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>

1 files changed, 120 insertions, 0 deletions

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,
+};