tcpc: add support for TCPC with integrated high-speed muxes

The TCPCI specification defines ane optional register
18h 'CONFIG_STANDARD_OUTPUT' providing a standardized way
of steering the high-speed muxes.

Implement the feature as a usb_mux_driver, under the conditional flag
CONFIG_USB_PD_TCPM_MUX.
The USB PD port index should be set in the port_addr field of the
'usb_mux' structure.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=chrome-os-partner:49605
TEST=run pdeval-stm32f072 connected to a Parade PS8751 board and test USB/DP
muxing.

Change-Id: I7e5f0b8ec70b1910b2cff9d106514baca8c899e5
Reviewed-on: https://chromium-review.googlesource.com/322956
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Shawn N <shawnn@chromium.org>

4 files changed, 71 insertions, 0 deletions

diff --git a/driver/tcpm/tcpci.c b/driver/tcpm/tcpci.c
index 2d268a961a..375e56aa5c 100644
--- a/driver/tcpm/tcpci.c
+++ b/driver/tcpm/tcpci.c
@@ -10,6 +10,7 @@
 #include "tcpm.h"
 #include "timer.h"
 #include "usb_charge.h"
+#include "usb_mux.h"
 #include "usb_pd.h"
 #include "usb_pd_tcpc.h"
 #include "util.h"
@@ -286,3 +287,60 @@ int tcpm_init(int port)
 		msleep(10);
 	}
 }
+
+#ifdef CONFIG_USB_PD_TCPM_MUX
+
+static int tcpm_mux_init(int i2c_addr)
+{
+	return EC_SUCCESS;
+}
+
+static int tcpm_mux_set(int i2c_addr, mux_state_t mux_state)
+{
+	int reg = 0;
+	int rv;
+	int port = i2c_addr; /* use port index in port_addr field */
+
+	rv = tcpc_read(port, TCPC_REG_CONFIG_STD_OUTPUT, &reg);
+	if (rv != EC_SUCCESS)
+		return rv;
+
+	reg &= ~TCPC_REG_CONFIG_STD_OUTPUT_MUX_MASK;
+	if (mux_state & MUX_USB_ENABLED)
+		reg |= TCPC_REG_CONFIG_STD_OUTPUT_MUX_USB;
+	if (mux_state & MUX_DP_ENABLED)
+		reg |= TCPC_REG_CONFIG_STD_OUTPUT_MUX_DP;
+	/* MUX_POLARITY_INVERTED: polarity is handled by the TCPC */
+
+	return tcpc_write(port, TCPC_REG_CONFIG_STD_OUTPUT, reg);
+}
+
+/* Reads control register and updates mux_state accordingly */
+static int tcpm_mux_get(int i2c_addr, mux_state_t *mux_state)
+{
+	int reg = 0;
+	int rv;
+	int port = i2c_addr; /* use port index in port_addr field */
+
+	*mux_state = 0;
+	rv = tcpc_read(port, TCPC_REG_CONFIG_STD_OUTPUT, &reg);
+	if (rv != EC_SUCCESS)
+		return rv;
+
+	if (reg & TCPC_REG_CONFIG_STD_OUTPUT_MUX_USB)
+		*mux_state |= MUX_USB_ENABLED;
+	if (reg & TCPC_REG_CONFIG_STD_OUTPUT_MUX_DP)
+		*mux_state |= MUX_DP_ENABLED;
+	/* MUX_POLARITY_INVERTED is always omitted */
+
+	return EC_SUCCESS;
+}
+
+
+const struct usb_mux_driver tcpm_usb_mux_driver = {
+	.init = tcpm_mux_init,
+	.set = tcpm_mux_set,
+	.get = tcpm_mux_get,
+};
+
+#endif /* CONFIG_USB_PD_TCPM_MUX */
diff --git a/driver/tcpm/tcpci.h b/driver/tcpm/tcpci.h
index d105ea5361..eb87b7d0e2 100644
--- a/driver/tcpm/tcpci.h
+++ b/driver/tcpm/tcpci.h
@@ -37,6 +37,12 @@
 #define TCPC_REG_POWER_STATUS_MASK 0x14
 #define TCPC_REG_FAULT_STATUS_MASK 0x15
 #define TCPC_REG_CONFIG_STD_OUTPUT 0x18
+
+#define TCPC_REG_CONFIG_STD_OUTPUT_MUX_MASK (3 << 2)
+#define TCPC_REG_CONFIG_STD_OUTPUT_MUX_NONE (0 << 2)
+#define TCPC_REG_CONFIG_STD_OUTPUT_MUX_USB  (1 << 2)
+#define TCPC_REG_CONFIG_STD_OUTPUT_MUX_DP   (2 << 2)
+
 #define TCPC_REG_TCPC_CTRL         0x19
 #define TCPC_REG_TCPC_CTRL_SET(polarity) (polarity)
 #define TCPC_REG_TCPC_CTRL_POLARITY(reg) ((reg) & 0x1)
diff --git a/include/config.h b/include/config.h
index d307b75ad2..bd86449519 100644
--- a/include/config.h
+++ b/include/config.h
@@ -1827,6 +1827,12 @@
 #undef CONFIG_USB_PD_TCPM_FUSB302
 
 /*
+ * Use this option if the TCPC port controller supports the optional register
+ * 18h CONFIG_STANDARD_OUTPUT to steer the high-speed muxes.
+ */
+#undef CONFIG_USB_PD_TCPM_MUX
+
+/*
  * Use this option if the TCPC port controller is on a seperate chip from
  * the TCPM layer and if VUBS detect GPIO is not available on the TCPM
  * mcu.
diff --git a/include/usb_mux.h b/include/usb_mux.h
index 1524caa3fa..4f38b8e68e 100644
--- a/include/usb_mux.h
+++ b/include/usb_mux.h
@@ -80,6 +80,7 @@ struct usb_mux {
 /* Supported USB mux drivers */
 extern const struct usb_mux_driver pi3usb30532_usb_mux_driver;
 extern const struct usb_mux_driver ps8740_usb_mux_driver;
+extern const struct usb_mux_driver tcpm_usb_mux_driver;
 
 /* USB muxes present in system, ordered by PD port #, defined at board-level */
 extern struct usb_mux usb_muxes[];