bc12: Initial driver for pi3usb9201

This CL adds support for the PI3USB9201 dual-role BC1.2 charging
chip. This chip has an I2C interface and has both host and client mode
support. The D+/D- switch control is automatic based on client mode
detection result and host mode settings.

BUG=b:123995100
BRANCH=none
TEST=Verfied that bc1.2 detection occurs following connected a charger
and a EC reboot. Verfired that the D+/D- switches are closed in both
client and host mode as expected.

Change-Id: I3d3a3a05b5387941032cafe0ec4ede7ab7b52d52
Signed-off-by: Scott Collyer <scollyer@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1459821
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Scott Collyer <scollyer@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>

4 files changed, 338 insertions, 0 deletions

diff --git a/driver/bc12/pi3usb9201.c b/driver/bc12/pi3usb9201.c
new file mode 100644
index 0000000000..3368b1fe25
--- /dev/null
+++ b/driver/bc12/pi3usb9201.c
@@ -0,0 +1,296 @@
+/* Copyright 2019 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.
+ */
+
+/* PI3USB9201 USB BC 1.2 Charger Detector driver. */
+
+#include "pi3usb9201.h"
+#include "charge_manager.h"
+#include "chipset.h"
+#include "common.h"
+#include "console.h"
+#include "gpio.h"
+#include "power.h"
+#include "task.h"
+#include "tcpm.h"
+#include "timer.h"
+#include "usb_charge.h"
+#include "usb_pd.h"
+#include "util.h"
+
+#define CPRINTS(format, args...) cprints(CC_USBCHARGE, format, ## args)
+
+enum pi3usb9201_mode {
+	PI3USB9201_POWER_DOWN,
+	PI3USB9201_SDP_HOST_MODE,
+	PI3USB9201_DCP_HOST_MODE,
+	PI3USB9201_CDP_HOST_MODE,
+	PI3USB9201_CLIENT_MODE,
+	PI3USB9201_RESERVED_1,
+	PI3USB9201_RESERVED_2,
+	PI3USB9201_USB_PATH_ON,
+};
+
+enum pi3usb9201_client_sts {
+	CHG_OTHER = 0,
+	CHG_2_4A,
+	CHG_2_0A,
+	CHG_1_0A,
+	CHG_RESERVED,
+	CHG_CDP,
+	CHG_SDP,
+	CHG_DCP,
+};
+
+struct bc12_status {
+	enum charge_supplier supplier;
+	int current_limit;
+};
+
+static const struct bc12_status bc12_chg_limits[] = {
+	[CHG_OTHER] = {CHARGE_SUPPLIER_OTHER, 500},
+	[CHG_2_4A] = {CHARGE_SUPPLIER_PROPRIETARY, 2400},
+	[CHG_2_0A] = {CHARGE_SUPPLIER_PROPRIETARY, 2000},
+	[CHG_1_0A] = {CHARGE_SUPPLIER_PROPRIETARY, 1000},
+	[CHG_RESERVED] = {CHARGE_SUPPLIER_NONE, 0},
+	[CHG_CDP] = {CHARGE_SUPPLIER_BC12_CDP, 1500},
+	[CHG_SDP] = {CHARGE_SUPPLIER_BC12_SDP, 500},
+#if defined(CONFIG_CHARGE_RAMP_SW) || defined(CONFIG_CHARGE_RAMP_HW)
+	/*
+	 * If ramping is supported, then for DCP set the current limit to be the
+	 * max supported for the port by the board. This because for DCP the
+	 * charger is allowed to set its own max up to 5A.
+	 */
+	[CHG_DCP] = {CHARGE_SUPPLIER_BC12_DCP, PD_MAX_CURRENT_MA},
+#else
+	[CHG_DCP] = {CHARGE_SUPPLIER_BC12_DCP, 500},
+#endif
+};
+
+static inline int raw_read8(int port, int offset, int *value)
+{
+	return i2c_read8(pi3usb2901_bc12_chips[port].i2c_port,
+			 pi3usb2901_bc12_chips[port].i2c_addr,
+			 offset, value);
+}
+
+static inline int raw_write8(int port, int offset, int value)
+{
+	return i2c_write8(pi3usb2901_bc12_chips[port].i2c_port,
+			  pi3usb2901_bc12_chips[port].i2c_addr,
+			  offset, value);
+}
+
+static int pi3usb9201_raw(int port, int reg, int mask, int val)
+{
+	int rv;
+	int reg_val;
+
+	rv = raw_read8(port, reg, &reg_val);
+	if (rv)
+		return rv;
+
+	reg_val &= ~mask;
+	reg_val |= val;
+
+	return raw_write8(port, reg, reg_val);
+}
+
+static int pi3usb9201_interrupt_mask(int port, int enable)
+{
+	return pi3usb9201_raw(port, PI3USB9201_REG_CTRL_1,
+			  PI3USB9201_REG_CTRL_1_INT_MASK,
+			  enable);
+}
+
+static int pi3usb9201_bc12_detect_ctrl(int port, int enable)
+{
+	return pi3usb9201_raw(port, PI3USB9201_REG_CTRL_2,
+			      PI3USB9201_REG_CTRL_2_START_DET,
+			      enable ? PI3USB9201_REG_CTRL_2_START_DET : 0);
+}
+
+static int pi3usb9201_set_mode(int port, int desired_mode)
+{
+	return pi3usb9201_raw(port, PI3USB9201_REG_CTRL_1,
+			      PI3USB9201_REG_CTRL_1_MODE_MASK,
+			      desired_mode << 1);
+}
+
+static void bc12_update_charge_manager(int port)
+{
+	int client_status;
+	int rv;
+	enum pi3usb9201_client_sts type;
+	struct charge_port_info new_chg;
+	enum charge_supplier supplier;
+
+	/* Set charge voltage to 5V */
+	new_chg.voltage = USB_CHARGER_VOLTAGE_MV;
+	/* Read BC 1.2 client mode detection result */
+	rv = raw_read8(port, PI3USB9201_REG_CLIENT_STS, &client_status);
+	/* Find set bit position. If no bits set will return 0 */
+	type = __builtin_ffs(client_status) - 1;
+
+	if (!rv && (type >= 0)) {
+		new_chg.current = bc12_chg_limits[type].current_limit;
+		supplier = bc12_chg_limits[type].supplier;
+	} else {
+		/*
+		 * If bc 1.2 detetion failed for some reason, then set limit to
+		 * minimum and set supplier to other.
+		 */
+		new_chg.current = 500;
+		supplier = CHARGE_SUPPLIER_OTHER;
+	}
+	CPRINTS("pi3usb9201[p%d]: sts = 0x%x, lim = %d mA, supplier = %d",
+		port, client_status, new_chg.current, supplier);
+	/* bc1.2 is complete and start bit does not auto clear */
+	pi3usb9201_bc12_detect_ctrl(port, 0);
+	/* Inform charge manager of new supplier type and current limit */
+	charge_manager_update_charge(supplier, port, &new_chg);
+}
+
+static int bc12_detect_start(int port)
+{
+	int rv;
+	/* Put pi3usb9201 into client mode */
+	rv = pi3usb9201_set_mode(port, PI3USB9201_CLIENT_MODE);
+	if (rv)
+		return rv;
+	/* Have pi3usb9201 start bc1.2 detection */
+	rv = pi3usb9201_bc12_detect_ctrl(port, 1);
+	if (rv)
+		return rv;
+	/* Unmask interrupt to wake task when detection completes */
+	return pi3usb9201_interrupt_mask(port, 0);
+}
+
+static void bc12_power_down(int port)
+{
+	/* Put pi3usb9201 into its power down mode */
+	pi3usb9201_set_mode(port, PI3USB9201_POWER_DOWN);
+	/* The start bc1.2 bit does not auto clear */
+	pi3usb9201_bc12_detect_ctrl(port, 0);
+	/* Mask interrupts unitl next bc1.2 detection event */
+	pi3usb9201_interrupt_mask(port, 1);
+	/* Let charge manager know there's no more charge available. */
+	charge_manager_update_charge(CHARGE_SUPPLIER_NONE, port, NULL);
+}
+
+static void bc12_handle_vbus_change(int port)
+{
+	int role = pd_get_role(port);
+	int vbus = pd_snk_is_vbus_provided(port);
+
+#ifndef CONFIG_USB_PD_VBUS_DETECT_TCPC
+	CPRINTS("VBUS p%d %d", port, vbus);
+#endif
+	/*
+	 * TODO(b/124061702): For host mode, currently only setting it to host
+	 * CDP mode. However, there are 3 host status bits to know things such
+	 * as an adapter connected, but no USB device present, or bc1.2 activity
+	 * detected.
+	 */
+	if (role == PD_ROLE_SOURCE &&
+	    board_vbus_source_enabled(port)) {
+		/*
+		 * For source role, if vbus is present, then set
+		 * CDP host mode (will close D+/D-) switches. If
+		 * vbus is not present, then put into power down
+		 * mode.
+		 */
+		if (pi3usb9201_set_mode(port,
+					PI3USB9201_CDP_HOST_MODE))
+			CPRINTS("pi3usb9201[p%d]: failed to set host mode",
+				port);
+	} else if (vbus) {
+		if (bc12_detect_start(port)) {
+			struct charge_port_info new_chg;
+
+			/*
+			 * VBUS is present, but starting bc1.2 detection failed
+			 * for some reason. So limit charge current to default
+			 * 500 mA for this case.
+			 */
+
+			new_chg.voltage = USB_CHARGER_VOLTAGE_MV;
+			new_chg.current = 500;
+			charge_manager_update_charge(CHARGE_SUPPLIER_OTHER,
+						     port, &new_chg);
+			CPRINTS("pi3usb9201[p%d]: bc1.2 start failed", port);
+		}
+	} else {
+		bc12_power_down(port);
+	}
+}
+
+void usb_charger_task(void *u)
+{
+	int port = (task_get_current() == TASK_ID_USB_CHG_P0 ? 0 : 1);
+	uint32_t evt;
+
+	/*
+	 * The is no specific initialization required for the pi3usb9201 other
+	 * than enabling the interrupt mask.
+	 */
+	pi3usb9201_interrupt_mask(port, 1);
+	/*
+	 * Upon EC reset, there likely won't be a VBUS status change to set the
+	 * event to wake up this task. So need to check if VBUS is
+	 * present to make sure that D+/D- switches remain in the correct state
+	 * and bc1.2 detection is triggered (for client mode) to set the correct
+	 * input current limit.
+	 */
+	bc12_handle_vbus_change(port);
+
+	while (1) {
+		/* Wait for interrupt */
+		evt = task_wait_event(-1);
+
+		/* Interrupt from the Pericom chip, determine charger type */
+		if (evt & USB_CHG_EVENT_BC12)
+			bc12_update_charge_manager(port);
+
+		if (evt & USB_CHG_EVENT_VBUS)
+			bc12_handle_vbus_change(port);
+	}
+}
+
+void usb_charger_set_switches(int port, enum usb_switch setting)
+{
+	/*
+	 * Switches are controlled automatically based on whether the port is
+	 * acting as a source or as sink and the result of BC1.2 detection.
+	 */
+}
+
+#if defined(CONFIG_CHARGE_RAMP_SW) || defined(CONFIG_CHARGE_RAMP_HW)
+int usb_charger_ramp_allowed(int supplier)
+{
+	/* Don't allow ramp if charge supplier is OTHER or SDP */
+	return !(supplier == CHARGE_SUPPLIER_OTHER ||
+		 supplier == CHARGE_SUPPLIER_BC12_SDP);
+}
+
+int usb_charger_ramp_max(int supplier, int sup_curr)
+{
+	/*
+	 * Use the level from the bc12_chg_limits table above except for
+	 * proprietary of CDP and in those cases the charge current from the
+	 * charge manager is already set at the max determined by bc1.2
+	 * detection.
+	 */
+	switch (supplier) {
+	case CHARGE_SUPPLIER_BC12_DCP:
+		return PD_MAX_CURRENT_MA;
+	case CHARGE_SUPPLIER_BC12_CDP:
+	case CHARGE_SUPPLIER_PROPRIETARY:
+		return sup_curr;
+	case CHARGE_SUPPLIER_BC12_SDP:
+	default:
+		return 500;
+	}
+}
+#endif /* CONFIG_CHARGE_RAMP_SW || CONFIG_CHARGE_RAMP_HW */
diff --git a/driver/bc12/pi3usb9201.h b/driver/bc12/pi3usb9201.h
new file mode 100644
index 0000000000..589aaab83e
--- /dev/null
+++ b/driver/bc12/pi3usb9201.h
@@ -0,0 +1,40 @@
+/* Copyright 2019 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.
+ */
+
+/* PI3USB9201 USB BC 1.2 Charger Detector driver definitions */
+
+/* 8-bit I2C address */
+#define PI3USB9201_I2C_ADDR_0 0xB8
+#define PI3USB9201_I2C_ADDR_1 0xBA
+#define PI3USB9201_I2C_ADDR_2 0xBC
+#define PI3USB9201_I2C_ADDR_3 0xBE
+
+#define PI3USB9201_REG_CTRL_1 0x0
+#define PI3USB9201_REG_CTRL_2 0x1
+#define PI3USB9201_REG_CLIENT_STS 0x2
+#define PI3USB9201_REG_HOST_STS 0x3
+
+/* Control_1 regiter bit definitions */
+#define PI3USB9201_REG_CTRL_1_INT_MASK (1 << 0)
+#define PI3USB9201_REG_CTRL_1_MODE (1 << 1)
+#define PI3USB9201_REG_CTRL_1_MODE_MASK (0x7 << 1)
+
+/* Control_2 regiter bit definitions */
+#define PI3USB9201_REG_CTRL_2_AUTO_SW (1 << 1)
+#define PI3USB9201_REG_CTRL_2_START_DET (1 << 3)
+
+/* Host status register bit definitions */
+#define PI3USB9201_REG_HOST_STS_BC12_DET (1 << 0)
+#define PI3USB9201_REG_HOST_STS_DEV_PLUG (1 << 1)
+#define PI3USB9201_REG_HOST_STS_DEV_UNPLUG (1 << 2)
+
+struct pi3usb2901_config_t {
+	const int i2c_port;
+	const int i2c_addr;
+};
+
+/* Configuration struct defined at board level */
+extern const struct pi3usb2901_config_t pi3usb2901_bc12_chips[];
+
diff --git a/driver/build.mk b/driver/build.mk
index 592498d941..0a81e0b41b 100644
--- a/driver/build.mk
+++ b/driver/build.mk
@@ -21,6 +21,7 @@ driver-$(CONFIG_SYNC)+=sync.o
 
 # BC1.2 Charger Detection Devices
 driver-$(CONFIG_BC12_DETECT_MAX14637)+=bc12/max14637.o
+driver-$(CONFIG_BC12_DETECT_PI3USB9201)+=bc12/pi3usb9201.o
 driver-$(CONFIG_BC12_DETECT_PI3USB9281)+=bc12/pi3usb9281.o
 
 # Gyrometers
diff --git a/include/config.h b/include/config.h
index 9ebb0bc4de..ee7ba39095 100644
--- a/include/config.h
+++ b/include/config.h
@@ -3513,6 +3513,7 @@
 
 /* External BC1.2 charger detection devices. */
 #undef CONFIG_BC12_DETECT_MAX14637
+#undef CONFIG_BC12_DETECT_PI3USB9201
 #undef CONFIG_BC12_DETECT_PI3USB9281
 /* Number of Pericom PI3USB9281 chips present in system */
 #undef CONFIG_BC12_DETECT_PI3USB9281_CHIP_COUNT