2 files changed, 13 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/ucb1400_ts.c b/drivers/input/touchscreen/ucb1400_ts.c
index 6954f5500108..3b345f9cf0c7 100644
--- a/drivers/input/touchscreen/ucb1400_ts.c
+++ b/drivers/input/touchscreen/ucb1400_ts.c
@@ -345,6 +345,7 @@ static int ucb1400_ts_detect_irq(struct ucb1400_ts *ucb)
 static int ucb1400_ts_probe(struct platform_device *dev)
 {
         int error, x_res, y_res;
+        u16 fcsr;
         struct ucb1400_ts *ucb = dev->dev.platform_data;
 
         ucb->ts_idev = input_allocate_device();
@@ -382,6 +383,14 @@ static int ucb1400_ts_probe(struct platform_device *dev)
         ucb->ts_idev->evbit[0]          = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
         ucb->ts_idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 
+        /*
+         * Enable ADC filter to prevent horrible jitter on Colibri.
+         * This also further reduces jitter on boards where ADCSYNC
+         * pin is connected.
+         */
+        fcsr = ucb1400_reg_read(ucb->ac97, UCB_FCSR);
+        ucb1400_reg_write(ucb->ac97, UCB_FCSR, fcsr | UCB_FCSR_AVE);
+
         ucb1400_adc_enable(ucb->ac97);
         x_res = ucb1400_ts_read_xres(ucb);
         y_res = ucb1400_ts_read_yres(ucb);
diff --git a/include/linux/ucb1400.h b/include/linux/ucb1400.h
index ed889f4168f3..ae779bb8cc0f 100644
--- a/include/linux/ucb1400.h
+++ b/include/linux/ucb1400.h
@@ -73,6 +73,10 @@
 
 #define UCB_ADC_DATA            0x68
 #define UCB_ADC_DAT_VALID       (1 << 15)
+
+#define UCB_FCSR                0x6c
+#define UCB_FCSR_AVE            (1 << 12)
+
 #define UCB_ADC_DAT_MASK        0x3ff
 
 #define UCB_ID                  0x7e