linux-kernel - [PATCH] Input: cyapa_gen3: use msleep() for long delay

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Message-Id: <1484478787-13178-1-git-send-email-hofrat@osadl.org>
Date:   Sun, 15 Jan 2017 12:13:07 +0100
From:   Nicholas Mc Guire <hofrat@...dl.org>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Henrik Rydberg <rydberg@...math.org>, Dudley Du <dudl@...ress.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nicholas Mc Guire <hofrat@...dl.org>
Subject: [PATCH] Input: cyapa_gen3: use msleep() for long delay

ulseep_range() uses hrtimers and provides no advantage over msleep()
for larger delays. Fix up the 50ms delays here to use msleep() and
reduce the load on the hrtimer subsystem. 

Signed-off-by: Nicholas Mc Guire <hofrat@...dl.org>
---
Problem found by coccinelle script

As the needed delay is specified in the comment as being "at least 50ms"
the msleep(50) should be fine here. 

Note that cyapa_gen3_bl_exit() is returning -EAGAIN in cases where it was
not yet ready to process the request, but the calling side 
cyapa_gen3_do_operational_check() does not check for -EAGAIN so in case of
the noted increased delay "...can take up to an additional 2 seconds. If 
the device power is running low, this may take even longer", maybe
cyapa_gen3_do_operational_check() may need a retry loop on -EAGAIN ?

Patch was compile tested with: x86_64_defconfig + CONFIG_MOUSE_CYAPA=m

Patch is against 4.10-rc3 (localversion-next is next-20170113)

 drivers/input/mouse/cyapa_gen3.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/mouse/cyapa_gen3.c b/drivers/input/mouse/cyapa_gen3.c
index f9600753..6e9ecb0 100644
--- a/drivers/input/mouse/cyapa_gen3.c
+++ b/drivers/input/mouse/cyapa_gen3.c
@@ -562,7 +562,7 @@ static int cyapa_gen3_bl_exit(struct cyapa *cyapa)
 	 * Wait for bootloader to exit, and operation mode to start.
 	 * Normally, this takes at least 50 ms.
 	 */
-	usleep_range(50000, 100000);
+	msleep(50);
 	/*
 	 * In addition, when a device boots for the first time after being
 	 * updated to new firmware, it must first calibrate its sensors, which
-- 
2.1.4