SPI bit order: Add configuration setting to indicate if an architecture-specif SPI implementation does or does not support LSB bit order.

drivers/lcd/memlcd.c

@@ -67,6 +67,10 @@
 #  error CONFIG_SPI_HWFEATURES=y and CONFIG_SPI_BITORDER=y required by this driver
 #endif
 
+#ifndef CONFIG_ARCH_HAVE_SPI_BITORDER
+#  warning This platform does not support SPI LSB-bit order
+#endif
+
 /* Cisplay resolution */
 
 #if defined CONFIG_MEMLCD_LS013B7DH01

drivers/spi/Kconfig

@@ -55,27 +55,42 @@ config SPI_HWFEATURES
 		basically the OR of any specific hardware feature and eanbles
 		the SPI hwfeatures() interface method.
 
+config ARCH_HAVE_SPI_CRCGENERATION
+	bool
+	default n
+
 config SPI_CRCGENERATION
 	bool
 	default n
 	select SPI_HWFEATURES
+	depends on ARCH_HAVE_SPI_CRCGENERATION
 	---help---
 		Selected by MCU Kconfig logic if implementation supports automatic
 		generation of SPI CRCs.  Enables the HWFEAT_CRCGENERATION option
 		as well as the hwfeartures() interface method.
 
+config ARCH_HAVE_SPI_CS_CONTROL
+	bool
+	default n
+
 config SPI_CS_CONTROL
 	bool "SPI CS Behavior Control"
 	default n
 	select SPI_HWFEATURES
+	depends on ARCH_HAVE_SPI_CS_CONTROL
 	---help---
 		Enables possibilities to define the behavior of CS.
 		Also enables the hwfeatures() interface method.
 
+config ARCH_HAVE_SPI_BITORDER
+	bool
+	default n
+
 config SPI_BITORDER
 	bool "SPI Bit Order Control"
 	default n
 	select SPI_HWFEATURES
+	depends on ARCH_HAVE_SPI_BITORDER
 	---help---
 		Enables capability to select MSB- or LSB-first hardware feature for
 		data transfers.

drivers/wireless/pn532.c

@@ -65,6 +65,10 @@
 #  error CONFIG_SPI_HWFEATURES=y and CONFIG_SPI_BITORDER=y required by this driver
 #endif
 
+#ifndef CONFIG_ARCH_HAVE_SPI_BITORDER
+#  warning This platform does not support SPI LSB-bit order
+#endif
+
 #ifdef CONFIG_WL_PN532_DEBUG
 #  define pn532err    _err
 #  define pn532info   _info