krane: Enable BC12 detection with gpio controlled.

Support CONFIG_BC12_DETECT_POWER_ROLE_TRIGGER.

Krane's BC12 detection is controlled by GPIO_BC12_DET_EN by
disconnecting USB-PHY, that is:
- Assert GPIO_BC12_DET_EN, then USB-PHY is disconnected
- Deassert GPIO_BC12_DET_EN, then USB-PHY is connected.

The current usb_chg_task will make USB devices not be enumerated, since
GPIO_BC12_DET_EN is deasserted only when VBUS attached and BC12 device
identified.  However, peripherals won't trigger BC12 detection so
GPIO_BC12_DET_EN always asserted.

To fix this problem, we trigger BC12 detection only when a port is
attached and hook USB_PD_CONNECTED to toggle BC12 detection.

We have to
- Assert GPIO_BC12_DET_EN on SRC device plugged to recognize BC12 charger.
- After BC12 device detected, we have to disable BC12 to connect USB-PHY
  back for enumerating USB devices.
- Deassert GPIO_BC12_DET_EN on SNK device plugged to enumerate USB
  devices.

TEST=Test with https://crrev.com/c/1408751/1, and see it is able to
     recognize Apple 2.4A charger and 5V2A DCP charger.
TEST=Boot w/ USB hub plugged (w/ and w/o external BC1.2 charger on the hub)
     and see USB devices are enumerated.
BUG=b:122866184
BRANCH=None

Change-Id: I5b3362305361c0c950288fc83072e9bc79082c08
Signed-off-by: Yilun Lin <yllin@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1575050
Tested-by: Yilun Lin <yllin@chromium.org>
Auto-Submit: Yilun Lin <yllin@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
Commit-Queue: Yilun Lin <yllin@chromium.org>

2 files changed, 24 insertions, 2 deletions

diff --git a/driver/charger/rt946x.c b/driver/charger/rt946x.c
index d38690892a..2915ba5155 100644
--- a/driver/charger/rt946x.c
+++ b/driver/charger/rt946x.c
@@ -257,6 +257,9 @@ static int rt946x_reset_to_zero(void)
 static int rt946x_enable_bc12_detection(int en)
 {
 #if defined(CONFIG_CHARGER_RT9467) || defined(CONFIG_CHARGER_MT6370)
+#ifdef CONFIG_CHARGER_MT6370_BC12_GPIO
+	gpio_set_level(GPIO_BC12_DET_EN, en);
+#endif /* CONFIG_CHARGER_MT6370_BC12_GPIO */
 	return (en ? rt946x_set_bit : rt946x_clr_bit)
 		(RT946X_REG_DPDM1, RT946X_MASK_USBCHGEN);
 #endif
@@ -941,6 +944,14 @@ int rt946x_toggle_bc12_detection(void)
 	return rt946x_enable_bc12_detection(1);
 }
 
+#ifdef CONFIG_CHARGER_MT6370_BC12_GPIO
+static void usb_pd_connect(void)
+{
+	rt946x_toggle_bc12_detection();
+}
+DECLARE_HOOK(HOOK_USB_PD_CONNECT, usb_pd_connect, HOOK_PRIO_DEFAULT);
+#endif
+
 void usb_charger_task(void *u)
 {
 	struct charge_port_info chg;
@@ -974,8 +985,9 @@ void usb_charger_task(void *u)
 #ifdef CONFIG_WIRELESS_CHARGER_P9221_R7
 				}
 #endif
-				rt946x_enable_bc12_detection(0);
 			}
+
+			rt946x_enable_bc12_detection(0);
 		}
 
 		/* VBUS detach event */
@@ -985,7 +997,9 @@ void usb_charger_task(void *u)
 			p9221_notify_vbus_change(0);
 #endif
 			charge_manager_update_charge(bc12_type, 0, NULL);
-			rt946x_enable_bc12_detection(1);
+
+			if (!IS_ENABLED(CONFIG_CHARGER_MT6370_BC12_GPIO))
+				rt946x_enable_bc12_detection(1);
 		}
 
 		task_wait_event(-1);
diff --git a/include/config.h b/include/config.h
index 15482a9687..08b9977dbf 100644
--- a/include/config.h
+++ b/include/config.h
@@ -776,6 +776,14 @@
 #undef CONFIG_CHARGER_MT6370_BACKLIGHT
 
 /*
+ * MT6370 BC1.2 USB-PHY control.
+ * If defined, USB-PHY connection is controlled by GPIO_BC12_DET_EN.
+ * Assert GPIO_BC12_DET_EN to detect BC1.2 device, and deassert
+ * GPIO_BC12_DET_EN to mux USB-PHY back.
+ */
+#undef CONFIG_CHARGER_MT6370_BC12_GPIO
+
+/*
  * Enable/disable system power monitor PSYS function: this enables output
  * from charger chip to SoC.
  */