hatch: Add support for MST (multi stream transport) enable

The MST chip for Hatch needs to be enabled when HPD signal from either
the Port 1 TCPC or HDMI port is high. This CL adds support to
enable the MST chip based on this criteria. For the Port 1 type C
port, the HPD signal level is derived from the USB PD policy level
where the HPD update driver method is called.

BRANCH=none
BUG=b:123894908
TEST=Used external HP Z27n monitor and verifed the display is extended
as expected when it's connected to either port 1 type C port or the
HDMI connector.

Change-Id: I1c46534bc7f32221f9e379dd9c74d5618c8f57e1
Signed-off-by: Scott Collyer <scollyer@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1406496
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Scott Collyer <scollyer@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>

6 files changed, 56 insertions, 0 deletions

diff --git a/baseboard/hatch/baseboard.c b/baseboard/hatch/baseboard.c
index 1347b066a7..326e1eb036 100644
--- a/baseboard/hatch/baseboard.c
+++ b/baseboard/hatch/baseboard.c
@@ -4,6 +4,7 @@
  */
 
 /* Hatch family-specific configuration */
+#include "atomic.h"
 #include "battery_fuel_gauge.h"
 #include "charge_manager.h"
 #include "charge_state_v2.h"
@@ -204,6 +205,8 @@ void baseboard_tcpc_init(void)
 	gpio_enable_interrupt(GPIO_USB_C0_TCPC_INT_ODL);
 	gpio_enable_interrupt(GPIO_USB_C1_TCPC_INT_ODL);
 
+	/* Enable HDMI HPD interrupt. */
+	gpio_enable_interrupt(GPIO_HDMI_CONN_HPD);
 }
 DECLARE_HOOK(HOOK_INIT, baseboard_tcpc_init, HOOK_PRIO_INIT_I2C + 1);
 
@@ -331,3 +334,15 @@ void board_set_charge_limit(int port, int supplier, int charge_ma,
 					   CONFIG_CHARGER_INPUT_CURRENT),
 				       charge_mv);
 }
+
+void baseboard_mst_enable_control(enum mst_source src, int level)
+{
+	static uint32_t mst_input_levels;
+
+	if (level)
+		atomic_or(&mst_input_levels, 1 << src);
+	else
+		atomic_clear(&mst_input_levels, 1 << src);
+
+	gpio_set_level(GPIO_EN_MST, mst_input_levels ? 1 : 0);
+}
diff --git a/baseboard/hatch/baseboard.h b/baseboard/hatch/baseboard.h
index aa14d7796e..b3f14e1154 100644
--- a/baseboard/hatch/baseboard.h
+++ b/baseboard/hatch/baseboard.h
@@ -143,8 +143,15 @@ enum power_signal {
 	POWER_SIGNAL_COUNT
 };
 
+enum mst_source {
+	MST_TYPE_C0,
+	MST_TYPE_C1,
+	MST_HDMI,
+};
+
 /* Forward declare common (within Hatch) board-specific functions */
 void board_reset_pd_mcu(void);
+void baseboard_mst_enable_control(enum mst_source, int level);
 
 #endif /* !__ASSEMBLER__ */
 
diff --git a/baseboard/hatch/usb_pd_policy.c b/baseboard/hatch/usb_pd_policy.c
index c1e1a12b68..2eb1cb6f4d 100644
--- a/baseboard/hatch/usb_pd_policy.c
+++ b/baseboard/hatch/usb_pd_policy.c
@@ -328,6 +328,10 @@ static void svdm_dp_post_config(int port)
 	if (!(dp_flags[port] & DP_FLAGS_HPD_HI_PENDING))
 		return;
 	mux->hpd_update(port, 1, 0);
+#ifdef USB_PD_PORT_TCPC
+	if (port == USB_PD_PORT_TCPC)
+		baseboard_mst_enable_control(port, 1);
+#endif
 }
 
 static int svdm_dp_attention(int port, uint32_t *payload)
@@ -343,6 +347,10 @@ static int svdm_dp_attention(int port, uint32_t *payload)
 		return 1;
 	}
 	mux->hpd_update(port, lvl, irq);
+#ifdef USB_PD_PORT_TCPC
+	if (port == USB_PD_PORT_TCPC)
+		baseboard_mst_enable_control(port, lvl);
+#endif
 
 	/* ack */
 	return 1;
@@ -354,6 +362,10 @@ static void svdm_exit_dp_mode(int port)
 
 	svdm_safe_dp_mode(port);
 	mux->hpd_update(port, 0, 0);
+#ifdef USB_PD_PORT_TCPC
+	if (port == USB_PD_PORT_TCPC)
+		baseboard_mst_enable_control(port, 0);
+#endif
 }
 
 static int svdm_enter_gfu_mode(int port, uint32_t mode_caps)
diff --git a/board/hatch/board.c b/board/hatch/board.c
index 44ffa432cb..e6cf4dfafa 100644
--- a/board/hatch/board.c
+++ b/board/hatch/board.c
@@ -69,6 +69,11 @@ static void tcpc_alert_event(enum gpio_signal signal)
 	schedule_deferred_pd_interrupt(port);
 }
 
+static void hdmi_hpd_interrupt(enum gpio_signal signal)
+{
+	baseboard_mst_enable_control(MST_HDMI, gpio_get_level(signal));
+}
+
 #include "gpio_list.h" /* Must come after other header files. */
 
 /******************************************************************************/
diff --git a/board/hatch/board.h b/board/hatch/board.h
index 3cfc6aff0a..b246a51c9d 100644
--- a/board/hatch/board.h
+++ b/board/hatch/board.h
@@ -37,6 +37,14 @@
 #define CONFIG_THROTTLE_AP
 #define CONFIG_STEINHART_HART_3V3_51K1_47K_4050B
 
+/* MST */
+/*
+ * TDOD (b/124068003): This inherently assumes the MST chip is connected to only
+ * one Type C port. This will need to be chagned to support 2 Type C ports
+ * connected to the same MST chip.
+ */
+#define USB_PD_PORT_TCPC 1
+
 /*
  * Macros for GPIO signals used in common code that don't match the
  * schematic names. Signal names in gpio.inc match the schematic and are
diff --git a/board/hatch/gpio.inc b/board/hatch/gpio.inc
index a2355b44b1..d6e77f795a 100644
--- a/board/hatch/gpio.inc
+++ b/board/hatch/gpio.inc
@@ -29,6 +29,14 @@ GPIO_INT(USB_C1_PPC_INT_ODL,   PIN(A, 2), GPIO_INT_FALLING, ppc_interrupt)
 GPIO_INT(USB_C0_TCPC_INT_ODL,  PIN(6, 2), GPIO_INT_FALLING, tcpc_alert_event)
 GPIO_INT(USB_C1_TCPC_INT_ODL,  PIN(F, 5), GPIO_INT_FALLING, tcpc_alert_event)
 
+GPIO_INT(HDMI_CONN_HPD,        PIN(7, 2), GPIO_INT_BOTH, hdmi_hpd_interrupt)
+/*
+ * This signal is not used by the EC for MST control, but leaving it here as an
+ * input as it may be useful for debugging/hw validation purposes. This can
+ * removed when EVT units are available.
+ */
+GPIO(TCPC_USB_C1_HPD,          PIN(9, 3), GPIO_INPUT)
+
 GPIO(SYS_RESET_L,              PIN(0, 2), GPIO_ODR_HIGH)        /* SYS_RST_ODL */
 GPIO(ENTERING_RW,              PIN(E, 3), GPIO_OUT_LOW)         /* EC_ENTERING_RW */
 GPIO(PCH_WAKE_L,               PIN(7, 4), GPIO_ODR_HIGH)        /* EC_PCH_WAKE_ODL */
@@ -58,6 +66,7 @@ GPIO(LED_3_L,                  PIN(C, 2), GPIO_OUT_HIGH)
 GPIO(LED_4_L,                  PIN(6, 0), GPIO_OUT_HIGH)
 GPIO(EC_KB_BL_EN,              PIN(8, 6), GPIO_OUT_LOW)         /* Keyboard backlight */
 GPIO(EN_PP5000_FAN,            PIN(6, 1), GPIO_OUT_LOW)
+GPIO(EN_MST,                   PIN(9, 6), GPIO_OUT_LOW)
 
 
 /* I2C pins - Alternate function below configures I2C module on these pins */