driver/mtd: ramtron multi-device spi bus support

Adds a device ID to ramtron_initialize, which is stored in the ramtron_dev_s structure.
This ID is used when calling SPI_SELECT to board specific logic to allow chip select on the SPI bus.

This change is NOT backwards compatible, as it changes the function signature of ramtron_initialize.

This implementation is based on the handling of chip select in nuttx/drivers/mtd/sst26.c:sst26_initialize_spi().

Additional Changes:
  - Add MB85RS64V to ramtron supported parts list.

Author: stbenn

drivers/mtd/ramtron.c

@@ -145,6 +145,7 @@ struct ramtron_dev_s
   FAR struct spi_dev_s *dev;               /* Saved SPI interface instance */
   uint8_t sectorshift;
   uint8_t pageshift;
+  uint16_t devid;                           /* SPI device ID to manage CS lines in board */
   uint32_t nsectors;
   uint32_t npages;
   uint32_t speed;                          /* Overridable via ioctl */
@@ -323,6 +324,18 @@ static const struct ramtron_parts_s g_ramtron_parts[] =
 #ifdef CONFIG_RAMTRON_CHUNKING
     , false,                      /* chunked */
     RAMTRON_EMULATE_PAGE_SIZE     /* chunksize */
+#endif
+  },
+  {
+    "MB85RS64V",                  /* name */
+    0x03,                         /* id1 */
+    0x02,                         /* id2 */
+    8L * 1024L,                   /* size */
+    2,                            /* addr_len */
+    20000000                      /* speed */
+#ifdef CONFIG_RAMTRON_CHUNKING
+    , false,                      /* chunked */
+    RAMTRON_EMULATE_PAGE_SIZE     /* chunksize */
 #endif
   },
   {
@@ -484,7 +497,7 @@ static inline int ramtron_readid(struct ramtron_dev_s *priv)
   /* Lock the SPI bus, configure the bus, and select this FLASH part. */
 
   ramtron_lock(priv);
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), true);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), true);
 
   /* Send the "Read ID (RDID)" command */
 
@@ -514,7 +527,7 @@ static inline int ramtron_readid(struct ramtron_dev_s *priv)
 
   /* Deselect the FLASH and unlock the bus */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), false);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), false);
   ramtron_unlock(priv->dev);
 
   /* Select part from the part list */
@@ -556,15 +569,15 @@ static void ramtron_writeenable(struct ramtron_dev_s *priv)
 {
   /* Select this FLASH part */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), true);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), true);
 
   /* Send "Write Enable (WREN)" command */
 
   SPI_SEND(priv->dev, RAMTRON_WREN);
 
   /* Deselect the FLASH */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), false);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), false);
   finfo("Enabled\n");
 }
 
@@ -604,7 +617,7 @@ static inline int ramtron_pagewrite(struct ramtron_dev_s *priv,
 
   /* Select this FLASH part */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), true);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), true);
 
   /* Send "Page Program (PP)" command */
 
@@ -620,7 +633,7 @@ static inline int ramtron_pagewrite(struct ramtron_dev_s *priv,
 
   /* Deselect the FLASH: Chip Select high */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), false);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), false);
   finfo("Written\n");
 
   return OK;
@@ -808,7 +821,7 @@ static ssize_t ramtron_read(FAR struct mtd_dev_s *dev,
 
   /* Select this FLASH part */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), true);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), true);
 
   /* Send "Read from Memory " instruction */
 
@@ -824,7 +837,7 @@ static ssize_t ramtron_read(FAR struct mtd_dev_s *dev,
 
   /* Deselect the FLASH and unlock the SPI bus */
 
-  SPI_SELECT(priv->dev, SPIDEV_FLASH(0), false);
+  SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->devid), false);
   ramtron_unlock(priv->dev);
 
   finfo("return nbytes: %d\n", (int)nbytes);
@@ -932,19 +945,22 @@ static int ramtron_ioctl(FAR struct mtd_dev_s *dev,
  *   as instances that can be bound to other functions
  *   (such as a block or character driver front end).
  *
+ * Note:
+ *   This implementation can handle multiple FLASH parts per SPI device by
+ *   using the spi_devid to handle chip select between devices. The spi_devid
+ *   passed to this function must be handled by the corresponding spi select
+ *   function in board files.
  ****************************************************************************/
 
-FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev)
+FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev,
+                                        uint16_t spi_devid)
 {
   FAR struct ramtron_dev_s *priv;
 
   finfo("dev: %p\n", dev);
 
   /* Allocate a state structure (we allocate the structure instead of using
    * a fixed, static allocation so that we can handle multiple FLASH devices.
-   * The current implementation would handle only one FLASH part per SPI
-   * device (only because of the SPIDEV_FLASH(0) definition) and so would
-   * have to be extended to handle multiple FLASH parts on the same SPI bus.
    */
 
   priv = (FAR struct ramtron_dev_s *)
@@ -962,10 +978,11 @@ FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev)
       priv->mtd.ioctl  = ramtron_ioctl;
       priv->mtd.name   = "ramtron";
       priv->dev        = dev;
+      priv->devid      = spi_devid;
 
       /* Deselect the FLASH */
 
-      SPI_SELECT(dev, SPIDEV_FLASH(0), false);
+      SPI_SELECT(dev, SPIDEV_FLASH(priv->devid), false);
 
       /* Identify the FLASH chip and get its capacity */
 

include/nuttx/mtd/mtd.h

@@ -510,12 +510,13 @@ void rammtd_uninitialize(FAR struct mtd_dev_s *dev);
  *   Create and initialize a Ramtron MTD device instance.
  *
  * Input Parameters:
- *   start - Address of the beginning of the allocated RAM regions.
- *   size  - The size in bytes of the allocated RAM region.
+ *   dev  - Pointer to the SPI device instance.
+ *   spi_devid - SPI device ID to manage CS lines in board
  *
  ****************************************************************************/
 
-FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev);
+FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev,
+                                        uint16_t spi_devid);
 
 /****************************************************************************
  * Name: sst25_initialize