CHROMIUM: Input: atmel_mxt_ts - recalibrate on system resume

In the suspend path, if we don't allow device wakeup, we put the
chip into deepsleep mode and the chip stops scanning during suspen.
On resume if the environment changes, the calibrated baseline before
suspend will no longer be valid.

In this patch we force a recalibration on resume if device wakeup is
disabled during suspend to handle the environment change.

Signed-off-by: Yufeng Shen <miletus@chromium.org>
BUG=chrome-os-partner:16171
TEST=I don't have a controlled environment to test this. So I only test
     normal suspend/resume to make sure no noise touches happen on resume
     and touch devices work as expected.
     1. With lid open, using powerd_suspend to suspend the system. Wakeup
     the system and make sure the touch device still works.
     Run "demsg | grep atmel"  to make sure no calibration message reported.
     2. Use lid close to suspend the system. Wakeup the system and make
     sure touch device still works.
     Run "demsg | grep atmel"  to make sure calibration message are reported.
     3. Also notice the case of lid open caused system resume, if something is
     on the touch surface (like opening the lid and quickly put the palm on the
     touch surface for a while), the system will get calibrated into a wrong
     baseline and touch device then won't work.

Change-Id: I62cb47fa1c97917a2c0f968e41ee4cd13f12187c
Reviewed-on: https://gerrit.chromium.org/gerrit/38051
Reviewed-by: Benson Leung <bleung@chromium.org>
Commit-Ready: Yufeng Shen <miletus@chromium.org>
Tested-by: Yufeng Shen <miletus@chromium.org>

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 8e75cced61f317b13135f62b036e4a6361170899..2412c48fb0dacb5592cbdf2e2588feae5852757c 100644 (file)
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -2829,11 +2829,6 @@ static int mxt_resume(struct device *dev)
 
        mutex_lock(&input_dev->mutex);
 
-       enable_irq(data->irq);
-
-       if (device_may_wakeup(dev) && data->irq_wake)
-               disable_irq_wake(data->irq);
-
        /* Restore the T9 Ctrl config to before-suspend value */
        if (data->T9_ctrl_valid) {
                ret = mxt_set_regs(data, MXT_TOUCH_MULTI_T9, 0, 0,
@@ -2850,8 +2845,22 @@ static int mxt_resume(struct device *dev)
                        dev_err(dev, "Set T7 power config failed, %d\n", ret);
        }
 
+       if (!device_may_wakeup(dev)) {
+               /* Recalibration in case of environment change */
+               ret = mxt_write_object(data, MXT_GEN_COMMAND_T6, 0,
+                                      MXT_COMMAND_CALIBRATE, 1);
+               if (ret)
+                       dev_err(dev, "Resume recalibration failed %d\n", ret);
+               msleep(MXT_CAL_TIME);
+       }
+
        mutex_unlock(&input_dev->mutex);
 
+       enable_irq(data->irq);
+
+       if (device_may_wakeup(dev) && data->irq_wake)
+               disable_irq_wake(data->irq);
+
        return 0;
 }
 #endif