guybrush: Add ANX7451 mux/retimer driver

Add basic support for ANX7451. Datasheets available in bug.
Support for tuning can be added later if needed.

BUG=b:179065240
BRANCH=None
TEST=Build

Change-Id: Ifafdec4412b73b0fd3f7de2131a8617bbfde6426
Signed-off-by: Rob Barnes <robbarnes@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2699667
Reviewed-by: Diana Z <dzigterman@chromium.org>

2 files changed, 129 insertions, 0 deletions

diff --git a/driver/usb_mux/anx7451.c b/driver/usb_mux/anx7451.c
new file mode 100644
index 0000000000..8af46f6388
--- /dev/null
+++ b/driver/usb_mux/anx7451.c
@@ -0,0 +1,92 @@
+/* Copyright 2021 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.
+ *
+ * ANX7451: 10G Active Mux (4x4) with
+ * Integrated Re-timers for USB3.2/DisplayPort
+ */
+
+#include "anx7451.h"
+#include "common.h"
+#include "console.h"
+#include "i2c.h"
+#include "time.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 inline int anx7451_read(const struct usb_mux *me,
+			       uint8_t reg, int *val)
+{
+	return i2c_read8(me->i2c_port, me->i2c_addr_flags, reg, val);
+}
+
+static inline int anx7451_write(const struct usb_mux *me,
+				uint8_t reg, uint8_t val)
+{
+	return i2c_write8(me->i2c_port, me->i2c_addr_flags, reg, val);
+}
+
+static int anx7451_set_mux(const struct usb_mux *me, mux_state_t mux_state)
+{
+	int reg;
+
+	/* ULP_CFG_MODE_EN overrides pin control. Always set it */
+	reg = ANX7451_ULP_CFG_MODE_EN;
+	if (mux_state & USB_PD_MUX_USB_ENABLED)
+		reg |= ANX7451_ULP_CFG_MODE_USB_EN;
+	if (mux_state & USB_PD_MUX_DP_ENABLED)
+		reg |= ANX7451_ULP_CFG_MODE_DP_EN;
+	if (mux_state & USB_PD_MUX_POLARITY_INVERTED)
+		reg |= ANX7451_ULP_CFG_MODE_FLIP;
+
+	return anx7451_write(me, ANX7451_REG_ULP_CFG_MODE, reg);
+}
+
+static int anx7451_get_mux(const struct usb_mux *me, mux_state_t *mux_state)
+{
+	int reg;
+
+	*mux_state = 0;
+	RETURN_ERROR(anx7451_read(me, ANX7451_REG_ULP_CFG_MODE, &reg));
+
+	if (reg & ANX7451_ULP_CFG_MODE_USB_EN)
+		*mux_state |= USB_PD_MUX_USB_ENABLED;
+	if (reg & ANX7451_ULP_CFG_MODE_DP_EN)
+		*mux_state |= USB_PD_MUX_DP_ENABLED;
+	if (reg & ANX7451_ULP_CFG_MODE_FLIP)
+		*mux_state |= USB_PD_MUX_POLARITY_INVERTED;
+
+	return EC_SUCCESS;
+}
+
+static int anx7451_init(const struct usb_mux *me)
+{
+	uint64_t now;
+
+	/*
+	 * ANX7451 requires 30ms to power on. EC and ANX7451 are on the same
+	 * power rail, so just wait 30ms since EC boot.
+	 */
+	now = get_time().val;
+	if (now < ANX7451_I2C_READY_DELAY_MS*MSEC)
+		usleep(ANX7451_I2C_READY_DELAY_MS*MSEC - now);
+
+	/* ULTRA_LOW_POWER must always be disabled (Fig 2-2) */
+	RETURN_ERROR(anx7451_write(me, ANX7451_REG_ULTRA_LOW_POWER,
+				   ANX7451_ULTRA_LOW_POWER_DIS));
+
+	/* Start mux in safe mode */
+	RETURN_ERROR(anx7451_set_mux(me, USB_PD_MUX_NONE));
+
+	return EC_SUCCESS;
+}
+
+const struct usb_mux_driver anx7451_usb_mux_driver = {
+	.init = anx7451_init,
+	.set = anx7451_set_mux,
+	.get = anx7451_get_mux
+	/* Low power mode is not supported on ANX7451 */
+};
diff --git a/driver/usb_mux/anx7451.h b/driver/usb_mux/anx7451.h
new file mode 100644
index 0000000000..21e5d66bf9
--- /dev/null
+++ b/driver/usb_mux/anx7451.h
@@ -0,0 +1,37 @@
+/* Copyright 2021 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.
+ *
+ * ANX7451: 10G Active Mux (4x4) with
+ * Integrated Re-timers for USB3.2/DisplayPort
+ */
+
+#ifndef __CROS_EC_USB_MUX_ANX7451_H
+#define __CROS_EC_USB_MUX_ANX7451_H
+
+#define ANX7451_I2C_READY_DELAY_MS	30
+
+/* I2C interface addresses */
+#define ANX7451_I2C_ADDR0_FLAGS		0x10
+#define ANX7451_I2C_ADDR1_FLAGS		0x14
+#define ANX7451_I2C_ADDR2_FLAGS		0x16
+#define ANX7451_I2C_ADDR3_FLAGS		0x11
+
+/*
+ * Ultra low power control register.
+ * On ANX7451, this register should always be 0 (disabled).
+ * See figure 2-2 in family programming guide.
+ */
+#define ANX7451_REG_ULTRA_LOW_POWER	0xE6
+/* #define ANX7451_ULTRA_LOW_POWER_EN	0x06 */
+#define ANX7451_ULTRA_LOW_POWER_DIS	0x00
+
+/* Mux control register  */
+#define ANX7451_REG_ULP_CFG_MODE	0xF8
+#define ANX7451_ULP_CFG_MODE_EN		BIT(4)
+#define ANX7451_ULP_CFG_MODE_SWAP	BIT(3)
+#define ANX7451_ULP_CFG_MODE_FLIP	BIT(2)
+#define ANX7451_ULP_CFG_MODE_DP_EN	BIT(1)
+#define ANX7451_ULP_CFG_MODE_USB_EN	BIT(0)
+
+#endif /* __CROS_EC_USB_MUX_ANX7451_H */