feat: 添加模式切换模块支持多协议键盘

添加了完整的模式切换功能，通过ADC采样检测模式拨码开关，
实现USB、BLE和2.4G三种工作模式的自动识别和切换。

- 新增mode_event事件用于传递模式状态
- 实现mode_switch_module模块，包含ADC初始化、
  模式识别算法和状态管理逻辑
- 配置CMakeLists.txt添加新源文件和头文件目录
- 更新设备树配置启用ADC和IO通道
- 添加Kconfig选项CONFIG_ADC=y
- 实现防抖机制和稳定的模式检测逻辑
- 集成到CAF事件系统，支持电源管理状态切换

CMakeLists.txt

@@ -4,8 +4,11 @@ find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(new_kbd)
 
 zephyr_include_directories(${CMAKE_CURRENT_SOURCE_DIR}/inc)
+zephyr_include_directories(${CMAKE_CURRENT_SOURCE_DIR}/src/events)
 
 target_sources(app PRIVATE
     src/main.c
+    src/events/mode_event.c
     src/modules/button_map_module.c
+    src/modules/mode_switch_module.c
 )

app.overlay

@@ -1,4 +1,9 @@
-/{};
+/ {
+    zephyr,user {
+        io-channels = <&adc 5>, <&adc 7>;
+    };
+};
+
 &gpio0 {
     status = "okay";
 };
@@ -14,3 +19,8 @@
 &led_0 {
     status = "okay";
 };
+
+/* 使能 SAADC，mode_switch_module 使用 channel 7 采样模式拨码电压。 */
+&adc {
+    status = "okay";
+};

prj.conf

@@ -17,3 +17,5 @@ CONFIG_CAF_BUTTONS=y
 CONFIG_CAF_BUTTONS_DEF_PATH="buttons_def.h"
 CONFIG_CAF_BUTTONS_SCAN_INTERVAL=5
 CONFIG_CAF_BUTTONS_DEBOUNCE_INTERVAL=10
+
+CONFIG_ADC=y

src/events/mode_event.c

@@ -0,0 +1,34 @@
+#include "mode_event.h"
+
+static const char *const mode_name[] = {
+	[MODE_TYPE_USB] = "USB",
+	[MODE_TYPE_BLE] = "BLE",
+	[MODE_TYPE_2G4] = "2.4G",
+};
+
+static void log_mode_event(const struct app_event_header *aeh)
+{
+	const struct mode_event *event = cast_mode_event(aeh);
+
+	__ASSERT_NO_MSG(event->mode_type < MODE_TYPE_COUNT);
+
+	APP_EVENT_MANAGER_LOG(aeh, "mode=%s(%u)", mode_name[event->mode_type], event->mode_type);
+}
+
+static void profile_mode_event(struct log_event_buf *buf,
+				    const struct app_event_header *aeh)
+{
+	const struct mode_event *event = cast_mode_event(aeh);
+
+	nrf_profiler_log_encode_uint8(buf, (uint8_t)event->mode_type);
+}
+
+APP_EVENT_INFO_DEFINE(mode_event,
+		  ENCODE(NRF_PROFILER_ARG_U8),
+		  ENCODE("mode"),
+		  profile_mode_event);
+
+APP_EVENT_TYPE_DEFINE(mode_event,
+		  log_mode_event,
+		  &mode_event_info,
+		  APP_EVENT_FLAGS_CREATE(APP_EVENT_TYPE_FLAGS_INIT_LOG_ENABLE));

src/events/mode_event.h

@@ -0,0 +1,23 @@
+#ifndef MODE_EVENT_H
+#define MODE_EVENT_H
+
+#include <app_event_manager.h>
+#include <app_event_manager_profiler_tracer.h>
+
+typedef enum
+{
+    MODE_TYPE_USB,
+    MODE_TYPE_BLE,
+    MODE_TYPE_2G4,
+    MODE_TYPE_COUNT,
+} mode_type_t;
+
+struct mode_event
+{
+    struct app_event_header header;
+    mode_type_t mode_type;
+};
+
+APP_EVENT_TYPE_DECLARE(mode_event);
+
+#endif

src/modules/mode_switch_module.c

@@ -0,0 +1,237 @@
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/drivers/adc.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/sys/atomic.h>
+#include <zephyr/sys/util.h>
+#include <stdlib.h>
+
+#include <app_event_manager.h>
+#include <caf/events/power_event.h>
+#include <caf/events/keep_alive_event.h>
+
+#define MODULE mode_switch
+#include <caf/events/module_state_event.h>
+
+#include "mode_event.h"
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(MODULE);
+
+#define MODE_USER_NODE DT_PATH(zephyr_user)
+#define MODE_ADC_IO_CH_IDX 0
+#define MODE_SAMPLE_INTERVAL_MS 50
+
+static const struct adc_dt_spec mode_adc =
+	ADC_DT_SPEC_GET_BY_IDX(MODE_USER_NODE, MODE_ADC_IO_CH_IDX);
+
+static struct k_work_delayable mode_sample_work;
+static int16_t adc_sample_buffer;
+
+static atomic_t active;
+static mode_type_t current_mode;
+static uint8_t mode_stable_status;
+
+static int init_adc(void)
+{
+	if (!adc_is_ready_dt(&mode_adc))
+	{
+		LOG_ERR("ADC device not ready");
+		return -ENODEV;
+	}
+
+	int err = adc_channel_setup_dt(&mode_adc);
+	if (err)
+	{
+		LOG_ERR("ADC channel setup failed (err=%d)", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static mode_type_t classify_mode_from_mv(int32_t mv)
+{
+	/*
+	 * 使用“距离最近中心点”的分类方式，避免阈值边界附近抖动时出现模式跳变。
+	 * 三个中心点直接对应硬件设计目标电压：USB=0mV、2.4G=1650mV、BLE=3300mV。
+	 */
+	static const int32_t centers[MODE_TYPE_COUNT] = {
+		[MODE_TYPE_USB] = 0,
+		[MODE_TYPE_BLE] = 3300,
+		[MODE_TYPE_2G4] = 1650,
+	};
+
+	int32_t best_diff = INT32_MAX;
+	mode_type_t best_mode = MODE_TYPE_USB;
+
+	for (size_t i = 0; i < MODE_TYPE_COUNT; i++)
+	{
+		int32_t diff = abs(mv - centers[i]);
+
+		if (diff < best_diff)
+		{
+			best_diff = diff;
+			best_mode = (mode_type_t)i;
+		}
+	}
+
+	return best_mode;
+}
+
+static int read_mode(mode_type_t *mode)
+{
+	struct adc_sequence sequence = {0};
+	int err = adc_sequence_init_dt(&mode_adc, &sequence);
+	if (err)
+	{
+		return err;
+	}
+
+	sequence.buffer = &adc_sample_buffer;
+	sequence.buffer_size = sizeof(adc_sample_buffer);
+
+	err = adc_read_dt(&mode_adc, &sequence);
+	if (err)
+	{
+		return err;
+	}
+
+	int32_t v = adc_sample_buffer;
+	err = adc_raw_to_millivolts_dt(&mode_adc, &v);
+	if (err)
+	{
+		return err;
+	}
+
+	*mode = classify_mode_from_mv(v);
+
+	return 0;
+}
+
+static void publish_mode_event(mode_type_t mode)
+{
+	if (current_mode == mode)
+		return;
+	
+	current_mode = mode;
+	struct mode_event *event = new_mode_event();
+
+	event->mode_type = mode;
+	APP_EVENT_SUBMIT(event);
+	/*
+	 * 模式切换是明确的人机交互动作。这里同步上报 keep_alive_event，
+	 * 让 power manager 重置休眠倒计时，避免用户刚切换模式就进入省电流程。
+	 */
+	keep_alive();
+}
+
+static void mode_sample_fn(struct k_work *work)
+{
+	ARG_UNUSED(work);
+
+	if (!atomic_get(&active))
+	{
+		return;
+	}
+
+	mode_type_t sampled_mode;
+	int err = read_mode(&sampled_mode);
+	if (err)
+	{
+		LOG_ERR("ADC read failed (err=%d)", err);
+		module_set_state(MODULE_STATE_ERROR);
+		return;
+	}
+
+	mode_stable_status = mode_stable_status << 2;
+	mode_stable_status |= (sampled_mode & 0x3);
+
+	switch (mode_stable_status)
+	{
+	case 0b00000000:
+		publish_mode_event(MODE_TYPE_USB);
+		break;
+	case 0b01010101:
+		publish_mode_event(MODE_TYPE_BLE);
+		break;
+	case 0b10101010:
+		publish_mode_event(MODE_TYPE_2G4);
+		break;
+	default:
+		break;
+	}
+
+	k_work_reschedule(&mode_sample_work, K_MSEC(MODE_SAMPLE_INTERVAL_MS));
+}
+
+static void mode_switch_suspend(void)
+{
+	atomic_set(&active, false);
+	(void)k_work_cancel_delayable(&mode_sample_work);
+	module_set_state(MODULE_STATE_STANDBY);
+}
+
+static void mode_switch_resume(void)
+{
+	if (atomic_get(&active))
+		return;
+	
+	atomic_set(&active, true);
+	k_work_reschedule(&mode_sample_work, K_NO_WAIT);
+	module_set_state(MODULE_STATE_READY);
+}
+
+static void init_mode_switch(void)
+{
+	if (atomic_get(&active))
+		return;
+
+	if (init_adc())
+	{
+		module_set_state(MODULE_STATE_ERROR);
+		return;
+	}
+
+	mode_stable_status = 0xFF;
+	current_mode = MODE_TYPE_COUNT;
+	atomic_set(&active, false);
+	k_work_init_delayable(&mode_sample_work, mode_sample_fn);
+
+	mode_switch_resume();
+}
+
+static bool app_event_handler(const struct app_event_header *aeh)
+{
+	if (is_module_state_event(aeh))
+	{
+		const struct module_state_event *event = cast_module_state_event(aeh);
+
+		if (check_state(event, MODULE_ID(main), MODULE_STATE_READY))
+		{
+			init_mode_switch();
+		}
+
+		return false;
+	}
+
+	if (is_power_down_event(aeh))
+	{
+		mode_switch_suspend();
+		return false;
+	}
+
+	if (is_wake_up_event(aeh))
+	{
+		mode_switch_resume();
+		return false;
+	}
+
+	__ASSERT_NO_MSG(false);
+	return false;
+}
+
+APP_EVENT_LISTENER(MODULE, app_event_handler);
+APP_EVENT_SUBSCRIBE(MODULE, module_state_event);
+APP_EVENT_SUBSCRIBE_EARLY(MODULE, power_down_event);
+APP_EVENT_SUBSCRIBE(MODULE, wake_up_event);