[PATCH 6/6] input: iqs269a: Disable channels before configuring them

Jeff LaBundy
2020-08-16T21:15:31Z

Unless it is being done as part of servicing a soft reset interrupt,
configuring channels on-the-fly (as is the case when writing to the
ati_trigger attribute) may cause GPIO3 (which reflects the state of
touch for a selected channel) to be inadvertently asserted.

To solve this problem, disable all channels before configuring them.
The desired channels are subsequently re-enabled as part of running
calibration (ATI).

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
drivers/input/misc/iqs269a.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/input/misc/iqs269a.c b/drivers/input/misc/iqs269a.c
index 4a0e4ec..cb2773a 100644
--- a/drivers/input/misc/iqs269a.c
+++ b/drivers/input/misc/iqs269a.c
@@ -61,6 +61,7 @@
#define IQS269_SYS_SETTINGS_REDO_ATI BIT(2)
#define IQS269_SYS_SETTINGS_ACK_RESET BIT(0)

+#define IQS269_FILT_STR_ACTIVE_CH 0x81
#define IQS269_FILT_STR_LP_LTA_MASK GENMASK(7, 6)
#define IQS269_FILT_STR_LP_LTA_SHIFT 6
#define IQS269_FILT_STR_LP_CNT_MASK GENMASK(5, 4)
@@ -1222,6 +1223,15 @@ static int iqs269_dev_init(struct iqs269_private *iqs269)
goto err_mutex;
}

+ /*
+ * Temporarily disable all channels to prevent the GPIO3 pin from being
+ * asserted during subsequent register writes in case this function was
+ * not preceded by a soft reset.
+ */
+ error = regmap_write(iqs269->regmap, IQS269_FILT_STR_ACTIVE_CH, 0);
+ if (error)
+ goto err_mutex;
+
error = regmap_update_bits(iqs269->regmap, IQS269_HALL_UI,
IQS269_HALL_UI_ENABLE,
iqs269->hall_enable ? ~0 : 0);
--
2.7.4