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authorDan Liang <Dan.Liang@atmel.com>2008-08-14 22:36:41 -0400
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2008-09-10 12:12:24 -0400
commitd8c1f317d1b3bb5c21175550968c86acfab3ff36 (patch)
tree739c0e70dc5d760bb48df37627a909f2ebab7958 /drivers/input
parent160f1fef7e52e974489b3c70fbd4e094c06965c2 (diff)
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Input: atmel_tsadcc - improve accuracy
Discard the last sample just before pen is up because it is quite often errorneous. Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Dan Liang <dan.liang@atmel.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/touchscreen/atmel_tsadcc.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/drivers/input/touchscreen/atmel_tsadcc.c b/drivers/input/touchscreen/atmel_tsadcc.c
index eee126b19e8b..a89a6a8f05e6 100644
--- a/drivers/input/touchscreen/atmel_tsadcc.c
+++ b/drivers/input/touchscreen/atmel_tsadcc.c
@@ -91,6 +91,9 @@ struct atmel_tsadcc {
char phys[32];
struct clk *clk;
int irq;
+ unsigned int prev_absx;
+ unsigned int prev_absy;
+ unsigned char bufferedmeasure;
};
static void __iomem *tsc_base;
@@ -100,10 +103,9 @@ static void __iomem *tsc_base;
static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
{
- struct input_dev *input_dev = ((struct atmel_tsadcc *)dev)->input;
+ struct atmel_tsadcc *ts_dev = (struct atmel_tsadcc *)dev;
+ struct input_dev *input_dev = ts_dev->input;
- unsigned int absx;
- unsigned int absy;
unsigned int status;
unsigned int reg;
@@ -121,6 +123,7 @@ static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
input_report_key(input_dev, BTN_TOUCH, 0);
+ ts_dev->bufferedmeasure = 0;
input_sync(input_dev);
} else if (status & ATMEL_TSADCC_PENCNT) {
@@ -138,16 +141,23 @@ static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
} else if (status & ATMEL_TSADCC_EOC(3)) {
/* Conversion finished */
- absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
- absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);
-
- absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
- absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
-
- input_report_abs(input_dev, ABS_X, absx);
- input_report_abs(input_dev, ABS_Y, absy);
- input_report_key(input_dev, BTN_TOUCH, 1);
- input_sync(input_dev);
+ if (ts_dev->bufferedmeasure) {
+ /* Last measurement is always discarded, since it can
+ * be erroneous.
+ * Always report previous measurement */
+ input_report_abs(input_dev, ABS_X, ts_dev->prev_absx);
+ input_report_abs(input_dev, ABS_Y, ts_dev->prev_absy);
+ input_report_key(input_dev, BTN_TOUCH, 1);
+ input_sync(input_dev);
+ } else
+ ts_dev->bufferedmeasure = 1;
+
+ /* Now make new measurement */
+ ts_dev->prev_absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
+ ts_dev->prev_absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);
+
+ ts_dev->prev_absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
+ ts_dev->prev_absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
}
return IRQ_HANDLED;
@@ -223,6 +233,7 @@ static int __devinit atmel_tsadcc_probe(struct platform_device *pdev)
}
ts_dev->input = input_dev;
+ ts_dev->bufferedmeasure = 0;
snprintf(ts_dev->phys, sizeof(ts_dev->phys),
"%s/input0", pdev->dev.bus_id);