usb_mux: ps8822: Initial version of driver

This CL adds the driver for the PS8822 usb demux. Currently, the
driver only supports the expected usb mux driver methods. It is
expected that any EQ setting functions would be board specific, though
more register definitions would need to be added to the .h file.

BUG=b:175660576
BRANCH=None
TEST=Connect on host port and then read back mode register to confirm
that it's been set as expected.

Signed-off-by: Scott Collyer <scollyer@google.com>
Change-Id: Ic425ffe41f4653cee7f5500b081d7b5f6ad1a3df
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2247361
Commit-Queue: Scott Collyer <scollyer@chromium.org>
Tested-by: Scott Collyer <scollyer@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Diana Z <dzigterman@chromium.org>

5 files changed, 144 insertions, 0 deletions

diff --git a/driver/build.mk b/driver/build.mk
index 405f775c52..fb9525f4dc 100644
--- a/driver/build.mk
+++ b/driver/build.mk
@@ -175,6 +175,7 @@ driver-$(CONFIG_USB_MUX_PS8740)+=usb_mux/ps8740.o
 driver-$(CONFIG_USB_MUX_PS8742)+=usb_mux/ps8740.o
 driver-$(CONFIG_USB_MUX_PS8743)+=usb_mux/ps8743.o
 driver-$(CONFIG_USB_MUX_TUSB1064)+=usb_mux/tusb1064.o
+driver-$(CONFIG_USB_MUX_PS8822)+=usb_mux/ps8822.o
 driver-$(CONFIG_USB_MUX_VIRTUAL)+=usb_mux/virtual.o
 
 # USB Hub with I2C interface
diff --git a/driver/usb_mux/ps8822.c b/driver/usb_mux/ps8822.c
new file mode 100644
index 0000000000..43ea22de3d
--- /dev/null
+++ b/driver/usb_mux/ps8822.c
@@ -0,0 +1,100 @@
+/* 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.
+ *
+ * Parade PS8822
+ * USB Type-C Redriving Switch for USB Host / DisplayPort.
+ */
+
+#include "common.h"
+#include "i2c.h"
+#include "ps8822.h"
+#include "usb_mux.h"
+#include "util.h"
+
+static int ps8822_read(const struct usb_mux *me, uint8_t reg, int *val)
+{
+	return i2c_read8(me->i2c_port, me->i2c_addr_flags,
+			 reg, val);
+}
+
+static int ps8822_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 ps8822_init(const struct usb_mux *me)
+{
+	char id[PS8822_ID_LEN + 1];
+	int reg;
+	int i;
+	int rv = 0;
+
+	/* Read ID registers */
+	for (i = 0; i < PS8822_ID_LEN; i++) {
+		rv |= ps8822_read(me, PS8822_REG_DEV_ID1 + i, &reg);
+		if (!rv)
+			id[i] = reg;
+	}
+
+	if (!rv) {
+		id[PS8822_ID_LEN] = '\0';
+		/* Set mode register to default value */
+		rv = ps8822_write(me, PS8822_REG_MODE, 0);
+		rv |= strcasecmp("PS8822", id);
+	}
+
+	return rv;
+}
+
+/* Writes control register to set switch mode */
+static int ps8822_set_mux(const struct usb_mux *me, mux_state_t mux_state)
+{
+	int reg;
+	int rv;
+
+	rv = ps8822_read(me, PS8822_REG_MODE, &reg);
+	if (rv)
+		return rv;
+
+	/* Assume standby, preserve PIN_E config bit */
+	reg &= ~(PS8822_MODE_ALT_DP_EN | PS8822_MODE_USB_EN | PS8822_MODE_FLIP);
+
+	if (mux_state & USB_PD_MUX_USB_ENABLED)
+		reg |= PS8822_MODE_USB_EN;
+	if (mux_state & USB_PD_MUX_DP_ENABLED)
+		reg |= PS8822_MODE_ALT_DP_EN;
+	if (mux_state & USB_PD_MUX_POLARITY_INVERTED)
+		reg |= PS8822_MODE_FLIP;
+
+	return ps8822_write(me, PS8822_REG_MODE, reg);
+}
+
+/* Reads control register and updates mux_state accordingly */
+static int ps8822_get_mux(const struct usb_mux *me, mux_state_t *mux_state)
+{
+	int reg;
+	int res;
+
+	res = ps8822_read(me, PS8822_REG_MODE, &reg);
+	if (res)
+		return res;
+
+	*mux_state = 0;
+	if (reg & PS8822_MODE_USB_EN)
+		*mux_state |= USB_PD_MUX_USB_ENABLED;
+	if (reg & PS8822_MODE_ALT_DP_EN)
+		*mux_state |= USB_PD_MUX_DP_ENABLED;
+	if (reg & PS8822_MODE_FLIP)
+		*mux_state |= USB_PD_MUX_POLARITY_INVERTED;
+
+	return EC_SUCCESS;
+}
+
+
+const struct usb_mux_driver ps8822_usb_mux_driver = {
+	.init = ps8822_init,
+	.set = ps8822_set_mux,
+	.get = ps8822_get_mux,
+};
diff --git a/driver/usb_mux/ps8822.h b/driver/usb_mux/ps8822.h
new file mode 100644
index 0000000000..d37e0600f5
--- /dev/null
+++ b/driver/usb_mux/ps8822.h
@@ -0,0 +1,39 @@
+/* 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.
+ *
+ * Parade PS8822
+ * USB Type-C Retiming Switch for USB Device / DisplayPort Sink
+ */
+
+#ifndef __CROS_EC_PS8822_H
+#define __CROS_EC_PS8822_H
+
+#include "usb_mux.h"
+
+#define PS8822_I2C_ADDR0_FLAG    0x10
+#define PS8822_I2C_ADDR1_FLAG    0x18
+#define PS8822_I2C_ADDR2_FLAG    0x58
+#define PS8822_I2C_ADDR3_FLAG    0x60
+
+/* Mode register for setting mux */
+#define PS8822_REG_MODE         0x01
+#define PS8822_MODE_ALT_DP_EN   BIT(7)
+#define PS8822_MODE_USB_EN      BIT(6)
+#define PS8822_MODE_FLIP        BIT(5)
+#define PS8822_MODE_PIN_E       BIT(4)
+
+#define PS8822_REG_CONFIG       0x02
+#define PS8822_CONFIG_HPD_IN_DIS BIT(7)
+#define PS8822_CONFIG_DP_PLUG    BIT(6)
+
+#define PS8822_REG_DEV_ID1      0x06
+#define PS8822_REG_DEV_ID2      0x07
+#define PS8822_REG_DEV_ID3      0x08
+#define PS8822_REG_DEV_ID4      0x09
+#define PS8822_REG_DEV_ID5      0x0A
+#define PS8822_REG_DEV_ID6      0x0B
+
+#define PS8822_ID_LEN 6
+
+#endif /* __CROS_EC_PS8822_H */
diff --git a/include/config.h b/include/config.h
index df235e91f3..ddf4778841 100644
--- a/include/config.h
+++ b/include/config.h
@@ -4762,6 +4762,9 @@
 /* Support the Texas Instrument TUSB1064 Type-C Redriving Switch (UFP) */
 #undef CONFIG_USB_MUX_TUSB1064
 
+/* Support the Parade PS8822 Type-C Redriving Demux Switch */
+#undef CONFIG_USB_MUX_PS8822
+
 /* 'Virtual' USB mux under host (not EC) control */
 #undef CONFIG_USB_MUX_VIRTUAL
 
diff --git a/include/usb_mux.h b/include/usb_mux.h
index 4391eed1e8..f3d18a7874 100644
--- a/include/usb_mux.h
+++ b/include/usb_mux.h
@@ -153,6 +153,7 @@ extern const struct usb_mux_driver it5205_usb_mux_driver;
 extern const struct usb_mux_driver pi3usb3x532_usb_mux_driver;
 extern const struct usb_mux_driver ps8740_usb_mux_driver;
 extern const struct usb_mux_driver ps8743_usb_mux_driver;
+extern const struct usb_mux_driver ps8822_usb_mux_driver;
 extern const struct usb_mux_driver tcpm_usb_mux_driver;
 extern const struct usb_mux_driver tusb1064_usb_mux_driver;
 extern const struct usb_mux_driver virtual_usb_mux_driver;