Falco: AC adapter identification command

This adds a function to identify the AC adapter. We'll need this to set
various battery charging limits, based on the capability. This only applies
to Falco, AFAIK.

BUG=chrome-os-partner:19594
BRANCH=none
TEST=manual

Plug in various approved adapters. From the EC console, run "adapter". It
should tell you the rated power for each one.

Change-Id: Id6d142fa81f20ec9233b0faa2fcb1d53cf7b7ef5
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/61515
Reviewed-by: Randall Spangler <rspangler@chromium.org>

board/falco/board.h

@@ -17,6 +17,7 @@
 /* Optional features */
 #define CONFIG_SMART_BATTERY
 #define CONFIG_BATTERY_FALCO
+#define CONFIG_EXTPOWER_FALCO
 #define CONFIG_BOARD_VERSION
 #define CONFIG_CHARGER
 #define CONFIG_CHARGER_BQ24738

common/build.mk

@@ -26,6 +26,7 @@ common-$(CONFIG_CHIPSET_HASWELL)+=chipset_haswell.o chipset_x86_common.o
 common-$(CONFIG_CHIPSET_IVYBRIDGE)+=chipset_ivybridge.o chipset_x86_common.o
 common-$(CONFIG_PMU_TPS65090)+=pmu_tps65090.o
 common-$(CONFIG_EOPTION)+=eoption.o
+common-$(CONFIG_EXTPOWER_FALCO)+=extpower_falco.o
 common-$(CONFIG_EXTPOWER_GPIO)+=extpower_gpio.o
 common-$(CONFIG_EXTPOWER_SNOW)+=extpower_snow.o
 common-$(CONFIG_EXTPOWER_USB)+=extpower_usb.o

common/extpower_falco.c

@@ -0,0 +1,49 @@
+/* Copyright (c) 2013 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.
+ */
+
+/* Special AC Adapter logic for Falco */
+
+#include "adc.h"
+#include "common.h"
+#include "console.h"
+#include "util.h"
+
+enum adapter_type {
+	ADAPTER_UNKNOWN,
+	ADAPTER_45W,
+	ADAPTER_65W,
+	ADAPTER_90W,
+};
+
+static const char * const adapter_str[] = {
+	"unknown",
+	"45W",
+	"65W",
+	"90W"
+};
+
+static enum adapter_type identify_adapter(void)
+{
+	int mv;
+	mv = adc_read_channel(ADC_AC_ADAPTER_ID_VOLTAGE);
+	if (mv >= 434 && mv <= 554)
+		return ADAPTER_45W;
+	if (mv >= 561 && mv <= 717)
+		return ADAPTER_65W;
+	if (mv >= 725 && mv <= 925)
+		return ADAPTER_90W;
+
+	return ADAPTER_UNKNOWN;
+}
+
+static int command_adapter(int argc, char **argv)
+{
+	ccprintf("%s\n", adapter_str[identify_adapter()]);
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(adapter, command_adapter,
+			NULL,
+			"Identify AC adapter type",
+			NULL);