[PATCH] MMC: wbsd delayed insertion

Wait 0.5 seconds before scanning for cards after an insertion interrupt.
The electrical connection needs this time to stabilise for some cards.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mmc/wbsd.c

@@ -1050,6 +1050,20 @@ static struct mmc_host_ops wbsd_ops = {
  *                                                                           *
 \*****************************************************************************/
 
+/*
+ * Helper function for card detection
+ */
+static void wbsd_detect_card(unsigned long data)
+{
+	struct wbsd_host *host = (struct wbsd_host*)data;
+
+	BUG_ON(host == NULL);
+
+	DBG("Executing card detection\n");
+
+	mmc_detect_change(host->mmc);	
+}
+
 /*
  * Tasklets
  */
@@ -1075,7 +1089,6 @@ static void wbsd_tasklet_card(unsigned long param)
 {
 	struct wbsd_host* host = (struct wbsd_host*)param;
 	u8 csr;
-	int change = 0;
 
 	spin_lock(&host->lock);
 
@@ -1094,14 +1107,20 @@ static void wbsd_tasklet_card(unsigned long param)
 		{
 			DBG("Card inserted\n");
 			host->flags |= WBSD_FCARD_PRESENT;
-			change = 1;
+
+			/*
+			 * Delay card detection to allow electrical connections
+			 * to stabilise.
+			 */
+			mod_timer(&host->timer, jiffies + HZ/2);
 		}
+
+		spin_unlock(&host->lock);
 	}
 	else if (host->flags & WBSD_FCARD_PRESENT)
 	{
 		DBG("Card removed\n");
 		host->flags &= ~WBSD_FCARD_PRESENT;
-		change = 1;
 
 		if (host->mrq)
 		{
@@ -1112,15 +1131,14 @@ static void wbsd_tasklet_card(unsigned long param)
 			host->mrq->cmd->error = MMC_ERR_FAILED;
 			tasklet_schedule(&host->finish_tasklet);
 		}
-	}
-
-	/*
-	 * Unlock first since we might get a call back.
-	 */
-	spin_unlock(&host->lock);
+
+		/*
+		 * Unlock first since we might get a call back.
+		 */
+		spin_unlock(&host->lock);
 
-	if (change)
 		mmc_detect_change(host->mmc);
+	}
 }
 
 static void wbsd_tasklet_fifo(unsigned long param)
@@ -1324,6 +1342,13 @@ static int __devinit wbsd_alloc_mmc(struct device* dev)
 
 	spin_lock_init(&host->lock);
 
+	/*
+	 * Set up detection timer
+	 */
+	init_timer(&host->timer);
+	host->timer.data = (unsigned long)host;
+	host->timer.function = wbsd_detect_card;
+
 	/*
 	 * Maximum number of segments. Worst case is one sector per segment
 	 * so this will be 64kB/512.
@@ -1351,11 +1376,17 @@ static int __devinit wbsd_alloc_mmc(struct device* dev)
 static void __devexit wbsd_free_mmc(struct device* dev)
 {
 	struct mmc_host* mmc;
+	struct wbsd_host* host;
 
 	mmc = dev_get_drvdata(dev);
 	if (!mmc)
 		return;
 
+	host = mmc_priv(mmc);
+	BUG_ON(host == NULL);
+
+	del_timer_sync(&host->timer);
+
 	mmc_free_host(mmc);
 
 	dev_set_drvdata(dev, NULL);

drivers/mmc/wbsd.h

@@ -187,4 +187,6 @@ struct wbsd_host
 	struct tasklet_struct	timeout_tasklet;
 	struct tasklet_struct	finish_tasklet;
 	struct tasklet_struct	block_tasklet;
+
+	struct timer_list	timer;		/* Card detection timer */
 };