269 lines
7.9 KiB
Python
269 lines
7.9 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""DI 通道的底层读取后端。
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每个后端只负责：open / close / read。
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电平语义（0=低，1=高）由上层 DIChannel 统一处理。
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后端类型：
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- EventBackend：/dev/input/eventN，事件驱动，可 poll。SE5 的 IN1。
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- SysfsBackend：/sys/.../gpio_status 或 /dev/tv_gpioin_N，轮询 + 抗抖。
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SE9 的 IN1、所有设备的 IN2。
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"""
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import errno
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import glob
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import os
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import select # noqa: F401 (留给上层使用)
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import struct
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import time
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from .config import (
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EV_KEY, VALUE_RELEASE, VALUE_PRESS, VALUE_REPEAT,
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DEFAULT_EVENT_DEVICE, GPIO_KEYS_NAME,
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DEBOUNCE, DEFAULT_INTERVAL,
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find_status_file,
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)
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EVENT_STRUCT = struct.Struct("llHHi") # aarch64 / x86_64 都是 24 字节
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# ---------------------------------------------------------------------------
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# 基类
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# ---------------------------------------------------------------------------
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class Backend:
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"""后端接口。"""
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can_poll = False
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def open(self):
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raise NotImplementedError
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def close(self):
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raise NotImplementedError
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def read(self):
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"""非阻塞读一次，返回 (level, ts) 或 None。
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level 是原始电平 0/1，尚未做 active_low 翻转。
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"""
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raise NotImplementedError
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@property
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def name(self):
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raise NotImplementedError
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# ---------------------------------------------------------------------------
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# /dev/input/eventN 后端（SE5 的 IN1）
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# ---------------------------------------------------------------------------
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class EventBackend(Backend):
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"""基于 input 事件设备，事件驱动。
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原始 value 语义：
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VALUE_PRESS(1) -> 硬件“按下”
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VALUE_RELEASE(0) -> 硬件“释放”
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本后端返回原始 value，极性翻转留给 DIChannel。
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"""
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can_poll = True
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def __init__(self, device=DEFAULT_EVENT_DEVICE, key=None,
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find_by_name=GPIO_KEYS_NAME):
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self.device = device
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self.key = key
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self.find_by_name = find_by_name
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self.fd = None
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self.buf = b""
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# ---- 自动查找 ----
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@staticmethod
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def find_event_device(name=GPIO_KEYS_NAME):
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"""按设备名找 eventN，找不到返回 None。"""
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for path in sorted(glob.glob("/dev/input/event*")):
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ev = path.rsplit("/", 1)[-1]
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namefile = f"/sys/class/input/{ev}/device/name"
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try:
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with open(namefile) as f:
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if f.read().strip() == name:
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return path
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except OSError:
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continue
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return None
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def resolve_device(self):
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if not self.device or self.device == "auto":
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return self.find_event_device(self.find_by_name) or DEFAULT_EVENT_DEVICE
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return self.device
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@property
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def name(self):
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dev = self.device or "(auto)"
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return f"event:{dev}"
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# ---- 生命周期 ----
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def open(self):
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if self.fd is None:
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dev = self.resolve_device()
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if not dev or not os.path.exists(dev):
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raise FileNotFoundError(
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errno.ENOENT,
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f"event 设备不存在：{dev}",
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dev,
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)
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self.device = dev
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self.fd = os.open(dev, os.O_RDONLY | os.O_NONBLOCK)
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def close(self):
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if self.fd is not None:
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try:
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os.close(self.fd)
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finally:
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self.fd = None
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def fileno(self):
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return self.fd
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# ---- 读取 ----
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def read(self):
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"""返回 (level, ts) 或 None；只汇报关心的 key。"""
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if self.fd is None:
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return None
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try:
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data = os.read(self.fd, EVENT_STRUCT.size * 64)
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except OSError:
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return None
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self.buf += data
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result = None
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while len(self.buf) >= EVENT_STRUCT.size:
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chunk = self.buf[:EVENT_STRUCT.size]
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self.buf = self.buf[EVENT_STRUCT.size:]
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sec, usec, etype, code, value = EVENT_STRUCT.unpack(chunk)
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if etype != EV_KEY:
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continue
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if self.key is not None and code != self.key:
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continue
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if value == VALUE_REPEAT:
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continue
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if value not in (VALUE_RELEASE, VALUE_PRESS):
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continue
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ts = sec + usec / 1e6
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result = (value, ts)
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return result
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# ---------------------------------------------------------------------------
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# sysfs 状态文件后端（SE9 的 IN1、所有 IN2）
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# ---------------------------------------------------------------------------
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class SysfsBackend(Backend):
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"""基于 /sys/.../gpio_status 或 /dev/tv_gpioin_N，轮询采样 + 抗抖。"""
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can_poll = False
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def __init__(self, path, debounce=DEBOUNCE, interval=DEFAULT_INTERVAL):
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self.path = path
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self.debounce = max(1, int(debounce))
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self.interval = interval
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self._cand = None
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self._cand_n = 0
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@property
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def name(self):
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return f"sysfs:{self.path}"
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def open(self):
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if not os.access(self.path, os.R_OK):
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raise FileNotFoundError(
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errno.ENOENT,
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f"状态文件不可读：{self.path}",
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self.path,
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)
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def close(self):
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pass
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# ---- 原始电平 ----
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def read_raw(self):
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try:
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with open(self.path, "r") as f:
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v = f.read()
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except OSError:
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return None
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v = v.strip().strip("\t\r\n ")
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return v if v in ("0", "1") else None
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# ---- 带抗抖的读取 ----
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def read(self):
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"""返回 (level, ts) 或 None。
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level 为抗抖确认后的稳定值；None 表示还没确认跳变。
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"""
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v = self.read_raw()
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if v is None:
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return None
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ts = time.time()
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if self._cand is None or v == self._cand:
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self._cand = v
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self._cand_n += 1
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else:
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self._cand = v
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self._cand_n = 1
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if self._cand_n >= self.debounce:
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self._cand_n = 0 # 复位，避免重复上报
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return (int(v), ts)
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return None
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# ---------------------------------------------------------------------------
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# 工厂
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# ---------------------------------------------------------------------------
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def make_backend(kind: str, **kwargs):
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"""kind = 'event' | 'sysfs'。"""
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if kind == "event":
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return EventBackend(**kwargs)
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if kind == "sysfs":
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return SysfsBackend(**kwargs)
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raise ValueError(f"未知后端类型：{kind}")
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def make_in1_backend(device=None, key=None, in_index=1):
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"""自动为 IN1 选择后端，适配 SE5 / SE9。
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优先级：
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1) 显式 device（非 auto） -> EventBackend
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2) 自动查找 gpio-keys 的 event 设备 -> EventBackend
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3) 查找 gpio-in-<in_index> 的状态文件 -> SysfsBackend
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4) 都找不到 -> 返回 EventBackend（open 时抛出可诊断的错误）
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"""
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# 1) 显式指定
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if device and device != "auto":
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return EventBackend(device, key=key)
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# 2) 自动查找 gpio-keys
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ev = EventBackend.find_event_device(GPIO_KEYS_NAME)
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if ev:
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return EventBackend(ev, key=key)
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# 3) 回退到 sysfs 状态文件
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status = find_status_file(in_index)
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if status:
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return SysfsBackend(status)
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# 4) 都找不到，返回一个 open 时会报错的 EventBackend
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return EventBackend(DEFAULT_EVENT_DEVICE, key=key)
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def find_event_device(name=GPIO_KEYS_NAME):
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"""模块级别别名，等价于 EventBackend.find_event_device."""
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return EventBackend.find_event_device(name)
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__all__ = [
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"Backend",
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"EventBackend",
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"SysfsBackend",
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"make_backend",
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"make_in1_backend",
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"find_status_file",
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"find_event_device",
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]
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