diff --git a/drivers/adc/adc_dw.c b/drivers/adc/adc_dw.c
index ab7afc37178..119a9a8f227 100644
--- a/drivers/adc/adc_dw.c
+++ b/drivers/adc/adc_dw.c
@@ -302,14 +302,13 @@ static int adc_dw_read_request(struct device *dev,
 
 	adc_context_start_read(&info->ctx, seq_tbl);
 	error = adc_context_wait_for_completion(&info->ctx);
-	adc_context_release(&info->ctx, error);
 
 	if (info->state == ADC_STATE_ERROR) {
 		info->state = ADC_STATE_IDLE;
 		return -EIO;
 	}
 
-	return 0;
+	return error;
 }
 
 static int adc_dw_read(struct device *dev, const struct adc_sequence *seq_tbl)
@@ -318,8 +317,9 @@ static int adc_dw_read(struct device *dev, const struct adc_sequence *seq_tbl)
 	int ret;
 
 	adc_context_lock(&info->ctx, false, NULL);
-
 	ret = adc_dw_read_request(dev, seq_tbl);
+	adc_context_release(&info->ctx, ret);
+
 	return ret;
 }
 
@@ -330,9 +330,13 @@ static int adc_dw_read_async(struct device *dev,
 			       struct k_poll_signal *async)
 {
 	struct adc_info *info = dev->driver_data;
+	int ret;
 
 	adc_context_lock(&info->ctx, true, async);
-	return adc_dw_read_request(dev, sequence);
+	ret = adc_dw_read_request(dev, sequence);
+	adc_context_release(&info->ctx, ret);
+
+	return ret;
 }
 #endif
 
diff --git a/drivers/adc/adc_intel_quark_d2000.c b/drivers/adc/adc_intel_quark_d2000.c
index 9ab4076831d..5c7ca5d20d4 100644
--- a/drivers/adc/adc_intel_quark_d2000.c
+++ b/drivers/adc/adc_intel_quark_d2000.c
@@ -289,20 +289,22 @@ static int adc_quark_d2000_read_request(struct device *dev,
 	}
 
 	adc_context_start_read(&info->ctx, seq_tbl);
-	error = adc_context_wait_for_completion(&info->ctx);
-	adc_context_release(&info->ctx, error);
 
-	return 0;
+	error = adc_context_wait_for_completion(&info->ctx);
+	return error;
 }
 
 static int adc_quark_d2000_read(struct device *dev,
 			   const struct adc_sequence *sequence)
 {
 	struct adc_quark_d2000_info *info = dev->driver_data;
+	int error;
 
 	adc_context_lock(&info->ctx, false, NULL);
+	error = adc_quark_d2000_read_request(dev, sequence);
+	adc_context_release(&info->ctx, error);
 
-	return adc_quark_d2000_read_request(dev, sequence);
+	return error;
 }
 
 #ifdef CONFIG_ADC_ASYNC
@@ -311,10 +313,13 @@ static int adc_quark_d2000_read_async(struct device *dev,
 				      struct k_poll_signal *async)
 {
 	struct adc_quark_d2000_info *info = dev->driver_data;
+	int error;
 
 	adc_context_lock(&info->ctx, true, async);
+	error = adc_quark_d2000_read_request(dev, sequence);
+	adc_context_release(&info->ctx, error);
 
-	return adc_quark_d2000_read_request(dev, sequence);
+	return error;
 }
 #endif
 
diff --git a/drivers/adc/adc_mcux_adc16.c b/drivers/adc/adc_mcux_adc16.c
index 7f214d9904e..86fde47ef85 100644
--- a/drivers/adc/adc_mcux_adc16.c
+++ b/drivers/adc/adc_mcux_adc16.c
@@ -124,9 +124,8 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 	data->buffer = sequence->buffer;
 
 	adc_context_start_read(&data->ctx, sequence);
-	error = adc_context_wait_for_completion(&data->ctx);
-	adc_context_release(&data->ctx, error);
 
+	error = adc_context_wait_for_completion(&data->ctx);
 	return error;
 }
 
@@ -134,9 +133,13 @@ static int mcux_adc16_read(struct device *dev,
 			   const struct adc_sequence *sequence)
 {
 	struct mcux_adc16_data *data = dev->driver_data;
+	int error;
 
 	adc_context_lock(&data->ctx, false, NULL);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&data->ctx, error);
+
+	return error;
 }
 
 #ifdef CONFIG_ADC_ASYNC
@@ -145,9 +148,13 @@ static int mcux_adc16_read_async(struct device *dev,
 				 struct k_poll_signal *async)
 {
 	struct mcux_adc16_data *data = dev->driver_data;
+	int error;
 
 	adc_context_lock(&data->ctx, true, async);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&data->ctx, error);
+
+	return error;
 }
 #endif
 
diff --git a/drivers/adc/adc_nrfx_adc.c b/drivers/adc/adc_nrfx_adc.c
index b4a18a2ba88..49ca6ab4aaf 100644
--- a/drivers/adc/adc_nrfx_adc.c
+++ b/drivers/adc/adc_nrfx_adc.c
@@ -136,7 +136,7 @@ static int check_buffer_size(const struct adc_sequence *sequence,
 
 static int start_read(struct device *dev, const struct adc_sequence *sequence)
 {
-	int error = 0;
+	int error;
 	u32_t selected_channels = sequence->channels;
 	u8_t active_channels;
 	u8_t channel_id;
@@ -203,11 +203,7 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 
 	adc_context_start_read(&m_data.ctx, sequence);
 
-	if (!error) {
-		error = adc_context_wait_for_completion(&m_data.ctx);
-		adc_context_release(&m_data.ctx, error);
-	}
-
+	error = adc_context_wait_for_completion(&m_data.ctx);
 	return error;
 }
 
@@ -215,8 +211,13 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 static int adc_nrfx_read(struct device *dev,
 			 const struct adc_sequence *sequence)
 {
+	int error;
+
 	adc_context_lock(&m_data.ctx, false, NULL);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&m_data.ctx, error);
+
+	return error;
 }
 
 #ifdef CONFIG_ADC_ASYNC
@@ -225,10 +226,15 @@ static int adc_nrfx_read_async(struct device *dev,
 			       const struct adc_sequence *sequence,
 			       struct k_poll_signal *async)
 {
+	int error;
+
 	adc_context_lock(&m_data.ctx, true, async);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&m_data.ctx, error);
+
+	return error;
 }
-#endif
+#endif /* CONFIG_ADC_ASYNC */
 
 DEVICE_DECLARE(adc_0);
 
diff --git a/drivers/adc/adc_nrfx_saadc.c b/drivers/adc/adc_nrfx_saadc.c
index ab2ba8167a6..3abb737d38b 100644
--- a/drivers/adc/adc_nrfx_saadc.c
+++ b/drivers/adc/adc_nrfx_saadc.c
@@ -247,7 +247,7 @@ static int check_buffer_size(const struct adc_sequence *sequence,
 
 static int start_read(struct device *dev, const struct adc_sequence *sequence)
 {
-	int error = 0;
+	int error;
 	u32_t selected_channels = sequence->channels;
 	u8_t active_channels;
 	u8_t channel_id;
@@ -322,8 +322,6 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 	adc_context_start_read(&m_data.ctx, sequence);
 
 	error = adc_context_wait_for_completion(&m_data.ctx);
-	adc_context_release(&m_data.ctx, error);
-
 	return error;
 }
 
@@ -331,8 +329,13 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 static int adc_nrfx_read(struct device *dev,
 			 const struct adc_sequence *sequence)
 {
+	int error;
+
 	adc_context_lock(&m_data.ctx, false, NULL);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&m_data.ctx, error);
+
+	return error;
 }
 
 #ifdef CONFIG_ADC_ASYNC
@@ -341,10 +344,15 @@ static int adc_nrfx_read_async(struct device *dev,
 			       const struct adc_sequence *sequence,
 			       struct k_poll_signal *async)
 {
+	int error;
+
 	adc_context_lock(&m_data.ctx, true, async);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&m_data.ctx, error);
+
+	return error;
 }
-#endif
+#endif /* CONFIG_ADC_ASYNC */
 
 static void saadc_irq_handler(void *param)
 {
diff --git a/drivers/adc/adc_sam_afec.c b/drivers/adc/adc_sam_afec.c
index ac09e3df527..072a02b42e8 100644
--- a/drivers/adc/adc_sam_afec.c
+++ b/drivers/adc/adc_sam_afec.c
@@ -242,8 +242,6 @@ static int start_read(struct device *dev, const struct adc_sequence *sequence)
 	adc_context_start_read(&data->ctx, sequence);
 
 	error = adc_context_wait_for_completion(&data->ctx);
-	adc_context_release(&data->ctx, error);
-
 	return error;
 }
 
@@ -251,9 +249,13 @@ static int adc_sam_read(struct device *dev,
 			const struct adc_sequence *sequence)
 {
 	struct adc_sam_data *data = DEV_DATA(dev);
+	int error;
 
 	adc_context_lock(&data->ctx, false, NULL);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&data->ctx, error);
+
+	return error;
 }
 
 static int adc_sam_init(struct device *dev)
@@ -302,9 +304,13 @@ static int adc_sam_read_async(struct device *dev,
 			      struct k_poll_signal *async)
 {
 	struct adc_sam_data *data = DEV_DATA(dev);
+	int error;
 
 	adc_context_lock(&data->ctx, true, async);
-	return start_read(dev, sequence);
+	error = start_read(dev, sequence);
+	adc_context_release(&data->ctx, error);
+
+	return error;
 }
 #endif