releases/3.19.2/iio-mxs-lradc-make-adc-reads-not-disable-touchscreen-interrupts.patch

From 86bf7f3ef7e961e91e16dceb31ae0f583483b204 Mon Sep 17 00:00:00 2001
From: Kristina Martšenko <kristina.martsenko@gmail.com>
Date: Sun, 25 Jan 2015 18:28:20 +0200
Subject: iio: mxs-lradc: make ADC reads not disable touchscreen interrupts
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From: Kristina Martšenko <kristina.martsenko@gmail.com>

commit 86bf7f3ef7e961e91e16dceb31ae0f583483b204 upstream.

Reading a channel through sysfs, or starting a buffered capture, will
currently turn off the touchscreen. This is because the read_raw() and
buffer preenable()/postdisable() callbacks disable interrupts for all
LRADC channels, including those the touchscreen uses.

So make the callbacks only disable interrupts for the channels they use.
This means channel 0 for read_raw() and channels 0-5 for the buffer (if
the touchscreen is enabled). Since the touchscreen uses different
channels (6 and 7), it no longer gets turned off.

Note that only i.MX28 is affected by this issue, i.MX23 should be fine.

Signed-off-by: Kristina Martšenko <kristina.martsenko@gmail.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/iio/adc/mxs-lradc.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

--- a/drivers/staging/iio/adc/mxs-lradc.c
+++ b/drivers/staging/iio/adc/mxs-lradc.c
@@ -220,6 +220,9 @@ struct mxs_lradc {
 	 */
 #define TOUCHSCREEN_VCHANNEL1		7
 #define TOUCHSCREEN_VCHANNEL2		6
+#define BUFFER_VCHANS_LIMITED		0x3f
+#define BUFFER_VCHANS_ALL		0xff
+	u8			buffer_vchans;
 
 	/*
 	 * Furthermore, certain LRADC channels are shared between touchscreen
@@ -819,7 +822,7 @@ static int mxs_lradc_read_single(struct
 	 * used if doing raw sampling.
 	 */
 	if (lradc->soc == IMX28_LRADC)
-		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
+		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_LRADC_IRQ_EN(0),
 			LRADC_CTRL1);
 	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 
@@ -1266,8 +1269,9 @@ static int mxs_lradc_buffer_preenable(st
 	}
 
 	if (lradc->soc == IMX28_LRADC)
-		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
-							LRADC_CTRL1);
+		mxs_lradc_reg_clear(lradc,
+			lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
+			LRADC_CTRL1);
 	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 
 	for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
@@ -1303,8 +1307,9 @@ static int mxs_lradc_buffer_postdisable(
 
 	mxs_lradc_reg_clear(lradc, 0xff, LRADC_CTRL0);
 	if (lradc->soc == IMX28_LRADC)
-		mxs_lradc_reg_clear(lradc, LRADC_CTRL1_MX28_LRADC_IRQ_EN_MASK,
-					LRADC_CTRL1);
+		mxs_lradc_reg_clear(lradc,
+			lradc->buffer_vchans << LRADC_CTRL1_LRADC_IRQ_EN_OFFSET,
+			LRADC_CTRL1);
 
 	kfree(lradc->buffer);
 	mutex_unlock(&lradc->lock);
@@ -1549,6 +1554,11 @@ static int mxs_lradc_probe(struct platfo
 
 	touch_ret = mxs_lradc_probe_touchscreen(lradc, node);
 
+	if (touch_ret == 0)
+		lradc->buffer_vchans = BUFFER_VCHANS_LIMITED;
+	else
+		lradc->buffer_vchans = BUFFER_VCHANS_ALL;
+
 	/* Grab all IRQ sources */
 	for (i = 0; i < of_cfg->irq_count; i++) {
 		lradc->irq[i] = platform_get_irq(pdev, i);