Add a driver for SST26F spi/qspi flash devices (SPI mode only)

drivers/mtd/Kconfig

@@ -783,6 +783,39 @@ config SST25XX_MEMORY_TYPE
 
 endif # MTD_SST25XX
 
+config MTD_SST26
+	bool "SPI/QSPI-based SST26XX FLASHes (16,32,64-MBit)"
+	default n
+	select SPI
+	---help---
+		These part are also different from SST25 and SST25XX, they support both SPI and QSPI.
+
+if MTD_SST26
+
+config SST26_SPIMODE
+	int "SST26 (Q)SPI Mode"
+	default 0
+
+config SST26_SPIFREQUENCY
+	int "SST26 (Q)SPI Frequency"
+	default 64000000
+
+config SST26_MANUFACTURER
+	hex "Manufacturers ID"
+	default 0xBF
+	---help---
+		Various manufacturers may have produced the parts.  0xBF is the manufacturer ID
+		for the parts manufactured by SST.
+
+config SST26_MEMORY_TYPE
+	hex "Memory type ID"
+	default 0x26
+	---help---
+		The memory type for SST26VF0xx series is 0x26, but this can be modified if needed
+		to support compatible devices from different manufacturers.
+
+endif # MTD_SST26
+
 config MTD_SST39FV
 	bool "SST39FV NOR FLASH"
 	default n

drivers/mtd/Make.defs

@@ -88,6 +88,10 @@ ifeq ($(CONFIG_MTD_SST25XX),y)
 CSRCS += sst25xx.c
 endif
 
+ifeq ($(CONFIG_MTD_SST26),y)
+CSRCS += sst26.c
+endif
+
 ifeq ($(CONFIG_MTD_SST39FV),y)
 CSRCS += sst39vf.c
 endif

include/nuttx/mtd/mtd.h

@@ -476,6 +476,18 @@ FAR struct mtd_dev_s *sst25_initialize(FAR struct spi_dev_s *dev);
 
 FAR struct mtd_dev_s *sst25xx_initialize(FAR struct spi_dev_s *dev);
 
+/****************************************************************************
+ * Name: sst26_initialize_spi
+ *
+ * Description:
+ *   Initializes the driver for SPI-based SST26 FLASH
+ *
+ *   Supports SST26VF016 SST26VF032 SST26VF064
+ *
+ ****************************************************************************/
+
+FAR struct mtd_dev_s *sst26_initialize_spi(FAR struct spi_dev_s *dev);
+
 /****************************************************************************
  * Name: sst39vf_initialize
  *