On 7/24/09 8:00 PM, Dmitry Torokhov wrote:

On Fri, Jul 24, 2009 at 06:14:37PM +0200, Richard Röjfors wrote:

quoted

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<redacted>
---
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);

I think this leaves the controller powered on and with with PENIRQ
disabled.

You are right, I think we should leave the patch like below, just get 
rid of the unnecessary read during startup.

--Richard

Input: tsc2007: Do not read coordinated when probing driver

From: Richard Röjfors <redacted>

Don't read coordinates during probe of the driver, just powering down 
the controller and wait for interrupts.


Signed-off-by: Richard Röjfors<redacted>
---
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 1056)

@@ -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) */

@@ -190,8 +196,7 @@
  	tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
  	tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);

-	/* power down */
-	tsc2007_xfer(tsc, PWRDOWN);
+	tsc2007_power_down(tsc);

  	return 0;
  }

@@ -305,7 +310,7 @@
  	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;

--

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