usb_mux: Add driver interface for USB-C muxes

In preparation for adding support for additional USB-C mux chips, add a
new high-level USB-C mux interface usb_mux.c. usb_mux functions are now
called from pd code instead of board-level functions. usb_mux calls down
into a mux chip-specific driver (currently pi3usb30532) or
board-specific drivers which toggle GPIOs (for legacy boards).

BUG=chrome-os-partner:41696
TEST=Manual on Glados in subsequent commit. Verify set() and get()
functions set and return consistent values. Verify that USB SS device
functions when muxes are set to dock or USB. Also, verify that DP
dongle and USB SS device are functional on both PD ports on samus_pd.
BRANCH=None

Change-Id: Ib6477f489310f3be1430585ea09fea26f57e3752
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/281435
Reviewed-by: Alec Berg <alecaberg@chromium.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/include/usb_mux.h b/include/usb_mux.h
new file mode 100644
index 0000000000..d451e9cf1c
--- /dev/null
+++ b/include/usb_mux.h
@@ -0,0 +1,116 @@
+/* Copyright (c) 2012 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.
+ */
+
+/* USB mux driver */
+
+#ifndef __CROS_EC_USB_MUX_H
+#define __CROS_EC_USB_MUX_H
+
+#include "usb_pd.h"
+
+/* USB-C mux state */
+typedef uint8_t mux_state_t;
+
+/* Mux state attributes */
+#define MUX_USB_ENABLED        (1 << 0) /* USB is enabled */
+#define MUX_DP_ENABLED         (1 << 1) /* DP is enabled */
+#define MUX_POLARITY_INVERTED  (1 << 2) /* Polarity is inverted */
+
+/* Mux modes, decoded to attributes */
+enum typec_mux {
+	TYPEC_MUX_NONE = 0,                /* Open switch */
+	TYPEC_MUX_USB  = MUX_USB_ENABLED,  /* USB only */
+	TYPEC_MUX_DP   = MUX_DP_ENABLED,   /* DP only */
+	TYPEC_MUX_DOCK = MUX_USB_ENABLED | /* Both USB and DP */
+			 MUX_DP_ENABLED,
+};
+
+/* Mux driver function pointers */
+struct usb_mux_driver {
+	/**
+	 * Initialize USB mux.
+	 *
+	 * @param port_addr Port/address driver-defined parameter.
+	 * @return EC_SUCCESS on success, non-zero error code on failure.
+	 */
+	int (*init)(int port_addr);
+
+	/**
+	 * Set USB mux state.
+	 *
+	 * @param port_addr Port/address driver-defined parameter.
+	 * @param mux_state State to set mux to.
+	 * @return EC_SUCCESS on success, non-zero error code on failure.
+	 */
+	int (*set)(int port_addr, mux_state_t mux_state);
+
+	/**
+	 * Get current state of USB mux.
+	 *
+	 * @param port_addr Port / address driver-defined parameter.
+	 * @param mux_state Gets set to current state of mux.
+	 * @return EC_SUCCESS on success, non-zero error code on failure.
+	 */
+	int (*get)(int port_addr, mux_state_t *mux_state);
+};
+
+/* Describes a USB mux present in the system */
+struct usb_mux {
+	/*
+	 * Driver-defined parameter, typically an i2c slave address
+	 * (for i2c muxes) or a port number (for GPIO 'muxes').
+	 */
+	const int port_addr;
+	/* Mux driver */
+	const struct usb_mux_driver *driver;
+};
+
+/* Supported USB mux drivers */
+extern const struct usb_mux_driver pi3usb30532_usb_mux_driver;
+
+/* USB muxes present in system, ordered by PD port #, defined at board-level */
+extern struct usb_mux usb_muxes[];
+
+/**
+ * Initialize USB mux to its default state.
+ *
+ * @param port  Port number.
+ */
+void usb_mux_init(int port);
+
+/**
+ * Configure superspeed muxes on type-C port.
+ *
+ * @param port port number.
+ * @param mux_mode mux selected function.
+ * @param usb_config usb2.0 selected function.
+ * @param polarity plug polarity (0=CC1, 1=CC2).
+ */
+void usb_mux_set(int port, enum typec_mux mux_mode,
+		 enum usb_switch usb_config, int polarity);
+
+/**
+ * Query superspeed mux status on type-C port.
+ *
+ * @param port port number.
+ * @param dp_str pointer to the DP string to return.
+ * @param usb_str pointer to the USB string to return.
+ * @return Non-zero if superspeed connection is enabled; otherwise, zero.
+ */
+int usb_mux_get(int port, const char **dp_str, const char **usb_str);
+
+/**
+ * Flip the superspeed muxes on type-C port.
+ *
+ * This is used for factory test automation. Note that this function should
+ * only flip the superspeed muxes and leave CC lines alone. Without further
+ * changes, this function MUST ONLY be used for testing purpose, because
+ * the protocol layer loses track of the superspeed polarity and DP/USB3.0
+ * connection may break.
+ *
+ * @param port port number.
+ */
+void usb_mux_flip(int port);
+#endif