drivers/spi: Add an SPI character driver that will permit access to the SPI bus for testing purposes. This driver is a simple wrapper around spi_transfer().

include/nuttx/fs/ioctl.h

@@ -83,9 +83,10 @@
 #define _LOOPBASE       (0x1e00) /* Loop device commands */
 #define _MODEMBASE      (0x1f00) /* Modem ioctl commands */
 #define _I2CBASE        (0x2000) /* I2C driver commands */
-#define _GPIOBASE       (0x2100) /* GPIO driver commands */
+#define _SPIBASE        (0x2100) /* SPI driver commands */
+#define _GPIOBASE       (0x2200) /* GPIO driver commands */
 
-/* boardctl commands share the same number space */
+/* boardctl() commands share the same number space */
 
 #define _BOARDBASE      (0xff00) /* boardctl commands */
 
@@ -385,7 +386,14 @@
 #define _I2CIOCVALID(c)    (_IOC_TYPE(c)==_I2CBASE)
 #define _I2CIOC(nr)        _IOC(_I2CBASE,nr)
 
+/* SPI driver ioctl definitions **********************************************/
+/* see nuttx/include/spi/spi_transfer.h */
+
+#define _SPIIOCVALID(c)    (_IOC_TYPE(c)==_SPIBASE)
+#define _SPIIOC(nr)        _IOC(_SPIBASE,nr)
+
 /* GPIO driver command definitions ******************************************/
+/* see nuttx/include/ioexpander/gpio.h */
 
 #define _GPIOCVALID(c)     (_IOC_TYPE(c)==_GPIOBASE)
 #define _GPIOC(nr)         _IOC(_GPIOBASE,nr)

include/nuttx/spi/spi_transfer.h

@@ -46,10 +46,26 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#include <nuttx/fs/ioctl.h>
 #include <nuttx/spi/spi.h>
 
 #ifdef CONFIG_SPI_EXCHANGE
 
+/* SPI Character Driver IOCTL Commands **************************************/
+/* The SPI driver is intended to support application testing of the SPI bus.
+ * The SPI driver simply provides a user-accessible wrapper around the
+ * OS internal spi_transfer() function.  The following IOCTL commands to
+ * supported by the SPI driver to perform SPI transfers
+ */
+
+/* Command:      SPIIOC_TRANSFER
+ * Description:  Perform a sequence of SPI transfers
+ * Argument:     A reference to an instance of struct spi_sequence_s.
+ * Dependencies: CONFIG_SPI_DRIVER
+ */
+
+#define SPIIOC_TRANSFER _SPIIOC(0x0001)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -129,6 +145,32 @@ struct spi_sequence_s
 
 int spi_transfer(FAR struct spi_dev_s *spi, FAR struct spi_sequence_s *seq);
 
+/****************************************************************************
+ * Name: spi_register
+ *
+ * Description:
+ *   Create and register the SPI character driver.
+ *
+ *   The SPI character driver is a simple character driver that supports SPI
+ *   transfers.  The intent of this driver is to support SPI testing.  It is
+ *   not suitable for use in any real driver application.
+ *
+ * Input Parameters:
+ *   spi - An instance of the lower half SPI driver
+ *   bus - The SPI bus number.  This will be used as the SPI device minor
+ *     number.  The SPI character device will be registered as /dev/spiN
+ *     where N is the minor number
+ *
+ * Returned Value:
+ *   OK if the driver was successfully register; A negated errno value is
+ *   returned on any failure.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_SPI_DRIVER
+int spi_register(FAR struct spi_dev_s *spi, int bus);
+#endif
+
 #undef EXTERN
 #if defined(__cplusplus)
 #define EXTERN extern "C"