From 713eb96dd137e1436198aa07094049ae0e0f9f1f Mon Sep 17 00:00:00 2001
From: Steve Sakoman <sakoman@gmail.com>
Date: Tue, 15 Dec 2009 15:24:10 -0800
Subject: [PATCH 15/28] drivers: input: touchscreen: ads7846: return ENODEV if device is not found

Signed-off-by: Steve Sakoman <sakoman@gmail.com>
---
 drivers/input/touchscreen/ads7846.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 14ea54b..c775e38 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -1325,11 +1325,18 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 	 * the touchscreen, in case it's not connected.
 	 */
 	if (ts->model == 7845)
-		ads7845_read12_ser(&spi->dev, PWRDOWN);
+		err = ads7845_read12_ser(&spi->dev, PWRDOWN);
 	else
-		(void) ads7846_read12_ser(&spi->dev,
+		err = ads7846_read12_ser(&spi->dev,
 				READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 
+	/* if sample is all 0's or all 1's then there is no device on spi */
+	if ( (err == 0x000) || (err == 0xfff)) {
+		dev_info(&spi->dev, "no device detected, test read result was 0x%08X\n", err);
+		err = -ENODEV;
+		goto err_free_irq;
+	}
+
 	err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
 	if (err)
 		goto err_remove_hwmon;
@@ -1353,7 +1360,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
  err_put_regulator:
 	regulator_put(ts->reg);
  err_free_gpio:
-	if (ts->gpio_pendown != -1)
+	if (!ts->get_pendown_state && ts->gpio_pendown != -1)
 		gpio_free(ts->gpio_pendown);
  err_cleanup_filter:
 	if (ts->filter_cleanup)
-- 
1.6.6.1

