Add framework for a SAM3U SPI driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4010 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/sam3u/sam3u_spi.c

+/****************************************************************************
+ * arch/arm/src/sam3u/sam3u_spi.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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 <stdint.h>
+#include <stdbool.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <arch/board/board.h>
+#include <nuttx/arch.h>
+#include <nuttx/spi.h>
+
+#include "up_internal.h"
+#include "up_arch.h"
+
+#include "chip.h"
+#include "sam3u_internal.h"
+#include "sam3u_pmc.h"
+#include "sam3u_spi.h"
+
+#ifdef CONFIG_SAM3U_SPI
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* Enables debug output from this file (needs CONFIG_DEBUG too) */
+
+#undef SPI_DEBUG     /* Define to enable debug */
+#undef SPI_VERBOSE   /* Define to enable verbose debug */
+
+#ifdef SPI_DEBUG
+#  define spidbg  lldbg
+#  ifdef SPI_VERBOSE
+#    define spivdbg lldbg
+#  else
+#    define spivdbg(x...)
+#  endif
+#else
+#  undef SPI_VERBOSE
+#  define spidbg(x...)
+#  define spivdbg(x...)
+#endif
+
+/* SPI Clocking */
+
+#warning "Missing logi"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct sam3u_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 */
+  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
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/* SPI methods */
+
+#ifndef CONFIG_SPI_OWNBUS
+static int      spi_lock(FAR struct spi_dev_s *dev, bool lock);
+#endif
+static void     spi_select(FAR struct spi_dev_s *dev, enum spi_dev_e devid, bool selected);
+static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency);
+static void     spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode);
+static void     spi_setbits(FAR struct spi_dev_s *dev, int nbits);
+static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t ch);
+static void     spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords);
+static void     spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct spi_ops_s g_spiops =
+{
+#ifndef CONFIG_SPI_OWNBUS
+  .lock              = spi_lock,
+#endif
+  .select            = sam3u_spiselect,
+  .setfrequency      = spi_setfrequency,
+  .setmode           = spi_setmode,
+  .setbits           = spi_setbits,
+  .status            = sam3u_spistatus,
+#ifdef CONFIG_SPI_CMDDATA
+  .cmddata           = sam3u_spicmddata,
+#endif
+  .send              = spi_send,
+  .sndblock          = spi_sndblock,
+  .recvblock         = spi_recvblock,
+  .registercallback  = 0,                 /* Not implemented */
+};
+
+static struct sam3u_spidev_s g_spidev =
+{
+  .spidev            = { &g_spiops },
+}; 
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: spi_lock
+ *
+ * Description:
+ *   On SPI busses where there are multiple devices, it will be necessary to
+ *   lock SPI to have exclusive access to the busses for a sequence of
+ *   transfers.  The bus should be locked before the chip is selected. After
+ *   locking the SPI bus, the caller should then also call the setfrequency,
+ *   setbits, and setmode methods to make sure that the SPI is properly
+ *   configured for the device.  If the SPI buss is being shared, then it
+ *   may have been left in an incompatible state.
+ *
+ * Input Parameters:
+ *   dev  - Device-specific state data
+ *   lock - true: Lock spi bus, false: unlock SPI bus
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_SPI_OWNBUS
+static int spi_lock(FAR struct spi_dev_s *dev, bool lock)
+{
+  FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
+
+  if (lock)
+    {
+      /* Take the semaphore (perhaps waiting) */
+
+      while (sem_wait(&priv->exclsem) != 0)
+        {
+          /* The only case that an error should occur here is if the wait was awakened
+           * by a signal.
+           */
+
+          ASSERT(errno == EINTR);
+        }
+    }
+  else
+    {
+      (void)sem_post(&priv->exclsem);
+    }
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: spi_setfrequency
+ *
+ * Description:
+ *   Set the SPI frequency.
+ *
+ * Input Parameters:
+ *   dev -       Device-specific state data
+ *   frequency - The SPI frequency requested
+ *
+ * Returned Value:
+ *   Returns the actual frequency selected
+ *
+ ****************************************************************************/
+
+static uint32_t spi_setfrequency(FAR struct spi_dev_s *dev, uint32_t frequency)
+{
+  FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
+  uint32_t actual;
+
+  /* Check if the requested frequence is the same as the frequency selection */
+
+#ifndef CONFIG_SPI_OWNBUS
+  if (priv->frequency == frequency)
+    {
+      /* We are already at this frequency.  Return the actual. */
+
+      return priv->actual;
+    }
+#endif
+
+  /* Configure SPI to a frequency as close as possible to the requested
+   * frequency.
+   */
+ 
+#warning "Missing logic"
+
+  /* Calculate the actual actual frequency that is used */
+
+#warning "Missing logic"
+  actual = 0;
+
+  /* Save the frequency setting */
+
+#ifndef CONFIG_SPI_OWNBUS
+  priv->frequency = frequency;
+  priv->actual    = actual;
+#endif
+
+  spidbg("Frequency %d->%d\n", frequency, actual);
+  return actual;
+}
+
+/****************************************************************************
+ * Name: spi_setmode
+ *
+ * Description:
+ *   Set the SPI mode. Optional.  See enum spi_mode_e for mode definitions
+ *
+ * Input Parameters:
+ *   dev -  Device-specific state data
+ *   mode - The SPI mode requested
+ *
+ * Returned Value:
+ *   none
+ *
+ ****************************************************************************/
+
+static void spi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
+{
+  FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
+  uint32_t regval;
+
+  /* Has the mode changed? */
+
+#ifndef CONFIG_SPI_OWNBUS
+  if (mode != priv->mode)
+    {
+#endif
+      /* Yes... Set the mode appropriately */
+#warning "Missing logic"
+
+      switch (mode)
+        {
+        case SPIDEV_MODE0: /* CPOL=0; CPHA=0 */
+          break;
+ 
+        case SPIDEV_MODE1: /* CPOL=0; CPHA=1 */
+          break;
+ 
+        case SPIDEV_MODE2: /* CPOL=1; CPHA=0 */
+          break;
+ 
+        case SPIDEV_MODE3: /* CPOL=1; CPHA=1 */
+          break;
+ 
+        default:
+          DEBUGASSERT(FALSE);
+          return;
+        }
+
+      /* Save the mode so that subsequent re-configurations will be faster */
+
+#ifndef CONFIG_SPI_OWNBUS
+      priv->mode = mode;
+    }
+#endif
+}
+
+/****************************************************************************
+ * Name: spi_setbits
+ *
+ * Description:
+ *   Set the number if bits per word.
+ *
+ * Input Parameters:
+ *   dev -  Device-specific state data
+ *   nbits - The number of bits requests
+ *
+ * Returned Value:
+ *   none
+ *
+ ****************************************************************************/
+
+static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
+{
+  FAR struct sam3u_spidev_s *priv = (FAR struct sam3u_spidev_s *)dev;
+  uint32_t regval;
+
+  /* Has the number of bits changed? */
+
+  DEBUGASSERT(priv && nbits > 7 && nbits < 17);
+#ifndef CONFIG_SPI_OWNBUS
+  if (nbits != priv->nbits)
+    {
+#endif
+      /* Yes... Set number of bits appropriately */
+#warning "Missing logic"
+
+      /* Save the selection so the subsequence re-configurations will be faster */
+
+#ifndef CONFIG_SPI_OWNBUS
+      priv->nbits = nbits;
+    }
+#endif
+}
+
+/****************************************************************************
+ * Name: spi_send
+ *
+ * Description:
+ *   Exchange one word on SPI
+ *
+ * Input Parameters:
+ *   dev - Device-specific state data
+ *   wd  - The word to send.  the size of the data is determined by the
+ *         number of bits selected for the SPI interface.
+ *
+ * Returned Value:
+ *   response
+ *
+ ****************************************************************************/
+
+static uint16_t spi_send(FAR struct spi_dev_s *dev, uint16_t wd)
+{
+  /* Write the data to transmitted to the SPI Data Register */
+#warning "Missing logic"
+
+  /* Wait for the data exchange to complete */
+#warning "Missing logic"
+
+ /* Clear any pending status and return the received data */
+#warning "Missing logic"
+  return 0;
+}
+
+/*************************************************************************
+ * Name: spi_sndblock
+ *
+ * Description:
+ *   Send a block of data on SPI
+ *
+ * Input Parameters:
+ *   dev -    Device-specific state data
+ *   buffer - A pointer to the buffer of data to be sent
+ *   nwords - the length of data to send from the buffer in number of words.
+ *            The wordsize is determined by the number of bits-per-word
+ *            selected for the SPI interface.  If nbits <= 8, the data is
+ *            packed into uint8_t's; if nbits >8, the data is packed into uint16_t's
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const void *buffer, size_t nwords)
+{
+  FAR uint8_t *ptr = (FAR uint8_t*)buffer;
+  uint8_t data;
+
+  spidbg("nwords: %d\n", nwords);
+  while (nwords)
+    {
+      /* Write the data to transmitted to the SPI Data Register */
+
+      data = *ptr++;
+#warning "Missing logic"
+
+      /* Wait for the data exchange to complete */
+#warning "Missing logic"
+
+     /* Clear any pending status */
+#warning "Missing logic"
+     nwords--;
+    }
+}
+
+/****************************************************************************
+ * Name: spi_recvblock
+ *
+ * Description:
+ *   Revice a block of data from SPI
+ *
+ * Input Parameters:
+ *   dev -    Device-specific state data
+ *   buffer - A pointer to the buffer in which to recieve data
+ *   nwords - the length of data that can be received in the buffer in number
+ *            of words.  The wordsize is determined by the number of bits-per-word
+ *            selected for the SPI interface.  If nbits <= 8, the data is
+ *            packed into uint8_t's; if nbits >8, the data is packed into uint16_t's
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+static void spi_recvblock(FAR struct spi_dev_s *dev, FAR void *buffer, size_t nwords)
+{
+  FAR uint8_t *ptr = (FAR uint8_t*)buffer;
+
+  spidbg("nwords: %d\n", nwords);
+  while (nwords)
+    {
+      /* Write some dummy data to the SPI Data Register in order to clock the
+       * read data.
+       */
+
+#warning "Missing logic"
+
+      /* Wait for the data exchange to complete */
+#warning "Missing logic"
+
+     /* Read the received data from the SPI Data Register */   
+#warning "Missing logic"
+
+     /* Clear any pending status */
+#warning "Missing logic"
+
+     /* Read the received data from the SPI Data Register */   
+
+#warning "Missing logic"
+     *ptr++ = 0;
+     nwords--;
+    }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_spiinitialize
+ *
+ * Description:
+ *   Initialize the selected SPI port
+ *
+ * Input Parameter:
+ *   Port number (for hardware that has mutiple SPI interfaces)
+ *
+ * Returned Value:
+ *   Valid SPI device structure reference on succcess; a NULL on failure
+ *
+ ****************************************************************************/
+
+FAR struct spi_dev_s *up_spiinitialize(int port)
+{
+  FAR struct sam3u_spidev_s *priv = &g_spidev;
+  irqstate_t flags;
+  uint32_t regval;
+
+  /* The SAM3U has only a single SPI port */
+
+  DEBUGASSERT(port == 0);
+
+  /* Apply power to the SPI block */
+
+  flags = irqsave();
+  regval = getreg32(SAM3U_PMC_PCER);
+  regval |= (1 << SAM3U_PID_SPI);
+#ifdef CONFIG_SAM3U_SPIINTERRUPT
+  regval |= (1 << SAM3U_IRQ_SPI);
+#endif
+  putreg32(regval, SAM3U_PMC_PCER);
+
+  /* Configure multiplexed pins as connected on the board. */
+
+  sam3u_configgpio(GPIO_SPI0_MISO);
+  sam3u_configgpio(GPIO_SPI0_MOSI);
+  sam3u_configgpio(GPIO_SPI0_SPCK);
+  sam3u_configgpio(GPIO_SPI0_NPCS2_PC14);
+
+  /* Execute a software reset of the SPI twice */
+
+  putreg32(SPI_CR_SWRST, SAM3U_SPI_CR);
+  putreg32(SPI_CR_SWRST, SAM3U_SPI_CR);
+
+  /* Configure clocking */
+#warning "Missing logic - Check SPI MR register"
+
+  irqrestore(flags);
+  
+  /* Configure 8-bit SPI mode and master mode */
+#warning "Missing logic"
+
+  /* Set the initial SPI configuration */
+
+#ifndef CONFIG_SPI_OWNBUS
+  priv->frequency = 0;
+  priv->nbits     = 8;
+  priv->mode      = SPIDEV_MODE0;
+#endif
+
+  /* Select a default frequency of approx. 400KHz */
+
+  spi_setfrequency((FAR struct spi_dev_s *)priv, 400000);
+
+  /* Initialize the SPI semaphore that enforces mutually exclusive access */
+
+#ifndef CONFIG_SPI_OWNBUS
+  sem_init(&priv->exclsem, 0, 1);
+#endif
+  return &priv->spidev;
+}
+#endif /* CONFIG_SAM3U_SPI */

arch/arm/src/sam3u/sam3u_spi.h

@@ -2,7 +2,7 @@
  * arch/arm/src/sam3u/sam3u_spi.h
  *
  *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
- *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions