Add MAX11802 touchscreeen driver from Petteri Aimonen

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5237 42af7a65-404d-4744-a932-0658087f49c3

6 files changed, 1669 insertions, 2 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index ad6521a9e..bfae8e367 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -3477,4 +3477,7 @@
 	* include/termios.h and lib/termios/libcf*speed.c: The non-standard,
 	  "hidden" c_speed cannot be type const or else static instantiations
 	  of termios will be required to initialize it (Mike Smith).
+	* drivers/input/max11802.c/h, and include/nuttx/input max11802.h:  Adds
+	  support for the Maxim MAX11802 touchscreen controller (contributed by
+	  Petteri Aimonen).
 
diff --git a/nuttx/drivers/input/Make.defs b/nuttx/drivers/input/Make.defs
index 6dbae268e..8b009760c 100644
--- a/nuttx/drivers/input/Make.defs
+++ b/nuttx/drivers/input/Make.defs
@@ -47,6 +47,10 @@ ifeq ($(CONFIG_INPUT_ADS7843E),y)
   CSRCS += ads7843e.c
 endif
 
+ifeq ($(CONFIG_INPUT_MAX11802),y)
+  CSRCS += max11802.c
+endif
+
 ifeq ($(CONFIG_INPUT_STMPE811),y)
   CSRCS += stmpe811_base.c
 ifneq ($(CONFIG_INPUT_STMPE811_TSC_DISABLE),y)
diff --git a/nuttx/drivers/input/max11802.c b/nuttx/drivers/input/max11802.c
new file mode 100644
index 000000000..ea3883cd0
--- /dev/null
+++ b/nuttx/drivers/input/max11802.c
@@ -0,0 +1,1313 @@
+/****************************************************************************
+ * drivers/input/max11802.c
+ *
+ *   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+ *   Authors: Gregory Nutt <gnutt@nuttx.org>
+ *            Petteri Aimonen <jpa@nx.mail.kapsi.fi>
+ *
+ * References:
+ *   "Low-Power, Ultra-Small Resistive Touch-Screen Controllers
+ *    with I2C/SPI Interface" Maxim IC, Rev 3, 10/2010
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <semaphore.h>
+#include <poll.h>
+#include <wdog.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/arch.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/spi.h>
+#include <nuttx/wqueue.h>
+
+#include <nuttx/input/touchscreen.h>
+#include <nuttx/input/max11802.h>
+
+#include "max11802.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* This is a value for the threshold that guantees a big difference on the
+ * first pendown (but can't overflow).
+ */
+
+#define INVALID_THRESHOLD 0x1000
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+/* Low-level SPI helpers */
+
+#ifdef CONFIG_SPI_OWNBUS
+static inline void max11802_configspi(FAR struct spi_dev_s *spi);
+#  define max11802_lock(spi)
+#  define max11802_unlock(spi)
+#else
+#  define max11802_configspi(spi);
+static void max11802_lock(FAR struct spi_dev_s *spi);
+static void max11802_unlock(FAR struct spi_dev_s *spi);
+#endif
+
+static uint16_t max11802_sendcmd(FAR struct max11802_dev_s *priv, uint8_t cmd, int *tags);
+
+/* Interrupts and data sampling */
+
+static void max11802_notify(FAR struct max11802_dev_s *priv);
+static int max11802_sample(FAR struct max11802_dev_s *priv,
+                           FAR struct max11802_sample_s *sample);
+static int max11802_waitsample(FAR struct max11802_dev_s *priv,
+                               FAR struct max11802_sample_s *sample);
+static void max11802_worker(FAR void *arg);
+static int max11802_interrupt(int irq, FAR void *context);
+
+/* Character driver methods */
+
+static int max11802_open(FAR struct file *filep);
+static int max11802_close(FAR struct file *filep);
+static ssize_t max11802_read(FAR struct file *filep, FAR char *buffer, size_t len);
+static int max11802_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
+#ifndef CONFIG_DISABLE_POLL
+static int max11802_poll(FAR struct file *filep, struct pollfd *fds, bool setup);
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* This the the vtable that supports the character driver interface */
+
+static const struct file_operations max11802_fops =
+{
+  max11802_open,    /* open */
+  max11802_close,   /* close */
+  max11802_read,    /* read */
+  0,                /* write */
+  0,                /* seek */
+  max11802_ioctl    /* ioctl */
+#ifndef CONFIG_DISABLE_POLL
+  , max11802_poll   /* poll */
+#endif
+};
+
+/* If only a single MAX11802 device is supported, then the driver state
+ * structure may as well be pre-allocated.
+ */
+
+#ifndef CONFIG_MAX11802_MULTIPLE
+static struct max11802_dev_s g_max11802;
+
+/* Otherwise, we will need to maintain allocated driver instances in a list */
+
+#else
+static struct max11802_dev_s *g_max11802list;
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: max11802_lock
+ *
+ * Description:
+ *   Lock the SPI bus and re-configure as necessary.  This function must be
+ *   to assure: (1) exclusive access to the SPI bus, and (2) to assure that
+ *   the shared bus is properly configured for the touchscreen controller.
+ *
+ * Parameters:
+ *   spi  - Reference to the SPI driver structure
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_SPI_OWNBUS
+static void max11802_lock(FAR struct spi_dev_s *spi)
+{
+  /* Lock the SPI bus because there are multiple devices competing for the
+   * SPI bus
+   */
+
+  (void)SPI_LOCK(spi, true);
+
+  /* We have the lock.  Now make sure that the SPI bus is configured for the
+   * MAX11802 (it might have gotten configured for a different device while
+   * unlocked)
+   */
+
+  SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true);
+  SPI_SETMODE(spi, CONFIG_MAX11802_SPIMODE);
+  SPI_SETBITS(spi, 8);
+  SPI_SETFREQUENCY(spi, CONFIG_MAX11802_FREQUENCY);
+  SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false);
+}
+#endif
+
+/****************************************************************************
+ * Function: max11802_unlock
+ *
+ * Description:
+ *   If we are sharing the SPI bus with other devices (CONFIG_SPI_OWNBUS
+ *   undefined) then we need to un-lock the SPI bus for each transfer,
+ *   possibly losing the current configuration.
+ *
+ * Parameters:
+ *   spi  - Reference to the SPI driver structure
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_SPI_OWNBUS
+static void max11802_unlock(FAR struct spi_dev_s *spi)
+{
+  /* Relinquish the SPI bus. */
+
+  (void)SPI_LOCK(spi, false);
+}
+#endif
+
+/****************************************************************************
+ * Function: max11802_configspi
+ *
+ * Description:
+ *   Configure the SPI for use with the MAX11802.  This function should be
+ *   called once during touchscreen initialization to configure the SPI
+ *   bus.  Note that if CONFIG_SPI_OWNBUS is not defined, then this function
+ *   does nothing.
+ *
+ * Parameters:
+ *   spi  - Reference to the SPI driver structure
+ *
+ * Returned Value:
+ *   None
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_SPI_OWNBUS
+static inline void max11802_configspi(FAR struct spi_dev_s *spi)
+{
+  /* Configure SPI for the MAX11802.  But only if we own the SPI bus.  Otherwise, don't
+   * bother because it might change.
+   */
+
+  SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, true);
+  SPI_SETMODE(spi, CONFIG_MAX11802_SPIMODE);
+  SPI_SETBITS(spi, 8);
+  SPI_SETFREQUENCY(spi, CONFIG_MAX11802_FREQUENCY);
+  SPI_SELECT(spi, SPIDEV_TOUCHSCREEN, false);
+}
+#endif
+
+/****************************************************************************
+ * Name: max11802_sendcmd
+ ****************************************************************************/
+
+static uint16_t max11802_sendcmd(FAR struct max11802_dev_s *priv, uint8_t cmd, int *tags)
+{
+  uint8_t  buffer[2];
+  uint16_t result;
+
+  /* Select the MAX11802 */
+
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+
+  /* Send the command */
+
+  (void)SPI_SEND(priv->spi, cmd);
+  
+  /* Read the data */
+
+  SPI_RECVBLOCK(priv->spi, buffer, 2);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+
+  result = ((uint16_t)buffer[0] << 8) | (uint16_t)buffer[1];
+  *tags = result & 0xF;
+  result >>= 4; // Get rid of tags
+  
+  ivdbg("cmd:%02x response:%04x\n", cmd, result);
+  return result;
+}
+
+/****************************************************************************
+ * Name: max11802_notify
+ ****************************************************************************/
+
+static void max11802_notify(FAR struct max11802_dev_s *priv)
+{
+#ifndef CONFIG_DISABLE_POLL
+  int i;
+#endif
+
+  /* If there are threads waiting for read data, then signal one of them
+   * that the read data is available.
+   */
+
+  if (priv->nwaiters > 0)
+    {
+      /* After posting this semaphore, we need to exit because the sample
+       * is no longer available.
+       */
+
+      sem_post(&priv->waitsem); 
+    }
+
+  /* If there are threads waiting on poll() for MAX11802 data to become available,
+   * then wake them up now.  NOTE: we wake up all waiting threads because we
+   * do not know that they are going to do.  If they all try to read the data,
+   * then some make end up blocking after all.
+   */
+
+#ifndef CONFIG_DISABLE_POLL
+  for (i = 0; i < CONFIG_MAX11802_NPOLLWAITERS; i++)
+    {
+      struct pollfd *fds = priv->fds[i];
+      if (fds)
+        {
+          fds->revents |= POLLIN;
+          ivdbg("Report events: %02x\n", fds->revents);
+          sem_post(fds->sem);
+        }
+    }
+#endif
+}
+
+/****************************************************************************
+ * Name: max11802_sample
+ ****************************************************************************/
+
+static int max11802_sample(FAR struct max11802_dev_s *priv,
+                          FAR struct max11802_sample_s *sample)
+{
+  irqstate_t flags;
+  int ret = -EAGAIN;
+
+  /* Interrupts must be disabled when this is called to (1) prevent posting
+   * of semaphores from interrupt handlers, and (2) to prevent sampled data
+   * from changing until it has been reported.
+   */
+
+  flags = irqsave();
+
+  /* Is there new MAX11802 sample data available? */
+
+  if (priv->penchange)
+    {
+      /* Yes.. the state has changed in some way.  Return a copy of the
+       * sampled data.
+       */
+
+      memcpy(sample, &priv->sample, sizeof(struct max11802_sample_s ));
+
+      /* Now manage state transitions */
+
+      if (sample->contact == CONTACT_UP)
+        {
+          /* Next.. no contact.  Increment the ID so that next contact ID
+           * will be unique.  X/Y positions are no longer valid.
+           */
+
+          priv->sample.contact = CONTACT_NONE;
+          priv->sample.valid   = false;
+          priv->id++;
+        }
+      else if (sample->contact == CONTACT_DOWN)
+       {
+          /* First report -- next report will be a movement */
+
+         priv->sample.contact = CONTACT_MOVE;
+       }
+
+      priv->penchange = false;
+      ret = OK;
+    }
+
+  irqrestore(flags);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max11802_waitsample
+ ****************************************************************************/
+
+static int max11802_waitsample(FAR struct max11802_dev_s *priv,
+                               FAR struct max11802_sample_s *sample)
+{
+  irqstate_t flags;
+  int ret;
+
+  /* Interrupts must be disabled when this is called to (1) prevent posting
+   * of semaphores from interrupt handlers, and (2) to prevent sampled data
+   * from changing until it has been reported.
+   *
+   * In addition, we will also disable pre-emption to prevent other threads
+   * from getting control while we muck with the semaphores.
+   */
+
+  sched_lock();
+  flags = irqsave();
+
+  /* Now release the semaphore that manages mutually exclusive access to
+   * the device structure.  This may cause other tasks to become ready to
+   * run, but they cannot run yet because pre-emption is disabled.
+   */
+
+  sem_post(&priv->devsem);
+
+  /* Try to get the a sample... if we cannot, then wait on the semaphore
+   * that is posted when new sample data is available.
+   */
+
+  while (max11802_sample(priv, sample) < 0)
+    {
+      /* Wait for a change in the MAX11802 state */
+ 
+      ivdbg("Waiting..\n");
+      priv->nwaiters++;
+      ret = sem_wait(&priv->waitsem);
+      priv->nwaiters--;
+
+      if (ret < 0)
+        {
+          /* If we are awakened by a signal, then we need to return
+           * the failure now.
+           */
+
+          idbg("sem_wait: %d\n", errno);
+          DEBUGASSERT(errno == EINTR);
+          ret = -EINTR;
+          goto errout;
+        }
+    }
+
+  ivdbg("Sampled\n");
+
+   /* Re-acquire the the semaphore that manages mutually exclusive access to
+   * the device structure.  We may have to wait here.  But we have our sample.
+   * Interrupts and pre-emption will be re-enabled while we wait.
+   */
+
+  ret = sem_wait(&priv->devsem);
+
+errout:
+  /* Then re-enable interrupts.  We might get interrupt here and there
+   * could be a new sample.  But no new threads will run because we still
+   * have pre-emption disabled.
+   */
+
+  irqrestore(flags);
+
+  /* Restore pre-emption.  We might get suspended here but that is okay
+   * because we already have our sample.  Note:  this means that if there
+   * were two threads reading from the MAX11802 for some reason, the data
+   * might be read out of order.
+   */
+
+  sched_unlock();
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max11802_schedule
+ ****************************************************************************/
+
+static int max11802_schedule(FAR struct max11802_dev_s *priv)
+{
+  FAR struct max11802_config_s *config;
+  int                           ret;
+
+  /* Get a pointer the callbacks for convenience (and so the code is not so
+   * ugly).
+   */
+
+  config = priv->config;
+  DEBUGASSERT(config != NULL);
+
+  /* Disable further interrupts.  MAX11802 interrupts will be re-enabled
+   * after the worker thread executes.
+   */
+
+  config->enable(config, false);
+
+  /* Disable the watchdog timer.  It will be re-enabled in the worker thread
+   * while the pen remains down.
+   */
+
+  wd_cancel(priv->wdog);
+
+  /* Transfer processing to the worker thread.  Since MAX11802 interrupts are
+   * disabled while the work is pending, no special action should be required
+   * to protected the work queue.
+   */
+
+  DEBUGASSERT(priv->work.worker == NULL);
+  ret = work_queue(HPWORK, &priv->work, max11802_worker, priv, 0);
+  if (ret != 0)
+    {
+      illdbg("Failed to queue work: %d\n", ret);
+    }
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: max11802_wdog
+ ****************************************************************************/
+
+static void max11802_wdog(int argc, uint32_t arg1, ...)
+{
+  FAR struct max11802_dev_s *priv = (FAR struct max11802_dev_s *)((uintptr_t)arg1);
+  (void)max11802_schedule(priv);
+}
+
+/****************************************************************************
+ * Name: max11802_worker
+ ****************************************************************************/
+
+static void max11802_worker(FAR void *arg)
+{
+  FAR struct max11802_dev_s    *priv = (FAR struct max11802_dev_s *)arg;
+  FAR struct max11802_config_s *config;
+  uint16_t                      x;
+  uint16_t                      y;
+  uint16_t                      xdiff;
+  uint16_t                      ydiff;
+  bool                          pendown;
+  int                           ret;
+  int                           tags, tags2;
+
+  ASSERT(priv != NULL);
+
+  /* Get a pointer the callbacks for convenience (and so the code is not so
+   * ugly).
+   */
+
+  config = priv->config;
+  DEBUGASSERT(config != NULL);
+
+  /* Disable the watchdog timer.  This is safe because it is started only
+   * by this function and this function is serialized on the worker thread.
+   */
+
+  wd_cancel(priv->wdog);
+
+  /* Lock the SPI bus so that we have exclusive access */
+
+  max11802_lock(priv->spi);
+  
+  /* Start coordinate measurement */
+  (void)max11802_sendcmd(priv, MAX11802_CMD_MEASUREXY, &tags);
+  
+  /* Get exclusive access to the driver data structure */
+
+  do
+    {
+      ret = sem_wait(&priv->devsem);
+
+      /* This should only fail if the wait was canceled by an signal
+       * (and the worker thread will receive a lot of signals).
+       */
+
+      DEBUGASSERT(ret == OK || errno == EINTR);
+    }
+  while (ret < 0);
+
+  /* Check for pen up or down by reading the PENIRQ GPIO. */
+
+  pendown = config->pendown(config);
+
+  /* Handle the change from pen down to pen up */
+
+  if (pendown)
+    ivdbg("\nPD\n");
+  else
+    ivdbg("\nPU\n");
+  
+  if (!pendown)
+    {
+      /* The pen is up.. reset thresholding variables. */
+
+      priv->threshx = INVALID_THRESHOLD;
+      priv->threshy = INVALID_THRESHOLD;
+
+      /* Ignore the interrupt if the pen was already up (CONTACT_NONE == pen up
+       * and already reported; CONTACT_UP == pen up, but not reported)
+       */
+
+      ivdbg("\nPC%d\n", priv->sample.contact);
+      
+      if (priv->sample.contact == CONTACT_NONE ||
+          priv->sample.contact == CONTACT_UP)
+
+        {
+          goto ignored;
+        }
+
+      /* The pen is up.  NOTE: We know from a previous test, that this is a
+       * loss of contact condition.  This will be changed to CONTACT_NONE
+       * after the loss of contact is sampled.
+       */
+
+       priv->sample.contact = CONTACT_UP;
+    }
+
+  /* It is a pen down event.  If the last loss-of-contact event has not been
+   * processed yet, then we have to ignore the pen down event (or else it will
+   * look like a drag event)
+   */
+
+  else if (priv->sample.contact == CONTACT_UP)
+    {
+      /* If we have not yet processed the last pen up event, then we
+       * cannot handle this pen down event. We will have to discard it.  That
+       * should be okay because we will set the timer to to sample again
+       * later.
+       */
+
+       ivdbg("Previous pen up event still in buffer\n");
+       max11802_notify(priv);
+       wd_start(priv->wdog, MAX11802_WDOG_DELAY, max11802_wdog, 1, (uint32_t)priv);
+       goto ignored;
+    }
+  else
+    {
+      /* Wait for data ready */
+      do {
+        /* Handle pen down events.  First, sample positional values. */
+      
+#ifdef CONFIG_MAX11802_SWAPXY
+        x = max11802_sendcmd(priv, MAX11802_CMD_YPOSITION, &tags);
+        y = max11802_sendcmd(priv, MAX11802_CMD_XPOSITION, &tags2);
+#else
+        x = max11802_sendcmd(priv, MAX11802_CMD_XPOSITION, &tags);
+        y = max11802_sendcmd(priv, MAX11802_CMD_YPOSITION, &tags2);
+#endif
+      } while (tags == 0xF || tags2 == 0xF);
+
+      /* Continue to sample the position while the pen is down */
+      wd_start(priv->wdog, MAX11802_WDOG_DELAY, max11802_wdog, 1, (uint32_t)priv);
+      
+      /* Check if data is valid */
+      if ((tags & 0x03) != 0)
+      {
+        ivdbg("Touch ended before measurement\n");
+        goto ignored;
+      }
+      
+      /* Perform a thresholding operation so that the results will be more stable.
+       * If the difference from the last sample is small, then ignore the event.
+       * REVISIT:  Should a large change in pressure also generate a event?
+       */
+
+      xdiff = x > priv->threshx ? (x - priv->threshx) : (priv->threshx - x);
+      ydiff = y > priv->threshy ? (y - priv->threshy) : (priv->threshy - y);
+
+      /* Check the thresholds.  Bail if there is no significant difference */
+
+      if (xdiff < CONFIG_MAX11802_THRESHX && ydiff < CONFIG_MAX11802_THRESHY)
+        {
+          /* Little or no change in either direction ... don't report anything. */
+
+          goto ignored;
+        }
+
+      /* When we see a big difference, snap to the new x/y thresholds */
+
+      priv->threshx       = x;
+      priv->threshy       = y;
+
+      /* Update the x/y position in the sample data */
+
+      priv->sample.x      = priv->threshx;
+      priv->sample.y      = priv->threshy;
+
+      /* The X/Y positional data is now valid */
+
+      priv->sample.valid = true;
+
+      /* If this is the first (acknowledged) pen down report, then report
+       * this as the first contact.  If contact == CONTACT_DOWN, it will be
+       * set to set to CONTACT_MOVE after the contact is first sampled.
+       */
+
+      if (priv->sample.contact != CONTACT_MOVE)
+        {
+          /* First contact */
+
+          priv->sample.contact = CONTACT_DOWN;
+        }
+    }
+
+  /* Indicate the availability of new sample data for this ID */
+
+  priv->sample.id = priv->id;
+  priv->penchange = true;
+
+  /* Notify any waiters that new MAX11802 data is available */
+
+  max11802_notify(priv);
+
+ignored:
+  config->enable(config, true);
+
+  /* Release our lock on the state structure and unlock the SPI bus */
+
+  sem_post(&priv->devsem);
+  max11802_unlock(priv->spi);
+}
+
+/****************************************************************************
+ * Name: max11802_interrupt
+ ****************************************************************************/
+
+static int max11802_interrupt(int irq, FAR void *context)
+{
+  FAR struct max11802_dev_s    *priv;
+  FAR struct max11802_config_s *config;
+  int                           ret;
+
+  /* Which MAX11802 device caused the interrupt? */
+
+#ifndef CONFIG_MAX11802_MULTIPLE
+  priv = &g_max11802;
+#else
+  for (priv = g_max11802list;
+       priv && priv->configs->irq != irq;
+       priv = priv->flink);
+
+  ASSERT(priv != NULL);
+#endif
+
+  /* Get a pointer the callbacks for convenience (and so the code is not so
+   * ugly).
+   */
+
+  config = priv->config;
+  DEBUGASSERT(config != NULL);
+
+  /* Schedule sampling to occur on the worker thread */
+
+  ret = max11802_schedule(priv);
+
+  /* Clear any pending interrupts and return success */
+
+  config->clear(config);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max11802_open
+ ****************************************************************************/
+
+static int max11802_open(FAR struct file *filep)
+{
+#ifdef CONFIG_MAX11802_REFCNT
+  FAR struct inode         *inode;
+  FAR struct max11802_dev_s *priv;
+  uint8_t                   tmp;
+  int                       ret;
+
+  ivdbg("Opening\n");
+
+  DEBUGASSERT(filep);
+  inode = filep->f_inode;
+
+  DEBUGASSERT(inode && inode->i_private);
+  priv  = (FAR struct max11802_dev_s *)inode->i_private;
+
+  /* Get exclusive access to the driver data structure */
+
+  ret = sem_wait(&priv->devsem);
+  if (ret < 0)
+    {
+      /* This should only happen if the wait was canceled by an signal */
+
+      DEBUGASSERT(errno == EINTR);
+      return -EINTR;
+    }
+
+  /* Increment the reference count */
+
+  tmp = priv->crefs + 1;
+  if (tmp == 0)
+    {
+      /* More than 255 opens; uint8_t overflows to zero */
+
+      ret = -EMFILE;
+      goto errout_with_sem;
+    }
+
+  /* When the reference increments to 1, this is the first open event
+   * on the driver.. and an opportunity to do any one-time initialization.
+   */
+
+  /* Save the new open count on success */
+
+  priv->crefs = tmp;
+
+errout_with_sem:
+  sem_post(&priv->devsem);
+  return ret;
+#else
+  ivdbg("Opening\n");
+  return OK;
+#endif
+}
+
+/****************************************************************************
+ * Name: max11802_close
+ ****************************************************************************/
+
+static int max11802_close(FAR struct file *filep)
+{
+#ifdef CONFIG_MAX11802_REFCNT
+  FAR struct inode         *inode;
+  FAR struct max11802_dev_s *priv;
+  int                       ret;
+
+  ivdbg("Closing\n");
+  DEBUGASSERT(filep);
+  inode = filep->f_inode;
+
+  DEBUGASSERT(inode && inode->i_private);
+  priv  = (FAR struct max11802_dev_s *)inode->i_private;
+
+  /* Get exclusive access to the driver data structure */
+
+  ret = sem_wait(&priv->devsem);
+  if (ret < 0)
+    {
+      /* This should only happen if the wait was canceled by an signal */
+
+      DEBUGASSERT(errno == EINTR);
+      return -EINTR;
+    }
+
+  /* Decrement the reference count unless it would decrement a negative
+   * value.  When the count decrements to zero, there are no further
+   * open references to the driver.
+   */
+
+  if (priv->crefs >= 1)
+    {
+      priv->crefs--;
+    }
+
+  sem_post(&priv->devsem);
+#endif
+  ivdbg("Closing\n");
+  return OK;
+}
+
+/****************************************************************************
+ * Name: max11802_read
+ ****************************************************************************/
+
+static ssize_t max11802_read(FAR struct file *filep, FAR char *buffer, size_t len)
+{
+  FAR struct inode          *inode;
+  FAR struct max11802_dev_s *priv;
+  FAR struct touch_sample_s *report;
+  struct max11802_sample_s   sample;
+  int                        ret;
+
+  ivdbg("buffer:%p len:%d\n", buffer, len);
+  DEBUGASSERT(filep);
+  inode = filep->f_inode;
+
+  DEBUGASSERT(inode && inode->i_private);
+  priv  = (FAR struct max11802_dev_s *)inode->i_private;
+
+  /* Verify that the caller has provided a buffer large enough to receive
+   * the touch data.
+   */
+
+  if (len < SIZEOF_TOUCH_SAMPLE_S(1))
+    {
+      /* We could provide logic to break up a touch report into segments and
+       * handle smaller reads... but why?
+       */
+
+      idbg("Unsupported read size: %d\n", len);
+      return -ENOSYS;
+    }
+
+  /* Get exclusive access to the driver data structure */
+
+  ret = sem_wait(&priv->devsem);
+  if (ret < 0)
+    {
+      /* This should only happen if the wait was canceled by an signal */
+
+      idbg("sem_wait: %d\n", errno);
+      DEBUGASSERT(errno == EINTR);
+      return -EINTR;
+    }
+
+  /* Try to read sample data. */
+
+  ret = max11802_sample(priv, &sample);
+  if (ret < 0)
+    {
+      /* Sample data is not available now.  We would ave to wait to get
+       * receive sample data.  If the user has specified the O_NONBLOCK
+       * option, then just return an error.
+       */
+
+      ivdbg("Sample data is not available\n");
+      if (filep->f_oflags & O_NONBLOCK)
+        {
+          ret = -EAGAIN;
+          goto errout;
+       }
+
+      /* Wait for sample data */
+
+      ret = max11802_waitsample(priv, &sample);
+      if (ret < 0)
+        {
+          /* We might have been awakened by a signal */
+
+          idbg("max11802_waitsample: %d\n", ret);
+          goto errout;
+        }
+    }
+
+  /* In any event, we now have sampled MAX11802 data that we can report
+   * to the caller.
+   */
+
+  report = (FAR struct touch_sample_s *)buffer;
+  memset(report, 0, SIZEOF_TOUCH_SAMPLE_S(1));
+  report->npoints            = 1;
+  report->point[0].id        = sample.id;
+  report->point[0].x         = sample.x;
+  report->point[0].y         = sample.y;
+
+  /* Report the appropriate flags */
+
+  if (sample.contact == CONTACT_UP)
+    {
+       /* Pen is now up.  Is the positional data valid?  This is important to
+        * know because the release will be sent to the window based on its
+        * last positional data.
+        */
+
+      if (sample.valid)
+        {
+          report->point[0].flags  = TOUCH_UP | TOUCH_ID_VALID | TOUCH_POS_VALID;
+        }
+      else
+        {
+          report->point[0].flags  = TOUCH_UP | TOUCH_ID_VALID;
+        }
+    }
+  else if (sample.contact == CONTACT_DOWN)
+    {
+      /* First contact */
+
+      report->point[0].flags  = TOUCH_DOWN | TOUCH_ID_VALID | TOUCH_POS_VALID;
+    }
+  else /* if (sample->contact == CONTACT_MOVE) */
+    {
+      /* Movement of the same contact */
+
+      report->point[0].flags  = TOUCH_MOVE | TOUCH_ID_VALID | TOUCH_POS_VALID;
+    }
+
+  ivdbg("  id:      %d\n", report->point[0].id);
+  ivdbg("  flags:   %02x\n", report->point[0].flags);
+  ivdbg("  x:       %d\n", report->point[0].x);
+  ivdbg("  y:       %d\n", report->point[0].y);
+
+  ret = SIZEOF_TOUCH_SAMPLE_S(1);
+
+errout:
+  sem_post(&priv->devsem);
+  ivdbg("Returning: %d\n", ret);
+  return ret;
+}
+
+/****************************************************************************
+ * Name:max11802_ioctl
+ ****************************************************************************/
+
+static int max11802_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+{
+  FAR struct inode         *inode;
+  FAR struct max11802_dev_s *priv;
+  int                       ret;
+
+  ivdbg("cmd: %d arg: %ld\n", cmd, arg);
+  DEBUGASSERT(filep);
+  inode = filep->f_inode;
+
+  DEBUGASSERT(inode && inode->i_private);
+  priv  = (FAR struct max11802_dev_s *)inode->i_private;
+
+  /* Get exclusive access to the driver data structure */
+
+  ret = sem_wait(&priv->devsem);
+  if (ret < 0)
+    {
+      /* This should only happen if the wait was canceled by an signal */
+
+      DEBUGASSERT(errno == EINTR);
+      return -EINTR;
+    }
+
+  /* Process the IOCTL by command */
+
+  switch (cmd)
+    {
+      case TSIOC_SETFREQUENCY:  /* arg: Pointer to uint32_t frequency value */
+        {
+          FAR uint32_t *ptr = (FAR uint32_t *)((uintptr_t)arg);
+          DEBUGASSERT(priv->config != NULL && ptr != NULL);
+          priv->config->frequency = SPI_SETFREQUENCY(priv->spi, *ptr);
+        }
+        break;
+
+      case TSIOC_GETFREQUENCY:  /* arg: Pointer to uint32_t frequency value */
+        {
+          FAR uint32_t *ptr = (FAR uint32_t *)((uintptr_t)arg);
+          DEBUGASSERT(priv->config != NULL && ptr != NULL);
+          *ptr = priv->config->frequency;
+        }
+        break;
+
+      default:
+        ret = -ENOTTY;
+        break;
+    }
+
+  sem_post(&priv->devsem);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: max11802_poll
+ ****************************************************************************/
+
+#ifndef CONFIG_DISABLE_POLL
+static int max11802_poll(FAR struct file *filep, FAR struct pollfd *fds,
+                        bool setup)
+{
+  FAR struct inode         *inode;
+  FAR struct max11802_dev_s *priv;
+  pollevent_t               eventset;
+  int                       ndx;
+  int                       ret = OK;
+  int                       i;
+
+  ivdbg("setup: %d\n", (int)setup);
+  DEBUGASSERT(filep && fds);
+  inode = filep->f_inode;
+
+  DEBUGASSERT(inode && inode->i_private);
+  priv  = (FAR struct max11802_dev_s *)inode->i_private;
+
+  /* Are we setting up the poll?  Or tearing it down? */
+
+  ret = sem_wait(&priv->devsem);
+  if (ret < 0)
+    {
+      /* This should only happen if the wait was canceled by an signal */
+
+      DEBUGASSERT(errno == EINTR);
+      return -EINTR;
+    }
+
+  if (setup)
+    {
+      /* Ignore waits that do not include POLLIN */
+
+      if ((fds->events & POLLIN) == 0)
+        {
+          ret = -EDEADLK;
+          goto errout;
+        }
+
+      /* This is a request to set up the poll.  Find an available
+       * slot for the poll structure reference
+       */
+
+      for (i = 0; i < CONFIG_MAX11802_NPOLLWAITERS; i++)
+        {
+          /* Find an available slot */
+
+          if (!priv->fds[i])
+            {
+              /* Bind the poll structure and this slot */
+
+              priv->fds[i] = fds;
+              fds->priv    = &priv->fds[i];
+              break;
+            }
+        }
+
+      if (i >= CONFIG_MAX11802_NPOLLWAITERS)
+        {
+          fds->priv    = NULL;
+          ret          = -EBUSY;
+          goto errout;
+        }
+
+      /* Should we immediately notify on any of the requested events? */
+
+      if (priv->penchange)
+        {
+          max11802_notify(priv);
+        }
+    }
+  else if (fds->priv)
+    {
+      /* This is a request to tear down the poll. */
+
+      struct pollfd **slot = (struct pollfd **)fds->priv;
+      DEBUGASSERT(slot != NULL);
+
+      /* Remove all memory of the poll setup */
+
+      *slot                = NULL;
+      fds->priv            = NULL;
+    }
+
+errout:
+  sem_post(&priv->devsem);
+  return ret;
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: max11802_register
+ *
+ * Description:
+ *   Configure the MAX11802 to use the provided SPI device instance.  This
+ *   will register the driver as /dev/inputN where N is the minor device
+ *   number
+ *
+ * Input Parameters:
+ *   dev     - An SPI driver instance
+ *   config  - Persistent board configuration data
+ *   minor   - The input device minor number
+ *
+ * Returned Value:
+ *   Zero is returned on success.  Otherwise, a negated errno value is
+ *   returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int max11802_register(FAR struct spi_dev_s *spi,
+                      FAR struct max11802_config_s *config, int minor)
+{
+  FAR struct max11802_dev_s *priv;
+  char devname[DEV_NAMELEN];
+#ifdef CONFIG_MAX11802_MULTIPLE
+  irqstate_t flags;
+#endif
+  int ret;
+
+  ivdbg("spi: %p minor: %d\n", spi, minor);
+
+  /* Debug-only sanity checks */
+
+  DEBUGASSERT(spi != NULL && config != NULL && minor >= 0 && minor < 100);
+
+  /* Create and initialize a MAX11802 device driver instance */
+
+#ifndef CONFIG_MAX11802_MULTIPLE
+  priv = &g_max11802;
+#else
+  priv = (FAR struct max11802_dev_s *)kmalloc(sizeof(struct max11802_dev_s));
+  if (!priv)
+    {
+      idbg("kmalloc(%d) failed\n", sizeof(struct max11802_dev_s));
+      return -ENOMEM;
+    }
+#endif
+
+  /* Initialize the MAX11802 device driver instance */
+
+  memset(priv, 0, sizeof(struct max11802_dev_s));
+  priv->spi     = spi;               /* Save the SPI device handle */
+  priv->config  = config;            /* Save the board configuration */
+  priv->wdog    = wd_create();       /* Create a watchdog timer */
+  priv->threshx = INVALID_THRESHOLD; /* Initialize thresholding logic */
+  priv->threshy = INVALID_THRESHOLD; /* Initialize thresholding logic */
+
+  sem_init(&priv->devsem,  0, 1);    /* Initialize device structure semaphore */
+  sem_init(&priv->waitsem, 0, 0);    /* Initialize pen event wait semaphore */
+
+  /* Make sure that interrupts are disabled */
+
+  config->clear(config);
+  config->enable(config, false);
+
+  /* Attach the interrupt handler */
+
+  ret = config->attach(config, max11802_interrupt);
+  if (ret < 0)
+    {
+      idbg("Failed to attach interrupt\n");
+      goto errout_with_priv;
+    }
+
+  idbg("Mode: %d Bits: 8 Frequency: %d\n",
+       CONFIG_MAX11802_SPIMODE, CONFIG_MAX11802_FREQUENCY);
+
+  /* Lock the SPI bus so that we have exclusive access */
+
+  max11802_lock(spi);
+
+  /* Configure the SPI interface */
+
+  max11802_configspi(spi);
+
+  /* Configure MAX11802 registers */
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+  (void)SPI_SEND(priv->spi, MAX11802_CMD_MODE_WR);
+  (void)SPI_SEND(priv->spi, MAX11802_MODE);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+  (void)SPI_SEND(priv->spi, MAX11802_CMD_AVG_WR);
+  (void)SPI_SEND(priv->spi, MAX11802_AVG);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+  (void)SPI_SEND(priv->spi, MAX11802_CMD_TIMING_WR);
+  (void)SPI_SEND(priv->spi, MAX11802_TIMING);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+  
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+  (void)SPI_SEND(priv->spi, MAX11802_CMD_DELAY_WR);
+  (void)SPI_SEND(priv->spi, MAX11802_DELAY);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+  
+  /* Test that the device access was successful. */
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, true);
+  (void)SPI_SEND(priv->spi, MAX11802_CMD_MODE_RD);
+  ret = SPI_SEND(priv->spi, 0);
+  SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);
+  
+  /* Unlock the bus */
+  max11802_unlock(spi);
+  
+  if (ret != MAX11802_MODE)
+  {
+    idbg("max11802 mode readback failed: %02x\n", ret);
+    goto errout_with_priv;
+  }
+  
+  /* Register the device as an input device */
+
+  (void)snprintf(devname, DEV_NAMELEN, DEV_FORMAT, minor);
+  ivdbg("Registering %s\n", devname);
+
+  ret = register_driver(devname, &max11802_fops, 0666, priv);
+  if (ret < 0)
+    {
+      idbg("register_driver() failed: %d\n", ret);
+      goto errout_with_priv;
+    }
+
+  /* If multiple MAX11802 devices are supported, then we will need to add
+   * this new instance to a list of device instances so that it can be
+   * found by the interrupt handler based on the recieved IRQ number.
+   */
+
+#ifdef CONFIG_MAX11802_MULTIPLE
+  priv->flink    = g_max11802list;
+  g_max11802list = priv;
+  irqrestore(flags);
+#endif
+
+  /* Schedule work to perform the initial sampling and to set the data
+   * availability conditions.
+   */
+
+  ret = work_queue(HPWORK, &priv->work, max11802_worker, priv, 0);
+  if (ret != 0)
+    {
+      idbg("Failed to queue work: %d\n", ret);
+      goto errout_with_priv;
+    }
+
+  /* And return success (?) */
+
+  return OK;
+
+errout_with_priv:
+  sem_destroy(&priv->devsem);
+#ifdef CONFIG_MAX11802_MULTIPLE
+  kfree(priv);
+#endif
+  return ret;
+}
diff --git a/nuttx/drivers/input/max11802.h b/nuttx/drivers/input/max11802.h
new file mode 100644
index 000000000..b6beec045
--- /dev/null
+++ b/nuttx/drivers/input/max11802.h
@@ -0,0 +1,167 @@
+/********************************************************************************************
+ * drivers/input/max11802.h
+ *
+ *   Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
+ *   Authors: Gregory Nutt <gnutt@nuttx.org>
+ *            Petteri Aimonen <jpa@nx.mail.kapsi.fi>
+ *
+ * References:
+ *   "Low-Power, Ultra-Small Resistive Touch-Screen Controllers
+ *    with I2C/SPI Interface" Maxim IC, Rev 3, 10/2010
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ********************************************************************************************/
+
+#ifndef __DRIVERS_INPUT_MAX11802_H
+#define __DRIVERS_INPUT_MAX11802_H
+
+/********************************************************************************************
+ * Included Files
+ ********************************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <semaphore.h>
+#include <poll.h>
+#include <wdog.h>
+#include <nuttx/wqueue.h>
+
+#include <nuttx/spi.h>
+#include <nuttx/clock.h>
+#include <nuttx/input/max11802.h>
+
+/********************************************************************************************
+ * Pre-Processor Definitions
+ ********************************************************************************************/
+/* Configuration ****************************************************************************/
+
+/* MAX11802 Interfaces *********************************************************************/
+
+/* LSB of register addresses specifies read (1) or write (0). */
+#define MAX11802_CMD_XPOSITION ((0x52 << 1) | 1)
+#define MAX11802_CMD_YPOSITION ((0x54 << 1) | 1)
+#define MAX11802_CMD_MEASUREXY (0x70 << 1)
+#define MAX11802_CMD_MODE_WR   (0x0B << 1)
+#define MAX11802_CMD_MODE_RD   ((0x0B << 1) | 1)
+#define MAX11802_CMD_AVG_WR    (0x03 << 1)
+#define MAX11802_CMD_TIMING_WR (0x05 << 1)
+#define MAX11802_CMD_DELAY_WR  (0x06 << 1)
+
+/* Register values to set */
+#define MAX11802_MODE    0x0E
+#define MAX11802_AVG     0x55
+#define MAX11802_TIMING  0x77
+#define MAX11802_DELAY   0x55
+
+/* Driver support **************************************************************************/
+/* This format is used to construct the /dev/input[n] device driver path.  It
+ * defined here so that it will be used consistently in all places.
+ */
+
+#define DEV_FORMAT   "/dev/input%d"
+#define DEV_NAMELEN  16
+
+/* Poll the pen position while the pen is down at this rate (50MS): */
+
+#define MAX11802_WDOG_DELAY  ((50 + (MSEC_PER_TICK-1))/ MSEC_PER_TICK)
+
+/********************************************************************************************
+ * Public Types
+ ********************************************************************************************/
+
+/* This describes the state of one contact */
+
+enum max11802_contact_3
+{
+  CONTACT_NONE = 0,                    /* No contact */
+  CONTACT_DOWN,                        /* First contact */
+  CONTACT_MOVE,                        /* Same contact, possibly different position */
+  CONTACT_UP,                          /* Contact lost */
+};
+
+/* This structure describes the results of one MAX11802 sample */
+
+struct max11802_sample_s
+{
+  uint8_t  id;                          /* Sampled touch point ID */
+  uint8_t  contact;                     /* Contact state (see enum ads7843e_contact_e) */
+  bool     valid;                       /* True: x,y contain valid, sampled data */
+  uint16_t x;                           /* Measured X position */
+  uint16_t y;                           /* Measured Y position */
+};
+
+/* This structure describes the state of one MAX11802 driver instance */
+
+struct max11802_dev_s
+{
+#ifdef CONFIG_ADS7843E_MULTIPLE
+  FAR struct ads7843e_dev_s *flink;     /* Supports a singly linked list of drivers */
+#endif
+  uint8_t nwaiters;                     /* Number of threads waiting for MAX11802 data */
+  uint8_t id;                           /* Current touch point ID */
+  volatile bool penchange;              /* An unreported event is buffered */
+  uint16_t threshx;                     /* Thresholding X value */
+  uint16_t threshy;                     /* Thresholding Y value */
+  sem_t devsem;                         /* Manages exclusive access to this structure */
+  sem_t waitsem;                        /* Used to wait for the availability of data */
+
+  FAR struct max11802_config_s *config; /* Board configuration data */
+  FAR struct spi_dev_s *spi;            /* Saved SPI driver instance */
+  struct work_s work;                   /* Supports the interrupt handling "bottom half" */
+  struct max11802_sample_s sample;      /* Last sampled touch point data */
+  WDOG_ID wdog;                         /* Poll the position while the pen is down */
+
+  /* The following is a list if poll structures of threads waiting for
+   * driver events. The 'struct pollfd' reference for each open is also
+   * retained in the f_priv field of the 'struct file'.
+   */
+
+#ifndef CONFIG_DISABLE_POLL
+  struct pollfd *fds[CONFIG_ADS7843E_NPOLLWAITERS];
+#endif
+};
+
+/********************************************************************************************
+ * Public Function Prototypes
+ ********************************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __DRIVERS_INPUT_ADS7843E_H */
diff --git a/nuttx/include/nuttx/compiler.h b/nuttx/include/nuttx/compiler.h
index 1e0af4382..bbb23d01d 100644
--- a/nuttx/include/nuttx/compiler.h
+++ b/nuttx/include/nuttx/compiler.h
@@ -87,11 +87,16 @@
 
 # define packed_struct __attribute__ ((packed))
 
-/* GCC does not support the reentrant or naked attributes */
+/* GCC does not support the reentrant attribute */
 
 # define reentrant_function
-# define naked_function
 
+/* The naked attribute informs GCC that the programmer will take care of
+ * the function prolog and epilog.
+ */
+
+# define naked_function __attribute__ ((naked,no_instrument_function))
+ 
 /* The inline_function attribute informs GCC that the function should always
  * be inlined, regardless of the level of optimization.  The noinline_function
  * indicates that the function should never be inlined.
diff --git a/nuttx/include/nuttx/input/max11802.h b/nuttx/include/nuttx/input/max11802.h
new file mode 100644
index 000000000..3d03bdd11
--- /dev/null
+++ b/nuttx/include/nuttx/input/max11802.h
@@ -0,0 +1,175 @@
+/****************************************************************************
+ * include/nuttx/input/max11802.h
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Authors: Gregory Nutt <gnutt@nuttx.org>
+ *            Petteri Aimonen <jpa@nx.mail.kapsi.fi>
+ *
+ * References:
+ *   "Low-Power, Ultra-Small Resistive Touch-Screen Controllers
+ *    with I2C/SPI Interface" Maxim IC, Rev 3, 10/2010
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_INPUT_MAX11802_H
+#define __INCLUDE_NUTTX_INPUT_MAX11802_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/spi.h>
+#include <stdbool.h>
+#include <nuttx/irq.h>
+
+#if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_MAX11802)
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************/
+/* SPI Frequency.  Default:  100KHz */
+
+#ifndef CONFIG_MAX11802_FREQUENCY
+#  define CONFIG_MAX11802_FREQUENCY 100000
+#endif
+
+/* Maximum number of threads than can be waiting for POLL events */
+
+#ifndef CONFIG_MAX11802_NPOLLWAITERS
+#  define CONFIG_MAX11802_NPOLLWAITERS 2
+#endif
+
+#ifndef CONFIG_MAX11802_SPIMODE
+#  define CONFIG_MAX11802_SPIMODE SPIDEV_MODE0
+#endif
+
+/* Thresholds */
+
+#ifndef CONFIG_MAX11802_THRESHX
+#  define CONFIG_MAX11802_THRESHX 12
+#endif
+
+#ifndef CONFIG_MAX11802_THRESHY
+#  define CONFIG_MAX11802_THRESHY 12
+#endif
+
+/* Check for some required settings.  This can save the user a lot of time
+ * in getting the right configuration.
+ */
+
+#ifdef CONFIG_DISABLE_SIGNALS
+#  error "Signals are required.  CONFIG_DISABLE_SIGNALS must not be selected."
+#endif
+
+#ifndef CONFIG_SCHED_WORKQUEUE
+#  error "Work queue support required.  CONFIG_SCHED_WORKQUEUE must be selected."
+#endif
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* A reference to a structure of this type must be passed to the MAX11802
+ * driver.  This structure provides information about the configuration
+ * of the MAX11802 and provides some board-specific hooks.
+ *
+ * Memory for this structure is provided by the caller.  It is not copied
+ * by the driver and is presumed to persist while the driver is active. The
+ * memory must be writable because, under certain circumstances, the driver
+ * may modify frequency or X plate resistance values.
+ */
+
+struct max11802_config_s
+{
+  /* Device characterization */
+
+  uint32_t frequency;  /* SPI frequency */
+
+  /* IRQ/GPIO access callbacks.  These operations all hidden behind
+   * callbacks to isolate the MAX11802 driver from differences in GPIO
+   * interrupt handling by varying boards and MCUs.  If possible,
+   * interrupts should be configured on both rising and falling edges
+   * so that contact and loss-of-contact events can be detected.
+   *
+   * attach  - Attach the MAX11802 interrupt handler to the GPIO interrupt
+   * enable  - Enable or disable the GPIO interrupt
+   * clear   - Acknowledge/clear any pending GPIO interrupt
+   * pendown - Return the state of the pen down GPIO input
+   */
+
+  int  (*attach)(FAR struct max11802_config_s *state, xcpt_t isr);
+  void (*enable)(FAR struct max11802_config_s *state, bool enable);
+  void (*clear)(FAR struct max11802_config_s *state);
+  bool (*pendown)(FAR struct max11802_config_s *state);
+};
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Name: max11802_register
+ *
+ * Description:
+ *   Configure the MAX11802 to use the provided SPI device instance.  This
+ *   will register the driver as /dev/inputN where N is the minor device
+ *   number
+ *
+ * Input Parameters:
+ *   spi     - An SPI driver instance
+ *   config  - Persistent board configuration data
+ *   minor   - The input device minor number
+ *
+ * Returned Value:
+ *   Zero is returned on success.  Otherwise, a negated errno value is
+ *   returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+EXTERN  int max11802_register(FAR struct spi_dev_s *spi,
+                             FAR struct max11802_config_s *config,
+                             int minor);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_INPUT && CONFIG_INPUT_MAX11802 */
+#endif /* __INCLUDE_NUTTX_INPUT_MAX11802_H */