linux-kernel - [PATCH 2/2] omap_hdq: use wait_event_timeout to wait for read to complete.

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Message-ID: <20120521234302.13661.65956.stgit@notabene.brown>
Date:	Tue, 22 May 2012 09:43:02 +1000
From:	NeilBrown <neilb@...e.de>
To:	Greg KH <gregkh@...uxfoundation.org>
Cc:	Evgeniy Polyakov <zbr@...emap.net>, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] omap_hdq: use wait_event_timeout to wait for read to
 complete.

There is no gain in having a loop - there is no risk of missing the
interrupt with wait_event_timeout.

Signed-off-by: NeilBrown <neilb@...e.de>
Acked-by: Evgeniy Polyakov <zbr@...emap.net>
---

 drivers/w1/masters/omap_hdq.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/w1/masters/omap_hdq.c b/drivers/w1/masters/omap_hdq.c
index 3036b61..848399b 100644
--- a/drivers/w1/masters/omap_hdq.c
+++ b/drivers/w1/masters/omap_hdq.c
@@ -354,7 +354,6 @@ static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
 {
 	int ret = 0;
 	u8 status;
-	unsigned long timeout = jiffies + OMAP_HDQ_TIMEOUT;
 
 	ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
 	if (ret < 0) {
@@ -372,15 +371,13 @@ static int hdq_read_byte(struct hdq_data *hdq_data, u8 *val)
 			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO,
 			OMAP_HDQ_CTRL_STATUS_DIR | OMAP_HDQ_CTRL_STATUS_GO);
 		/*
-		 * The RX comes immediately after TX. It
-		 * triggers another interrupt before we
-		 * sleep. So we have to wait for RXCOMPLETE bit.
+		 * The RX comes immediately after TX.
 		 */
-		while (!(hdq_data->hdq_irqstatus
-			& OMAP_HDQ_INT_STATUS_RXCOMPLETE)
-			&& time_before(jiffies, timeout)) {
-			schedule_timeout_uninterruptible(1);
-		}
+		wait_event_timeout(hdq_wait_queue,
+				   (hdq_data->hdq_irqstatus
+				    & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
+				   OMAP_HDQ_TIMEOUT);
+
 		hdq_reg_merge(hdq_data, OMAP_HDQ_CTRL_STATUS, 0,
 			OMAP_HDQ_CTRL_STATUS_DIR);
 		status = hdq_data->hdq_irqstatus;


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