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authorEric Millbrandt <emillbrandt@dekaresearch.com>2010-09-03 10:31:05 -0700
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2010-09-05 12:14:36 -0700
commiteb54ddd4d78e62647b7096e4ada7389dbdf2cea7 (patch)
treecef6a031b465523fac6e0f5c1b1466e1aa986b02 /drivers/input/touchscreen/wm97xx-core.c
parentd3622e6f05b2134deb5ba8ca2f6bcce5391e7e6d (diff)
Input: wm97xx-core - add retries to wm97xx_read_aux_adc
Add logic to wm97xx_read_aux_adc() to retry reading the adc if the sample failed. This could occur if the previous sample was still in the return register or the sample timed-out. Also avoid a pathologic failure mode by disabling the digitizer and returning -EBUSY after 5 retries. Signed-off-by: Eric Millbrandt <emillbrandt@dekaresearch.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/touchscreen/wm97xx-core.c')
-rw-r--r--drivers/input/touchscreen/wm97xx-core.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
index 770537c1462..6b75c9f660a 100644
--- a/drivers/input/touchscreen/wm97xx-core.c
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -125,6 +125,8 @@ int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
{
int power_adc = 0, auxval;
u16 power = 0;
+ int rc = 0;
+ int timeout = 0;
/* get codec */
mutex_lock(&wm->codec_mutex);
@@ -143,7 +145,9 @@ int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
/* Turn polling mode on to read AUX ADC */
wm->pen_probably_down = 1;
- wm->codec->poll_sample(wm, adcsel, &auxval);
+
+ while (rc != RC_VALID && timeout++ < 5)
+ rc = wm->codec->poll_sample(wm, adcsel, &auxval);
if (power_adc)
wm97xx_reg_write(wm, AC97_EXTENDED_MID, power | 0x8000);
@@ -152,8 +156,15 @@ int wm97xx_read_aux_adc(struct wm97xx *wm, u16 adcsel)
wm->pen_probably_down = 0;
+ if (timeout >= 5) {
+ dev_err(wm->dev,
+ "timeout reading auxadc %d, disabling digitiser\n",
+ adcsel);
+ wm->codec->dig_enable(wm, false);
+ }
+
mutex_unlock(&wm->codec_mutex);
- return auxval & 0xfff;
+ return (rc == RC_VALID ? auxval & 0xfff : -EBUSY);
}
EXPORT_SYMBOL_GPL(wm97xx_read_aux_adc);