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, 150 insertions, 0 deletions

diff --git a/driver/usb_mux.c b/driver/usb_mux.c
new file mode 100644
index 0000000000..04427f7615
--- /dev/null
+++ b/driver/usb_mux.c
@@ -0,0 +1,150 @@
+/* Copyright 2015 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 high-level driver. */
+
+#include "common.h"
+#include "console.h"
+#include "usb_mux.h"
+#include "util.h"
+
+#define CPRINTS(format, args...) cprints(CC_USBCHARGE, format, ## args)
+#define CPRINTF(format, args...) cprintf(CC_USBCHARGE, format, ## args)
+
+static int enable_debug_prints;
+
+void usb_mux_init(int port)
+{
+	const struct usb_mux *mux = &usb_muxes[port];
+	int res;
+
+	ASSERT(port >= 0 && port < CONFIG_USB_PD_PORT_COUNT);
+	res = mux->driver->init(mux->port_addr);
+	if (res)
+		CPRINTS("Error initializing mux port(%d): %d", port, res);
+}
+
+/*
+ * TODO(crbug.com/505480): Setting muxes often involves I2C transcations,
+ * which can block. Consider implementing an asynchronous task.
+ */
+void usb_mux_set(int port, enum typec_mux mux_mode,
+		 enum usb_switch usb_mode, int polarity)
+{
+	const struct usb_mux *mux = &usb_muxes[port];
+	int res;
+	mux_state_t mux_state;
+
+	/* Configure USB2.0 */
+	board_set_usb_switches(port, usb_mode);
+
+	/* Configure superspeed lanes */
+	mux_state = polarity ? mux_mode | MUX_POLARITY_INVERTED : mux_mode;
+	res = mux->driver->set(mux->port_addr, mux_state);
+	if (res) {
+		CPRINTS("Error setting mux port(%d): %d", port, res);
+		return;
+	}
+
+	if (enable_debug_prints)
+		CPRINTS(
+		     "usb/dp mux: port(%d) typec_mux(%d) usb2(%d) polarity(%d)",
+		     port, mux_mode, usb_mode, polarity);
+}
+
+int usb_mux_get(int port, const char **dp_str, const char **usb_str)
+{
+	const struct usb_mux *mux = &usb_muxes[port];
+	int res;
+	mux_state_t mux_state;
+	const char *dp, *usb;
+
+	res = mux->driver->get(mux->port_addr, &mux_state);
+	if (res) {
+		CPRINTS("Error setting mux port(%d): %d", port, res);
+		return 0;
+	}
+
+	dp = mux_state & MUX_POLARITY_INVERTED ? "DP2" : "DP1";
+	usb = mux_state & MUX_POLARITY_INVERTED ? "USB2" : "USB1";
+
+	*dp_str = mux_state & MUX_DP_ENABLED ? dp : NULL;
+	*usb_str = mux_state & MUX_USB_ENABLED ? usb : NULL;
+
+	return *dp_str || *usb_str;
+}
+
+void usb_mux_flip(int port)
+{
+	const struct usb_mux *mux = &usb_muxes[port];
+	int res;
+	mux_state_t mux_state;
+
+	res = mux->driver->get(mux->port_addr, &mux_state);
+	if (res) {
+		CPRINTS("Error getting mux port(%d): %d", port, res);
+		return;
+	}
+
+	if (mux_state & MUX_POLARITY_INVERTED)
+		mux_state &= ~MUX_POLARITY_INVERTED;
+	else
+		mux_state |= MUX_POLARITY_INVERTED;
+
+	res = mux->driver->set(mux->port_addr, mux_state);
+	if (res)
+		CPRINTS("Error setting mux port(%d): %d", port, res);
+}
+
+#ifdef CONFIG_CMD_TYPEC
+static int command_typec(int argc, char **argv)
+{
+	const char * const mux_name[] = {"none", "usb", "dp", "dock"};
+	char *e;
+	int port;
+	enum typec_mux mux = TYPEC_MUX_NONE;
+	int i;
+
+	if (argc == 2 && !strcasecmp(argv[1], "debug")) {
+		enable_debug_prints = 1;
+		return EC_SUCCESS;
+	}
+
+	if (argc < 2)
+		return EC_ERROR_PARAM_COUNT;
+
+	port = strtoi(argv[1], &e, 10);
+	if (*e || port >= CONFIG_USB_PD_PORT_COUNT)
+		return EC_ERROR_PARAM1;
+
+	if (argc < 3) {
+		const char *dp_str, *usb_str;
+		ccprintf("Port C%d: polarity:CC%d\n",
+			port, pd_get_polarity(port) + 1);
+		if (usb_mux_get(port, &dp_str, &usb_str))
+			ccprintf("Superspeed %s%s%s\n",
+				 dp_str ? dp_str : "",
+				 dp_str && usb_str ? "+" : "",
+				 usb_str ? usb_str : "");
+		else
+			ccprintf("No Superspeed connection\n");
+
+		return EC_SUCCESS;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(mux_name); i++)
+		if (!strcasecmp(argv[2], mux_name[i]))
+			mux = i;
+	usb_mux_set(port, mux, mux == TYPEC_MUX_NONE ?
+				      USB_SWITCH_DISCONNECT :
+				      USB_SWITCH_CONNECT,
+			  pd_get_polarity(port));
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(typec, command_typec,
+			"[port|debug] [none|usb|dp|dock]",
+			"Control type-C connector muxing",
+			NULL);
+#endif