yorp: add board version

Hard code value to 0 for now.

BRANCH=none
BUG=b:76448181
TEST=none

Change-Id: Iefe91fb02a958f40a1ff63c122792a390a545290
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/984517
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

board/yorp/board.c

@@ -84,6 +84,12 @@ const struct adc_t adc_channels[] = {
 	/* Vbus C1 sensing (10x voltage divider). PPVAR_USB_C1_VBUS */
 	[ADC_VBUS_C1] = {
 		"VBUS_C1", NPCX_ADC_CH9, ADC_MAX_VOLT*10, ADC_READ_MAX+1, 0},
+	/* Board ID 1. Least Significant nibble */
+	[ADC_BRD_ID1] = {
+		"BRD_ID1", NPCX_ADC_CH6, ADC_MAX_VOLT, ADC_READ_MAX+1, 0},
+	/* Board ID 2. Most Significant nibble */
+	[ADC_BRD_ID2] = {
+		"BRD_ID2", NPCX_ADC_CH7, ADC_MAX_VOLT, ADC_READ_MAX+1, 0},
 };
 BUILD_ASSERT(ARRAY_SIZE(adc_channels) == ADC_CH_COUNT);
 
@@ -259,6 +265,82 @@ uint16_t tcpc_get_alert_status(void)
 	return status;
 }
 
+static const int UNKNOWN_BRD_ID = -1;
+static const int board_id_thresh_mv[] = {
+	/* Vin = 3.3V, Ideal voltage, R2 values listed below */
+	/* R1 = 51.1 kOhm */
+	200,  /* 124 mV, 2.0 Kohm */
+	366,  /* 278 mV, 4.7 Kohm */
+	550,  /* 456 mV, 8.2  Kohm */
+	752,  /* 644 mV, 12.4 Kohm */
+	927,  /* 860 mV, 18.0 Kohm */
+	1073, /* 993 mV, 22.0 Kohm */
+	1235, /* 1152 mV, 27.4 Kohm */
+	1386, /* 1318 mV, 34.0 Kohm */
+	1552, /* 1453 mV, 40.2 Kohm */
+	/* R1 = 10.0 kOhm */
+	1739, /* 1650 mV, 10.0 Kohm */
+	1976, /* 1827 mV, 12.4 Kohm */
+	2197, /* 2121 mV, 18.0 Kohm */
+	2344, /* 2269 mV, 22.0 Kohm */
+	2484, /* 2418 mV, 27.4 Kohm */
+	2636, /* 2550 mV, 34.0 Kohm */
+	2823, /* 2721 mV, 47.0 Kohm */
+};
+
+static int read_board_id_adc(enum adc_channel chan)
+{
+	int mv;
+	int i;
+
+	mv = adc_read_channel(chan);
+	cprints(CC_SYSTEM, "BOARD ID ADC %d = %d mV",
+		chan == ADC_BRD_ID1 ? 1 : 2, mv);
+
+	if (mv == ADC_READ_ERROR)
+		return UNKNOWN_BRD_ID;
+
+	for (i = 0; i < ARRAY_SIZE(board_id_thresh_mv); i++)
+		if (mv < board_id_thresh_mv[i])
+			return i;
+
+	return UNKNOWN_BRD_ID;
+}
+
+
+int board_get_version(void)
+{
+	static int version = UNKNOWN_BRD_ID;
+	int level;
+
+	if (version != UNKNOWN_BRD_ID)
+		return version;
+
+	/* Enabled Board ID circuit and wait for it to stabilize. */
+	gpio_set_level(GPIO_EC_BRD_ID_EN, 1);
+	msleep(1);
+
+	level = read_board_id_adc(ADC_BRD_ID1);
+	if (level == UNKNOWN_BRD_ID)
+		goto error;
+	version = level & 0x0F;
+
+	level = read_board_id_adc(ADC_BRD_ID2);
+	if (level == UNKNOWN_BRD_ID)
+		goto error;
+	version = version | ((level & 0x0F) << 4);
+
+	gpio_set_level(GPIO_EC_BRD_ID_EN, 0);
+	cprints(CC_SYSTEM, "Board version: %d", version);
+	return version;
+
+error:
+	gpio_set_level(GPIO_EC_BRD_ID_EN, 0);
+	cprints(CC_SYSTEM, "Board version unknown!");
+	version = UNKNOWN_BRD_ID;
+	return version;
+}
+
 /* Motion sensors */
 /* Mutexes */
 static struct mutex g_lid_mutex;

board/yorp/board.h

@@ -30,6 +30,8 @@
 #define CONFIG_VBOOT_HASH
 #define CONFIG_VSTORE
 #define CONFIG_VSTORE_SLOT_COUNT 1
+#define CONFIG_BOARD_VERSION
+#define CONFIG_BOARD_SPECIFIC_VERSION
 
 /* EC console commands  */
 #define CONFIG_CMD_ACCELS
@@ -141,6 +143,8 @@
 enum adc_channel {
 	ADC_VBUS_C0,
 	ADC_VBUS_C1,
+	ADC_BRD_ID1,
+	ADC_BRD_ID2,
 	ADC_CH_COUNT
 };
 
@@ -170,7 +174,9 @@ enum sensor_id {
 	SENSOR_COUNT
 };
 
+/* Forward declare board-specific functions */
 void board_reset_pd_mcu(void);
+int board_get_version(void);
 
 #endif /* !__ASSEMBLER__ */
 

board/yorp/gpio.inc

@@ -106,6 +106,9 @@ GPIO(USB_C1_HPD_1V8_ODL, PIN(C, 6), GPIO_ODR_HIGH |	/* C1 DP Hotplug Detect */
 GPIO(BAT_LED_ORANGE_L,		PIN(C, 3), GPIO_OUT_HIGH)	/* LED_1_L */
 GPIO(BAT_LED_BLUE_L,		PIN(C, 4), GPIO_OUT_HIGH)	/* LED_2_L */
 
+/* Board IDs */
+GPIO(EC_BRD_ID_EN, 	 PIN(9, 6), GPIO_OUT_LOW)
+
 /* Alternate functions GPIO definitions */
 /* Cr50 requires no pull-ups on UART pins. */
 ALTERNATE(PIN_MASK(6, 0x30), 0, MODULE_UART, 0)		/* UART from EC to Servo */