Re-architected SAM3/4 SPI interface; Change BUSY bit handling in the ADS7843E driver

13 files changed, 226 insertions, 253 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index f7d096e12..9f21e5769 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -4978,3 +4978,15 @@
 	  configs/sam4l-xplained/README.txt, and
 	  configs/sam4l-xplained/include/board.h:  Add support for the SPI-
 	  based SD card on the I/O1 module (2013-6-15).
+	* arch/arm/src/sam34/sam_spi.c:  Re-architect the SAM3/4 SPI driver
+	  so that is it compatible with the SPI drivers of other MCUs
+	  (2013-6-16).
+	* configs/sam3u-ek/src/up_touchscreen.c and configs/sam4l-xplained/src/sam_mmcsd.c:
+	  Changed needed because of the above change the the SAM3/4 SPI
+	  interface (2013-6-16).
+	* drivers/input/ads7843e.c:  Remove the wait for the touchscreen busy
+	  bit.  I don't see the busy bit changing on the SAM3U-EK board.  But
+	  maybe it is not supposed to.  From my reading of the ADS7843 spec, it
+	  would not be appropriate to wait for the BUSY bit to de-asserted
+	  anyway (since it is only de-asserted when we read the data)
+	  (2013-6-16).
\ No newline at end of file
diff --git a/nuttx/arch/arm/src/sam34/chip/sam_spi.h b/nuttx/arch/arm/src/sam34/chip/sam_spi.h
index 887b7f656..a0344c6a8 100644
--- a/nuttx/arch/arm/src/sam34/chip/sam_spi.h
+++ b/nuttx/arch/arm/src/sam34/chip/sam_spi.h
@@ -49,6 +49,9 @@
 /****************************************************************************************
  * Pre-processor Definitions
  ****************************************************************************************/
+/* General definitions ******************************************************************/
+
+#define SAM_SPI_NCS               4    /* Four chip selects */
 
 /* SPI register offsets *****************************************************************/
 
diff --git a/nuttx/arch/arm/src/sam34/sam_spi.c b/nuttx/arch/arm/src/sam34/sam_spi.c
index cf7518d0d..65ebfa922 100644
--- a/nuttx/arch/arm/src/sam34/sam_spi.c
+++ b/nuttx/arch/arm/src/sam34/sam_spi.c
@@ -43,6 +43,7 @@
 #include <sys/types.h>
 #include <stdint.h>
 #include <stdbool.h>
+#include <stdlib.h>
 #include <semaphore.h>
 #include <errno.h>
 #include <debug.h>
@@ -67,6 +68,7 @@
 /****************************************************************************
  * Definitions
  ****************************************************************************/
+/* Configuration ************************************************************/
 /* Select MCU-specific settings
  *
  * For the SAM3U, SPI is driven by the main clock.
@@ -81,6 +83,7 @@
 #  error Unrecognized SAM architecture
 #endif
 
+/* Debug *******************************************************************/
 /* Check if SPI debut is enabled (non-standard.. no support in
  * include/debug.h
  */
@@ -106,26 +109,16 @@
  * Private Types
  ****************************************************************************/
 
-/* The state of one chip select */
+/* The state of the one chip select */
 
-#ifndef CONFIG_SPI_OWNBUS
-struct sam_chipselect_s
+struct sam_spidev_s
 {
+  struct spi_dev_s spidev;     /* Externally visible part of the SPI interface */
+#ifndef CONFIG_SPI_OWNBUS
   uint32_t         frequency;  /* Requested clock frequency */
   uint32_t         actual;     /* Actual clock frequency */
   uint8_t          nbits;      /* Width of word in bits (8 to 16) */
   uint8_t          mode;       /* Mode 0,1,2,3 */
-};
-#endif
-
-/* The overall state of the SPI interface */
-
-struct sam_spidev_s
-{
-  struct spi_dev_s spidev;     /* Externally visible part of the SPI interface */
-#ifndef CONFIG_SPI_OWNBUS
-  sem_t            exclsem;    /* Held while chip is selected for mutual exclusion */
-  struct sam_chipselect_s csstate[4];
 #endif
   uint8_t          cs;         /* Chip select number */
 };
@@ -194,12 +187,17 @@ static const struct spi_ops_s g_spiops =
   .registercallback  = 0,                 /* Not implemented */
 };
 
-/* SPI device structure */
+#ifdef CONFIG_SPI_OWNBUS
+/* Single chip select device structure structure */
 
-static struct sam_spidev_s g_spidev =
-{
-  .spidev            = { &g_spiops },
-};
+static struct sam_spidev_s g_spidev;
+
+#else
+/* Held while chip is selected for mutual exclusion */
+
+static sem_t g_spisem;
+static bool g_spinitialized = false;
+#endif
 
 /* This array maps chip select numbers (0-3) to CSR register addresses */
 
@@ -330,14 +328,12 @@ static inline uint32_t spi_cs2pcs(FAR struct sam_spidev_s *priv)
 #ifndef CONFIG_SPI_OWNBUS
 static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
 {
-  FAR struct sam_spidev_s *priv = (FAR struct sam_spidev_s *)dev;
-
   spivdbg("lock=%d\n", lock);
   if (lock)
     {
       /* Take the semaphore (perhaps waiting) */
 
-      while (sem_wait(&priv->exclsem) != 0)
+      while (sem_wait(&g_spisem) != 0)
         {
           /* The only case that an error should occur here is if the wait was awakened
            * by a signal.
@@ -348,8 +344,9 @@ static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
     }
   else
     {
-      (void)sem_post(&priv->exclsem);
+      (void)sem_post(&g_spisem);
     }
+
   return OK;
 }
 #endif
@@ -381,15 +378,7 @@ static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
   spivdbg("selected=%d\n", selected);
   if (selected)
     {
-      /* At this point, we expect no chip selected */
-
-      DEBUGASSERT(priv->cs == 0xff);
-
-      /* Get the chip select number used with this SPI device */
-
-      priv->cs = sam_spicsnumber(devid);
       spivdbg("cs=%d\n", priv->cs);
-      DEBUGASSERT(priv->cs >= 0 && priv->cs <= 3);
 
       /* Before writing the TDR, the PCS field in the SPI_MR register must be set
        * in order to select a slave.
@@ -400,19 +389,6 @@ static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
       regval |= (spi_cs2pcs(priv) << SPI_MR_PCS_SHIFT);
       putreg32(regval, SAM_SPI_MR);
     }
-  else
-    {
-      /* At this point, we expect the chip to have already been selected */
-
-#ifdef CONFIG_DEBUG
-      int cs = sam_spicsnumber(devid);
-      DEBUGASSERT(priv->cs == cs);
-#endif
-
-      /* Mark no chip selected */
-
-      priv->cs = 0xff;
-    }
 
   /* Perform any board-specific chip select operations. PIO chip select
    * pins may be programmed by the board specific logic in one of two
@@ -429,7 +405,7 @@ static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
    */
 
   sam_spiselect(devid, selected);
- }
+}
 
 /****************************************************************************
  * Name: spi_setfrequency
@@ -457,16 +433,15 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
   uint32_t regaddr;
 
   spivdbg("cs=%d frequency=%d\n", priv->cs, frequency);
-  DEBUGASSERT(priv->cs >= 0 && priv->cs <= 3);
 
   /* Check if the requested frequency is the same as the frequency selection */
 
 #ifndef CONFIG_SPI_OWNBUS
-  if (priv->csstate[priv->cs].frequency == frequency)
+  if (priv->frequency == frequency)
     {
       /* We are already at this frequency.  Return the actual. */
 
-      return priv->csstate[priv->cs].actual;
+      return priv->actual;
     }
 #endif
 
@@ -492,7 +467,7 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
 
   regaddr = g_csraddr[priv->cs];
   regval  = getreg32(regaddr);
-  regval &= ~(SPI_CSR_SCBR_MASK|SPI_CSR_DLYBS_MASK|SPI_CSR_DLYBCT_MASK);
+  regval &= ~(SPI_CSR_SCBR_MASK | SPI_CSR_DLYBS_MASK | SPI_CSR_DLYBCT_MASK);
   regval |= scbr << SPI_CSR_SCBR_SHIFT;
 
   /* DLYBS: Delay Before SPCK.  This field defines the delay from NPCS valid to the
@@ -534,8 +509,8 @@ static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
   /* Save the frequency setting */
 
 #ifndef CONFIG_SPI_OWNBUS
-  priv->csstate[priv->cs].frequency = frequency;
-  priv->csstate[priv->cs].actual    = actual;
+  priv->frequency = frequency;
+  priv->actual    = actual;
 #endif
 
   spidbg("Frequency %d->%d\n", frequency, actual);
@@ -564,19 +539,18 @@ static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
   uint32_t regaddr;
 
   spivdbg("cs=%d mode=%d\n", priv->cs, mode);
-  DEBUGASSERT(priv->cs >= 0 && priv->cs <= 3);
 
   /* Has the mode changed? */
 
 #ifndef CONFIG_SPI_OWNBUS
-  if (mode != priv->csstate[priv->cs].mode)
+  if (mode != priv->mode)
     {
 #endif
       /* Yes... Set the mode appropriately */
 
       regaddr = g_csraddr[priv->cs];
       regval  = getreg32(regaddr);
-      regval &= ~(SPI_CSR_CPOL|SPI_CSR_NCPHA);
+      regval &= ~(SPI_CSR_CPOL | SPI_CSR_NCPHA);
 
       switch (mode)
         {
@@ -606,7 +580,7 @@ static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
       /* Save the mode so that subsequent re-configurations will be faster */
 
 #ifndef CONFIG_SPI_OWNBUS
-      priv->csstate[priv->cs].mode = mode;
+      priv->mode = mode;
     }
 #endif
 }
@@ -634,7 +608,6 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
 
   spivdbg("cs=%d nbits=%d\n", priv->cs, nbits);
   DEBUGASSERT(priv && nbits > 7 && nbits < 17);
-  DEBUGASSERT(priv->cs >= 0 && priv->cs <= 3);
 
   /* NOTE:  The logic in spi_send and in spi_exchange only handles 8-bit
    * data at the present time.  So the following extra assertion is a
@@ -646,7 +619,7 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
   /* Has the number of bits changed? */
 
 #ifndef CONFIG_SPI_OWNBUS
-  if (nbits != priv->csstate[priv->cs].nbits)
+  if (nbits != priv->nbits)
     {
 #endif
       /* Yes... Set number of bits appropriately */
@@ -662,7 +635,7 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
       /* Save the selection so the subsequence re-configurations will be faster */
 
 #ifndef CONFIG_SPI_OWNBUS
-      priv->csstate[priv->cs].nbits = nbits;
+      priv->nbits = nbits;
     }
 #endif
 }
@@ -889,70 +862,106 @@ static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nw
  *   Initialize the selected SPI port
  *
  * Input Parameter:
- *   Port number (for hardware that has mutiple SPI interfaces)
+ *   cs - Chip select number (identifying the "logical" SPI port)
  *
  * Returned Value:
  *   Valid SPI device structure reference on succcess; a NULL on failure
  *
  ****************************************************************************/
 
-FAR struct spi_dev_s *up_spiinitialize(int port)
+FAR struct spi_dev_s *up_spiinitialize(int cs)
 {
-  FAR struct sam_spidev_s *priv = &g_spidev;
+  FAR struct sam_spidev_s *priv;
   irqstate_t flags;
 
-  /* The SAM3U has only a single SPI port */
+  /* The support SAM parts have only a single SPI port */
 
-  spivdbg("port=%d\n", port);
-  DEBUGASSERT(port == 0);
+  spivdbg("cs=%d\n", cs);
+  DEBUGASSERT(cs >= 0 && cs <= SAM_SPI_NCS);
 
-  /* Set up the initial state */
+#ifdef CONFIG_SPI_OWNBUS
+  /* There is only one device on the bus and, therefore, there is only one
+   * supported chip select.  In this case, use the single, pre-allocated
+   * chip select structure.
+   */
 
-  priv->cs = 0xff;
+  priv = &g_spidev;
 
-  /* Enable clocking to the SPI block */
+#else
+  /* Allocate a new state structure for this chip select.  NOTE that there
+   * is no protection if the same chip select is used in two different
+   * chip select structures.
+   */
 
-  flags = irqsave();
-  sam_spi_enableclk();
+  priv = (FAR struct sam_spidev_s *)zalloc(sizeof(struct sam_spidev_s));
+  if (!priv)
+    {
+      spivdbg("ERROR:  Failed to allocate a chip select structure\n", cs);
+      return NULL;
+    }
+#endif
 
-  /* Configure multiplexed pins as connected on the board.  Chip select pins
-   * must be configured by board-specific logic.
+  /* Set up the initial state for this chip select structure.  Other fields
+   * were zeroed by zalloc().
    */
 
-  sam_configgpio(GPIO_SPI0_MISO);
-  sam_configgpio(GPIO_SPI0_MOSI);
-  sam_configgpio(GPIO_SPI0_SPCK);
+  priv->spidev.ops = &g_spiops;
+  priv->cs = cs;
 
-  /* Disable SPI clocking */
+#ifndef CONFIG_SPI_OWNBUS
+  /* Has the SPI hardware been initialized? */
+
+  if (!g_spinitialized)
+#endif
+    {
+      /* Enable clocking to the SPI block */
+
+      flags = irqsave();
+      sam_spi_enableclk();
+
+      /* Configure multiplexed pins as connected on the board.  Chip select
+       * pins must be configured by board-specific logic.
+       */
+
+      sam_configgpio(GPIO_SPI0_MISO);
+      sam_configgpio(GPIO_SPI0_MOSI);
+      sam_configgpio(GPIO_SPI0_SPCK);
 
-  putreg32(SPI_CR_SPIDIS, SAM_SPI_CR);
+      /* Disable SPI clocking */
 
-  /* Execute a software reset of the SPI (twice) */
+      putreg32(SPI_CR_SPIDIS, SAM_SPI_CR);
 
-  putreg32(SPI_CR_SWRST, SAM_SPI_CR);
-  putreg32(SPI_CR_SWRST, SAM_SPI_CR);
-  irqrestore(flags);
+      /* Execute a software reset of the SPI (twice) */
 
-  /* Configure the SPI mode register */
+      putreg32(SPI_CR_SWRST, SAM_SPI_CR);
+      putreg32(SPI_CR_SWRST, SAM_SPI_CR);
+      irqrestore(flags);
 
-  putreg32(SPI_MR_MSTR | SPI_MR_MODFDIS, SAM_SPI_MR);
+      /* Configure the SPI mode register */
 
-  /* And enable the SPI */
+      putreg32(SPI_MR_MSTR | SPI_MR_MODFDIS, SAM_SPI_MR);
 
-  putreg32(SPI_CR_SPIEN, SAM_SPI_CR);
-  up_mdelay(20);
+      /* And enable the SPI */
 
-  /* Flush any pending transfers */
+      putreg32(SPI_CR_SPIEN, SAM_SPI_CR);
+      up_mdelay(20);
 
-  (void)getreg32(SAM_SPI_SR);
-  (void)getreg32(SAM_SPI_RDR);
+      /* Flush any pending transfers */
 
-  /* Initialize the SPI semaphore that enforces mutually exclusive access */
+      (void)getreg32(SAM_SPI_SR);
+      (void)getreg32(SAM_SPI_RDR);
 
 #ifndef CONFIG_SPI_OWNBUS
-  sem_init(&priv->exclsem, 0, 1);
+      /* Initialize the SPI semaphore that enforces mutually exclusive
+       * access to the SPI registers.
+       */
+
+      sem_init(&g_spisem, 0, 1);
+      g_spinitialized = true;
 #endif
-  spi_dumpregs("After initialization");
+      spi_dumpregs("After initialization");
+    }
+
   return &priv->spidev;
 }
 #endif /* CONFIG_SAM34_SPI */
diff --git a/nuttx/arch/arm/src/sam34/sam_spi.h b/nuttx/arch/arm/src/sam34/sam_spi.h
index 77e6e26f3..dfcfe20b3 100644
--- a/nuttx/arch/arm/src/sam34/sam_spi.h
+++ b/nuttx/arch/arm/src/sam34/sam_spi.h
@@ -79,15 +79,13 @@ extern "C"
  ************************************************************************************/
 
 /****************************************************************************
- * Name:  sam_spicsnumber, sam_spiselect, sam_spistatus, and sam_spicmddata
+ * Name:  sam_spiselect, sam_spistatus, and sam_spicmddata
  *
  * Description:
  *   These external functions must be provided by board-specific logic.  They
  *   include:
  *
- *   o sam_spicsnumber and sam_spiselect which are helper functions to
- *     manage the board-specific aspects of the unique SAM3/4 chip select
- *     architecture.
+ *   o sam_spiselect is a functions tomanage the board-specific chip selects
  *   o sam_spistatus and sam_spicmddata:  Implementations of the status
  *     and cmddata methods of the SPI interface defined by struct spi_ops_
  *     (see include/nuttx/spi.h). All other methods including
@@ -97,10 +95,9 @@ extern "C"
  *
  *   1. Provide logic in sam_boardinitialize() to configure SPI chip select
  *      pins.
- *   2. Provide sam_spicsnumber(), sam_spiselect() and sam_spistatus()
- *      functions in your board-specific logic.  These functions will perform
- *      chip selection and status operations using GPIOs in the way your board
- *      is configured.
+ *   2. Provide sam_spiselect() and sam_spistatus() functions in your board-
+ *      specific logic.  These functions will perform chip selection and
+ *      status operations using GPIOs in the way your board is configured.
  *   2. If CONFIG_SPI_CMDDATA is defined in the NuttX configuration, provide
  *      sam_spicmddata() functions in your board-specific logic.  This
  *      function will perform cmd/data selection operations using GPIOs in
@@ -119,31 +116,6 @@ struct spi_dev_s;
 enum spi_dev_e;
 
 /****************************************************************************
- * Name: sam_spicsnumber
- *
- * Description:
- *   The SAM3/4 has 4 CS registers for controlling device features.  This
- *   function must be provided by board-specific code.  Given a logical device
- *   ID, this function returns a number from 0 to 3 that identifies one of
- *   these SAM3/4 CS resources.
- *
- *   If CONFIG_SPI_OWNBUS is not defined and the GPIO is controlled by
- *   sam_spiselect, then the same CS register may be used to control
- *   multiple devices.
- *
- * Input Parameters:
- *   dev - SPI device info
- *   devid - Identifies the (logical) device
- *
- * Returned Values:
- *   On success, a CS number from 0 to 3 is returned; A negated errno may
- *   be returned on a failure.
- *
- ****************************************************************************/
-
-int sam_spicsnumber(enum spi_dev_e devid);
-
-/****************************************************************************
  * Name: sam_spiselect
  *
  * Description:
diff --git a/nuttx/configs/sam3u-ek/README.txt b/nuttx/configs/sam3u-ek/README.txt
index 59aa65144..32d994329 100644
--- a/nuttx/configs/sam3u-ek/README.txt
+++ b/nuttx/configs/sam3u-ek/README.txt
@@ -572,20 +572,24 @@ Configuration sub-directories
        application.  You can enable the touchscreen and test by modifying the
        default configuration in the following ways:
 
-          Drivers:
+          Device Drivers
+            CONFIG_SPI=y                      : Enable SPI support
+            CONFIG_SPI_EXCHANGE=y             : The exchange() method is supported
+            CONFIG_SPI_OWNBUS=y               : Smaller code if this is the only SPI device
+
             CONFIG_INPUT=y                    : Enable support for input devices
             CONFIG_INPUT_ADS7843E=y           : Enable support for the XPT2048
-            CONFIG_ADS7843E_SPIDEV=0          : Use SPI for communication
+            CONFIG_ADS7843E_SPIDEV=2          : Use SPI CS 2 for communication
             CONFIG_ADS7843E_SPIMODE=0         : Use SPI mode 0
             CONFIG_ADS7843E_THRESHX=39        : These will probably need to be tuned
             CONFIG_ADS7843E_THRESHY=51
-            CONFIG_SPI=y                      : Enable SPI support
-            CONFIG_SPI_EXCHANGE=n             : exchange() method is not supported
+
+          System Type -> Peripherals:
+            CONFIG_SAM34_SPI=y                : Enable support for SPI
 
           System Type:
             CONFIG_GPIO_IRQ=y                 : GPIO interrupt support
             CONFIG_GPIOA_IRQ=y                : Enable GPIO interrupts from port A
-            CONFIG_SAM34_SPI=y                : Enable support for SPI
 
           RTOS Features:
             CONFIG_DISABLE_SIGNALS=n          : Signals are required
diff --git a/nuttx/configs/sam3u-ek/src/sam3u-ek.h b/nuttx/configs/sam3u-ek/src/sam3u-ek.h
index 909abc42a..af68df42a 100644
--- a/nuttx/configs/sam3u-ek/src/sam3u-ek.h
+++ b/nuttx/configs/sam3u-ek/src/sam3u-ek.h
@@ -190,6 +190,7 @@
 
 #define GPIO_TSC_NPCS2 (GPIO_OUTPUT | GPIO_CFG_PULLUP | GPIO_OUTPUT_SET | \
                         GPIO_PORT_PIOC | GPIO_PIN14)
+#define TSC_CSNUM      2
 
 /************************************************************************************
  * Public Types
@@ -225,13 +226,13 @@ void weak_function sam_spiinitialize(void);
 
 void weak_function sam_usbinitialize(void);
 
-/****************************************************************************
+/************************************************************************************
  * Name: sam_hsmciinit
  *
  * Description:
  *   Initialize HSMCI support
  *
- ****************************************************************************/
+ ************************************************************************************/
 
 #ifdef CONFIG_SAM34_HSMCI
 int weak_function sam_hsmciinit(void);
@@ -239,21 +240,21 @@ int weak_function sam_hsmciinit(void);
 # define sam_hsmciinit()
 #endif
 
-/****************************************************************************
+/************************************************************************************
  * Name: up_ledinit
- ****************************************************************************/
+ ************************************************************************************/
 
 #ifdef CONFIG_ARCH_LEDS
 void up_ledinit(void);
 #endif
 
-/****************************************************************************
+/************************************************************************************
  * Name: sam_cardinserted
  *
  * Description:
  *   Check if a card is inserted into the selected HSMCI slot
  *
- ****************************************************************************/
+ ************************************************************************************/
 
 #ifdef CONFIG_SAM34_HSMCI
 bool sam_cardinserted(unsigned char slot);
@@ -261,13 +262,13 @@ bool sam_cardinserted(unsigned char slot);
 #  define sam_cardinserted(slot) (false)
 #endif
 
-/****************************************************************************
+/************************************************************************************
  * Name: sam_writeprotected
  *
  * Description:
  *   Check if a card is inserted into the selected HSMCI slot
  *
- ****************************************************************************/
+ ************************************************************************************/
 
 #ifdef CONFIG_SAM34_HSMCI
 bool sam_writeprotected(unsigned char slot);
@@ -277,4 +278,3 @@ bool sam_writeprotected(unsigned char slot);
 
 #endif /* __ASSEMBLY__ */
 #endif /* __CONFIGS_SAM3U_EK_SRC_SAM3U_EK_H */
-
diff --git a/nuttx/configs/sam3u-ek/src/up_spi.c b/nuttx/configs/sam3u-ek/src/up_spi.c
index b14029f5d..5d4073237 100644
--- a/nuttx/configs/sam3u-ek/src/up_spi.c
+++ b/nuttx/configs/sam3u-ek/src/up_spi.c
@@ -107,28 +107,25 @@ void weak_function sam_spiinitialize(void)
 }
 
 /****************************************************************************
- * Name:  sam_spicsnumber, sam_spiselect, sam_spistatus, and sam_spicmddata
+ * Name:  sam_spiselect, sam_spistatus, and sam_spicmddata
  *
  * Description:
  *   These external functions must be provided by board-specific logic.  They
  *   include:
  *
- *   o sam_spicsnumber and sam_spiselect which are helper functions to
- *     manage the board-specific aspects of the unique SAM3U chip select
- *     architecture.
+ *   o sam_spiselect is a functions tomanage the board-specific chip selects
  *   o sam_spistatus and sam_spicmddata:  Implementations of the status
  *     and cmddata methods of the SPI interface defined by struct spi_ops_
  *     (see include/nuttx/spi.h). All other methods including
- *     up_spiinitialize()) are provided by common SAM3U logic.
+ *     up_spiinitialize()) are provided by common SAM3/4 logic.
  *
  *  To use this common SPI logic on your board:
  *
  *   1. Provide logic in sam_boardinitialize() to configure SPI chip select
  *      pins.
- *   2. Provide sam_spicsnumber(), sam_spiselect() and sam_spistatus()
- *      functions in your board-specific logic.  These functions will perform
- *      chip selection and status operations using GPIOs in the way your board
- *      is configured.
+ *   2. Provide sam_spiselect() and sam_spistatus() functions in your board-
+ *      specific logic.  These functions will perform chip selection and
+ *      status operations using GPIOs in the way your board is configured.
  *   2. If CONFIG_SPI_CMDDATA is defined in the NuttX configuration, provide
  *      sam_spicmddata() functions in your board-specific logic.  This
  *      function will perform cmd/data selection operations using GPIOs in
@@ -143,41 +140,6 @@ void weak_function sam_spiinitialize(void)
  ****************************************************************************/
 
 /****************************************************************************
- * Name: sam_spicsnumber
- *
- * Description:
- *   The SAM3U has 4 CS registers for controlling device features.  This
- *   function must be provided by board-specific code.  Given a logical device
- *   ID, this function returns a number from 0 to 3 that identifies one of
- *   these SAM3U CS resources.
- *
- * Input Parameters:
- *   devid - Identifies the (logical) device
- *
- * Returned Values:
- *   On success, a CS number from 0 to 3 is returned; A negated errno may
- *   be returned on a failure.
- *
- ****************************************************************************/
-
-int sam_spicsnumber(enum spi_dev_e devid)
-{
-  int cs = -EINVAL;
-
-#if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E)
-  if (devid == SPIDEV_TOUCHSCREEN)
-    {
-      /* Assert the CS pin to the OLED display */
-
-      cs = 2;
-    }
-#endif
-
-  spidbg("devid: %d CS: %d\n", (int)devid, cs);
-  return cs;
-}
-
-/****************************************************************************
  * Name: sam_spiselect
  *
  * Description:
diff --git a/nuttx/configs/sam3u-ek/src/up_touchscreen.c b/nuttx/configs/sam3u-ek/src/up_touchscreen.c
index ea2ad3d0a..46a814c6f 100644
--- a/nuttx/configs/sam3u-ek/src/up_touchscreen.c
+++ b/nuttx/configs/sam3u-ek/src/up_touchscreen.c
@@ -75,11 +75,11 @@
 #endif
 
 #ifndef CONFIG_ADS7843E_SPIDEV
-#  define CONFIG_ADS7843E_SPIDEV 0
+#  define CONFIG_ADS7843E_SPIDEV TSC_CSNUM
 #endif
 
-#if CONFIG_ADS7843E_SPIDEV != 0
-#  error "CONFIG_ADS7843E_SPIDEV must be zero"
+#if CONFIG_ADS7843E_SPIDEV != TSC_CSNUM
+#  error "CONFIG_ADS7843E_SPIDEV must have the same value as TSC_CSNUM"
 #endif
 
 #ifndef CONFIG_ADS7843E_DEVMINOR
@@ -247,12 +247,12 @@ int arch_tcinitialize(int minor)
 
   sam_gpioirq(GPIO_TCS_IRQ);
 
-  /* Get an instance of the SPI interface */
+  /* Get an instance of the SPI interface for the touchscreen chip select */
 
-  dev = up_spiinitialize(CONFIG_ADS7843E_SPIDEV);
+  dev = up_spiinitialize(TSC_CSNUM);
   if (!dev)
     {
-      idbg("Failed to initialize SPI bus %d\n", CONFIG_ADS7843E_SPIDEV);
+      idbg("Failed to initialize SPI chip select %d\n", TSC_CSNUM);
       return -ENODEV;
     }
 
@@ -261,7 +261,7 @@ int arch_tcinitialize(int minor)
   ret = ads7843e_register(dev, &g_tscinfo, CONFIG_ADS7843E_DEVMINOR);
   if (ret < 0)
     {
-      idbg("Failed to initialize SPI bus %d\n", CONFIG_ADS7843E_SPIDEV);
+      idbg("Failed to initialize SPI chip select %d\n", TSC_CSNUM);
       /* up_spiuninitialize(dev); */
       return -ENODEV;
     }
diff --git a/nuttx/configs/sam4l-xplained/README.txt b/nuttx/configs/sam4l-xplained/README.txt
index 79b6f5bc8..4b67f6513 100644
--- a/nuttx/configs/sam4l-xplained/README.txt
+++ b/nuttx/configs/sam4l-xplained/README.txt
@@ -698,8 +698,9 @@ Configuration sub-directories
         CONFIG_SAM34_SPI=y                : Enable the SAM4L SPI peripheral
 
       Board Selection -> Common Board Options
-        CONFIG_NSH_MMCSDSLOTNO=0          : Only one slot, slot 0
-        CONFIG_NSH_MMCSDSPIPORTNO=0       : Only one SPI port, port 0
+        CONFIG_NSH_MMCSDSLOTNO=0          : Only one MMC/SD slot, slot 0
+        CONFIG_NSH_MMCSDSPIPORTNO=0       : Use CS=0 if the I/O1 is in EXT1, OR
+        CONFIG_NSH_MMCSDSPIPORTNO=2       : Use CS=2 if the I/O1 is in EXT2
 
       Board Selection -> SAM4L Xplained Pro Modules
         CONFIG_SAM4L_XPLAINED_IOMODULE=y      : I/O1 module is connected
@@ -708,7 +709,8 @@ Configuration sub-directories
 
       Device Drivers
         CONFIG_SPI=y                      : Enable SPI support
-        CONFIG_SPI_EXCHANGE=y             : The exchang() method is supported
+        CONFIG_SPI_EXCHANGE=y             : The exchange() method is supported
+        CONFIG_SPI_OWNBUS=y               : Smaller code if this is the only SPI device
 
         CONFIG_MMCSD=y                    : Enable MMC/SD support
         CONFIG_MMCSD_NSLOTS=1             : Only one MMC/SD card slot
@@ -725,3 +727,6 @@ Configuration sub-directories
       jumper.  Otherwise, you have lookpack on USART0 and NSH will *not*
       behave very well (since its outgoing prompts also appear as incoming
       commands).
+
+      STATUS:  As of 2013-6-16, the SPI interface is not communicating with
+      the SD card.
\ No newline at end of file
diff --git a/nuttx/configs/sam4l-xplained/src/sam_mmcsd.c b/nuttx/configs/sam4l-xplained/src/sam_mmcsd.c
index be4a334ec..c23adf324 100644
--- a/nuttx/configs/sam4l-xplained/src/sam_mmcsd.c
+++ b/nuttx/configs/sam4l-xplained/src/sam_mmcsd.c
@@ -46,6 +46,8 @@
 #include <nuttx/spi.h>
 #include <nuttx/mmcsd.h>
 
+#include "sam4l-xplained.h"
+
 #ifdef CONFIG_SAM4L_XPLAINED_IOMODULE
 
 /****************************************************************************
@@ -65,7 +67,6 @@
 #  error MMC/SD support is required (CONFIG_MMCSD)
 #endif
 
-#define SAM34_MMCSDSPIPORTNO 0 /* Port is SPI (there is only one port) */
 #define SAM34_MMCSDSLOTNO    0 /* There is only one slot */
 
 /****************************************************************************
@@ -89,34 +90,34 @@ int sam_sdinitialize(int minor)
   FAR struct spi_dev_s *spi;
   int ret;
 
-  /* Get the SPI port */
+  /* Get the SPI driver instance for the SD chip select */
 
-  fvdbg("Initializing SPI port %d\n", SAM34_MMCSDSPIPORTNO);
+  fvdbg("Initializing SPI chip select %d\n", SD_CSNO);
 
-  spi = up_spiinitialize(SAM34_MMCSDSPIPORTNO);
+  spi = up_spiinitialize(SD_CSNO);
   if (!spi)
     {
-      fdbg("Failed to initialize SPI port %d\n", SAM34_MMCSDSPIPORTNO);
+      fdbg("Failed to initialize SPI chip select %d\n", SD_CSNO);
       return -ENODEV;
     }
 
-  fvdbg("Successfully initialized SPI port %d\n", SAM34_MMCSDSPIPORTNO);
+  fvdbg("Successfully initialized SPI chip select %d\n", SD_CSNO);
 
-  /* Bind the SPI port to the slot */
+  /* Bind the SPI device for the chip select to the slot */
 
-  fvdbg("Binding SPI port %d to MMC/SD slot %d\n",
-          SAM34_MMCSDSPIPORTNO, SAM34_MMCSDSLOTNO);
+  fvdbg("Binding SPI chip select %d to MMC/SD slot %d\n",
+          SD_CSNO, SAM34_MMCSDSLOTNO);
 
   ret = mmcsd_spislotinitialize(minor, SAM34_MMCSDSLOTNO, spi);
   if (ret < 0)
     {
-      fdbg("Failed to bind SPI port %d to MMC/SD slot %d: %d\n",
-            SAM34_MMCSDSPIPORTNO, SAM34_MMCSDSLOTNO, ret);
+      fdbg("Failed to bind SPI chip select %d to MMC/SD slot %d: %d\n",
+            SD_CSNO, SAM34_MMCSDSLOTNO, ret);
       return ret;
     }
 
-  fvdbg("Successfuly bound SPI port %d to MMC/SD slot %d\n",
-        SAM34_MMCSDSPIPORTNO, SAM34_MMCSDSLOTNO);
+  fvdbg("Successfuly bound SPI chip select %d to MMC/SD slot %d\n",
+        SD_CSNO, SAM34_MMCSDSLOTNO);
 
   return OK;
 }
diff --git a/nuttx/configs/sam4l-xplained/src/sam_nsh.c b/nuttx/configs/sam4l-xplained/src/sam_nsh.c
index e5c77a926..a2b8b8534 100644
--- a/nuttx/configs/sam4l-xplained/src/sam_nsh.c
+++ b/nuttx/configs/sam4l-xplained/src/sam_nsh.c
@@ -52,15 +52,14 @@
 /* Support for the SD card slot on the I/O1 module */
 /* Verify NSH PORT and SLOT settings */
 
-#  define SAM34_MMCSDSPIPORTNO 0 /* Port is SPI (there is only one port) */
 #  define SAM34_MMCSDSLOTNO    0 /* There is only one slot */
 
 #  if defined(CONFIG_NSH_MMCSDSLOTNO) && CONFIG_NSH_MMCSDSLOTNO != SAM34_MMCSDSLOTNO
 #    error Only one MMC/SD slot:  Slot 0 (CONFIG_NSH_MMCSDSLOTNO)
 #  endif
 
-#  if defined(CONFIG_NSH_MMCSDSPIPORTNO) && CONFIG_NSH_MMCSDSPIPORTNO != SAM34_MMCSDSPIPORTNO
-#    error Only one MMC/SD port:  Port 0 (CONFIG_NSH_MMCSDSPIPORTNO)
+#  if defined(CONFIG_NSH_MMCSDSPIPORTNO) && CONFIG_NSH_MMCSDSPIPORTNO != SD_CSNO
+#    error CONFIG_NSH_MMCSDSPIPORTNO must have the same value as SD_CSNO
 #  endif
 
 /* Default MMC/SD minor number */
diff --git a/nuttx/configs/sam4l-xplained/src/sam_spi.c b/nuttx/configs/sam4l-xplained/src/sam_spi.c
index b977db246..465f59e61 100644
--- a/nuttx/configs/sam4l-xplained/src/sam_spi.c
+++ b/nuttx/configs/sam4l-xplained/src/sam_spi.c
@@ -104,28 +104,25 @@ void weak_function sam_spiinitialize(void)
 }
 
 /****************************************************************************
- * Name:  sam_spicsnumber, sam_spiselect, sam_spistatus, and sam_spicmddata
+ * Name:  sam_spiselect, sam_spistatus, and sam_spicmddata
  *
  * Description:
  *   These external functions must be provided by board-specific logic.  They
  *   include:
  *
- *   o sam_spicsnumber and sam_spiselect which are helper functions to
- *     manage the board-specific aspects of the unique SAM3U chip select
- *     architecture.
+ *   o sam_spiselect is a functions tomanage the board-specific chip selects
  *   o sam_spistatus and sam_spicmddata:  Implementations of the status
  *     and cmddata methods of the SPI interface defined by struct spi_ops_
  *     (see include/nuttx/spi.h). All other methods including
- *     up_spiinitialize()) are provided by common SAM3U logic.
+ *     up_spiinitialize()) are provided by common SAM3/4 logic.
  *
  *  To use this common SPI logic on your board:
  *
  *   1. Provide logic in sam_boardinitialize() to configure SPI chip select
  *      pins.
- *   2. Provide sam_spicsnumber(), sam_spiselect() and sam_spistatus()
- *      functions in your board-specific logic.  These functions will perform
- *      chip selection and status operations using GPIOs in the way your board
- *      is configured.
+ *   2. Provide sam_spiselect() and sam_spistatus() functions in your board-
+ *      specific logic.  These functions will perform chip selection and
+ *      status operations using GPIOs in the way your board is configured.
  *   2. If CONFIG_SPI_CMDDATA is defined in the NuttX configuration, provide
  *      sam_spicmddata() functions in your board-specific logic.  This
  *      function will perform cmd/data selection operations using GPIOs in
@@ -140,41 +137,6 @@ void weak_function sam_spiinitialize(void)
  ****************************************************************************/
 
 /****************************************************************************
- * Name: sam_spicsnumber
- *
- * Description:
- *   The SAM3U has 4 CS registers for controlling device features.  This
- *   function must be provided by board-specific code.  Given a logical device
- *   ID, this function returns a number from 0 to 3 that identifies one of
- *   these SAM3U CS resources.
- *
- * Input Parameters:
- *   devid - Identifies the (logical) device
- *
- * Returned Values:
- *   On success, a CS number from 0 to 3 is returned; A negated errno may
- *   be returned on a failure.
- *
- ****************************************************************************/
-
-int sam_spicsnumber(enum spi_dev_e devid)
-{
-  int cs = -EINVAL;
-
-#ifdef CONFIG_SAM4L_XPLAINED_IOMODULE
-  if (devid == SPIDEV_MMCSD)
-    {
-      /* Return the chip select number */
-
-      cs = SD_CSNO;
-    }
-#endif
-
-  spidbg("devid: %d CS: %d\n", (int)devid, cs);
-  return cs;
-}
-
-/****************************************************************************
  * Name: sam_spiselect
  *
  * Description:
diff --git a/nuttx/drivers/input/ads7843e.c b/nuttx/drivers/input/ads7843e.c
index 98893a2f6..7d1a0c3ea 100644
--- a/nuttx/drivers/input/ads7843e.c
+++ b/nuttx/drivers/input/ads7843e.c
@@ -104,7 +104,9 @@ static void ads7843e_lock(FAR struct spi_dev_s *spi);
 static void ads7843e_unlock(FAR struct spi_dev_s *spi);
 #endif
 
+#if 0
 static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv);
+#endif
 static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd);
 
 /* Interrupts and data sampling */
@@ -268,6 +270,7 @@ static inline void ads7843e_configspi(FAR struct spi_dev_s *spi)
  * Name: ads7843e_waitbusy
  ****************************************************************************/
 
+#if 0 /* Not used */
 static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv)
 {
   /* BUSY is high impedance when the ads7843e not selected.  When the
@@ -277,9 +280,41 @@ static inline void ads7843e_waitbusy(FAR struct ads7843e_dev_s *priv)
 
   while (priv->config->busy(priv->config));
 }
+#endif
 
 /****************************************************************************
  * Name: ads7843e_sendcmd
+ *
+ * Description.
+ *   The command/data sequences is as follows:
+ *
+ *            DCLK
+ *              1  2   3   4   5    6   7   8         1   2  3  4  ...
+ *              S  A2  A1  A0 MODE SER PD1 PD0
+ *                                 DFR
+ *   START      CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
+ *   CMD
+ *   Aquisition                    AAAAAAAAAAA
+ *   TIME
+ *   BUSY                                     BBBBBBBB
+ *   Reported
+ *   12-bit                                           DDDDDDDDDDDD...
+ *   response
+ *
+ *   The BUSY output is high imedance when /CS is high.  BUSY goes low when
+ *   /CS goes low (within 200ns).  BUSY goes high on the falling edge of the
+ *   8th clock (within 200ns); BUSY goes low again after the falling edge of
+ *   first clock of the 12-bit data read, at the leading edge of the MS bit
+ *   11 of the 12-bit data response.
+ *
+ *   The acquisition time is 3 clock cycles and so should be complete at the
+ *   end of the command transfer.  Other places say that this time is
+ *   nominally 2 microseconds.
+ *
+ *   So what good is this BUSY?  Many boards do not even bother to bring it
+ *   to the MCU.  It looks like busy will stick high until we read the data
+ *   so it does not really make any sense to wait on it.
+ *
  ****************************************************************************/
 
 static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd)
@@ -294,9 +329,18 @@ static uint16_t ads7843e_sendcmd(FAR struct ads7843e_dev_s *priv, uint8_t cmd)
   /* Send the command */
 
   (void)SPI_SEND(priv->spi, cmd);
+
+#if 1
+  /* Wait a tiny amount to make sure that the aquisition time is complete */
+
+   up_udelay(3); /* 3 microseconds */
+#else
+  /* Wait until busy is no longer asserted */
+
   ads7843e_waitbusy(priv);
+#endif
 
-  /* Read the data */
+  /* Read the 12-bit data (LS 4 bits will be padded with zero) */
 
   SPI_RECVBLOCK(priv->spi, buffer, 2);
   SPI_SELECT(priv->spi, SPIDEV_TOUCHSCREEN, false);