1 files changed, 86 insertions, 0 deletions
diff --git a/common/capsense.c b/common/capsense.c
new file mode 100644
index 0000000000..e0df749933
--- /dev/null
+++ b/common/capsense.c
@@ -0,0 +1,86 @@
+/* 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.
+ */
+
+#include "common.h"
+#include "console.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "i2c.h"
+#include "keyboard_protocol.h"
+#include "timer.h"
+
+/* Console output macro */
+#define CPRINTF(format, args...) cprintf(CC_KEYBOARD, format, ## args)
+
+#define CAPSENSE_I2C_ADDR 0x08
+#define CAPSENSE_MASK_BITS 8
+#define CAPSENSE_POLL_INTERVAL (20 * MSEC)
+
+static int capsense_read_bitmask(void)
+{
+	int rv;
+	uint8_t val = 0;
+
+	i2c_lock(I2C_PORT_CAPSENSE, 1);
+	rv = i2c_xfer(I2C_PORT_CAPSENSE, CAPSENSE_I2C_ADDR,
+		      0, 0, &val, 1, I2C_XFER_SINGLE);
+	i2c_lock(I2C_PORT_CAPSENSE, 0);
+
+	if (rv)
+		CPRINTF("[%T %s failed: error %d]\n", __func__, rv);
+
+	return val;
+}
+
+static void capsense_init(void)
+{
+	gpio_enable_interrupt(GPIO_CAPSENSE_INT_L);
+}
+DECLARE_HOOK(HOOK_INIT, capsense_init, HOOK_PRIO_DEFAULT);
+
+/*
+ * Keep checking polling the capsense until all the buttons are released.
+ * We're not worrying about debouncing, since the capsense module should do
+ * that for us.
+ */
+static void capsense_change_deferred(void)
+{
+	static uint8_t cur_val;
+	uint8_t new_val;
+	int i, n, c;
+
+	new_val = capsense_read_bitmask();
+	if (new_val != cur_val) {
+		CPRINTF("[%T capsense 0x%02x: ", new_val);
+		for (i = 0; i < CAPSENSE_MASK_BITS; i++) {
+			/* See what changed */
+			n = (new_val >> i) & 0x01;
+			c = (cur_val >> i) & 0x01;
+			CPRINTF("%s", n ? " X " : " _ ");
+			if (n == c)
+				continue;
+#ifdef HAS_TASK_KEYPROTO
+			/* Treat it as a keyboard event. */
+			keyboard_update_button(i + KEYBOARD_BUTTON_CAPSENSE_1,
+					       n);
+#endif
+		}
+		CPRINTF("]\n");
+		cur_val = new_val;
+	}
+
+	if (cur_val)
+		hook_call_deferred(capsense_change_deferred,
+				   CAPSENSE_POLL_INTERVAL);
+}
+DECLARE_DEFERRED(capsense_change_deferred);
+
+/*
+ * Somebody's poking at us.
+ */
+void capsense_interrupt(enum gpio_signal signal)
+{
+	hook_call_deferred(capsense_change_deferred, 0);
+}