Input: ads7846 - optionally leave Vref on during differential measurements

On some LCDs leaving the Vref on provides much better readings.

Signed-off-by: Jarkko Oikarinen <jarkko.oikarinen@nokia.com>
Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index 1663f940ca11..3387e44dfd13 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -14,6 +14,8 @@ enum ads7846_filter {
 struct ads7846_platform_data {
         u16     model;                  /* 7843, 7845, 7846. */
         u16     vref_delay_usecs;       /* 0 for external vref; etc */
+        int     keep_vref_on:1;         /* set to keep vref on for differential
+                                         * measurements as well */
         u16     x_plate_ohms;
         u16     y_plate_ohms;