drivers: spi: siwx91x: Simplify error management

In functions requiring to lock/release resources, it is less error prone to
have only one exit point and user goto to manage errors.

The behavior of the new code is exactly identical to the initial one.

Signed-off-by: Jérôme Pouiller <[email protected]>
Upstream-status: pr <zephyrproject-rtos#100762>

Author: jerome-pouiller

drivers/spi/spi_silabs_siwx91x_gspi.c

@@ -626,7 +626,7 @@ static int gspi_siwx91x_transceive(const struct device *dev, const struct spi_co
 				   spi_callback_t cb, void *userdata)
 {
 	struct gspi_siwx91x_data *data = dev->data;
-	int ret = 0;
+	int ret;
 
 	ret = pm_device_runtime_get(dev);
 	if (ret < 0) {
@@ -635,40 +635,38 @@ static int gspi_siwx91x_transceive(const struct device *dev, const struct spi_co
 
 	if (!spi_siwx91x_is_dma_enabled_instance(dev) && asynchronous) {
 		ret = -ENOTSUP;
-		pm_device_runtime_put(dev);
-		return ret;
+		goto pm;
 	}
 
 	spi_context_lock(&data->ctx, asynchronous, cb, userdata, config);
-	/* Configure the device if it is not already configured */
 	if (!spi_context_configured(&data->ctx, config)) {
 		ret = gspi_siwx91x_config(dev, config, cb, userdata);
 		if (ret) {
-			spi_context_release(&data->ctx, ret);
-			pm_device_runtime_put(dev);
-			return ret;
+			goto context;
 		}
 	}
 
 	spi_context_buffers_setup(&data->ctx, tx_bufs, rx_bufs,
 				  SPI_WORD_SIZE_GET(config->operation) / 8);
 
-	/* Check if DMA is enabled */
 	if (spi_siwx91x_is_dma_enabled_instance(dev)) {
-		/* Perform DMA transceive */
 		ret = gspi_siwx91x_transceive_dma(dev, config);
-		if (ret < 0) {
-			pm_device_runtime_put(dev);
-		}
-		spi_context_release(&data->ctx, ret);
 	} else {
-		/* Perform synchronous polling transceive */
 		ret = gspi_siwx91x_transceive_polling_sync(dev, &data->ctx);
-		spi_context_unlock_unconditionally(&data->ctx);
-		pm_device_runtime_put(dev);
 	}
 
+	if (spi_siwx91x_is_dma_enabled_instance(dev) && !ret) {
+		/* pm_device_runtime_put(dev) is called from the dma callback */
+		spi_context_release(&data->ctx, ret);
+		return ret;
+	}
+
+context:
+	spi_context_release(&data->ctx, ret);
+pm:
+	pm_device_runtime_put(dev);
 	return ret;
+
 }
 
 static int gspi_siwx91x_transceive_sync(const struct device *dev, const struct spi_config *config,