[PATCH 2/2] tsc2007: reduced number of I2C transfers

Richard Röjfors
2009-07-24T16:14:40Z

Decreases the number of I2C transactions transferred by the driver.
During probe we don't need to ask for the coordinates from the controller.
When polling the controller we don't need to power down and enable IRQ
if we are going to poll again.

Signed-off-by: Richard Röjfors <richard.rojfors.ext@mocean-labs.com>
---
Index: linux-2.6.31-rc2/drivers/input/touchscreen/tsc2007.c
===================================================================
--- linux-2.6.31-rc2/drivers/input/touchscreen/tsc2007.c (revision 1040)
+++ linux-2.6.31-rc2/drivers/input/touchscreen/tsc2007.c (revision 1053)
@@ -178,6 +178,12 @@
ts->penstate = PEN_STATE_UP;
}

+static void tsc2007_power_down(struct tsc2007 *tsc)
+{
+ /* power down */
+ tsc2007_xfer(tsc, PWRDOWN);
+}
+
static int tsc2007_read_values(struct tsc2007 *tsc)
{
/* y- still on; turn on only y+ (and ADC) */
@@ -188,11 +194,8 @@

/* turn y+ off, x- on; we'll use formula #1 */
tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
- tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);
+ tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2 | TSC2007_POWER_OFF_IRQ_EN);

- /* power down */
- tsc2007_xfer(tsc, PWRDOWN);
-
return 0;
}

@@ -217,6 +220,7 @@
input_sync(input);

ts->penstate = PEN_STATE_UP;
+ tsc2007_power_down(ts);
enable_irq(ts->irq);
} else {
/* pen is still down, continue with the measurement */
@@ -305,7 +309,7 @@
input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);

- tsc2007_read_values(ts);
+ tsc2007_power_down(ts);

ts->irq = client->irq;