@@ -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
new file mode 100644
@@ -0,0 +1,338 @@
+// 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 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 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 adc_to_mv(chip, channel, ua_src, fladc);
+ else
+ return fladc;
+}
+
+static int 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 = 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 = 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 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 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 = read_resistance_kohm(chip, CC1_SCALE2, READ1_SLEEP_MS, false);
+ cc2_k = read_resistance_kohm(chip, CC2_SCALE2, READ2_SLEEP_MS, false);
+
+ sbu1_k = read_resistance_kohm(chip, SBU1, READ1_SLEEP_MS, false);
+ sbu2_k = read_resistance_kohm(chip, SBU2, READ2_SLEEP_MS, false);
+ 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 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 is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce)
+{
+ u8 cc_status, pwr_cntl;
+ enum contamiant_state state;
+
+ 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 = detect_contaminant(chip);
+
+ max_tcpci_write8(chip, TCPC_ROLE_CTRL, role_ctrl_backup);
+ if (state == DETECTED) {
+ 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 = detect_contaminant(chip);
+ if (state == DETECTED) {
+ enable_dry_detection(chip);
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(is_contaminant);
+
+MODULE_DESCRIPTION("MAXIM TCPC CONTAMINANT Module");
+MODULE_AUTHOR("Badhri Jagan Sridharan <badhri@google.com>");
+MODULE_LICENSE("GPL");
new file mode 100644
@@ -0,0 +1,91 @@
+/* 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;
+ enum tcpm_state tcpm_current_state;
+ bool potential_contaminant;
+};
+
+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 is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce);
+
+#endif // TCPCI_MAXIM_H_
similarity index 90%
rename from drivers/usb/typec/tcpm/tcpci_maxim.c
rename to 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) {
+ if (!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 +418,38 @@ 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 (!is_contaminant(chip, chip->tcpm_current_state != TOGGLING))
+ tcpm_port_clean(chip->port);
+}
+
+static bool max_tcpci_is_potential_contaminant(struct tcpci *tcpci, struct tcpci_data *tdata,
+ enum tcpm_state current_state)
+{
+ struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
+ enum tcpm_state tcpm_prev_state = chip->tcpm_current_state;
+
+ /*
+ * Return previous determinted contaminant status when tcpm is in CHECK_CONTAMINANT
+ * state. Do not update the tcpm current state either.
+ */
+ if (current_state == CHECK_CONTAMINANT)
+ return chip->potential_contaminant;
+
+ chip->tcpm_current_state = current_state;
+
+ if ((tcpm_prev_state == SRC_ATTACH_WAIT && current_state == SRC_UNATTACHED) ||
+ (tcpm_prev_state == SNK_ATTACH_WAIT && current_state == SNK_UNATTACHED))
+ chip->potential_contaminant = true;
+ else
+ chip->potential_contaminant = false;
+
+ return chip->potential_contaminant;
+}
+
static int max_tcpci_probe(struct i2c_client *client)
{
int ret;
@@ -471,6 +483,8 @@ 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;
+ chip->data.is_potential_contaminant = max_tcpci_is_potential_contaminant;
max_tcpci_init_regs(chip);
chip->tcpci = tcpci_register_port(chip->dev, &chip->data);
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 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 | 338 ++++++++++++++++++ drivers/usb/typec/tcpm/tcpci_maxim.h | 91 +++++ .../{tcpci_maxim.c => tcpci_maxim_core.c} | 78 ++-- 4 files changed, 476 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} (90%)