NFC: digital: Add a delay between poll cycles

This replaces the polling work struct with a delayed work struct and add
a 10 ms delay between 2 poll cycles. This avoids to flood the device
with 'switch off'/'switch on' commands.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 11 insertions, 7 deletions

diff --git a/include/net/nfc/digital.h b/include/net/nfc/digital.h
index 0ae101eef0f4..506e3f6eabef 100644
--- a/include/net/nfc/digital.h
+++ b/include/net/nfc/digital.h
@@ -220,7 +220,7 @@ struct nfc_digital_dev {
         struct list_head cmd_queue;
         struct mutex cmd_lock;
 
-        struct work_struct poll_work;
+        struct delayed_work poll_work;
 
         u8 curr_protocol;
         u8 curr_rf_tech;
diff --git a/net/nfc/digital_core.c b/net/nfc/digital_core.c
index dd9003f38822..27769ac89d27 100644
--- a/net/nfc/digital_core.c
+++ b/net/nfc/digital_core.c
@@ -30,6 +30,9 @@
 
 #define DIGITAL_PROTO_ISO15693_RF_TECH  NFC_PROTO_ISO15693_MASK
 
+/* Delay between each poll frame (ms) */
+#define DIGITAL_POLL_INTERVAL 10
+
 struct digital_cmd {
         struct list_head queue;
 
@@ -419,7 +422,8 @@ void digital_poll_next_tech(struct nfc_digital_dev *ddev)
 
         mutex_unlock(&ddev->poll_lock);
 
-        schedule_work(&ddev->poll_work);
+        schedule_delayed_work(&ddev->poll_work,
+                              msecs_to_jiffies(DIGITAL_POLL_INTERVAL));
 }
 
 static void digital_wq_poll(struct work_struct *work)
@@ -428,7 +432,7 @@ static void digital_wq_poll(struct work_struct *work)
         struct digital_poll_tech *poll_tech;
         struct nfc_digital_dev *ddev = container_of(work,
                                                     struct nfc_digital_dev,
-                                                    poll_work);
+                                                    poll_work.work);
         mutex_lock(&ddev->poll_lock);
 
         if (!ddev->poll_tech_count) {
@@ -543,7 +547,7 @@ static int digital_start_poll(struct nfc_dev *nfc_dev, __u32 im_protocols,
                 return -EINVAL;
         }
 
-        schedule_work(&ddev->poll_work);
+        schedule_delayed_work(&ddev->poll_work, 0);
 
         return 0;
 }
@@ -564,7 +568,7 @@ static void digital_stop_poll(struct nfc_dev *nfc_dev)
 
         mutex_unlock(&ddev->poll_lock);
 
-        cancel_work_sync(&ddev->poll_work);
+        cancel_delayed_work_sync(&ddev->poll_work);
 
         digital_abort_cmd(ddev);
 }
@@ -770,7 +774,7 @@ struct nfc_digital_dev *nfc_digital_allocate_device(struct nfc_digital_ops *ops,
         INIT_WORK(&ddev->cmd_complete_work, digital_wq_cmd_complete);
 
         mutex_init(&ddev->poll_lock);
-        INIT_WORK(&ddev->poll_work, digital_wq_poll);
+        INIT_DELAYED_WORK(&ddev->poll_work, digital_wq_poll);
 
         if (supported_protocols & NFC_PROTO_JEWEL_MASK)
                 ddev->protocols |= NFC_PROTO_JEWEL_MASK;
@@ -832,7 +836,7 @@ void nfc_digital_unregister_device(struct nfc_digital_dev *ddev)
         ddev->poll_tech_count = 0;
         mutex_unlock(&ddev->poll_lock);
 
-        cancel_work_sync(&ddev->poll_work);
+        cancel_delayed_work_sync(&ddev->poll_work);
         cancel_work_sync(&ddev->cmd_work);
         cancel_work_sync(&ddev->cmd_complete_work);