diff mbox series

[v8,1/3] usb: typec: tcpm: Add callbacks to mitigate wakeups due to contaminant

Message ID 20221210060119.944931-1-badhri@google.com
State Superseded
Headers show
Series [v8,1/3] usb: typec: tcpm: Add callbacks to mitigate wakeups due to contaminant | expand

Commit Message

Badhri Jagan Sridharan Dec. 10, 2022, 6:01 a.m. UTC 
On some of the TCPC implementations, when the Type-C port is exposed
to contaminants, such as water, TCPC stops toggling while reporting OPEN
either by the time TCPM reads CC pin status or during CC debounce
window. This causes TCPM to be stuck in TOGGLING state. If TCPM is made
to restart toggling, the behavior recurs causing redundant CPU wakeups
till the USB-C port is free of contaminant.

[206199.287817] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[206199.640337] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[206199.985789] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]

(or)

[ 7853.867577] Start toggling
[ 7853.889921] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[ 7855.698765] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected]
[ 7855.698790] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
[ 7855.698826] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
[ 7855.703559] CC1: 0 -> 0, CC2: 5 -> 5 [state SNK_ATTACH_WAIT, polarity 0, connected]
[ 7855.856555] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected]
[ 7855.856581] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
[ 7855.856613] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @ 170 ms [rev3 NONE_AMS]
[ 7856.027744] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed 170 ms]
[ 7856.181949] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[ 7856.187896] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[ 7857.645630] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
[ 7857.647291] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected]
[ 7857.647298] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
[ 7857.647310] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
[ 7857.808106] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected]
[ 7857.808123] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
[ 7857.808150] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @ 170 ms [rev3 NONE_AMS]
[ 7857.978727] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed 170 ms]

To mitigate redundant TCPM wakeups, TCPCs which do have the needed hardware
can implement the check_contaminant callback which is invoked by TCPM
to evaluate for presence of contaminant. Lower level TCPC driver can
restart toggling through TCPM_PORT_CLEAN event when the driver detects
that USB-C port is free of contaminant. check_contaminant callback also passes
the disconnect_while_debounce flag which when true denotes that the CC pins
transitioned to OPEN state during the CC debounce window.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
Changes since v6:
* folded the debounce logic into tcpm state machine and removed tcpm
* state export.
* Added a helper to determine whether the port is in toggling state.
* Excluded CHECK_CONTAMINANT from tcpm_log.
Changes since v5:
* Updated commit message. Removed change id.
Changes since v4:
* None
Changes since v3:
* None
Changes since V2:
* Offloaded tcpm from maintaining disconnect_while_debouncing logic
* to lower level maxim tcpc driver based on feedback.
---
 drivers/usb/typec/tcpm/tcpm.c | 51 ++++++++++++++++++++++++++++++++++-
 include/linux/usb/tcpm.h      |  8 ++++++
 2 files changed, 58 insertions(+), 1 deletion(-)


base-commit: 1524ceb14dd5ebd6f724d993c5ec1a9a8d445d8e

Comments

Badhri Jagan Sridharan Dec. 10, 2022, 6:14 a.m. UTC | #1 
Please disregard. Messed up versions. Version 9 is what it is.

On Fri, Dec 9, 2022 at 10:01 PM Badhri Jagan Sridharan
<badhri@google.com> wrote:
>
> On some of the TCPC implementations, when the Type-C port is exposed
> to contaminants, such as water, TCPC stops toggling while reporting OPEN
> either by the time TCPM reads CC pin status or during CC debounce
> window. This causes TCPM to be stuck in TOGGLING state. If TCPM is made
> to restart toggling, the behavior recurs causing redundant CPU wakeups
> till the USB-C port is free of contaminant.
>
> [206199.287817] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [206199.640337] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [206199.985789] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
>
> (or)
>
> [ 7853.867577] Start toggling
> [ 7853.889921] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 7855.698765] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected]
> [ 7855.698790] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [ 7855.698826] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [ 7855.703559] CC1: 0 -> 0, CC2: 5 -> 5 [state SNK_ATTACH_WAIT, polarity 0, connected]
> [ 7855.856555] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected]
> [ 7855.856581] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [ 7855.856613] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @ 170 ms [rev3 NONE_AMS]
> [ 7856.027744] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed 170 ms]
> [ 7856.181949] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 7856.187896] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 7857.645630] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]
> [ 7857.647291] CC1: 0 -> 0, CC2: 0 -> 5 [state TOGGLING, polarity 0, connected]
> [ 7857.647298] state change TOGGLING -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [ 7857.647310] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS]
> [ 7857.808106] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected]
> [ 7857.808123] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [rev3 NONE_AMS]
> [ 7857.808150] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @ 170 ms [rev3 NONE_AMS]
> [ 7857.978727] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed 170 ms]
>
> To mitigate redundant TCPM wakeups, TCPCs which do have the needed hardware
> can implement the check_contaminant callback which is invoked by TCPM
> to evaluate for presence of contaminant. Lower level TCPC driver can
> restart toggling through TCPM_PORT_CLEAN event when the driver detects
> that USB-C port is free of contaminant. check_contaminant callback also passes
> the disconnect_while_debounce flag which when true denotes that the CC pins
> transitioned to OPEN state during the CC debounce window.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> ---
> Changes since v6:
> * folded the debounce logic into tcpm state machine and removed tcpm
> * state export.
> * Added a helper to determine whether the port is in toggling state.
> * Excluded CHECK_CONTAMINANT from tcpm_log.
> Changes since v5:
> * Updated commit message. Removed change id.
> Changes since v4:
> * None
> Changes since v3:
> * None
> Changes since V2:
> * Offloaded tcpm from maintaining disconnect_while_debouncing logic
> * to lower level maxim tcpc driver based on feedback.
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 51 ++++++++++++++++++++++++++++++++++-
>  include/linux/usb/tcpm.h      |  8 ++++++
>  2 files changed, 58 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 904c7b4ce2f0..5f514e5e6e2a 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -36,6 +36,7 @@
>  #define FOREACH_STATE(S)                       \
>         S(INVALID_STATE),                       \
>         S(TOGGLING),                    \
> +       S(CHECK_CONTAMINANT),                   \
>         S(SRC_UNATTACHED),                      \
>         S(SRC_ATTACH_WAIT),                     \
>         S(SRC_ATTACHED),                        \
> @@ -249,6 +250,7 @@ enum frs_typec_current {
>  #define TCPM_RESET_EVENT       BIT(2)
>  #define TCPM_FRS_EVENT         BIT(3)
>  #define TCPM_SOURCING_VBUS     BIT(4)
> +#define TCPM_PORT_CLEAN                BIT(5)
>
>  #define LOG_BUFFER_ENTRIES     1024
>  #define LOG_BUFFER_ENTRY_SIZE  128
> @@ -483,6 +485,13 @@ struct tcpm_port {
>          * SNK_READY for non-pd link.
>          */
>         bool slow_charger_loop;
> +
> +       /*
> +        * When true indicates that the lower level drivers indicate potential presence
> +        * of contaminant in the connector pins based on the tcpm state machine
> +        * transitions.
> +        */
> +       bool potential_contaminant;
>  #ifdef CONFIG_DEBUG_FS
>         struct dentry *dentry;
>         struct mutex logbuffer_lock;    /* log buffer access lock */
> @@ -647,7 +656,7 @@ static void tcpm_log(struct tcpm_port *port, const char *fmt, ...)
>         /* Do not log while disconnected and unattached */
>         if (tcpm_port_is_disconnected(port) &&
>             (port->state == SRC_UNATTACHED || port->state == SNK_UNATTACHED ||
> -            port->state == TOGGLING))
> +            port->state == TOGGLING || port->state == CHECK_CONTAMINANT))
>                 return;
>
>         va_start(args, fmt);
> @@ -3904,15 +3913,28 @@ static void run_state_machine(struct tcpm_port *port)
>         unsigned int msecs;
>         enum tcpm_state upcoming_state;
>
> +       if (port->tcpc->check_contaminant && port->state != CHECK_CONTAMINANT)
> +               port->potential_contaminant = ((port->enter_state == SRC_ATTACH_WAIT &&
> +                                               port->state == SRC_UNATTACHED) ||
> +                                              (port->enter_state == SNK_ATTACH_WAIT &&
> +                                               port->state == SNK_UNATTACHED));
> +
>         port->enter_state = port->state;
>         switch (port->state) {
>         case TOGGLING:
>                 break;
> +       case CHECK_CONTAMINANT:
> +               port->tcpc->check_contaminant(port->tcpc);
> +               break;
>         /* SRC states */
>         case SRC_UNATTACHED:
>                 if (!port->non_pd_role_swap)
>                         tcpm_swap_complete(port, -ENOTCONN);
>                 tcpm_src_detach(port);
> +               if (port->potential_contaminant) {
> +                       tcpm_set_state(port, CHECK_CONTAMINANT, 0);
> +                       break;
> +               }
>                 if (tcpm_start_toggling(port, tcpm_rp_cc(port))) {
>                         tcpm_set_state(port, TOGGLING, 0);
>                         break;
> @@ -4150,6 +4172,10 @@ static void run_state_machine(struct tcpm_port *port)
>                         tcpm_swap_complete(port, -ENOTCONN);
>                 tcpm_pps_complete(port, -ENOTCONN);
>                 tcpm_snk_detach(port);
> +               if (port->potential_contaminant) {
> +                       tcpm_set_state(port, CHECK_CONTAMINANT, 0);
> +                       break;
> +               }
>                 if (tcpm_start_toggling(port, TYPEC_CC_RD)) {
>                         tcpm_set_state(port, TOGGLING, 0);
>                         break;
> @@ -4926,6 +4952,9 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
>                 else if (tcpm_port_is_sink(port))
>                         tcpm_set_state(port, SNK_ATTACH_WAIT, 0);
>                 break;
> +       case CHECK_CONTAMINANT:
> +               /* Wait for Toggling to be resumed */
> +               break;
>         case SRC_UNATTACHED:
>         case ACC_UNATTACHED:
>                 if (tcpm_port_is_debug(port) || tcpm_port_is_audio(port) ||
> @@ -5425,6 +5454,11 @@ static void tcpm_pd_event_handler(struct kthread_work *work)
>                         port->vbus_source = true;
>                         _tcpm_pd_vbus_on(port);
>                 }
> +               if (events & TCPM_PORT_CLEAN) {
> +                       tcpm_log(port, "port clean");
> +                       if (port->state == CHECK_CONTAMINANT)
> +                               tcpm_set_state(port, TOGGLING, 0);
> +               }
>
>                 spin_lock(&port->pd_event_lock);
>         }
> @@ -5477,6 +5511,21 @@ void tcpm_sourcing_vbus(struct tcpm_port *port)
>  }
>  EXPORT_SYMBOL_GPL(tcpm_sourcing_vbus);
>
> +void tcpm_port_clean(struct tcpm_port *port)
> +{
> +       spin_lock(&port->pd_event_lock);
> +       port->pd_events |= TCPM_PORT_CLEAN;
> +       spin_unlock(&port->pd_event_lock);
> +       kthread_queue_work(port->wq, &port->event_work);
> +}
> +EXPORT_SYMBOL_GPL(tcpm_port_clean);
> +
> +bool tcpm_port_is_toggling(struct tcpm_port *port)
> +{
> +       return port->port_type == TYPEC_PORT_DRP && port->state == TOGGLING;
> +}
> +EXPORT_SYMBOL_GPL(tcpm_port_is_toggling);
> +
>  static void tcpm_enable_frs_work(struct kthread_work *work)
>  {
>         struct tcpm_port *port = container_of(work, struct tcpm_port, enable_frs);
> diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
> index bffc8d3e14ad..ab7ca872950b 100644
> --- a/include/linux/usb/tcpm.h
> +++ b/include/linux/usb/tcpm.h
> @@ -114,6 +114,11 @@ enum tcpm_transmit_type {
>   *              Optional; The USB Communications Capable bit indicates if port
>   *              partner is capable of communication over the USB data lines
>   *              (e.g. D+/- or SS Tx/Rx). Called to notify the status of the bit.
> + * @check_contaminant:
> + *             Optional; The callback is called when CC pins report open status
> + *             at the end of the deboumce period or when the port is still
> + *             toggling. Chip level drivers are expected to check for contaminant
> + *             and call tcpm_clean_port when the port is clean.
>   */
>  struct tcpc_dev {
>         struct fwnode_handle *fwnode;
> @@ -148,6 +153,7 @@ struct tcpc_dev {
>                                                  bool pps_active, u32 requested_vbus_voltage);
>         bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev);
>         void (*set_partner_usb_comm_capable)(struct tcpc_dev *dev, bool enable);
> +       void (*check_contaminant)(struct tcpc_dev *dev);
>  };
>
>  struct tcpm_port;
> @@ -165,5 +171,7 @@ void tcpm_pd_transmit_complete(struct tcpm_port *port,
>                                enum tcpm_transmit_status status);
>  void tcpm_pd_hard_reset(struct tcpm_port *port);
>  void tcpm_tcpc_reset(struct tcpm_port *port);
> +void tcpm_port_clean(struct tcpm_port *port);
> +bool tcpm_port_is_toggling(struct tcpm_port *port);
>
>  #endif /* __LINUX_USB_TCPM_H */
>
> base-commit: 1524ceb14dd5ebd6f724d993c5ec1a9a8d445d8e
> --
> 2.39.0.rc1.256.g54fd8350bd-goog
>
Badhri Jagan Sridharan Dec. 10, 2022, 6:14 a.m. UTC | #2 
Please disregard. Messed up versions. Version 9 is what it is.

On Fri, Dec 9, 2022 at 10:01 PM Badhri Jagan Sridharan
<badhri@google.com> wrote:
>
> Maxim TCPC has additional ADCs and low current(1ua) current source
> to measure the impedance of CC and SBU pins. When tcpm invokes
> the check_contaminant callback, Maxim TCPC measures the impedance
> of the CC & SBU pins and when the impedance measured is less than
> 1MOhm, it is assumed that USB-C port is contaminated. CC comparators
> are also checked to differentiate between presence of sink and
> contaminant. Once USB-C is deemed to be contaminated, MAXIM TCPC
> has additional hardware to disable normal DRP toggling cycle and
> enable 1ua on CC pins once every 2.4secs/4.8secs. Maxim TCPC
> interrupts AP once the impedance on the CC pin is above the
> 1MOhm threshold. The Maxim tcpc driver then signals TCPM_PORT_CLEAN
> to restart toggling.
>
> Renaming tcpci_maxim.c to tcpci_maxim_core.c and moving reg read/write
> helper functions to the tcpci_maxim.h header file.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
> ---
> Changes since v6:
> * Refactored logic for check_contaminant and removed
> * is_potential_contaminant.
> Changes since v5:
> * None
> Changes since v4:
> * Missed committing local changes to fix ktest robot warnings.
>   Updated the patch in v5.
> Changes since v3:
> * Renamed functions and removed the unecessary EXPORT.
> * Fixed ktest robot warning.
> Changes since v2:
> * Implemented is_potential_contaminant to offload
> * disconnect_while_debouncing
> Changes since v1:
> * Renamed tcpci_maxim.c to tcpci_maxim_core.c and compiling
>   tcpci_maxim_core.o with maxim_contaminant.o as a single module
>   as suggested by Guenter Roeck
> * Got rid of exporting symbols for reg read/write helper functions
>   and moved them to header as suggested by Heikki Krogerus
> * Sqashed the commit which exposed the max_tcpci_read helper functions
>   into this one.
> ---
>  drivers/usb/typec/tcpm/Makefile               |   1 +
>  drivers/usb/typec/tcpm/maxim_contaminant.c    | 337 ++++++++++++++++++
>  drivers/usb/typec/tcpm/tcpci_maxim.h          |  89 +++++
>  .../{tcpci_maxim.c => tcpci_maxim_core.c}     |  53 ++-
>  4 files changed, 448 insertions(+), 32 deletions(-)
>  create mode 100644 drivers/usb/typec/tcpm/maxim_contaminant.c
>  create mode 100644 drivers/usb/typec/tcpm/tcpci_maxim.h
>  rename drivers/usb/typec/tcpm/{tcpci_maxim.c => tcpci_maxim_core.c} (93%)
>
> diff --git a/drivers/usb/typec/tcpm/Makefile b/drivers/usb/typec/tcpm/Makefile
> index 906d9dced8e7..08e57bb499cb 100644
> --- a/drivers/usb/typec/tcpm/Makefile
> +++ b/drivers/usb/typec/tcpm/Makefile
> @@ -8,3 +8,4 @@ obj-$(CONFIG_TYPEC_RT1711H)             += tcpci_rt1711h.o
>  obj-$(CONFIG_TYPEC_MT6360)             += tcpci_mt6360.o
>  obj-$(CONFIG_TYPEC_TCPCI_MT6370)       += tcpci_mt6370.o
>  obj-$(CONFIG_TYPEC_TCPCI_MAXIM)                += tcpci_maxim.o
> +tcpci_maxim-y                          += tcpci_maxim_core.o maxim_contaminant.o
> diff --git a/drivers/usb/typec/tcpm/maxim_contaminant.c b/drivers/usb/typec/tcpm/maxim_contaminant.c
> new file mode 100644
> index 000000000000..23b5ed65cba8
> --- /dev/null
> +++ b/drivers/usb/typec/tcpm/maxim_contaminant.c
> @@ -0,0 +1,337 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2022 Google, Inc
> + *
> + * USB-C module to reduce wakeups due to contaminants.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/irqreturn.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/usb/tcpci.h>
> +#include <linux/usb/tcpm.h>
> +#include <linux/usb/typec.h>
> +
> +#include "tcpci_maxim.h"
> +
> +enum fladc_select {
> +       CC1_SCALE1 = 1,
> +       CC1_SCALE2,
> +       CC2_SCALE1,
> +       CC2_SCALE2,
> +       SBU1,
> +       SBU2,
> +};
> +
> +#define FLADC_1uA_LSB_MV               25
> +/* High range CC */
> +#define FLADC_CC_HIGH_RANGE_LSB_MV     208
> +/* Low range CC */
> +#define FLADC_CC_LOW_RANGE_LSB_MV      126
> +
> +/* 1uA current source */
> +#define FLADC_CC_SCALE1                        1
> +/* 5 uA current source */
> +#define FLADC_CC_SCALE2                        5
> +
> +#define FLADC_1uA_CC_OFFSET_MV         300
> +#define FLADC_CC_HIGH_RANGE_OFFSET_MV  624
> +#define FLADC_CC_LOW_RANGE_OFFSET_MV   378
> +
> +#define CONTAMINANT_THRESHOLD_SBU_K    1000
> +#define        CONTAMINANT_THRESHOLD_CC_K      1000
> +
> +#define READ1_SLEEP_MS                 10
> +#define READ2_SLEEP_MS                 5
> +
> +#define STATUS_CHECK(reg, mask, val)   (((reg) & (mask)) == (val))
> +
> +#define IS_CC_OPEN(cc_status) \
> +       (STATUS_CHECK((cc_status), TCPC_CC_STATUS_CC1_MASK << TCPC_CC_STATUS_CC1_SHIFT,  \
> +                     TCPC_CC_STATE_SRC_OPEN) && STATUS_CHECK((cc_status),               \
> +                                                             TCPC_CC_STATUS_CC2_MASK << \
> +                                                             TCPC_CC_STATUS_CC2_SHIFT,  \
> +                                                             TCPC_CC_STATE_SRC_OPEN))
> +
> +static int max_contaminant_adc_to_mv(struct max_tcpci_chip *chip, enum fladc_select channel,
> +                                    bool ua_src, u8 fladc)
> +{
> +       /* SBU channels only have 1 scale with 1uA. */
> +       if ((ua_src && (channel == CC1_SCALE2 || channel == CC2_SCALE2 || channel == SBU1 ||
> +                       channel == SBU2)))
> +               /* Mean of range */
> +               return FLADC_1uA_CC_OFFSET_MV + (fladc * FLADC_1uA_LSB_MV);
> +       else if (!ua_src && (channel == CC1_SCALE1 || channel == CC2_SCALE1))
> +               return FLADC_CC_HIGH_RANGE_OFFSET_MV + (fladc * FLADC_CC_HIGH_RANGE_LSB_MV);
> +       else if (!ua_src && (channel == CC1_SCALE2 || channel == CC2_SCALE2))
> +               return FLADC_CC_LOW_RANGE_OFFSET_MV + (fladc * FLADC_CC_LOW_RANGE_LSB_MV);
> +
> +       dev_err(chip->dev, "ADC ERROR: SCALE UNKNOWN");
> +
> +       return -EINVAL;
> +}
> +
> +static int max_contaminant_read_adc_mv(struct max_tcpci_chip *chip, enum fladc_select channel,
> +                                      int sleep_msec, bool raw, bool ua_src)
> +{
> +       struct regmap *regmap = chip->data.regmap;
> +       u8 fladc;
> +       int ret;
> +
> +       /* Channel & scale select */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_ADC_CTRL1, ADCINSEL_MASK,
> +                                channel << ADC_CHANNEL_OFFSET);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* Enable ADC */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_ADC_CTRL1, ADCEN, ADCEN);
> +       if (ret < 0)
> +               return ret;
> +
> +       usleep_range(sleep_msec * 1000, (sleep_msec + 1) * 1000);
> +       ret = max_tcpci_read8(chip, TCPC_VENDOR_FLADC_STATUS, &fladc);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* Disable ADC */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_ADC_CTRL1, ADCEN, 0);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_ADC_CTRL1, ADCINSEL_MASK, 0);
> +       if (ret < 0)
> +               return ret;
> +
> +       if (!raw)
> +               return max_contaminant_adc_to_mv(chip, channel, ua_src, fladc);
> +       else
> +               return fladc;
> +}
> +
> +static int max_contaminant_read_resistance_kohm(struct max_tcpci_chip *chip,
> +                                               enum fladc_select channel, int sleep_msec, bool raw)
> +{
> +       struct regmap *regmap = chip->data.regmap;
> +       int mv;
> +       int ret;
> +
> +       if (channel == CC1_SCALE1 || channel == CC2_SCALE1 || channel == CC1_SCALE2 ||
> +           channel == CC2_SCALE2) {
> +               /* Enable 1uA current source */
> +               ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL_MASK,
> +                                        ULTRA_LOW_POWER_MODE);
> +               if (ret < 0)
> +                       return ret;
> +
> +               /* Enable 1uA current source */
> +               ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCRPCTRL_MASK, UA_1_SRC);
> +               if (ret < 0)
> +                       return ret;
> +
> +               /* OVP disable */
> +               ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCOVPDIS, CCOVPDIS);
> +               if (ret < 0)
> +                       return ret;
> +
> +               mv = max_contaminant_read_adc_mv(chip, channel, sleep_msec, raw, true);
> +               /* OVP enable */
> +               ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCOVPDIS, 0);
> +               if (ret < 0)
> +                       return ret;
> +               /* returns KOhm as 1uA source is used. */
> +               return mv;
> +       }
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, SBUOVPDIS, SBUOVPDIS);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* SBU switches auto configure when channel is selected. */
> +       /* Enable 1ua current source */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, SBURPCTRL, SBURPCTRL);
> +       if (ret < 0)
> +               return ret;
> +
> +       mv = max_contaminant_read_adc_mv(chip, channel, sleep_msec, raw, true);
> +       /* Disable current source */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, SBURPCTRL, 0);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* OVP disable */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, SBUOVPDIS, 0);
> +       if (ret < 0)
> +               return ret;
> +
> +       return mv;
> +}
> +
> +static void max_contaminant_read_comparators(struct max_tcpci_chip *chip, u8 *vendor_cc_status2_cc1,
> +                                            u8 *vendor_cc_status2_cc2)
> +{
> +       struct regmap *regmap = chip->data.regmap;
> +       int ret;
> +
> +       /* Enable 80uA source */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCRPCTRL_MASK, UA_80_SRC);
> +       if (ret < 0)
> +               return;
> +
> +       /* Enable comparators */
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL1, CCCOMPEN, CCCOMPEN);
> +       if (ret < 0)
> +               return;
> +
> +       /* Sleep to allow comparators settle */
> +       usleep_range(5000, 6000);
> +       ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_ORIENTATION, PLUG_ORNT_CC1);
> +       if (ret < 0)
> +               return;
> +
> +       usleep_range(5000, 6000);
> +       ret = max_tcpci_read8(chip, VENDOR_CC_STATUS2, vendor_cc_status2_cc1);
> +       if (ret < 0)
> +               return;
> +
> +       ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_ORIENTATION, PLUG_ORNT_CC2);
> +       if (ret < 0)
> +               return;
> +
> +       usleep_range(5000, 6000);
> +       ret = max_tcpci_read8(chip, VENDOR_CC_STATUS2, vendor_cc_status2_cc2);
> +       if (ret < 0)
> +               return;
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL1, CCCOMPEN, 0);
> +       if (ret < 0)
> +               return;
> +       regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCRPCTRL_MASK, 0);
> +}
> +
> +static int max_contaminant_detect_contaminant(struct max_tcpci_chip *chip)
> +{
> +       int cc1_k, cc2_k, sbu1_k, sbu2_k;
> +       u8 vendor_cc_status2_cc1 = 0xff, vendor_cc_status2_cc2 = 0xff;
> +       u8 role_ctrl = 0, role_ctrl_backup = 0;
> +       int inferred_state = NOT_DETECTED;
> +
> +       max_tcpci_read8(chip, TCPC_ROLE_CTRL, &role_ctrl);
> +       role_ctrl_backup = role_ctrl;
> +       role_ctrl = 0x0F;
> +       max_tcpci_write8(chip, TCPC_ROLE_CTRL, role_ctrl);
> +
> +       cc1_k = max_contaminant_read_resistance_kohm(chip, CC1_SCALE2, READ1_SLEEP_MS, false);
> +       cc2_k = max_contaminant_read_resistance_kohm(chip, CC2_SCALE2, READ2_SLEEP_MS, false);
> +
> +       sbu1_k = max_contaminant_read_resistance_kohm(chip, SBU1, READ1_SLEEP_MS, false);
> +       sbu2_k = max_contaminant_read_resistance_kohm(chip, SBU2, READ2_SLEEP_MS, false);
> +       max_contaminant_read_comparators(chip, &vendor_cc_status2_cc1, &vendor_cc_status2_cc2);
> +
> +       if ((!(CC1_VUFP_RD0P5 & vendor_cc_status2_cc1) ||
> +            !(CC2_VUFP_RD0P5 & vendor_cc_status2_cc2)) &&
> +           !(CC1_VUFP_RD0P5 & vendor_cc_status2_cc1 && CC2_VUFP_RD0P5 & vendor_cc_status2_cc2))
> +               inferred_state = SINK;
> +       else if ((cc1_k < CONTAMINANT_THRESHOLD_CC_K || cc2_k < CONTAMINANT_THRESHOLD_CC_K) &&
> +                (sbu1_k < CONTAMINANT_THRESHOLD_SBU_K || sbu2_k < CONTAMINANT_THRESHOLD_SBU_K))
> +               inferred_state = DETECTED;
> +
> +       if (inferred_state == NOT_DETECTED)
> +               max_tcpci_write8(chip, TCPC_ROLE_CTRL, role_ctrl_backup);
> +       else
> +               max_tcpci_write8(chip, TCPC_ROLE_CTRL, (TCPC_ROLE_CTRL_DRP | 0xA));
> +
> +       return inferred_state;
> +}
> +
> +static int max_contaminant_enable_dry_detection(struct max_tcpci_chip *chip)
> +{
> +       struct regmap *regmap = chip->data.regmap;
> +       u8 temp;
> +       int ret;
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL3, CCWTRDEB_MASK | CCWTRSEL_MASK
> +                                   | WTRCYCLE_MASK, CCWTRDEB_1MS << CCWTRDEB_SHIFT |
> +                                   CCWTRSEL_1V << CCWTRSEL_SHIFT | WTRCYCLE_4_8_S <<
> +                                   WTRCYCLE_SHIFT);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = regmap_update_bits(regmap, TCPC_ROLE_CTRL, TCPC_ROLE_CTRL_DRP, TCPC_ROLE_CTRL_DRP);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL1, CCCONNDRY, CCCONNDRY);
> +       if (ret < 0)
> +               return ret;
> +       ret = max_tcpci_read8(chip, TCPC_VENDOR_CC_CTRL1, &temp);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL_MASK,
> +                                ULTRA_LOW_POWER_MODE);
> +       if (ret < 0)
> +               return ret;
> +       ret = max_tcpci_read8(chip, TCPC_VENDOR_CC_CTRL2, &temp);
> +       if (ret < 0)
> +               return ret;
> +
> +       /* Enable Look4Connection before sending the command */
> +       ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL, TCPC_TCPC_CTRL_EN_LK4CONN_ALRT,
> +                                TCPC_TCPC_CTRL_EN_LK4CONN_ALRT);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = max_tcpci_write8(chip, TCPC_COMMAND, TCPC_CMD_LOOK4CONNECTION);
> +       if (ret < 0)
> +               return ret;
> +       return 0;
> +}
> +
> +bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce)
> +{
> +       u8 cc_status, pwr_cntl;
> +
> +       max_tcpci_read8(chip, TCPC_CC_STATUS, &cc_status);
> +       max_tcpci_read8(chip, TCPC_POWER_CTRL, &pwr_cntl);
> +
> +       if (chip->contaminant_state == NOT_DETECTED || chip->contaminant_state == SINK) {
> +               if (!disconnect_while_debounce)
> +                       msleep(100);
> +
> +               max_tcpci_read8(chip, TCPC_CC_STATUS, &cc_status);
> +               if (IS_CC_OPEN(cc_status)) {
> +                       u8 role_ctrl, role_ctrl_backup;
> +
> +                       max_tcpci_read8(chip, TCPC_ROLE_CTRL, &role_ctrl);
> +                       role_ctrl_backup = role_ctrl;
> +                       role_ctrl |= 0x0F;
> +                       role_ctrl &= ~(TCPC_ROLE_CTRL_DRP);
> +                       max_tcpci_write8(chip, TCPC_ROLE_CTRL, role_ctrl);
> +
> +                       chip->contaminant_state = max_contaminant_detect_contaminant(chip);
> +
> +                       max_tcpci_write8(chip, TCPC_ROLE_CTRL, role_ctrl_backup);
> +                       if (chip->contaminant_state == DETECTED) {
> +                               max_contaminant_enable_dry_detection(chip);
> +                               return true;
> +                       }
> +               }
> +               return false;
> +       } else if (chip->contaminant_state == DETECTED) {
> +               if (STATUS_CHECK(cc_status, TCPC_CC_STATUS_TOGGLING, 0)) {
> +                       chip->contaminant_state = max_contaminant_detect_contaminant(chip);
> +                       if (chip->contaminant_state == DETECTED) {
> +                               max_contaminant_enable_dry_detection(chip);
> +                               return true;
> +                       }
> +               }
> +       }
> +
> +       return false;
> +}
> +
> +MODULE_DESCRIPTION("MAXIM TCPC CONTAMINANT Module");
> +MODULE_AUTHOR("Badhri Jagan Sridharan <badhri@google.com>");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.h b/drivers/usb/typec/tcpm/tcpci_maxim.h
> new file mode 100644
> index 000000000000..2c1c4d161b0d
> --- /dev/null
> +++ b/drivers/usb/typec/tcpm/tcpci_maxim.h
> @@ -0,0 +1,89 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright 2022 Google, Inc
> + *
> + * MAXIM TCPC header file.
> + */
> +#ifndef TCPCI_MAXIM_H_
> +#define TCPCI_MAXIM_H_
> +
> +#define VENDOR_CC_STATUS2                       0x85
> +#define CC1_VUFP_RD0P5                          BIT(1)
> +#define CC2_VUFP_RD0P5                          BIT(5)
> +#define TCPC_VENDOR_FLADC_STATUS                0x89
> +
> +#define TCPC_VENDOR_CC_CTRL1                    0x8c
> +#define CCCONNDRY                               BIT(7)
> +#define CCCOMPEN                                BIT(5)
> +
> +#define TCPC_VENDOR_CC_CTRL2                    0x8d
> +#define SBUOVPDIS                               BIT(7)
> +#define CCOVPDIS                                BIT(6)
> +#define SBURPCTRL                               BIT(5)
> +#define CCLPMODESEL_MASK                        GENMASK(4, 3)
> +#define ULTRA_LOW_POWER_MODE                    BIT(3)
> +#define CCRPCTRL_MASK                           GENMASK(2, 0)
> +#define UA_1_SRC                                1
> +#define UA_80_SRC                               3
> +
> +#define TCPC_VENDOR_CC_CTRL3                    0x8e
> +#define CCWTRDEB_MASK                           GENMASK(7, 6)
> +#define CCWTRDEB_SHIFT                          6
> +#define CCWTRDEB_1MS                            1
> +#define CCWTRSEL_MASK                           GENMASK(5, 3)
> +#define CCWTRSEL_SHIFT                          3
> +#define CCWTRSEL_1V                             0x4
> +#define CCLADDERDIS                             BIT(2)
> +#define WTRCYCLE_MASK                           BIT(0)
> +#define WTRCYCLE_SHIFT                          0
> +#define WTRCYCLE_2_4_S                          0
> +#define WTRCYCLE_4_8_S                          1
> +
> +#define TCPC_VENDOR_ADC_CTRL1                   0x91
> +#define ADCINSEL_MASK                           GENMASK(7, 5)
> +#define ADC_CHANNEL_OFFSET                      5
> +#define ADCEN                                   BIT(0)
> +
> +enum contamiant_state {
> +       NOT_DETECTED,
> +       DETECTED,
> +       SINK,
> +};
> +
> +/*
> + * @potential_contaminant:
> + *             Last returned result to tcpm indicating whether the TCPM port
> + *             has potential contaminant.
> + */
> +struct max_tcpci_chip {
> +       struct tcpci_data data;
> +       struct tcpci *tcpci;
> +       struct device *dev;
> +       struct i2c_client *client;
> +       struct tcpm_port *port;
> +       enum contamiant_state contaminant_state;
> +};
> +
> +static inline int max_tcpci_read16(struct max_tcpci_chip *chip, unsigned int reg, u16 *val)
> +{
> +       return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u16));
> +}
> +
> +static inline int max_tcpci_write16(struct max_tcpci_chip *chip, unsigned int reg, u16 val)
> +{
> +       return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u16));
> +}
> +
> +static inline int max_tcpci_read8(struct max_tcpci_chip *chip, unsigned int reg, u8 *val)
> +{
> +       return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u8));
> +}
> +
> +static inline int max_tcpci_write8(struct max_tcpci_chip *chip, unsigned int reg, u8 val)
> +{
> +       return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u8));
> +}
> +
> +bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce);
> +
> +#endif  // TCPCI_MAXIM_H_
> diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.c b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
> similarity index 93%
> rename from drivers/usb/typec/tcpm/tcpci_maxim.c
> rename to drivers/usb/typec/tcpm/tcpci_maxim_core.c
> index 83e140ffcc3e..f32cda2a5e3a 100644
> --- a/drivers/usb/typec/tcpm/tcpci_maxim.c
> +++ b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
> @@ -1,6 +1,6 @@
> -// SPDX-License-Identifier: GPL-2.0
> +// SPDX-License-Identifier: GPL-2.0+
>  /*
> - * Copyright (C) 2020, Google LLC
> + * Copyright (C) 2020 - 2022, Google LLC
>   *
>   * MAXIM TCPCI based TCPC driver
>   */
> @@ -15,6 +15,8 @@
>  #include <linux/usb/tcpm.h>
>  #include <linux/usb/typec.h>
>
> +#include "tcpci_maxim.h"
> +
>  #define PD_ACTIVITY_TIMEOUT_MS                         10000
>
>  #define TCPC_VENDOR_ALERT                              0x80
> @@ -39,14 +41,6 @@
>  #define MAX_BUCK_BOOST_SOURCE                          0xa
>  #define MAX_BUCK_BOOST_SINK                            0x5
>
> -struct max_tcpci_chip {
> -       struct tcpci_data data;
> -       struct tcpci *tcpci;
> -       struct device *dev;
> -       struct i2c_client *client;
> -       struct tcpm_port *port;
> -};
> -
>  static const struct regmap_range max_tcpci_tcpci_range[] = {
>         regmap_reg_range(0x00, 0x95)
>  };
> @@ -68,26 +62,6 @@ static struct max_tcpci_chip *tdata_to_max_tcpci(struct tcpci_data *tdata)
>         return container_of(tdata, struct max_tcpci_chip, data);
>  }
>
> -static int max_tcpci_read16(struct max_tcpci_chip *chip, unsigned int reg, u16 *val)
> -{
> -       return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u16));
> -}
> -
> -static int max_tcpci_write16(struct max_tcpci_chip *chip, unsigned int reg, u16 val)
> -{
> -       return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u16));
> -}
> -
> -static int max_tcpci_read8(struct max_tcpci_chip *chip, unsigned int reg, u8 *val)
> -{
> -       return regmap_raw_read(chip->data.regmap, reg, val, sizeof(u8));
> -}
> -
> -static int max_tcpci_write8(struct max_tcpci_chip *chip, unsigned int reg, u8 val)
> -{
> -       return regmap_raw_write(chip->data.regmap, reg, &val, sizeof(u8));
> -}
> -
>  static void max_tcpci_init_regs(struct max_tcpci_chip *chip)
>  {
>         u16 alert_mask = 0;
> @@ -348,8 +322,14 @@ static irqreturn_t _max_tcpci_irq(struct max_tcpci_chip *chip, u16 status)
>         if (status & TCPC_ALERT_VBUS_DISCNCT)
>                 tcpm_vbus_change(chip->port);
>
> -       if (status & TCPC_ALERT_CC_STATUS)
> -               tcpm_cc_change(chip->port);
> +       if (status & TCPC_ALERT_CC_STATUS) {
> +               if (chip->contaminant_state == DETECTED || tcpm_port_is_toggling(chip->port)) {
> +                       if (!max_contaminant_is_contaminant(chip, false))
> +                               tcpm_port_clean(chip->port);
> +               } else {
> +                       tcpm_cc_change(chip->port);
> +               }
> +       }
>
>         if (status & TCPC_ALERT_POWER_STATUS)
>                 process_power_status(chip);
> @@ -438,6 +418,14 @@ static int tcpci_init(struct tcpci *tcpci, struct tcpci_data *data)
>         return -1;
>  }
>
> +static void max_tcpci_check_contaminant(struct tcpci *tcpci, struct tcpci_data *tdata)
> +{
> +       struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
> +
> +       if (!max_contaminant_is_contaminant(chip, true))
> +               tcpm_port_clean(chip->port);
> +}
> +
>  static int max_tcpci_probe(struct i2c_client *client)
>  {
>         int ret;
> @@ -471,6 +459,7 @@ static int max_tcpci_probe(struct i2c_client *client)
>         chip->data.auto_discharge_disconnect = true;
>         chip->data.vbus_vsafe0v = true;
>         chip->data.set_partner_usb_comm_capable = max_tcpci_set_partner_usb_comm_capable;
> +       chip->data.check_contaminant = max_tcpci_check_contaminant;
>
>         max_tcpci_init_regs(chip);
>         chip->tcpci = tcpci_register_port(chip->dev, &chip->data);
> --
> 2.39.0.rc1.256.g54fd8350bd-goog
>
diff mbox series

Patch

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 904c7b4ce2f0..5f514e5e6e2a 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -36,6 +36,7 @@ 
 #define FOREACH_STATE(S)			\
 	S(INVALID_STATE),			\
 	S(TOGGLING),			\
+	S(CHECK_CONTAMINANT),			\
 	S(SRC_UNATTACHED),			\
 	S(SRC_ATTACH_WAIT),			\
 	S(SRC_ATTACHED),			\
@@ -249,6 +250,7 @@  enum frs_typec_current {
 #define TCPM_RESET_EVENT	BIT(2)
 #define TCPM_FRS_EVENT		BIT(3)
 #define TCPM_SOURCING_VBUS	BIT(4)
+#define TCPM_PORT_CLEAN		BIT(5)
 
 #define LOG_BUFFER_ENTRIES	1024
 #define LOG_BUFFER_ENTRY_SIZE	128
@@ -483,6 +485,13 @@  struct tcpm_port {
 	 * SNK_READY for non-pd link.
 	 */
 	bool slow_charger_loop;
+
+	/*
+	 * When true indicates that the lower level drivers indicate potential presence
+	 * of contaminant in the connector pins based on the tcpm state machine
+	 * transitions.
+	 */
+	bool potential_contaminant;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
 	struct mutex logbuffer_lock;	/* log buffer access lock */
@@ -647,7 +656,7 @@  static void tcpm_log(struct tcpm_port *port, const char *fmt, ...)
 	/* Do not log while disconnected and unattached */
 	if (tcpm_port_is_disconnected(port) &&
 	    (port->state == SRC_UNATTACHED || port->state == SNK_UNATTACHED ||
-	     port->state == TOGGLING))
+	     port->state == TOGGLING || port->state == CHECK_CONTAMINANT))
 		return;
 
 	va_start(args, fmt);
@@ -3904,15 +3913,28 @@  static void run_state_machine(struct tcpm_port *port)
 	unsigned int msecs;
 	enum tcpm_state upcoming_state;
 
+	if (port->tcpc->check_contaminant && port->state != CHECK_CONTAMINANT)
+		port->potential_contaminant = ((port->enter_state == SRC_ATTACH_WAIT &&
+						port->state == SRC_UNATTACHED) ||
+					       (port->enter_state == SNK_ATTACH_WAIT &&
+						port->state == SNK_UNATTACHED));
+
 	port->enter_state = port->state;
 	switch (port->state) {
 	case TOGGLING:
 		break;
+	case CHECK_CONTAMINANT:
+		port->tcpc->check_contaminant(port->tcpc);
+		break;
 	/* SRC states */
 	case SRC_UNATTACHED:
 		if (!port->non_pd_role_swap)
 			tcpm_swap_complete(port, -ENOTCONN);
 		tcpm_src_detach(port);
+		if (port->potential_contaminant) {
+			tcpm_set_state(port, CHECK_CONTAMINANT, 0);
+			break;
+		}
 		if (tcpm_start_toggling(port, tcpm_rp_cc(port))) {
 			tcpm_set_state(port, TOGGLING, 0);
 			break;
@@ -4150,6 +4172,10 @@  static void run_state_machine(struct tcpm_port *port)
 			tcpm_swap_complete(port, -ENOTCONN);
 		tcpm_pps_complete(port, -ENOTCONN);
 		tcpm_snk_detach(port);
+		if (port->potential_contaminant) {
+			tcpm_set_state(port, CHECK_CONTAMINANT, 0);
+			break;
+		}
 		if (tcpm_start_toggling(port, TYPEC_CC_RD)) {
 			tcpm_set_state(port, TOGGLING, 0);
 			break;
@@ -4926,6 +4952,9 @@  static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
 		else if (tcpm_port_is_sink(port))
 			tcpm_set_state(port, SNK_ATTACH_WAIT, 0);
 		break;
+	case CHECK_CONTAMINANT:
+		/* Wait for Toggling to be resumed */
+		break;
 	case SRC_UNATTACHED:
 	case ACC_UNATTACHED:
 		if (tcpm_port_is_debug(port) || tcpm_port_is_audio(port) ||
@@ -5425,6 +5454,11 @@  static void tcpm_pd_event_handler(struct kthread_work *work)
 			port->vbus_source = true;
 			_tcpm_pd_vbus_on(port);
 		}
+		if (events & TCPM_PORT_CLEAN) {
+			tcpm_log(port, "port clean");
+			if (port->state == CHECK_CONTAMINANT)
+				tcpm_set_state(port, TOGGLING, 0);
+		}
 
 		spin_lock(&port->pd_event_lock);
 	}
@@ -5477,6 +5511,21 @@  void tcpm_sourcing_vbus(struct tcpm_port *port)
 }
 EXPORT_SYMBOL_GPL(tcpm_sourcing_vbus);
 
+void tcpm_port_clean(struct tcpm_port *port)
+{
+	spin_lock(&port->pd_event_lock);
+	port->pd_events |= TCPM_PORT_CLEAN;
+	spin_unlock(&port->pd_event_lock);
+	kthread_queue_work(port->wq, &port->event_work);
+}
+EXPORT_SYMBOL_GPL(tcpm_port_clean);
+
+bool tcpm_port_is_toggling(struct tcpm_port *port)
+{
+	return port->port_type == TYPEC_PORT_DRP && port->state == TOGGLING;
+}
+EXPORT_SYMBOL_GPL(tcpm_port_is_toggling);
+
 static void tcpm_enable_frs_work(struct kthread_work *work)
 {
 	struct tcpm_port *port = container_of(work, struct tcpm_port, enable_frs);
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index bffc8d3e14ad..ab7ca872950b 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -114,6 +114,11 @@  enum tcpm_transmit_type {
  *              Optional; The USB Communications Capable bit indicates if port
  *              partner is capable of communication over the USB data lines
  *              (e.g. D+/- or SS Tx/Rx). Called to notify the status of the bit.
+ * @check_contaminant:
+ *		Optional; The callback is called when CC pins report open status
+ *		at the end of the deboumce period or when the port is still
+ *		toggling. Chip level drivers are expected to check for contaminant
+ *		and call tcpm_clean_port when the port is clean.
  */
 struct tcpc_dev {
 	struct fwnode_handle *fwnode;
@@ -148,6 +153,7 @@  struct tcpc_dev {
 						 bool pps_active, u32 requested_vbus_voltage);
 	bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev);
 	void (*set_partner_usb_comm_capable)(struct tcpc_dev *dev, bool enable);
+	void (*check_contaminant)(struct tcpc_dev *dev);
 };
 
 struct tcpm_port;
@@ -165,5 +171,7 @@  void tcpm_pd_transmit_complete(struct tcpm_port *port,
 			       enum tcpm_transmit_status status);
 void tcpm_pd_hard_reset(struct tcpm_port *port);
 void tcpm_tcpc_reset(struct tcpm_port *port);
+void tcpm_port_clean(struct tcpm_port *port);
+bool tcpm_port_is_toggling(struct tcpm_port *port);
 
 #endif /* __LINUX_USB_TCPM_H */