drivers: adc: Fix handling of invalid sampling requests

Commit aad21ecb31 introduced an incorrect
pattern of handling ADC sampling requests with invalid parameters in
both nRF ADC drivers. After discarding such request, the drivers do not
release properly the access lock and therefore become unusable.
Unfortunately, this pattern were later on copied in all other ADC
drivers in the source tree.
This commit adds the proper lock releasing in all the affected drivers.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>

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
 

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
 

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
 

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);
-	}
-
 	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);
 

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)
 {

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