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References: <20221223102122.1038499-1-badhri@google.com> <20221223102122.1038499-3-badhri@google.com>
 <f37b0c70-7950-3ca0-a3ce-db6d0af8b4ad@roeck-us.net>
In-Reply-To: <f37b0c70-7950-3ca0-a3ce-db6d0af8b4ad@roeck-us.net>
From:   Badhri Jagan Sridharan <badhri@google.com>
Date:   Sat, 14 Jan 2023 01:35:37 -0800
Message-ID: <CAPTae5LSBf2Q24h4XRjDNvpavJifAo=BQ7tp4b=AA3U8VhXBZA@mail.gmail.com>
Subject: Re: [PATCH v11 3/3] usb: typec: maxim_contaminant: Implement
 check_contaminant callback
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kyle Tso <kyletso@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Jan 12, 2023 at 6:53 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 12/23/22 02:21, Badhri Jagan Sridharan 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>
>
> I never looked at details here, but this time I did.
> Some comments inline.
>
> > ---
> > Changes since v10:
> > * none
> > Changes since v9:
> > * None.
> > Changes since V7:
> > * None. Skipped versions by mistake.
> > 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");
> > +
>
> This may create a lot of noise if it really happens. dev_err_once(), maybe ?
>
> > +     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);
>
> The return value is not checked. Is that oin purpose ? If so
> may be worth a comment that the update below is necessary even after a failure.
>
> > +             /* 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);
>
> Same here.
>
> > +     /* 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);
> > +
>
> More unchecked return values.
>
> > +     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);
>
> Return values are not checked here either, and also not further below.
> That makes me wonder if that is really on purpose. I can't imagine that
> results would be useful if any of the above functions return errors.

Wasn't intentional not to check. Fixed all the missing error handling in v13.
Please ignore the v12 of the patchset and review the v13.

Thanks,
Badhri

>
> Thanks,
> Guenter
>
> > +     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);
>