6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Amit Sunil Dhamne amitsd@google.com
[ Upstream commit cabb6c5f4d9e7f49bdf8c0a13c74bd93ee35f45a ]
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 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-v1-1-801ce8... Link: https://lore.kernel.org/r/20250815-fix-upstream-contaminant-v2-1-6c8d6c3adaf... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [ adapted macro names from CCLPMODESEL to CCLPMODESEL_MASK ] Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/tcpm/maxim_contaminant.c | 6 ++++++ drivers/usb/typec/tcpm/tcpci_maxim.h | 1 + 2 files changed, 7 insertions(+)
--- a/drivers/usb/typec/tcpm/maxim_contaminant.c +++ b/drivers/usb/typec/tcpm/maxim_contaminant.c @@ -5,6 +5,7 @@ * USB-C module to reduce wakeups due to contaminants. */
+#include <linux/bitfield.h> #include <linux/device.h> #include <linux/irqreturn.h> #include <linux/module.h> @@ -189,6 +190,11 @@ static int max_contaminant_read_comparat if (ret < 0) return ret;
+ /* Disable low power mode */ + ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL_MASK, + FIELD_PREP(CCLPMODESEL_MASK, + 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); --- 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_MASK GENMASK(4, 3) +#define LOW_POWER_MODE_DISABLE 0 #define ULTRA_LOW_POWER_MODE BIT(3) #define CCRPCTRL_MASK GENMASK(2, 0) #define UA_1_SRC 1