1 files changed, 31 insertions, 21 deletions

diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 8fd7fc39c4fd..ff97897feaf2 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -33,6 +33,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/module.h>
 #include <asm/irq.h>
+#include <asm/unaligned.h>
 
 /*
  * This code has been heavily tested on a Nokia 770, and lightly
@@ -199,6 +200,26 @@ struct ads7846 {
 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 
+static int get_pendown_state(struct ads7846 *ts)
+{
+        if (ts->get_pendown_state)
+                return ts->get_pendown_state();
+
+        return !gpio_get_value(ts->gpio_pendown);
+}
+
+static void ads7846_report_pen_up(struct ads7846 *ts)
+{
+        struct input_dev *input = ts->input;
+
+        input_report_key(input, BTN_TOUCH, 0);
+        input_report_abs(input, ABS_PRESSURE, 0);
+        input_sync(input);
+
+        ts->pendown = false;
+        dev_vdbg(&ts->spi->dev, "UP\n");
+}
+
 /* Must be called with ts->lock held */
 static void ads7846_stop(struct ads7846 *ts)
 {
@@ -215,6 +236,10 @@ static void ads7846_stop(struct ads7846 *ts)
 static void ads7846_restart(struct ads7846 *ts)
 {
         if (!ts->disabled && !ts->suspended) {
+                /* Check if pen was released since last stop */
+                if (ts->pendown && !get_pendown_state(ts))
+                        ads7846_report_pen_up(ts);
+
                 /* Tell IRQ thread that it may poll the device. */
                 ts->stopped = false;
                 mb();
@@ -411,7 +436,7 @@ static int ads7845_read12_ser(struct device *dev, unsigned command)
 
         if (status == 0) {
                 /* BE12 value, then padding */
-                status = be16_to_cpu(*((u16 *)&req->sample[1]));
+                status = get_unaligned_be16(&req->sample[1]);
                 status = status >> 3;
                 status &= 0x0fff;
         }
@@ -606,14 +631,6 @@ static const struct attribute_group ads784x_attr_group = {
 
 /*--------------------------------------------------------------------------*/
 
-static int get_pendown_state(struct ads7846 *ts)
-{
-        if (ts->get_pendown_state)
-                return ts->get_pendown_state();
-
-        return !gpio_get_value(ts->gpio_pendown);
-}
-
 static void null_wait_for_sync(void)
 {
 }
@@ -786,10 +803,11 @@ static void ads7846_report_state(struct ads7846 *ts)
                 /* compute touch pressure resistance using equation #2 */
                 Rt = z2;
                 Rt -= z1;
-                Rt *= x;
                 Rt *= ts->x_plate_ohms;
+                Rt = DIV_ROUND_CLOSEST(Rt, 16);
+                Rt *= x;
                 Rt /= z1;
-                Rt = (Rt + 2047) >> 12;
+                Rt = DIV_ROUND_CLOSEST(Rt, 256);
         } else {
                 Rt = 0;
         }
@@ -868,16 +886,8 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
                                    msecs_to_jiffies(TS_POLL_PERIOD));
         }
 
-        if (ts->pendown && !ts->stopped) {
-                struct input_dev *input = ts->input;
-
-                input_report_key(input, BTN_TOUCH, 0);
-                input_report_abs(input, ABS_PRESSURE, 0);
-                input_sync(input);
-
-                ts->pendown = false;
-                dev_vdbg(&ts->spi->dev, "UP\n");
-        }
+        if (ts->pendown && !ts->stopped)
+                ads7846_report_pen_up(ts);
 
         return IRQ_HANDLED;
 }