driver: add IT5205 mux driver

Add support the ITE IT5205 Type-C USB alternate mode mux.

BRANCH=none
BUG=none
TEST=1. Successfully verify chip ID.
     2. Verify set_mux() and get_mux() functions set and return
        consistent values.
     3. The mux control register setting as expected after set_mux().

Change-Id: I9ff066dc9e74683df1371b70290e2aeaa86cb96b
Signed-off-by: Dino Li <Dino.Li@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/741211
Reviewed-by: Shawn N <shawnn@chromium.org>

5 files changed, 157 insertions, 0 deletions

diff --git a/driver/build.mk b/driver/build.mk
index 21579d44ae..4fa78d25bc 100644
--- a/driver/build.mk
+++ b/driver/build.mk
@@ -99,6 +99,7 @@ driver-$(CONFIG_USB_PD_TCPM_PS8805)+=tcpm/ps8xxx.o
 driver-$(CONFIG_USBC_SS_MUX)+=usb_mux.o
 
 # USB muxes
+driver-$(CONFIG_USB_MUX_IT5205)+=usb_mux_it5205.o
 driver-$(CONFIG_USB_MUX_PI3USB30532)+=usb_mux_pi3usb30532.o
 driver-$(CONFIG_USB_MUX_PS8740)+=usb_mux_ps874x.o
 driver-$(CONFIG_USB_MUX_PS8743)+=usb_mux_ps874x.o
diff --git a/driver/usb_mux_it5205.c b/driver/usb_mux_it5205.c
new file mode 100644
index 0000000000..c6b9a91778
--- /dev/null
+++ b/driver/usb_mux_it5205.c
@@ -0,0 +1,120 @@
+/* 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.
+ *
+ * ITE IT5205 Type-C USB alternate mode mux.
+ */
+
+#include "common.h"
+#include "console.h"
+#include "i2c.h"
+#include "usb_mux.h"
+#include "usb_mux_it5205.h"
+#include "util.h"
+
+#define MUX_STATE_DP_USB_MASK (MUX_USB_ENABLED | MUX_DP_ENABLED)
+
+static int it5205_read(int i2c_addr, uint8_t reg, int *val)
+{
+	return i2c_read8(I2C_PORT_USB_MUX, i2c_addr, reg, val);
+}
+
+static int it5205_write(int i2c_addr, uint8_t reg, uint8_t val)
+{
+	return i2c_write8(I2C_PORT_USB_MUX, i2c_addr, reg, val);
+}
+
+struct mux_chip_id_t {
+	uint8_t chip_id;
+	uint8_t reg;
+};
+
+static const struct mux_chip_id_t mux_chip_id_verify[] = {
+	{ '5', IT5205_REG_CHIP_ID3},
+	{ '2', IT5205_REG_CHIP_ID2},
+	{ '0', IT5205_REG_CHIP_ID1},
+	{ '5', IT5205_REG_CHIP_ID0},
+};
+
+static int it5205_init(int i2c_addr)
+{
+	int i, val, ret;
+
+	/* bit[0]: mux power on, bit[7-1]: reserved. */
+	ret = it5205_write(i2c_addr, IT5205_REG_MUXPDR, 0);
+	if (ret)
+		return ret;
+	/*  Verify chip ID registers. */
+	for (i = 0; i < ARRAY_SIZE(mux_chip_id_verify); i++) {
+		ret = it5205_read(i2c_addr, mux_chip_id_verify[i].reg, &val);
+		if (ret)
+			return ret;
+
+		if (val != mux_chip_id_verify[i].chip_id)
+			return EC_ERROR_UNKNOWN;
+	}
+
+	return EC_SUCCESS;
+}
+
+/* Writes control register to set switch mode */
+static int it5205_set_mux(int i2c_addr, mux_state_t mux_state)
+{
+	uint8_t reg;
+
+	switch (mux_state & MUX_STATE_DP_USB_MASK) {
+	case MUX_USB_ENABLED:
+		reg = IT5205_USB;
+		break;
+	case MUX_DP_ENABLED:
+		reg = IT5205_DP;
+		break;
+	case MUX_STATE_DP_USB_MASK:
+		reg = IT5205_DP_USB;
+		break;
+	default:
+		reg = 0;
+		break;
+	}
+
+	if (mux_state & MUX_POLARITY_INVERTED)
+		reg |= IT5205_POLARITY_INVERTED;
+
+	return it5205_write(i2c_addr, IT5205_REG_MUXCR, reg);
+}
+
+/* Reads control register and updates mux_state accordingly */
+static int it5205_get_mux(int i2c_addr, mux_state_t *mux_state)
+{
+	int reg, ret;
+
+	ret = it5205_read(i2c_addr, IT5205_REG_MUXCR, &reg);
+	if (ret)
+		return ret;
+
+	switch (reg & IT5205_DP_USB_CTRL_MASK) {
+	case IT5205_USB:
+		*mux_state = MUX_USB_ENABLED;
+		break;
+	case IT5205_DP:
+		*mux_state = MUX_DP_ENABLED;
+		break;
+	case IT5205_DP_USB:
+		*mux_state = MUX_STATE_DP_USB_MASK;
+		break;
+	default:
+		*mux_state = 0;
+		break;
+	}
+
+	if (reg & IT5205_POLARITY_INVERTED)
+		*mux_state |= MUX_POLARITY_INVERTED;
+
+	return EC_SUCCESS;
+}
+
+const struct usb_mux_driver it5205_usb_mux_driver = {
+	.init = it5205_init,
+	.set = it5205_set_mux,
+	.get = it5205_get_mux,
+};
diff --git a/driver/usb_mux_it5205.h b/driver/usb_mux_it5205.h
new file mode 100644
index 0000000000..0cebeed71a
--- /dev/null
+++ b/driver/usb_mux_it5205.h
@@ -0,0 +1,32 @@
+/* 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.
+ *
+ * ITE IT5205 Type-C USB alternate mode mux.
+ */
+
+#ifndef __CROS_EC_USB_MUX_IT5205_H
+#define __CROS_EC_USB_MUX_IT5205_H
+
+/* 8 bit i2c slave address is 0xb0 or 0x90 depends on address setting pin. */
+
+/* Chip ID registers */
+#define IT5205_REG_CHIP_ID3 0x4
+#define IT5205_REG_CHIP_ID2 0x5
+#define IT5205_REG_CHIP_ID1 0x6
+#define IT5205_REG_CHIP_ID0 0x7
+
+/* MUX power down register */
+#define IT5205_REG_MUXPDR        0x10
+#define IT5205_MUX_POWER_DOWN    (1 << 0)
+
+/* MUX control register */
+#define IT5205_REG_MUXCR         0x11
+#define IT5205_POLARITY_INVERTED (1 << 4)
+
+#define IT5205_DP_USB_CTRL_MASK  0x0f
+#define IT5205_DP                0x0f
+#define IT5205_DP_USB            0x03
+#define IT5205_USB               0x07
+
+#endif /* __CROS_EC_USB_MUX_IT5205_H */
diff --git a/include/config.h b/include/config.h
index 9cd3698ea3..eb6d3e1d47 100644
--- a/include/config.h
+++ b/include/config.h
@@ -2836,6 +2836,9 @@
 /******************************************************************************/
 /* USB port switch */
 
+/* Support the ITE IT5205 Type-C USB alternate mode mux. */
+#undef CONFIG_USB_MUX_IT5205
+
 /* Support the Pericom PI3USB30532 USB3.0/DP1.2 Matrix Switch */
 #undef CONFIG_USB_MUX_PI3USB30532
 
diff --git a/include/usb_mux.h b/include/usb_mux.h
index 8df27af44b..151c397995 100644
--- a/include/usb_mux.h
+++ b/include/usb_mux.h
@@ -88,6 +88,7 @@ struct usb_mux {
 };
 
 /* Supported USB mux drivers */
+extern const struct usb_mux_driver it5205_usb_mux_driver;
 extern const struct usb_mux_driver pi3usb30532_usb_mux_driver;
 extern const struct usb_mux_driver ps874x_usb_mux_driver;
 extern const struct usb_mux_driver tcpm_usb_mux_driver;