servo_v4: support autodetect of CCD

This allows a servo_v4 to export case closed debugging
automatically, if it detects that it's been plugged into
a ccd device.

BUG=chromium:571476
TEST=Connect to reef in both orientations.
BRANCH=None

Change-Id: I8e2781056b22e834132bc4bb839ef2763fa0b4b8
Signed-off-by: Nick Sanders <nsanders@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/375359
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

1 files changed, 214 insertions, 2 deletions

diff --git a/board/servo_v4/board.c b/board/servo_v4/board.c
index 03410442db..6b742d3ebd 100644
--- a/board/servo_v4/board.c
+++ b/board/servo_v4/board.c
@@ -28,6 +28,9 @@
 #include "util.h"
 
 
+#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ## args)
+
+
 /******************************************************************************
  * Build GPIO tables and expose a subset of the GPIOs over USB.
  */
@@ -62,12 +65,12 @@ GPIO_USB_DET_PP_CHG,
 GPIO_USB_DUT_CC2_RPUSB,
 GPIO_USB_DUT_CC2_RD,
 GPIO_USB_DUT_CC2_RA,		/* 20 */
-GPIO_USB_DUT_CC1_PR3A0,
+GPIO_USB_DUT_CC1_RP3A0,
 GPIO_USB_DUT_CC1_RP1A5,
 GPIO_USB_DUT_CC1_RPUSB,
 GPIO_USB_DUT_CC1_RD,
 GPIO_USB_DUT_CC1_RA,		/* 25 */
-GPIO_USB_DUT_CC2_PR3A0,
+GPIO_USB_DUT_CC2_RP3A0,
 GPIO_USB_DUT_CC2_RP1A5,
 
 };
@@ -266,6 +269,187 @@ static void init_ioexpander(void)
 	i2c_write8(1, 0x40, 0x7, 0x0);
 }
 
+/* State of CC lines presented to DUT */
+/* Dual Rd pulldown, classic debug device. */
+#define CCD_ID_RDRD	0
+/* RpUSB + Rp1A5, indicates a self powered dongle. */
+#define CCD_ID_RPUSB	1
+/* One Rd. Device w/o CCD */
+#define CCD_ID_NONE	4
+
+static int ccd_id = CCD_ID_NONE;
+
+/* Set CC values according to requested mode. */
+static void init_ccd(int mode)
+{
+	int cc1_rd = GPIO_INPUT;
+	int cc2_rd = GPIO_INPUT;
+	int cc1_rpusb = GPIO_INPUT;
+	int cc2_rpusb = GPIO_INPUT;
+	int cc1_rp1a5 = GPIO_INPUT;
+	int cc2_rp1a5 = GPIO_INPUT;
+	int cc1_rp3a0 = GPIO_INPUT;
+	int cc2_rp3a0 = GPIO_INPUT;
+
+	switch (mode) {
+	case CCD_ID_RDRD:
+		cc1_rd = GPIO_OUT_LOW;
+		cc2_rd = GPIO_OUT_LOW;
+		break;
+
+	case CCD_ID_RPUSB:
+		cc1_rpusb = GPIO_OUT_HIGH;
+		cc2_rp1a5 = GPIO_OUT_HIGH;
+		break;
+
+	default:
+		cc1_rd = GPIO_OUT_LOW;
+		mode = CCD_ID_NONE;
+		break;
+	}
+
+	gpio_set_flags(GPIO_USB_DUT_CC1_RD, cc1_rd);
+	gpio_set_flags(GPIO_USB_DUT_CC2_RD, cc2_rd);
+	gpio_set_flags(GPIO_USB_DUT_CC1_RPUSB, cc1_rpusb);
+	gpio_set_flags(GPIO_USB_DUT_CC2_RPUSB, cc2_rpusb);
+	gpio_set_flags(GPIO_USB_DUT_CC1_RP1A5, cc1_rp1a5);
+	gpio_set_flags(GPIO_USB_DUT_CC2_RP1A5, cc2_rp1a5);
+	gpio_set_flags(GPIO_USB_DUT_CC1_RP3A0, cc1_rp3a0);
+	gpio_set_flags(GPIO_USB_DUT_CC2_RP3A0, cc2_rp3a0);
+
+	/* Disable CCD until we can detect orientation */
+	gpio_set_level(GPIO_SBU_MUX_EN, 0);
+	write_ioexpander(0, 0, 0);
+
+	ccd_id = mode;
+}
+
+
+/* Define voltage thresholds for CCD and SBU USB detection */
+#define GND_MAX_MV	350
+#define PULL_0V35_MV	350
+#define PULL_0V55_MV	550
+#define PULL_0V9_MV	900
+#define PULL_1V1_MV	1100
+#define PULL_2V0_MV	2000
+#define POWER_MIN_MV	3000
+#define USB_HIGH_MV	1500
+
+/* Check if presented CCD was accepted by the device */
+static int check_ccd_request(int cc1, int cc2)
+{
+	if ((ccd_id == CCD_ID_RDRD) &&
+	    (cc1 > PULL_0V35_MV) && (cc1 < PULL_0V55_MV) &&
+	    (cc2 > PULL_0V35_MV) && (cc2 < PULL_0V55_MV))
+		return 1;
+
+	if ((ccd_id == CCD_ID_RPUSB) &&
+	    (cc1 > PULL_0V35_MV) && (cc1 < PULL_0V55_MV) &&
+	    (cc2 > PULL_0V9_MV) && (cc2 < PULL_1V1_MV))
+		return 1;
+
+	return 0;
+}
+
+/* Check if CC lines indicate an unplug event */
+static int check_usb_disconnect(int cc1, int cc2)
+{
+	if ((cc1 < GND_MAX_MV) && (cc2 < GND_MAX_MV))
+		return 1;
+
+	if ((cc1 > POWER_MIN_MV) && (cc2 > POWER_MIN_MV))
+		return 1;
+
+	return 0;
+}
+
+
+/* Current mode for CCD USB line connection */
+/* Cable not plugged in */
+#define CCD_MODE_DISCONNECTED	0
+/* Cable plugged in, CCD detected in default orientation */
+#define CCD_MODE_CONNECTED	1
+/* Cable plugged in, CCD detected in flip orientation */
+#define CCD_MODE_CONNECTED_FLIP	2
+/* Cable plugged in, nothing detected on SBU lines */
+#define CCD_MODE_CONNECTED_NONE	3
+/* No type-c cable in servo. */
+#define CCD_MODE_USBA		4
+
+static int mode = CCD_MODE_DISCONNECTED;
+
+/*
+ * We don't have an available interrupt, so we'll just check this
+ * every second. Update state every tick if necessary.
+ */
+static void usb_sbu_tick(void)
+{
+	int cc1, cc2;
+
+	/* Check if we have a CCD cable */
+	if ((mode == CCD_MODE_USBA) || !gpio_get_level(GPIO_DONGLE_DET)) {
+		mode = CCD_MODE_USBA;
+		return;
+	}
+
+	/* Check CC lines via ADC */
+	cc1 = adc_read_channel(ADC_DUT_CC1_PD);
+	cc2 = adc_read_channel(ADC_DUT_CC2_PD);
+
+	if (mode == CCD_MODE_DISCONNECTED) {
+		/* Check if both CC lines are pulled, and we are connected */
+		if (check_ccd_request(cc1, cc2)) {
+			int sbu1;
+			int sbu2;
+
+			/*
+			 * Give the onboard CCD micro 100ms
+			 * to notice and enable USB, then check adc levels.
+			 */
+			usleep(100000);
+			sbu1 = adc_read_channel(ADC_SBU1_DET);
+			sbu2 = adc_read_channel(ADC_SBU2_DET);
+
+			CPRINTS("CCD: Plug detect cc1:%d cc2:%d "
+				"sbu1:%d, sbu2:%d",
+				cc1, cc2, sbu1, sbu2);
+
+			/* USB FS pulls one line high for connect request */
+			if ((sbu1 > USB_HIGH_MV) && (sbu2 < GND_MAX_MV)) {
+				/* SBU flip = 1 */
+				write_ioexpander(0, 2, 1);
+				usleep(10000);
+				gpio_set_level(GPIO_SBU_MUX_EN, 1);
+				mode = CCD_MODE_CONNECTED;
+				CPRINTS("CCD: connected flip");
+			} else if ((sbu2 > USB_HIGH_MV) &&
+				   (sbu1 < GND_MAX_MV)) {
+				/* SBU flip = 0 */
+				write_ioexpander(0, 2, 0);
+				usleep(10000);
+				gpio_set_level(GPIO_SBU_MUX_EN, 1);
+				mode = CCD_MODE_CONNECTED_FLIP;
+				CPRINTS("CCD: connected noflip");
+			} else {
+				mode = CCD_MODE_CONNECTED_NONE;
+				CPRINTS("CCD: connected none");
+			}
+		}
+	} else {
+		/* mode == CCD_MODE_CONNECTED[_FLIP] */
+		if (check_usb_disconnect(cc1, cc2)) {
+			/* We are not connected to anything */
+
+			/* Turn off CCD */
+			gpio_set_level(GPIO_SBU_MUX_EN, 0);
+			CPRINTS("CCD: disconnect");
+			mode = CCD_MODE_DISCONNECTED;
+		}
+	}
+}
+DECLARE_HOOK(HOOK_TICK, usb_sbu_tick, HOOK_PRIO_DEFAULT);
+
+
 static void board_init(void)
 {
 	/* USB to serial queues */
@@ -288,5 +472,33 @@ static void board_init(void)
 	/* Enable uservo USB by default. */
 	init_ioexpander();
 	init_uservo_port();
+
+	/* Enable CCD if type-c */
+	if (gpio_get_level(GPIO_DONGLE_DET))
+		init_ccd(CCD_ID_RPUSB);
 }
 DECLARE_HOOK(HOOK_INIT, board_init, HOOK_PRIO_DEFAULT);
+
+static int command_ccd(int argc, char **argv)
+{
+	int mode = CCD_ID_NONE;
+
+	if (argc < 2)
+		return EC_ERROR_PARAM_COUNT;
+
+	/* Handle requested mode */
+	if (!strcasecmp(argv[1], "rdrd"))
+		mode = CCD_ID_RDRD;
+	else if (!strcasecmp(argv[1], "rpusb"))
+		mode = CCD_ID_RPUSB;
+	else if (!strcasecmp(argv[1], "off"))
+		mode = CCD_ID_NONE;
+	else
+		return EC_ERROR_PARAM1;
+
+	init_ccd(mode);
+	ccprintf("DUT CC lines set to %s\n", argv[1]);
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(ccd, command_ccd,
+	"[rdrd|rpusb|off]", "Set pullups or pulldowns to indicate CCD");