ENOMEM;
+		goto err_info_alloc;
+	}
+
+	info->buflen = max(PN544_MSG_MAX_SIZE, PN544_MAX_I2C_TRANSFER);
+	info->buf = kzalloc(info->buflen, GFP_KERNEL);
+	if (!info->buf) {
+		dev_err(&client->dev,
+			"Cannot allocate memory for pn544_info->buf.\n");
+		r = -ENOMEM;
+		goto err_buf_alloc;
+	}
+
+	info->regs[0].supply = reg_vdd_io;
+	info->regs[1].supply = reg_vbat;
+	r = regulator_bulk_get(&client->dev, ARRAY_SIZE(info->regs),
+				 info->regs);
+	if (r < 0)
+		goto err_kmalloc;
+
+	info->i2c_dev = client;
+	info->state = PN544_ST_COLD;
+	info->read_irq = PN544_NONE;
+	mutex_init(&info->read_mutex);
+	mutex_init(&info->mutex);
+	init_waitqueue_head(&info->read_wait);
+	i2c_set_clientdata(client, info);
+	pdata = client->dev.platform_data;
+	if (!pdata) {
+		dev_err(&client->dev, "No platform data\n");
+		r = -EINVAL;
+		goto err_reg;
+	}
+
+	if (!pdata->request_resources) {
+		dev_err(&client->dev, "request_resources() missing\n");
+		r = -EINVAL;
+		goto err_reg;
+	}
+
+	r = pdata->request_resources(client);
+	if (r) {
+		dev_err(&client->dev, "Cannot get platform resources\n");
+		goto err_reg;
+	}
+
+	r = request_threaded_irq(client->irq, NULL, pn544_irq_thread_fn,
+				 IRQF_TRIGGER_RISING, PN544_DRIVER_NAME,
+				 info);
+	if (r < 0) {
+		dev_err(&client->dev, "Unable to register IRQ handler\n");
+		goto err_res;
+	}
+
+	/* If we don't have the test we don't need the sysfs file */
+	if (pdata->test) {
+		r = device_create_file(&client->dev, &pn544_attr);
+		if (r) {
+			dev_err(&client->dev,
+				"sysfs registration failed, error %d\n", r);
+			goto err_irq;
+		}
+	}
+
+	info->miscdev.minor = MISC_DYNAMIC_MINOR;
+	info->miscdev.name = PN544_DRIVER_NAME;
+	info->miscdev.fops = &pn544_fops;
+	info->miscdev.parent = &client->dev;
+	r = misc_register(&info->miscdev);
+	if (r < 0) {
+		dev_err(&client->dev, "Device registration failed\n");
+		goto err_sysfs;
+	}
+
+	dev_dbg(&client->dev, "%s: info: %p, pdata %p, client %p\n",
+		__func__, info, pdata, client);
+
+	return 0;
+
+err_sysfs:
+	if (pdata->test)
+		device_remove_file(&client->dev, &pn544_attr);
+err_irq:
+	free_irq(client->irq, info);
+err_res:
+	if (pdata->free_resources)
+		pdata->free_resources();
+err_reg:
+	regulator_bulk_free(ARRAY_SIZE(info->regs), info->regs);
+err_kmalloc:
+	kfree(info->buf);
+err_buf_alloc:
+	kfree(info);
+err_info_alloc:
+	return r;
+}
+
+static __devexit int pn544_remove(struct i2c_client *client)
+{
+	struct pn544_info *info = i2c_get_clientdata(client);
+	struct pn544_nfc_platform_data *pdata = client->dev.platform_data;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	misc_deregister(&info->miscdev);
+	if (pdata->test)
+		device_remove_file(&client->dev, &pn544_attr);
+
+	if (info->state != PN544_ST_COLD) {
+		if (pdata->disable)
+			pdata->disable();
+
+		info->read_irq = PN544_NONE;
+	}
+
+	free_irq(client->irq, info);
+	if (pdata->free_resources)
+		pdata->free_resources();
+
+	regulator_bulk_free(ARRAY_SIZE(info->regs), info->regs);
+	kfree(info->buf);
+	kfree(info);
+
+	return 0;
+}
+
+static struct i2c_driver pn544_driver = {
+	.driver = {
+		.name = PN544_DRIVER_NAME,
+#ifdef CONFIG_PM
+		.pm = &pn544_pm_ops,
+#endif
+	},
+	.probe = pn544_probe,
+	.id_table = pn544_id_table,
+	.remove = __devexit_p(pn544_remove),
+};
+
+static int __init pn544_init(void)
+{
+	int r;
+
+	pr_debug(DRIVER_DESC ": %s\n", __func__);
+
+	r = i2c_add_driver(&pn544_driver);
+	if (r) {
+		pr_err(PN544_DRIVER_NAME ": driver registration failed\n");
+		return r;
+	}
+
+	return 0;
+}
+
+static void __exit pn544_exit(void)
+{
+	i2c_del_driver(&pn544_driver);
+	pr_info(DRIVER_DESC ", Exiting.\n");
+}
+
+module_init(pn544_init);
+module_exit(pn544_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);

include/linux/nfc/pn544.h

···
+/*
+ * Driver include for the PN544 NFC chip.
+ *
+ * Copyright (C) Nokia Corporation
+ *
+ * Author: Jari Vanhala <[e-mail]>
+ * Contact: Matti Aaltoenn <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _PN544_H_
+#define _PN544_H_
+
+#include <linux/i2c.h>
+
+#define PN544_DRIVER_NAME	"pn544"
+#define PN544_MAXWINDOW_SIZE	7
+#define PN544_WINDOW_SIZE	4
+#define PN544_RETRIES		10
+#define PN544_MAX_I2C_TRANSFER	0x0400
+#define PN544_MSG_MAX_SIZE	0x21 /* at normal HCI mode */
+
+/* ioctl */
+#define PN544_CHAR_BASE		'P'
+#define PN544_IOR(num, dtype)	_IOR(PN544_CHAR_BASE, num, dtype)
+#define PN544_IOW(num, dtype)	_IOW(PN544_CHAR_BASE, num, dtype)
+#define PN544_GET_FW_MODE	PN544_IOW(1, unsigned int)
+#define PN544_SET_FW_MODE	PN544_IOW(2, unsigned int)
+#define PN544_GET_DEBUG		PN544_IOW(3, unsigned int)
+#define PN544_SET_DEBUG		PN544_IOW(4, unsigned int)
+
+/* Timing restrictions (ms) */
+#define PN544_RESETVEN_TIME	30 /* 7 */
+#define PN544_PVDDVEN_TIME	0
+#define PN544_VBATVEN_TIME	0
+#define PN544_GPIO4VEN_TIME	0
+#define PN544_WAKEUP_ACK	5
+#define PN544_WAKEUP_GUARD	(PN544_WAKEUP_ACK + 1)
+#define PN544_INACTIVITY_TIME	1000
+#define PN544_INTERFRAME_DELAY	200 /* us */
+#define PN544_BAUDRATE_CHANGE	150 /* us */
+
+/* Debug bits */
+#define PN544_DEBUG_BUF		0x01
+#define PN544_DEBUG_READ	0x02
+#define PN544_DEBUG_WRITE	0x04
+#define PN544_DEBUG_IRQ		0x08
+#define PN544_DEBUG_CALLS	0x10
+#define PN544_DEBUG_MODE	0x20
+
+/* Normal (HCI) mode */
+#define PN544_LLC_HCI_OVERHEAD	3 /* header + crc (to length) */
+#define PN544_LLC_MIN_SIZE	(1 + PN544_LLC_HCI_OVERHEAD) /* length + */
+#define PN544_LLC_MAX_DATA	(PN544_MSG_MAX_SIZE - 2)
+#define PN544_LLC_MAX_HCI_SIZE	(PN544_LLC_MAX_DATA - 2)
+
+struct pn544_llc_packet {
+	unsigned char length; /* of rest of packet */
+	unsigned char header;
+	unsigned char data[PN544_LLC_MAX_DATA]; /* includes crc-ccitt */
+};
+
+/* Firmware upgrade mode */
+#define PN544_FW_HEADER_SIZE	3
+/* max fw transfer is 1024bytes, but I2C limits it to 0xC0 */
+#define PN544_MAX_FW_DATA	(PN544_MAX_I2C_TRANSFER - PN544_FW_HEADER_SIZE)
+
+struct pn544_fw_packet {
+	unsigned char command; /* status in answer */
+	unsigned char length[2]; /* big-endian order (msf) */
+	unsigned char data[PN544_MAX_FW_DATA];
+};
+
+#ifdef __KERNEL__
+/* board config */
+struct pn544_nfc_platform_data {
+	int (*request_resources) (struct i2c_client *client);
+	void (*free_resources) (void);
+	void (*enable) (int fw);
+	int (*test) (void);
+	void (*disable) (void);
+};
+#endif /* __KERNEL__ */
+
+#endif /* _PN544_H_ */