Amenia/Reef: Add software charge ramp for BC1.2 & nonstandard BC1.2

Setting the higher limit of input current for BC1.2 & nonstandard
BC1.2 devices than their maximum current rating results in an
anti-collapse. BD99955 does not have a way to do hardware charge
ramp or to detect the anti-collapse for these chargers. Hence added
code to support software charge ramp for BC1.2 & nonstandard BC1.2
so that the input current is set to maximum of the respective
charger.

BUG=chrome-os-partner:54990, chrome-os-partner:55517
BRANCH=none
TEST=Manually tested on Amenia & Reef. BC1.2 & nonstandard BC12
     devices can negotiate their respective maximum current rating.

Change-Id: I0033b3662362bd7822ad01cf4360d18caabd5249
Signed-off-by: Vijay Hiremath <vijay.p.hiremath@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/358106
Commit-Ready: Vijay P Hiremath <vijay.p.hiremath@intel.com>
Tested-by: Vijay P Hiremath <vijay.p.hiremath@intel.com>
Reviewed-by: Shawn N <shawnn@chromium.org>

8 files changed, 124 insertions, 25 deletions

diff --git a/board/amenia/board.c b/board/amenia/board.c
index 7026903ab1..82bfb238b2 100644
--- a/board/amenia/board.c
+++ b/board/amenia/board.c
@@ -9,6 +9,7 @@
 #include "als.h"
 #include "button.h"
 #include "charge_manager.h"
+#include "charge_ramp.h"
 #include "charge_state.h"
 #include "charger.h"
 #include "chipset.h"
@@ -361,6 +362,48 @@ void board_set_charge_limit(int port, int supplier, int charge_ma)
 					   CONFIG_CHARGER_INPUT_CURRENT));
 }
 
+/**
+ * Return whether ramping is allowed for given supplier
+ */
+int board_is_ramp_allowed(int supplier)
+{
+	/* Don't allow ramping in RO when write protected */
+	if (system_get_image_copy() != SYSTEM_IMAGE_RW
+		&& system_is_locked())
+		return 0;
+	else
+		return (supplier == CHARGE_SUPPLIER_BC12_DCP ||
+			supplier == CHARGE_SUPPLIER_BC12_SDP ||
+			supplier == CHARGE_SUPPLIER_BC12_CDP ||
+			supplier == CHARGE_SUPPLIER_OTHER);
+}
+
+/**
+ * Return the maximum allowed input current
+ */
+int board_get_ramp_current_limit(int supplier, int sup_curr)
+{
+	return bd99955_get_bc12_ilim(supplier);
+}
+
+/**
+ * Return if board is consuming full amount of input current
+ */
+int board_is_consuming_full_charge(void)
+{
+	int chg_perc = charge_get_percent();
+
+	return chg_perc > 2 && chg_perc < 95;
+}
+
+/**
+ * Return if VBUS is sagging too low
+ */
+int board_is_vbus_too_low(enum chg_ramp_vbus_state ramp_state)
+{
+	return charger_get_vbus_level() < BD99955_BC12_MIN_VOLTAGE;
+}
+
 /* Enable or disable input devices, based upon chipset state and tablet mode */
 static void enable_input_devices(void)
 {
diff --git a/board/amenia/board.h b/board/amenia/board.h
index ac846ff42c..6b09c33e17 100644
--- a/board/amenia/board.h
+++ b/board/amenia/board.h
@@ -28,6 +28,7 @@
 #define CONFIG_BOARD_VERSION
 #define CONFIG_BUTTON_COUNT 2
 #define CONFIG_CHARGE_MANAGER
+#define CONFIG_CHARGE_RAMP
 
 #define CONFIG_CHARGER
 #define CONFIG_CHARGER_V2
diff --git a/board/amenia/ec.tasklist b/board/amenia/ec.tasklist
index 6abae5e7ba..b7ed91b073 100644
--- a/board/amenia/ec.tasklist
+++ b/board/amenia/ec.tasklist
@@ -19,6 +19,7 @@
 #define CONFIG_TASK_LIST \
 	TASK_ALWAYS(HOOKS, hook_task, NULL, LARGER_TASK_STACK_SIZE) \
 	TASK_ALWAYS(ALS, als_task, NULL, TASK_STACK_SIZE) \
+	TASK_ALWAYS(CHG_RAMP, chg_ramp_task, NULL, TASK_STACK_SIZE) \
 	TASK_ALWAYS(USB_CHG, usb_charger_task, NULL, TASK_STACK_SIZE) \
 	TASK_ALWAYS(CHARGER, charger_task, NULL, LARGER_TASK_STACK_SIZE) \
 	TASK_NOTEST(MOTIONSENSE, motion_sense_task, NULL, VENTI_TASK_STACK_SIZE) \
diff --git a/board/reef/board.c b/board/reef/board.c
index 93dcb2dfeb..d7343e9ffe 100644
--- a/board/reef/board.c
+++ b/board/reef/board.c
@@ -10,6 +10,7 @@
 #include "als.h"
 #include "button.h"
 #include "charge_manager.h"
+#include "charge_ramp.h"
 #include "charge_state.h"
 #include "charger.h"
 #include "chipset.h"
@@ -533,6 +534,48 @@ void board_set_charge_limit(int port, int supplier, int charge_ma)
 					   CONFIG_CHARGER_INPUT_CURRENT));
 }
 
+/**
+ * Return whether ramping is allowed for given supplier
+ */
+int board_is_ramp_allowed(int supplier)
+{
+	/* Don't allow ramping in RO when write protected */
+	if (system_get_image_copy() != SYSTEM_IMAGE_RW
+		&& system_is_locked())
+		return 0;
+	else
+		return (supplier == CHARGE_SUPPLIER_BC12_DCP ||
+			supplier == CHARGE_SUPPLIER_BC12_SDP ||
+			supplier == CHARGE_SUPPLIER_BC12_CDP ||
+			supplier == CHARGE_SUPPLIER_OTHER);
+}
+
+/**
+ * Return the maximum allowed input current
+ */
+int board_get_ramp_current_limit(int supplier, int sup_curr)
+{
+	return bd99955_get_bc12_ilim(supplier);
+}
+
+/**
+ * Return if board is consuming full amount of input current
+ */
+int board_is_consuming_full_charge(void)
+{
+	int chg_perc = charge_get_percent();
+
+	return chg_perc > 2 && chg_perc < 95;
+}
+
+/**
+ * Return if VBUS is sagging too low
+ */
+int board_is_vbus_too_low(enum chg_ramp_vbus_state ramp_state)
+{
+	return charger_get_vbus_level() < BD99955_BC12_MIN_VOLTAGE;
+}
+
 /* Enable or disable input devices, based upon chipset state and tablet mode */
 static void enable_input_devices(void)
 {
diff --git a/board/reef/board.h b/board/reef/board.h
index 109eca8dcc..02efe5b454 100644
--- a/board/reef/board.h
+++ b/board/reef/board.h
@@ -40,6 +40,7 @@
 
 /* Charger */
 #define CONFIG_CHARGE_MANAGER
+#define CONFIG_CHARGE_RAMP
 #define CONFIG_CHARGER
 #define CONFIG_CHARGER_V2
 #define CONFIG_CHARGER_BD99955
diff --git a/board/reef/ec.tasklist b/board/reef/ec.tasklist
index fe4d3eaa10..4ea21ebef8 100644
--- a/board/reef/ec.tasklist
+++ b/board/reef/ec.tasklist
@@ -23,6 +23,7 @@
 #define CONFIG_TASK_LIST \
 	TASK_ALWAYS(HOOKS, hook_task, NULL, LARGER_TASK_STACK_SIZE) \
 	TASK_ALWAYS(ALS, als_task, NULL, TASK_STACK_SIZE) \
+	TASK_ALWAYS(CHG_RAMP, chg_ramp_task, NULL, TASK_STACK_SIZE) \
 	TASK_ALWAYS(USB_CHG, usb_charger_task, NULL, TASK_STACK_SIZE) \
 	TASK_ALWAYS(CHARGER, charger_task, NULL, LARGER_TASK_STACK_SIZE) \
 	TASK_NOTEST(MOTIONSENSE, motion_sense_task, NULL, VENTI_TASK_STACK_SIZE) \
diff --git a/driver/charger/bd99955.c b/driver/charger/bd99955.c
index d73669dbe9..2f0af04145 100644
--- a/driver/charger/bd99955.c
+++ b/driver/charger/bd99955.c
@@ -208,31 +208,6 @@ static int bd99955_get_bc12_device_type(enum bd99955_charge_port port)
 	}
 }
 
-static int bd99955_get_bc12_ilim(int charge_supplier)
-{
-	switch (charge_supplier) {
-	case CHARGE_SUPPLIER_BC12_CDP:
-		return 1500;
-	case CHARGE_SUPPLIER_BC12_DCP:
-		return 2000;
-	case CHARGE_SUPPLIER_BC12_SDP:
-		return 900;
-	case CHARGE_SUPPLIER_OTHER:
-		/*
-		 * TODO: Setting the higher limit of current may result in an
-		 * anti-collapse hence limiting the current to 1A. (If the
-		 * charger response is slow or BD99955 cannot detect the type
-		 * of the charger, anti-collapse status is not updated in the
-		 * VBUS/VCC_STATUS register. Hence it is not possible to decide
-		 * whether to overwrite the ILIM values to come out of the
-		 * anti-collapse).
-		 */
-		return 1000;
-	default:
-		return 500;
-	}
-}
-
 static int bd99955_enable_usb_switch(enum bd99955_charge_port port,
 					enum usb_switch setting)
 {
@@ -824,6 +799,30 @@ int bd99955_get_battery_temp(int *temp_ptr)
 #endif
 
 #ifdef HAS_TASK_USB_CHG
+int bd99955_get_bc12_ilim(int charge_supplier)
+{
+	switch (charge_supplier) {
+	case CHARGE_SUPPLIER_BC12_CDP:
+		return 1500;
+	case CHARGE_SUPPLIER_BC12_DCP:
+		return 2000;
+	case CHARGE_SUPPLIER_BC12_SDP:
+		return 900;
+	case CHARGE_SUPPLIER_OTHER:
+#ifdef CONFIG_CHARGE_RAMP
+		return 2400;
+#else
+		/*
+		 * Setting the higher limit of current may result in an
+		 * anti-collapse hence limiting the current to 1A.
+		 */
+		return 1000;
+#endif
+	default:
+		return 500;
+	}
+}
+
 int bd99955_bc12_enable_charging(enum bd99955_charge_port port, int enable)
 {
 	int rv;
diff --git a/driver/charger/bd99955.h b/driver/charger/bd99955.h
index e4c557eb1d..41334ecb1c 100644
--- a/driver/charger/bd99955.h
+++ b/driver/charger/bd99955.h
@@ -46,6 +46,14 @@ enum bd99955_charge_port {
 #define DISCHARGE_VSYSREG	8960
 #define CHARGE_VSYSREG		6144
 
+/*
+ * BC1.2 minimum voltage threshold.
+ * BC1.2 charging port output voltage range is 4.75V to 5.25V,
+ * BD99955 Anti-Collapse Threshold Voltage Accuracy is -100mV to +100mV,
+ * and Delta of 50mV.
+ */
+#define BD99955_BC12_MIN_VOLTAGE	4600
+
 /* Battery Charger Commands */
 #define BD99955_CMD_CHG_CURRENT		0x14
 #define BD99955_CMD_CHG_VOLTAGE		0x15
@@ -301,6 +309,8 @@ static inline enum bd99955_charge_port bd99955_pd_port_to_chg_port(int port)
 int bd99955_is_vbus_provided(int port);
 /* Select input port from {VCC, VBUS, VCC&VBUS, NONE}. */
 int bd99955_select_input_port(enum bd99955_charge_port port);
+/* Get input current limit for BC1.2 suppliers */
+int bd99955_get_bc12_ilim(int charge_supplier);
 /* Enable/Disable charging triggered by BC1.2 */
 int bd99955_bc12_enable_charging(enum bd99955_charge_port port, int enable);
 /* Interrupt handler for USB charger VBUS */