Kunimitsu: Fix leak on pin for battery_present.

Since battery pin 5 is the voltage across internal 10Kohm
thermistor and is not either 0V or 3.3V, typically 330mV
with external 100Kohm.
Using GPIO configuration to detect this pin causes extra
power consumption and this pin is reconfigured as ADC.

BUG=cros-bug-49610
BRANCH=glados
TEST=check if battery is detected. Use 'adc' console command
and check if it shows 'BATTPRES' with volatage in mV.

Change-Id: I907b94629b0581a6a27e6f0cecda12ddef09a4f0
Signed-off-by: Kyoung Kim <kyoung.il.kim@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/322771
Commit-Ready: Kyoung Il Kim <kyoung.il.kim@intel.com>
Tested-by: Kyoung Il Kim <kyoung.il.kim@intel.com>
Reviewed-by: Shawn N <shawnn@chromium.org>

3 files changed, 32 insertions, 6 deletions

diff --git a/board/kunimitsu/board.c b/board/kunimitsu/board.c
index 2a899c3392..5a8b9eef07 100644
--- a/board/kunimitsu/board.c
+++ b/board/kunimitsu/board.c
@@ -3,9 +3,10 @@
  * found in the LICENSE file.
  */
 /* Skylake Chrome Reference Design board-specific configuration */
-
+#include "adc.h"
 #include "adc_chip.h"
 #include "als.h"
+#include "battery.h"
 #include "button.h"
 #include "charge_manager.h"
 #include "charge_state.h"
@@ -100,6 +101,8 @@ BUILD_ASSERT(ARRAY_SIZE(power_signal_list) == POWER_SIGNAL_COUNT);
 
 /* ADC channels */
 const struct adc_t adc_channels[] = {
+	/* read voltage in battery thermistor as battery present */
+	[ADC_BATT_PRESENT] = {"BATTPRES", 3300, 1024, 0, 0},
 	/* Vbus sensing. Converted to mV, full ADC is equivalent to 30V. */
 	[ADC_VBUS] = {"VBUS", 30000, 1024, 0, 1},
 	/* Adapter current output or battery discharging current */
@@ -628,3 +631,23 @@ static void board_handle_reboot(void)
 		; /* wait here */
 }
 DECLARE_HOOK(HOOK_INIT, board_handle_reboot, HOOK_PRIO_FIRST);
+
+#ifdef CONFIG_BATTERY_PRESENT_CUSTOM
+/*
+ * Physical detection of battery via ADC.
+ *
+ * Uppper limit of valid voltage level(mV), when battery is attached to ADC port,
+ * is across the internal thermistor with external pullup resistor.
+ */
+#define BATT_PRESENT_MV  1500
+enum battery_present battery_is_present(void)
+{
+	/*
+	 * if voltage is below certain level(dependant on ratio of
+	 * internal thermistor and external pullup resister),
+	 * battery is attached.
+	 */
+	return (adc_read_channel(ADC_BATT_PRESENT) > BATT_PRESENT_MV) ?
+		BP_NO : BP_YES;
+}
+#endif
diff --git a/board/kunimitsu/board.h b/board/kunimitsu/board.h
index 1eb1e3bdb0..4db8382b9f 100644
--- a/board/kunimitsu/board.h
+++ b/board/kunimitsu/board.h
@@ -11,7 +11,7 @@
 /* Optional features */
 #define CONFIG_ADC
 #define CONFIG_BATTERY_CUT_OFF
-#define CONFIG_BATTERY_PRESENT_GPIO GPIO_BAT_PRESENT_L
+#define CONFIG_BATTERY_PRESENT_CUSTOM
 #define CONFIG_BATTERY_SMART
 #define CONFIG_BOARD_VERSION
 #define CONFIG_BUTTON_COUNT 2
@@ -158,6 +158,7 @@
 
 /* ADC signal */
 enum adc_channel {
+	ADC_BATT_PRESENT,
 	ADC_VBUS,
 	ADC_AMON_BMON,
 	ADC_PSYS,
diff --git a/board/kunimitsu/gpio.inc b/board/kunimitsu/gpio.inc
index b62aa978ea..f063f4b515 100644
--- a/board/kunimitsu/gpio.inc
+++ b/board/kunimitsu/gpio.inc
@@ -54,7 +54,6 @@ GPIO(USB_C0_DP_HPD,         PIN(46),  GPIO_OUT_LOW)
 GPIO(USB_C1_DP_HPD,         PIN(51),  GPIO_OUT_LOW)
 GPIO(CPU_PROCHOT,           PIN(52),  GPIO_OUT_LOW)
 GPIO(ENABLE_TOUCHPAD,       PIN(53),  GPIO_OUT_LOW)
-GPIO(BAT_PRESENT_L,         PIN(56),  GPIO_INPUT)
 GPIO(USB_PD_WAKE,           PIN(60),  GPIO_OUT_LOW)
 /* When asserted, ME does not lock security descriptor */
 GPIO(PCH_SEC_DISABLE_L,     PIN(65),  GPIO_ODR_HIGH)
@@ -145,9 +144,12 @@ ALTERNATE(PIN_MASK(2,  0x3f), 2, MODULE_I2C, GPIO_ODR_HIGH)
 /* I2C0_1 CLK - GPIO134 */
 ALTERNATE(PIN_MASK(13, 0x10), 2, MODULE_I2C, GPIO_ODR_HIGH)
 
-/* ADC pins */
-/* ADC1 - GPIO057 / PPVAR_BOOSTIN_SENSE */
-ALTERNATE(PIN_MASK(5,  0x80), 1, MODULE_ADC, GPIO_ANALOG)
+/*
+ * ADC pins
+ * ADC0 - GPIO056 / EC_BATT_TMP/BATT_BAT_PRESENT_L
+ * ADC1 - GPIO057 / PPVAR_BOOSTIN_SENSE
+ */
+ALTERNATE(PIN_MASK(5,  0xC0), 1, MODULE_ADC, GPIO_ANALOG)
 /* ADC3 - GPIO061 / IADP_ACMON_BMON. ADC4 - GPIO062 / PMON_PSYS */
 ALTERNATE(PIN_MASK(6,  0x06), 1, MODULE_ADC, GPIO_ANALOG)