Input: ads7846 - add possibility to use external vref on ads7846

Just set vref_mv in your platform config to use external vref. Otherwise
the internal one is used.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/spi/ads7846.h b/include/linux/spi/ads7846.h
index 92bd0839d5b4..c64de9dd7631 100644
--- a/include/linux/spi/ads7846.h
+++ b/include/linux/spi/ads7846.h
@@ -14,7 +14,8 @@ enum ads7846_filter {
 struct ads7846_platform_data {
         u16     model;                  /* 7843, 7845, 7846, 7873. */
         u16     vref_delay_usecs;       /* 0 for external vref; etc */
-        u16     vref_mv;                /* external vref value, milliVolts */
+        u16     vref_mv;                /* external vref value, milliVolts
+                                         * ads7846: if 0, use internal vref */
         bool    keep_vref_on;           /* set to keep vref on for differential
                                          * measurements as well */
         bool    swap_xy;                /* swap x and y axes */