drivers: spi: stm32: invert ll_func_spi_dma_busy logic

Inverts ll_func_spi_dma_busy logic so that the function returns true if
the SPI DMA is busy (as suggested by the name) instead of the other way
around.
Also completes the check for H7-compatible with the LL_SPI_IsActiveFlag_EOT
function when transfer size is set.

Signed-off-by: Guillaume Gautier <guillaume.gautier-ext@st.com>

Author: gautierg-st

drivers/spi/spi_stm32.c

@@ -1443,12 +1443,12 @@ static int transceive_dma(const struct device *dev,
 #endif /* SPI_SR_FTLVL */
 
 #ifdef CONFIG_SPI_STM32_ERRATA_BUSY
-		WAIT_FOR(ll_func_spi_dma_busy(spi) != 0,
+		WAIT_FOR(!ll_func_spi_dma_busy(spi),
 			 CONFIG_SPI_STM32_BUSY_FLAG_TIMEOUT,
 			 k_yield());
 #else
 		/* wait until spi is no more busy (spi TX fifo is really empty) */
-		while (ll_func_spi_dma_busy(spi) == 0) {
+		while (ll_func_spi_dma_busy(spi)) {
 		}
 #endif /* CONFIG_SPI_STM32_ERRATA_BUSY */
 

drivers/spi/spi_stm32.h

@@ -97,15 +97,19 @@ static inline uint32_t ll_func_dma_get_reg_addr(SPI_TypeDef *spi, uint32_t locat
 /* checks that DMA Tx packet is fully transmitted over the SPI */
 static inline uint32_t ll_func_spi_dma_busy(SPI_TypeDef *spi)
 {
-#ifdef LL_SPI_SR_TXC
-	return LL_SPI_IsActiveFlag_TXC(spi);
+#if DT_HAS_COMPAT_STATUS_OKAY(st_stm32h7_spi)
+	if (LL_SPI_GetTransferSize(spi) == 0) {
+		return LL_SPI_IsActiveFlag_TXC(spi) == 0;
+	} else {
+		return LL_SPI_IsActiveFlag_EOT(spi) == 0;
+	}
 #else
 	/* the SPI Tx empty and busy flags are needed */
-	return (LL_SPI_IsActiveFlag_TXE(spi) &&
-		!LL_SPI_IsActiveFlag_BSY(spi));
+	return (!LL_SPI_IsActiveFlag_TXE(spi) ||
+		LL_SPI_IsActiveFlag_BSY(spi));
 #endif /* LL_SPI_SR_TXC */
 }
-#endif /* CONFIG_SPI_STM32_DMA */
+#endif /* st_stm32h7_spi */
 
 static inline uint32_t ll_func_tx_is_not_full(SPI_TypeDef *spi)
 {