[v7,3/3] usb: typec: maxim_contaminant: Implement check_contaminant callback

  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%)
  

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
>