Refactor ADC code and add Link charger current ADC support

Refactor ADC code and move board/chip-specific part to corresponding
directories.
Implement function and console command to read Link charger current.

BUG=chrome-os-partner:7527
TEST=Read EC temperature and POT input on BDS.

Change-Id: I7fafd310ea49d9b2781f10c3453f5488da29a08a

4 files changed, 57 insertions, 0 deletions

diff --git a/board/bds/board.c b/board/bds/board.c
index 71bc810444..631cf29079 100644
--- a/board/bds/board.c
+++ b/board/bds/board.c
@@ -9,6 +9,25 @@
 #include "power_button.h"
 #include "registers.h"
 #include "util.h"
+#include "lm4_adc.h"
+#include "adc.h"
+
+/* ADC channels. Must be in the exactly same order as in enum adc_channel. */
+const struct adc_t adc_channels[ADC_CH_COUNT] =
+{
+	/* EC internal temperature is calculated by
+	 * 273 + (295 - 450 * ADC_VALUE / ADC_READ_MAX) / 2
+	 * = -225 * ADC_VALUE / ADC_READ_MAX + 420.5
+	 */
+	{"ECTemp", LM4_ADC_SEQ0, -225, ADC_READ_MAX, 420,
+	 LM4_NO_AIN, 0x0e /* TS0 | IE0 | END0 */},
+
+	/* Charger current is mapped from 0~4000mA to 0~1.6V.
+	 * And ADC maps 0~3.3V to ADC_READ_MAX.
+	 */
+	{"ChargerCurrent", LM4_ADC_SEQ1, 33 * 4000, ADC_READ_MAX * 16, 0,
+	 LM4_AIN(ADC_IN0), 0x06 /* IE0 | END0 */},
+};
 
 
 /* GPIO signal list.  Must match order from enum gpio_signal. */
diff --git a/board/bds/board.h b/board/bds/board.h
index 9b28cd6e46..fbd4f153ca 100644
--- a/board/bds/board.h
+++ b/board/bds/board.h
@@ -46,6 +46,16 @@
 /* TODO: really just need a lookup table for channels to inputs */
 #define ADC_IN0 0  /* Turn POT on badger board */
 
+enum adc_channel
+{
+	/* EC internal die temperature in degrees K. */
+	ADC_CH_EC_TEMP = 0,
+	/* Treat BDS pot input as charger current. */
+	ADC_CH_CHARGER_CURRENT,
+
+	ADC_CH_COUNT
+};
+
 /* I2C ports */
 #define I2C_PORT_BATTERY 5  // port 0 / PB2:3 on Link, open on badger
 #define I2C_PORT_CHARGER 5  // port 1 / PA6:7 on Link, user LED on badger
diff --git a/board/link/board.c b/board/link/board.c
index 20a2437b00..67d975686e 100644
--- a/board/link/board.c
+++ b/board/link/board.c
@@ -11,6 +11,8 @@
 #include "registers.h"
 #include "util.h"
 #include "x86_power.h"
+#include "lm4_adc.h"
+#include "adc.h"
 
 #ifndef CONFIG_TASK_X86POWER
 #define x86_power_interrupt NULL
@@ -99,6 +101,22 @@ const struct gpio_info gpio_list[GPIO_COUNT] = {
 	{"USB2_ILIM_SEL",       LM4_GPIO_E, (1<<0), GPIO_OUT_LOW, NULL},
 };
 
+/* ADC channels. Must be in the exactly same order as in enum adc_channel. */
+const struct adc_t adc_channels[ADC_CH_COUNT] =
+{
+	/* EC internal temperature is calculated by
+	 * 273 + (295 - 450 * ADC_VALUE / ADC_READ_MAX) / 2
+	 * = -225 * ADC_VALUE / ADC_READ_MAX + 420.5
+	 */
+	{"ECTemp", LM4_ADC_SEQ0, -225, ADC_READ_MAX, 420,
+	 LM4_NO_AIN, 0x0e /* TS0 | IE0 | END0 */},
+
+	/* Charger current is mapped from 0~4000mA to 0~1.6V.
+	 * And ADC maps 0~3.3V to ADC_READ_MAX.
+	 */
+	{"ChargerCurrent", LM4_ADC_SEQ1, 33 * 4000, ADC_READ_MAX * 16, 0,
+	 LM4_AIN(ADC_IN0), 0x06 /* IE0 | END0 */},
+};
 
 void configure_board(void)
 {
diff --git a/board/link/board.h b/board/link/board.h
index 923ae716ad..0387bc45fc 100644
--- a/board/link/board.h
+++ b/board/link/board.h
@@ -46,6 +46,16 @@
 /* TODO: assign real ADC inputs */
 #define ADC_IN0 11  /* Charger current */
 
+enum adc_channel
+{
+	/* EC internal die temperature in degrees K. */
+	ADC_CH_EC_TEMP = 0,
+	/* Charger current in mA. */
+	ADC_CH_CHARGER_CURRENT,
+
+	ADC_CH_COUNT
+};
+
 /* I2C ports */
 #define I2C_PORT_BATTERY 0
 #define I2C_PORT_CHARGER 1