NFC: IRQ gpio usage modification in nfc_read

Modified condition to ensure data is read
only after interrupt has occurred.

Spurious interrupt handling is done in nfc_read
instead of irq handler.

Change-Id: Ie2362610fe922e792e6358b4386c828fdd754fa8
Signed-off-by: Gaurav Singhal <gsinghal@codeaurora.org>

diff --git a/drivers/nfc/nq-nci.c b/drivers/nfc/nq-nci.c
index 918f8c8..9b962a6 100644 (file)
--- a/drivers/nfc/nq-nci.c
+++ b/drivers/nfc/nq-nci.c
@@ -107,36 +107,14 @@ static void nqx_disable_irq(struct nqx_dev *nqx_dev)
        spin_unlock_irqrestore(&nqx_dev->irq_enabled_lock, flags);
 }
 
-static void nqx_enable_irq(struct nqx_dev *nqx_dev)
-{
-       unsigned long flags;
-
-       spin_lock_irqsave(&nqx_dev->irq_enabled_lock, flags);
-       if (!nqx_dev->irq_enabled) {
-               nqx_dev->irq_enabled = true;
-               enable_irq(nqx_dev->client->irq);
-       }
-       spin_unlock_irqrestore(&nqx_dev->irq_enabled_lock, flags);
-}
-
 static irqreturn_t nqx_dev_irq_handler(int irq, void *dev_id)
 {
        struct nqx_dev *nqx_dev = dev_id;
        unsigned long flags;
-       int ret;
 
        if (device_may_wakeup(&nqx_dev->client->dev))
                pm_wakeup_event(&nqx_dev->client->dev, WAKEUP_SRC_TIMEOUT);
 
-       ret = gpio_get_value(nqx_dev->irq_gpio);
-       if (!ret) {
-#ifdef NFC_KERNEL_BU
-               dev_info(&nqx_dev->client->dev,
-                       "nqx nfc : nqx_dev_irq_handler error = %d\n", ret);
-#endif
-               return IRQ_HANDLED;
-       }
-
        nqx_disable_irq(nqx_dev);
        spin_lock_irqsave(&nqx_dev->irq_enabled_lock, flags);
        nqx_dev->count_irq++;
@@ -175,15 +153,24 @@ static ssize_t nfc_read(struct file *filp, char __user *buf,
                        ret = -EAGAIN;
                        goto err;
                }
-               if (!nqx_dev->irq_enabled) {
-                       enable_irq(nqx_dev->client->irq);
-                       nqx_dev->irq_enabled = true;
+               while (1) {
+                       ret = 0;
+                       if (!nqx_dev->irq_enabled) {
+                               nqx_dev->irq_enabled = true;
+                               enable_irq(nqx_dev->client->irq);
+                       }
+                       if (!gpio_get_value(nqx_dev->irq_gpio)) {
+                               ret = wait_event_interruptible(nqx_dev->read_wq,
+                                       !nqx_dev->irq_enabled);
+                       }
+                       if (ret)
+                               goto err;
+                       nqx_disable_irq(nqx_dev);
+
+                       if (gpio_get_value(nqx_dev->irq_gpio))
+                               break;
+                       dev_err_ratelimited(&nqx_dev->client->dev, "gpio is low, no need to read data\n");
                }
-               ret = wait_event_interruptible(nqx_dev->read_wq,
-                               gpio_get_value(nqx_dev->irq_gpio));
-               if (ret)
-                       goto err;
-               nqx_disable_irq(nqx_dev);
        }
 
        tmp = nqx_dev->kbuf;
@@ -393,7 +380,6 @@ int nfc_ioctl_power_states(struct file *filp, unsigned long arg)
                /* hardware dependent delay */
                msleep(100);
        } else if (arg == 1) {
-               nqx_enable_irq(nqx_dev);
                dev_dbg(&nqx_dev->client->dev,
                        "gpio_set_value enable: %s: info: %p\n",
                        __func__, nqx_dev);