[PATCH] NFC: added the sysfs entry for nfcsim workqueue delay

[Saurabh Sengar]

added the sysfs entry for nfcsim workqueue delay, as tx_delay

Signed-off-by: Saurabh Sengar <saurabh.truth@xxxxxxxxx>
---
Hi,

As I have understood form TODO comment, I have implemented the sysfs entry
for this device.
Sorry, in case this patch is not meeting the expectation.
I am just finding my way to contribute in linux kernel :)

Regards,
Saurabh

 drivers/nfc/nfcsim.c | 38 +++++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

diff --git a/drivers/nfc/nfcsim.c b/drivers/nfc/nfcsim.c
index 93111fa..d1ace87 100644
--- a/drivers/nfc/nfcsim.c
+++ b/drivers/nfc/nfcsim.c
@@ -32,6 +32,8 @@
 #define NFCSIM_POLL_TARGET	2
 #define NFCSIM_POLL_DUAL	(NFCSIM_POLL_INITIATOR | NFCSIM_POLL_TARGET)
 
+#define TX_DEFAULT_DELAY	5
+
 struct nfcsim {
 	struct nfc_dev *nfc_dev;
 
@@ -62,12 +64,41 @@ static struct nfcsim *dev1;
 
 static struct workqueue_struct *wq;
 
+
+static int tx_delay = TX_DEFAULT_DELAY;
+
+static ssize_t show_tx_delay(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	int n;
+
+	n = scnprintf(buf, PAGE_SIZE, "%d\n", tx_delay);
+	return n;
+}
+
+static ssize_t store_tx_delay(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	if (kstrtouint(buf, 0, &tx_delay) < 0)
+		return -EINVAL;
+
+	if (tx_delay < 0)
+		return -EINVAL;
+
+	return count;
+}
+
+static DEVICE_ATTR(tx_delay, 0644, show_tx_delay, store_tx_delay);
+
 static void nfcsim_cleanup_dev(struct nfcsim *dev, u8 shutdown)
 {
 	DEV_DBG(dev, "shutdown=%d\n", shutdown);
 
 	mutex_lock(&dev->lock);
 
+	device_remove_file(&dev->nfc_dev->dev, &dev_attr_tx_delay);
 	dev->polling_mode = NFCSIM_POLL_NONE;
 	dev->shutting_down = shutdown;
 	dev->cb = NULL;
@@ -320,10 +351,8 @@ static int nfcsim_tx(struct nfc_dev *nfc_dev, struct nfc_target *target,
 	 * If packet transmission occurs immediately between them, we have a
 	 * non-stop flow of several tens of thousands SYMM packets per second
 	 * and a burning cpu.
-	 *
-	 * TODO: Add support for a sysfs entry to control this delay.
 	 */
-	queue_delayed_work(wq, &peer->recv_work, msecs_to_jiffies(5));
+	queue_delayed_work(wq, &peer->recv_work, msecs_to_jiffies(tx_delay));
 
 	mutex_unlock(&peer->lock);
 
@@ -461,6 +490,9 @@ static struct nfcsim *nfcsim_init_dev(void)
 	if (rc)
 		goto free_nfc_dev;
 
+	rc = device_create_file(&dev->nfc_dev->dev, &dev_attr_tx_delay);
+	if (rc)
+		pr_err("error creating sysfs entry\n");
 	return dev;
 
 free_nfc_dev:
-- 
1.9.1

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