driver: Add support for TI BQ24392.

The BQ24932 is a dual single-pole single-throw USB 2.0 high-speed
isolation switch with charger detection capabilities.  The device's
charger detection circuitry can support USB Battery Charging
Specification version 1.2 (BC1.2), Apple, TomTom, and other non-standard
chargers.

BUG=None
BRANCH=None
TEST=`make -j buildall`
TEST=Enable support for the BQ24392 on a board.  Verify that it
complies.

Change-Id: I82f426f1eedabdbb6b951a6ce0252135de3368db
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/592133
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Shawn N <shawnn@chromium.org>

driver/bc12/bq24392.c

@@ -0,0 +1,143 @@
+/* Copyright 2017 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/*
+ * BQ24392 USB BC 1.2 Charger Detector driver.
+ *
+ * NOTE: The driver assumes that CHG_AL_N and SW_OPEN are not connected,
+ * therefore the value of CHG_DET indicates whether the source is NOT a
+ * low-power standard downstream port (SDP).  In order to use higher currents,
+ * the system will have to charge ramp.
+ */
+
+#include "charge_manager.h"
+#include "common.h"
+#include "gpio.h"
+#include "task.h"
+#include "tcpm.h"
+#include "timer.h"
+#include "usb_charge.h"
+#include "util.h"
+
+struct bq24392_pins {
+	enum gpio_signal chip_enable;
+	enum gpio_signal chg_det;
+};
+
+static const struct bq24392_pins pin_tbl[] = {
+	{ GPIO_USB_C0_BC12_VBUS_ON, GPIO_USB_C0_BC12_CHG_DET },
+#ifdef HAS_TASK_USB_CHG_P1
+	{ GPIO_USB_C1_BC12_VBUS_ON, GPIO_USB_C1_BC12_CHG_DET },
+#endif
+#ifdef HAS_TASK_USB_CHG_P2
+	{ GPIO_USB_C2_BC12_VBUS_ON, GPIO_USB_C2_BC12_CHG_DET },
+#endif
+};
+
+/**
+ * Perform BC1.2 detection and update charge manager.
+ *
+ * @param port: The Type-C port where VBUS is present.
+ */
+static void bc12_detect(const int port)
+{
+	int is_high_power;
+	struct charge_port_info new_chg;
+	enum gpio_signal chip_enable;
+	enum gpio_signal chg_det;
+
+	chip_enable = pin_tbl[port].chip_enable;
+	chg_det = pin_tbl[port].chg_det;
+
+	/* Enable the IC to begin detection. */
+	gpio_set_level(chip_enable, 1);
+
+	/*
+	 * Apple or TomTom charger detection can take as long as 600ms.  Wait a
+	 * little bit longer for margin.
+	 */
+	msleep(630);
+
+	/*
+	 * The driver assumes that CHG_AL_N and SW_OPEN are not connected,
+	 * therefore the value of CHG_DET indicates whether the source is NOT a
+	 * low-power standard downstream port (SDP).  The system will have to
+	 * ramp the current to determine the limit.
+	 */
+	is_high_power = gpio_get_level(chg_det);
+
+	new_chg.voltage = USB_CHARGER_VOLTAGE_MV;
+#ifdef CONFIG_CHARGE_RAMP
+	new_chg.current = is_high_power ? 2400 : 500;
+#else
+	/*
+	 * If the board doesn't support charge ramping, then assume the lowest
+	 * denominator; that is assume the charger detected is a weak dedicated
+	 * charging port (DCP) which can only supply 500mA.
+	 */
+	new_chg.current = 500;
+#endif /* !defined(CONFIG_CHARGE_RAMP) */
+
+	charge_manager_update_charge(CHARGE_SUPPLIER_OTHER, port, &new_chg);
+}
+
+/**
+ * Turn off the BQ24392 detector.
+ *
+ * @param port: Which USB Type-C port's BC1.2 detector to turn off.
+ */
+static void power_down_ic(const int port)
+{
+	struct charge_port_info no_chg = { 0 };
+	enum gpio_signal chip_enable = pin_tbl[port].chip_enable;
+
+	/* Turn off the IC. */
+	gpio_set_level(chip_enable, 0);
+
+	/* Let charge manager know there's no more charge available. */
+	charge_manager_update_charge(CHARGE_SUPPLIER_OTHER, port, &no_chg);
+}
+
+/**
+ * If VBUS is present, determine the charger type, otherwise power down the IC.
+ *
+ * @param port: Which USB Type-C port to examine.
+ */
+static void detect_or_power_down_ic(const int port)
+{
+	int vbus_present;
+
+#ifdef CONFIG_USB_PD_VBUS_DETECT_TCPC
+	vbus_present = tcpm_get_vbus_level(port);
+#else
+	vbus_present = pd_snk_is_vbus_provided(port);
+#endif /* !defined(CONFIG_USB_PD_VBUS_DETECT_TCPC) */
+
+	if (vbus_present)
+		bc12_detect(port);
+	else
+		power_down_ic(port);
+}
+
+void usb_charger_task(const int port)
+{
+	uint32_t evt;
+
+	ASSERT(port >= 0 && port <= 2);
+
+	detect_or_power_down_ic(port);
+
+	while (1) {
+		evt = task_wait_event(-1);
+
+		if (evt & USB_CHG_EVENT_VBUS)
+			detect_or_power_down_ic(port);
+	}
+}
+
+void usb_charger_set_switches(int port, enum usb_switch setting)
+{
+	/* The BQ24392 automatically sets up the USB 2.0 high-speed switches. */
+}

driver/build.mk

@@ -16,6 +16,9 @@ driver-$(CONFIG_MAG_BMI160_BMM150)+=mag_bmm150.o
 driver-$(CONFIG_ACCELGYRO_LSM6DSM)+=accelgyro_lsm6dsm.o
 driver-$(CONFIG_ACCEL_LIS2DH)+=accel_lis2dh.o stm_mems_common.o
 
+# BC1.2 Charger Detection Devices
+driver-$(CONFIG_BC12_DETECT_BQ24392)+=bc12/bq24392.o
+
 # Gyrometers
 driver-$(CONFIG_GYRO_L3GD20H)+=gyro_l3gd20h.o
 

include/config.h

@@ -2590,6 +2590,9 @@
 /* Common USB / BC1.2 charger detection routines */
 #undef CONFIG_USB_CHARGER
 
+/* External BC1.2 charger detection devices. */
+#undef CONFIG_BC12_DETECT_BQ24392
+
 /* Enable USB serial console module. */
 #undef CONFIG_USB_CONSOLE