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usb: typec: maxim_contaminant: disable low power mode when reading comparator values

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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: 02b332a063 ("usb: typec: maxim_contaminant: Implement check_contaminant callback")
Cc: stable <stable@kernel.org>
Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
Rule: add
Link: https://lore.kernel.org/stable/20250814-fix-upstream-contaminant-v1-1-801ce8089031%40google.com
Link: https://lore.kernel.org/r/20250815-fix-upstream-contaminant-v2-1-6c8d6c3adafb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Amit Sunil Dhamne 2025-08-15 11:31:51 -07:00 committed by Greg Kroah-Hartman
parent 45eae113dc
commit cabb6c5f4d
2 changed files with 6 additions and 0 deletions
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5
drivers/usb/typec/tcpm/maxim_contaminant.c
View File

@ -188,6 +188,11 @@ static int max_contaminant_read_comparators(struct max_tcpci_chip *chip, u8 *ven
if (ret < 0) if (ret < 0)
return ret; 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 */ /* Sleep to allow comparators settle */
usleep_range(5000, 6000); usleep_range(5000, 6000);
ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_ORIENTATION, PLUG_ORNT_CC1); ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_ORIENTATION, PLUG_ORNT_CC1);

1
drivers/usb/typec/tcpm/tcpci_maxim.h
View File

@ -21,6 +21,7 @@
#define CCOVPDIS BIT(6) #define CCOVPDIS BIT(6)
#define SBURPCTRL BIT(5) #define SBURPCTRL BIT(5)
#define CCLPMODESEL GENMASK(4, 3) #define CCLPMODESEL GENMASK(4, 3)
#define LOW_POWER_MODE_DISABLE 0
#define ULTRA_LOW_POWER_MODE 1 #define ULTRA_LOW_POWER_MODE 1
#define CCRPCTRL GENMASK(2, 0) #define CCRPCTRL GENMASK(2, 0)
#define UA_1_SRC 1 #define UA_1_SRC 1