[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>

2 files changed, 43 insertions, 10 deletions

diff --git a/drivers/mmc/wbsd.c b/drivers/mmc/wbsd.c
index b7fbd30b49a0..0bd9b53fa898 100644
--- a/drivers/mmc/wbsd.c
+++ b/drivers/mmc/wbsd.c
@@ -1051,6 +1051,20 @@ 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)
@@ -1325,6 +1343,13 @@ 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);
diff --git a/drivers/mmc/wbsd.h b/drivers/mmc/wbsd.h
index 864f30828d01..9f5383e6e593 100644
--- a/drivers/mmc/wbsd.h
+++ b/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 */
 };