Original pull request had added these checks to a deleted file. Replicating that change to allow builds on the NRF52840_DK (see original PR #4088 to see the explanation for the removal of spi async)

kegilbert · kegilbert · commit f324647aae96 · 2017-06-08T17:31:24.000-05:00
diff --git a/targets/TARGET_NORDIC/TARGET_NRF5/spi_api.c b/targets/TARGET_NORDIC/TARGET_NRF5/spi_api.c
@@ -141,11 +141,13 @@ static void master_event_handler(uint8_t spi_idx,
 
     if (p_event->type == NRF_DRV_SPI_EVENT_DONE) {
         p_spi_info->flag.busy = false;
+#if DEVICE_SPI_ASYNCH
         if (p_spi_info->handler) {
             void (*handler)(void) = (void (*)(void))p_spi_info->handler;
             p_spi_info->handler = 0;
             handler();
         }
+#endif
     }
 }
 #define MASTER_EVENT_HANDLER(idx) \

Original file line number	Diff line number	Diff line change
`@@ -141,11 +141,13 @@ static void master_event_handler(uint8_t spi_idx,`
`141`	`141`
`142`	`142`	`if (p_event->type == NRF_DRV_SPI_EVENT_DONE) {`
`143`	`143`	`p_spi_info->flag.busy = false;`
	`144`	`+#if DEVICE_SPI_ASYNCH`
`144`	`145`	`if (p_spi_info->handler) {`
`145`	`146`	`void (handler)(void) = (void ()(void))p_spi_info->handler;`
`146`	`147`	`p_spi_info->handler = 0;`
`147`	`148`	`handler();`
`148`	`149`	`}`
	`150`	`+#endif`
`149`	`151`	`}`
`150`	`152`	`}`
`151`	`153`	`#define MASTER_EVENT_HANDLER(idx) \`