From: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
Low power mode is enabled when reading CC resistance as part of
`max_contaminant_read_resistance_kohm()` and left in that state.
However, it's supposed to work with 1uA current source. To read CC
comparator values current source is changed to 80uA. This causes a storm
of CC interrupts as it (falsely) detects a potential contaminant. To
prevent this, disable low power mode current sourcing before reading
comparator values.
Fixes: 02b332a06397 ("usb: typec: maxim_contaminant: Implement check_contaminant callback")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
Reviewed-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
---
drivers/usb/typec/tcpm/maxim_contaminant.c | 5 +++++
drivers/usb/typec/tcpm/tcpci_maxim.h | 1 +
2 files changed, 6 insertions(+)
diff --git a/drivers/usb/typec/tcpm/maxim_contaminant.c b/drivers/usb/typec/tcpm/maxim_contaminant.c
index 0cdda06592fd3cc34e2179ccd49ef677f8ec9792..818cfe226ac7716de2fcbce205c67ea16acba592 100644
--- a/drivers/usb/typec/tcpm/maxim_contaminant.c
+++ b/drivers/usb/typec/tcpm/maxim_contaminant.c
@@ -188,6 +188,11 @@ static int max_contaminant_read_comparators(struct max_tcpci_chip *chip, u8 *ven
if (ret < 0)
return ret;
+ /* Disable low power mode */
+ ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL,
+ FIELD_PREP(CCLPMODESEL,
+ LOW_POWER_MODE_DISABLE));
+
/* Sleep to allow comparators settle */
usleep_range(5000, 6000);
ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_ORIENTATION, PLUG_ORNT_CC1);
diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.h b/drivers/usb/typec/tcpm/tcpci_maxim.h
index 76270d5c283880dc49b13cabe7d682f2c2bf15fe..b33540a42a953dc6d8197790ee4af3b6f52791ce 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim.h
+++ b/drivers/usb/typec/tcpm/tcpci_maxim.h
@@ -21,6 +21,7 @@
#define CCOVPDIS BIT(6)
#define SBURPCTRL BIT(5)
#define CCLPMODESEL GENMASK(4, 3)
+#define LOW_POWER_MODE_DISABLE 0
#define ULTRA_LOW_POWER_MODE 1
#define CCRPCTRL GENMASK(2, 0)
#define UA_1_SRC 1
--
2.51.0.rc1.167.g924127e9c0-goog
