atmel_spi: Driver for the Atmel SPI controller

This adds a driver for the SPI controller found on most AT91 and AVR32
chips, implementing the new SPI API.

Changed in v4:
  - Update to new API
  - Handle zero-length transfers appropriately. The user may send a
    zero-length SPI transfer with SPI_XFER_END set in order to
    deactivate the chip select after a series of transfers with chip
    select active. This is useful e.g. when polling the status
    register of DataFlash.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/include/asm-avr32/arch-at32ap700x/gpio.h b/include/asm-avr32/arch-at32ap700x/gpio.h
index b10a3e4..ef20cea 100644
--- a/include/asm-avr32/arch-at32ap700x/gpio.h
+++ b/include/asm-avr32/arch-at32ap700x/gpio.h
@@ -216,5 +216,9 @@
 #ifdef AT32AP700x_CHIP_HAS_MMCI
 void gpio_enable_mmci(void);
 #endif
+#ifdef AT32AP700x_CHIP_HAS_SPI
+void gpio_enable_spi0(unsigned long cs_mask);
+void gpio_enable_spi1(unsigned long cs_mask);
+#endif
 
 #endif /* __ASM_AVR32_ARCH_GPIO_H__ */