1 files changed, 16 insertions, 16 deletions

diff --git a/drivers/mfd/pcf50633-adc.c b/drivers/mfd/pcf50633-adc.c
index c2d05becfa97..3d31e97d6a45 100644
--- a/drivers/mfd/pcf50633-adc.c
+++ b/drivers/mfd/pcf50633-adc.c
@@ -73,15 +73,10 @@ static void trigger_next_adc_job_if_any(struct pcf50633 *pcf)
         struct pcf50633_adc *adc = __to_adc(pcf);
         int head;
 
-        mutex_lock(&adc->queue_mutex);
-
         head = adc->queue_head;
 
-        if (!adc->queue[head]) {
-                mutex_unlock(&adc->queue_mutex);
+        if (!adc->queue[head])
                 return;
-        }
-        mutex_unlock(&adc->queue_mutex);
 
         adc_setup(pcf, adc->queue[head]->mux, adc->queue[head]->avg);
 }
@@ -99,16 +94,17 @@ adc_enqueue_request(struct pcf50633 *pcf, struct pcf50633_adc_request *req)
 
         if (adc->queue[tail]) {
                 mutex_unlock(&adc->queue_mutex);
+                dev_err(pcf->dev, "ADC queue is full, dropping request\n");
                 return -EBUSY;
         }
 
         adc->queue[tail] = req;
+        if (head == tail)
+                trigger_next_adc_job_if_any(pcf);
         adc->queue_tail = (tail + 1) & (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
 
         mutex_unlock(&adc->queue_mutex);
 
-        trigger_next_adc_job_if_any(pcf);
-
         return 0;
 }
 
@@ -124,6 +120,7 @@ pcf50633_adc_sync_read_callback(struct pcf50633 *pcf, void *param, int result)
 int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
 {
         struct pcf50633_adc_request *req;
+        int err;
 
         /* req is freed when the result is ready, in interrupt handler */
         req = kzalloc(sizeof(*req), GFP_KERNEL);
@@ -136,9 +133,13 @@ int pcf50633_adc_sync_read(struct pcf50633 *pcf, int mux, int avg)
         req->callback_param = req;
 
         init_completion(&req->completion);
-        adc_enqueue_request(pcf, req);
+        err = adc_enqueue_request(pcf, req);
+        if (err)
+                return err;
+
         wait_for_completion(&req->completion);
 
+        /* FIXME by this time req might be already freed */
         return req->result;
 }
 EXPORT_SYMBOL_GPL(pcf50633_adc_sync_read);
@@ -159,9 +160,7 @@ int pcf50633_adc_async_read(struct pcf50633 *pcf, int mux, int avg,
         req->callback = callback;
         req->callback_param = callback_param;
 
-        adc_enqueue_request(pcf, req);
-
-        return 0;
+        return adc_enqueue_request(pcf, req);
 }
 EXPORT_SYMBOL_GPL(pcf50633_adc_async_read);
 
@@ -184,7 +183,7 @@ static void pcf50633_adc_irq(int irq, void *data)
         struct pcf50633_adc *adc = data;
         struct pcf50633 *pcf = adc->pcf;
         struct pcf50633_adc_request *req;
-        int head;
+        int head, res;
 
         mutex_lock(&adc->queue_mutex);
         head = adc->queue_head;
@@ -199,12 +198,13 @@ static void pcf50633_adc_irq(int irq, void *data)
         adc->queue_head = (head + 1) &
                                       (PCF50633_MAX_ADC_FIFO_DEPTH - 1);
 
+        res = adc_result(pcf);
+        trigger_next_adc_job_if_any(pcf);
+
         mutex_unlock(&adc->queue_mutex);
 
-        req->callback(pcf, req->callback_param, adc_result(pcf));
+        req->callback(pcf, req->callback_param, res);
         kfree(req);
-
-        trigger_next_adc_job_if_any(pcf);
 }
 
 static int __devinit pcf50633_adc_probe(struct platform_device *pdev)