On Thu, Aug 14, 2025 at 07:34:10PM -0700, Amit Sunil Dhamne via B4 Relay wrote:
> From: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
>
> Presently in `max_contaminant_is_contaminant()` if there's no
> contaminant detected previously, CC is open & stopped toggling and no
> contaminant is currently present, TCPC.RC would be programmed to do DRP
> toggling. However, it didn't actively look for a connection. This would
> lead to Type-C not detect *any* new connections. Hence, in the above
> situation, re-enable toggling & program TCPC to look for a new
> connection.
>
> Also, return early if TCPC was looking for connection as this indicates
> TCPC has neither detected a potential connection nor a change in
> contaminant state.
>
> In addition, once dry detection is complete (port is dry), restart
> toggling.
>
> Fixes: 02b332a06397e ("usb: typec: maxim_contaminant: Implement check_contaminant callback")
> Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> Reviewed-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
> ---
> drivers/usb/typec/tcpm/maxim_contaminant.c | 53 ++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/maxim_contaminant.c b/drivers/usb/typec/tcpm/maxim_contaminant.c
> index 818cfe226ac7716de2fcbce205c67ea16acba592..af8da6dc60ae0bc5900f6614514d51f41eded8ab 100644
> --- a/drivers/usb/typec/tcpm/maxim_contaminant.c
> +++ b/drivers/usb/typec/tcpm/maxim_contaminant.c
> @@ -329,6 +329,39 @@ static int max_contaminant_enable_dry_detection(struct max_tcpci_chip *chip)
> return 0;
> }
>
> +static int max_contaminant_enable_toggling(struct max_tcpci_chip *chip)
> +{
> + struct regmap *regmap = chip->data.regmap;
> + int ret;
> +
> + /* Disable dry detection if enabled. */
> + ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL,
> + FIELD_PREP(CCLPMODESEL,
> + LOW_POWER_MODE_DISABLE));
> + if (ret)
> + return ret;
> +
> + ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL1, CCCONNDRY, 0);
> + if (ret)
> + return ret;
> +
> + ret = max_tcpci_write8(chip, TCPC_ROLE_CTRL, TCPC_ROLE_CTRL_DRP |
> + FIELD_PREP(TCPC_ROLE_CTRL_CC1,
> + TCPC_ROLE_CTRL_CC_RD) |
> + FIELD_PREP(TCPC_ROLE_CTRL_CC2,
> + TCPC_ROLE_CTRL_CC_RD));
> + if (ret)
> + return ret;
> +
> + ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL,
> + TCPC_TCPC_CTRL_EN_LK4CONN_ALRT,
> + TCPC_TCPC_CTRL_EN_LK4CONN_ALRT);
> + if (ret)
> + return ret;
> +
> + return max_tcpci_write8(chip, TCPC_COMMAND, TCPC_CMD_LOOK4CONNECTION);
> +}
> +
> bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce,
> bool *cc_handled)
> {
> @@ -345,6 +378,12 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
> if (ret < 0)
> return false;
>
> + if (cc_status & TCPC_CC_STATUS_TOGGLING) {
> + if (chip->contaminant_state == DETECTED)
> + return true;
> + return false;
> + }
> +
> if (chip->contaminant_state == NOT_DETECTED || chip->contaminant_state == SINK) {
> if (!disconnect_while_debounce)
> msleep(100);
> @@ -377,6 +416,12 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
> max_contaminant_enable_dry_detection(chip);
> return true;
> }
> +
> + ret = max_contaminant_enable_toggling(chip);
> + if (ret)
> + dev_err(chip->dev,
> + "Failed to enable toggling, ret=%d",
> + ret);
> }
> } else if (chip->contaminant_state == DETECTED) {
> if (!(cc_status & TCPC_CC_STATUS_TOGGLING)) {
> @@ -384,6 +429,14 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
> if (chip->contaminant_state == DETECTED) {
> max_contaminant_enable_dry_detection(chip);
> return true;
> + } else {
> + ret = max_contaminant_enable_toggling(chip);
> + if (ret) {
> + dev_err(chip->dev,
> + "Failed to enable toggling, ret=%d",
> + ret);
> + return true;
> + }
> }
> }
> }
>
> --
> 2.51.0.rc1.167.g924127e9c0-goog
>
>
<formletter>
This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.
</formletter>
