From 341deefe8f4584b09564193cb46d8cf386f491a5 Mon Sep 17 00:00:00 2001
From: Philip Rakity <prakity@marvell.com>
Date: Tue, 11 Oct 2011 20:54:55 -0700
Subject: [PATCH] Input: tsc2007 - make sure that X plate resistance is
 specified

Abort driver initialization if X plate resistance was not specified in
platform data as it will cause pressure to be always calculated as 0,
and making userspace ignore touch coordinates.

Signed-off-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---
 drivers/input/touchscreen/tsc2007.c | 6 ++++++
 include/linux/i2c/tsc2007.h         | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index 0acca68cc52b..1f674cb6c55b 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -310,6 +310,12 @@ static int __devinit tsc2007_probe(struct i2c_client *client,
 	ts->get_pendown_state = pdata->get_pendown_state;
 	ts->clear_penirq      = pdata->clear_penirq;
 
+	if (pdata->x_plate_ohms == 0) {
+		dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
+		err = -EINVAL;
+		goto err_free_mem;
+	}
+
 	snprintf(ts->phys, sizeof(ts->phys),
 		 "%s/input0", dev_name(&client->dev));
 
diff --git a/include/linux/i2c/tsc2007.h b/include/linux/i2c/tsc2007.h
index 591427a63b06..506a9f7af51e 100644
--- a/include/linux/i2c/tsc2007.h
+++ b/include/linux/i2c/tsc2007.h
@@ -5,7 +5,7 @@
 
 struct tsc2007_platform_data {
 	u16	model;				/* 2007. */
-	u16	x_plate_ohms;
+	u16	x_plate_ohms;	/* must be non-zero value */
 	u16	max_rt; /* max. resistance above which samples are ignored */
 	unsigned long poll_delay; /* delay (in ms) after pen-down event
 				     before polling starts */
-- 
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