homestar : Add Initial Support

create initial ec code for homestar, copied by reference
board strongbad/coachz ec files to a new directory renamed
for variant.

BUG=b:181198678
TEST=make -j BOARD=homestar
    Verify build and powered on coachz board
BRANCH=Trogdor

Change-Id: I6129d19039fe629b27f149046d6047705e2481f5
Signed-off-by: Dolan <liuyong5@huaqin.corp-partner.google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2717431
Tested-by: Simon Zhou <zhouguohui@huaqin.corp-partner.google.com>
Reviewed-by: Wai-Hong Tam <waihong@google.com>
Commit-Queue: Wai-Hong Tam <waihong@google.com>

1 files changed, 230 insertions, 0 deletions

diff --git a/board/homestar/base_detect.c b/board/homestar/base_detect.c
new file mode 100644
index 0000000000..59303fa1b2
--- /dev/null
+++ b/board/homestar/base_detect.c
@@ -0,0 +1,230 @@
+/* Copyright 2021 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.
+ */
+
+/* Homestar base detection code */
+
+#include "adc.h"
+#include "adc_chip.h"
+#include "board.h"
+#include "chipset.h"
+#include "common.h"
+#include "console.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "host_command.h"
+#include "system.h"
+#include "tablet_mode.h"
+#include "timer.h"
+#include "util.h"
+
+#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ## args)
+#define CPRINTF(format, args...) cprintf(CC_SYSTEM, format, ## args)
+
+/* Base detection and debouncing */
+#define BASE_DETECT_EN_DEBOUNCE_US (350 * MSEC)
+#define BASE_DETECT_DIS_DEBOUNCE_US (20 * MSEC)
+
+/*
+ * If the base status is unclear (i.e. not within expected ranges, read
+ * the ADC value again every 500ms.
+ */
+#define BASE_DETECT_RETRY_US (500 * MSEC)
+
+/*
+ * Lid has 604K pull-up, base has 30.1K pull-down, so the
+ * ADC value should be around 30.1/(604+30.1)*3300 = 156
+ *
+ * We add a significant margin on the maximum value, due to noise on the line,
+ * especially when PWM is active. See b/64193554 for details.
+ */
+#define BASE_DETECT_MIN_MV 120
+#define BASE_DETECT_MAX_MV 300
+
+/* Minimum ADC value to indicate base is disconnected for sure */
+#define BASE_DETECT_DISCONNECT_MIN_MV 1500
+
+/*
+ * Base EC pulses detection pin for 500 us to signal out of band USB wake (that
+ * can be used to wake system from deep S3).
+ */
+#define BASE_DETECT_PULSE_MIN_US 400
+#define BASE_DETECT_PULSE_MAX_US 650
+
+static uint64_t base_detect_debounce_time;
+
+static void base_detect_deferred(void);
+DECLARE_DEFERRED(base_detect_deferred);
+
+enum base_status {
+	BASE_UNKNOWN = 0,
+	BASE_DISCONNECTED = 1,
+	BASE_CONNECTED = 2,
+};
+
+static enum base_status current_base_status;
+
+/*
+ * This function is called whenever there is a change in the base detect
+ * status. Actions taken include:
+ * 1. Change in power to base
+ * 2. Indicate mode change to host.
+ * 3. Indicate tablet mode to host. Current assumption is that if base is
+ * disconnected then the system is in tablet mode, else if the base is
+ * connected, then the system is not in tablet mode.
+ */
+static void base_detect_change(enum base_status status)
+{
+	int connected = (status == BASE_CONNECTED);
+
+	if (current_base_status == status)
+		return;
+
+	CPRINTS("Base %sconnected", connected ? "" : "not ");
+	gpio_set_level(GPIO_EN_BASE, connected);
+	tablet_set_mode(!connected);
+	current_base_status = status;
+}
+
+/* Measure detection pin pulse duration (used to wake AP from deep S3). */
+static uint64_t pulse_start;
+static uint32_t pulse_width;
+
+static void print_base_detect_value(int v, int tmp_pulse_width)
+{
+	CPRINTS("%s = %d (pulse %d)", adc_channels[ADC_BASE_DET].name,
+			v, tmp_pulse_width);
+}
+
+static void base_detect_deferred(void)
+{
+	uint64_t time_now = get_time().val;
+	int v;
+	uint32_t tmp_pulse_width = pulse_width;
+
+	if (base_detect_debounce_time > time_now) {
+		hook_call_deferred(&base_detect_deferred_data,
+				   base_detect_debounce_time - time_now);
+		return;
+	}
+
+	v = adc_read_channel(ADC_BASE_DET);
+	if (v == ADC_READ_ERROR)
+		return;
+
+	print_base_detect_value(v, tmp_pulse_width);
+
+	if (v >= BASE_DETECT_MIN_MV && v <= BASE_DETECT_MAX_MV) {
+		if (current_base_status != BASE_CONNECTED) {
+			base_detect_change(BASE_CONNECTED);
+		} else if (tmp_pulse_width >= BASE_DETECT_PULSE_MIN_US &&
+			   tmp_pulse_width <= BASE_DETECT_PULSE_MAX_US) {
+			CPRINTS("Sending event to AP");
+			host_set_single_event(EC_HOST_EVENT_KEY_PRESSED);
+		}
+		return;
+	}
+
+	if (v >= BASE_DETECT_DISCONNECT_MIN_MV) {
+		base_detect_change(BASE_DISCONNECTED);
+		return;
+	}
+
+	/* Unclear base status, schedule again in a while. */
+	hook_call_deferred(&base_detect_deferred_data, BASE_DETECT_RETRY_US);
+}
+
+static inline int detect_pin_connected(enum gpio_signal det_pin)
+{
+	return gpio_get_level(det_pin) == 0;
+}
+
+void base_detect_interrupt(enum gpio_signal signal)
+{
+	uint64_t time_now = get_time().val;
+	int debounce_us;
+
+	if (detect_pin_connected(signal))
+		debounce_us = BASE_DETECT_EN_DEBOUNCE_US;
+	else
+		debounce_us = BASE_DETECT_DIS_DEBOUNCE_US;
+
+	if (base_detect_debounce_time <= time_now) {
+		/*
+		 * Detect and measure detection pin pulse, when base is
+		 * connected. Only a single pulse is measured over a debounce
+		 * period. If no pulse, or multiple pulses are detected,
+		 * pulse_width is set to 0.
+		 */
+		if (current_base_status == BASE_CONNECTED &&
+		    !detect_pin_connected(signal)) {
+			pulse_start = time_now;
+		} else {
+			pulse_start = 0;
+		}
+		pulse_width = 0;
+
+		hook_call_deferred(&base_detect_deferred_data, debounce_us);
+	} else {
+		if (current_base_status == BASE_CONNECTED &&
+		    detect_pin_connected(signal) && !pulse_width &&
+		    pulse_start) {
+			/* First pulse within period. */
+			pulse_width = time_now - pulse_start;
+		} else {
+			pulse_start = 0;
+			pulse_width = 0;
+		}
+	}
+
+	base_detect_debounce_time = time_now + debounce_us;
+}
+
+static void base_enable(void)
+{
+	/* Enable base detection interrupt. */
+	base_detect_debounce_time = get_time().val;
+	hook_call_deferred(&base_detect_deferred_data, 0);
+	gpio_enable_interrupt(GPIO_BASE_DET_L);
+}
+DECLARE_HOOK(HOOK_CHIPSET_STARTUP, base_enable, HOOK_PRIO_DEFAULT);
+
+static void base_disable(void)
+{
+	/*
+	 * Disable base detection interrupt and disable power to base.
+	 * Set the state UNKNOWN so the next startup will initialize a
+	 * correct state and notify AP.
+	 */
+	gpio_disable_interrupt(GPIO_BASE_DET_L);
+	base_detect_change(BASE_UNKNOWN);
+}
+DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, base_disable, HOOK_PRIO_DEFAULT);
+
+static void base_init(void)
+{
+	/*
+	 * If we jumped to this image and chipset is already in S0, enable
+	 * base.
+	 */
+	if (system_jumped_late() && chipset_in_state(CHIPSET_STATE_ON))
+		base_enable();
+}
+DECLARE_HOOK(HOOK_INIT, base_init, HOOK_PRIO_DEFAULT+1);
+
+void base_force_state(int state)
+{
+	if (state == 1) {
+		gpio_disable_interrupt(GPIO_BASE_DET_L);
+		base_detect_change(BASE_CONNECTED);
+		CPRINTS("BD forced connected");
+	} else if (state == 0) {
+		gpio_disable_interrupt(GPIO_BASE_DET_L);
+		base_detect_change(BASE_DISCONNECTED);
+		CPRINTS("BD forced disconnected");
+	} else {
+		base_enable();
+		CPRINTS("BD forced reset");
+	}
+}