rambi: glimmer: Disable key scanning in suspend when lid is open

Added ability to disable the keyboard to wake from suspend when the lid
is outside a certain angle range. This has been added to glimmer by
defining CONFIG_LID_ANGLE_KEY_SCAN in its board.h.

Also modified the lid angle calculation to include a reliability
flag which can be used to tell when the hinge aligns too closely
with gravity and the lid angle value is unreliable.

BUG=none
BRANCH=rambi
TEST=Tested on a glimmer:

In S3, verified that when the lid is open past ~180 deg, the keyboard
does not wake the machine. Also verified that if you align hinge with
gravity, the keyboard enabled/disabled status remains the same (since
we can't actually trust the lid angle value).

Change-Id: I45b2c7c3c4bbcae61d3a0f8b5baa461ab8dabfb0
Original-Change-Id: If1a1592d259902d38941936961854b81b3a75b95
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/190061
Reviewed-on: https://chromium-review.googlesource.com/191612
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/common/lid_angle.c b/common/lid_angle.c
new file mode 100644
index 0000000000..e7a3139ebb
--- /dev/null
+++ b/common/lid_angle.c
@@ -0,0 +1,81 @@
+/* Copyright (c) 2014 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.
+ */
+
+/* Lid angle module for Chrome EC */
+
+#include "chipset.h"
+#include "common.h"
+#include "console.h"
+#include "keyboard_scan.h"
+#include "lid_angle.h"
+#include "lid_switch.h"
+#include "motion_sense.h"
+
+/* Console output macros */
+#define CPUTS(outstr) cputs(CC_LIDANGLE, outstr)
+#define CPRINTF(format, args...) cprintf(CC_LIDANGLE, format, ## args)
+
+/*
+ * Define the number of previous lid angle measurements to keep for determining
+ * whether to enable or disable key scanning. Note, that in order to change
+ * the state of key scanning, all stored measurements of the lid angle buffer
+ * must be in the specified range.
+ */
+#define KEY_SCAN_LID_ANGLE_BUFFER_SIZE 4
+
+void lidangle_keyscan_update(float lid_ang)
+{
+	static float lidangle_buffer[KEY_SCAN_LID_ANGLE_BUFFER_SIZE];
+	static int index;
+
+	int i;
+	int keys_accept = 1, keys_ignore = 1;
+
+	/* Record most recent lid angle in circular buffer. */
+	lidangle_buffer[index] = lid_ang;
+	index = (index == KEY_SCAN_LID_ANGLE_BUFFER_SIZE-1) ? 0 : index+1;
+
+#ifdef CONFIG_LID_SWITCH
+	/*
+	 * If lid is closed, don't need to check if keyboard scanning should
+	 * be enabled.
+	 */
+	if (!lid_is_open())
+		return;
+#endif
+
+	if (chipset_in_state(CHIPSET_STATE_SUSPEND)) {
+		for (i = 0; i < KEY_SCAN_LID_ANGLE_BUFFER_SIZE; i++) {
+			/*
+			 * If any lid angle samples are unreliable, then
+			 * don't change keyboard scanning state.
+			 */
+			if (lidangle_buffer[i] == LID_ANGLE_UNRELIABLE)
+				return;
+
+			/*
+			 * Force all elements of the lid angle buffer to be
+			 * in range of one of the conditions in order to change
+			 * to the corresponding key scanning state.
+			 */
+			if (!LID_IN_RANGE_TO_ACCEPT_KEYS(lidangle_buffer[i]))
+				keys_accept = 0;
+			if (!LID_IN_RANGE_TO_IGNORE_KEYS(lidangle_buffer[i]))
+				keys_ignore = 0;
+		}
+
+		/* Enable or disable keyboard scanning if necessary. */
+		if (keys_accept && !keyboard_scan_is_enabled()) {
+			CPRINTF("[%T Enabling keyboard scan, lid ang at %d]\n",
+					(int)lidangle_buffer[index]);
+			keyboard_scan_enable(1);
+		} else if (keys_ignore && !keys_accept &&
+				keyboard_scan_is_enabled()) {
+			CPRINTF("[%T Disabling keyboard scan, lid ang at %d]\n",
+					(int)lidangle_buffer[index]);
+			keyboard_scan_enable(0);
+		}
+	}
+}