[3.16.y-ckt stable] Patch "iio: mxs-lradc: only update the buffer when its conversions have finished" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    iio: mxs-lradc: only update the buffer when its conversions have finished

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From fc39fdcab5e37a4e3067609219125425d047320d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristina=20Mart=C5=A1enko?= <kristina.martsenko at gmail.com>
Date: Sun, 25 Jan 2015 18:28:22 +0200
Subject: iio: mxs-lradc: only update the buffer when its conversions have
 finished
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 89bb35e200bee745c539a96666e0792301ca40f1 upstream.

Using the touchscreen while running buffered capture results in the
buffer reporting lots of wrong values, often just zeros. This is because
we push readings to the buffer every time a touchscreen interrupt
arrives, including when the buffer's own conversions have not yet
finished. So let's only push to the buffer when its conversions are
ready.

Signed-off-by: Kristina Martšenko <kristina.martsenko at gmail.com>
Reviewed-by: Marek Vasut <marex at denx.de>
Signed-off-by: Jonathan Cameron <jic23 at kernel.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/staging/iio/adc/mxs-lradc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/iio/adc/mxs-lradc.c b/drivers/staging/iio/adc/mxs-lradc.c
index 565366fcfe3e..4907efaf5e3d 100644
--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -1157,10 +1157,12 @@ static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
 				LRADC_CTRL1_LRADC_IRQ(TOUCHSCREEN_VCHANNEL2));
 	}

-	if (iio_buffer_enabled(iio))
-		iio_trigger_poll(iio->trig, iio_get_time_ns());
-	else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
+	if (iio_buffer_enabled(iio)) {
+		if (reg & lradc->buffer_vchans)
+			iio_trigger_poll(iio->trig, iio_get_time_ns());
+	} else if (reg & LRADC_CTRL1_LRADC_IRQ(0)) {
 		complete(&lradc->completion);
+	}

 	mxs_lradc_reg_clear(lradc, reg & clr_irq, LRADC_CTRL1);