/
gpio.py
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gpio.py
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# GPIO Factory helper
#
# Copyright (C) 2021 Eric Callahan <arksine.code@gmail.com>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
from __future__ import annotations
import os
import re
import asyncio
import pathlib
import logging
import periphery
from ..utils import KERNEL_VERSION
# Annotation imports
from typing import (
TYPE_CHECKING,
Any,
Awaitable,
Callable,
Dict,
Optional
)
if TYPE_CHECKING:
from ..confighelper import ConfigHelper
from ..eventloop import EventLoop
GpioEventCallback = Callable[[float, float, int], Optional[Awaitable[None]]]
GPIO_PATTERN = r"""
(?P<bias>[~^])?
(?P<inverted>!)?
(?:(?P<chip_id>gpiochip[0-9]+)/)?
(?P<pin_name>gpio(?P<pin_id>[0-9]+))
"""
BIAS_FLAG_TO_DESC: Dict[str, str] = {
"^": "pull_up",
"~": "pull_down",
"*": "disable" if KERNEL_VERSION >= (5, 5) else "default"
}
class GpioFactory:
def __init__(self, config: ConfigHelper) -> None:
self.server = config.get_server()
self.reserved_gpios: Dict[str, GpioBase] = {}
def setup_gpio_out(self, pin_name: str, initial_value: int = 0) -> GpioOutputPin:
initial_value = int(not not initial_value)
pparams = self._parse_pin(pin_name, initial_value)
gpio = self._request_gpio(pparams)
try:
gpio_out = GpioOutputPin(gpio, pparams)
except Exception:
logging.exception("Error Instantiating GpioOutputPin")
gpio.close()
raise
full_name = pparams["full_name"]
self.reserved_gpios[full_name] = gpio_out
return gpio_out
def register_gpio_event(
self, pin_name: str, callback: GpioEventCallback
) -> GpioEvent:
pin_params = self._parse_pin(pin_name, req_type="event")
gpio = self._request_gpio(pin_params)
event_loop = self.server.get_event_loop()
try:
gpio_event = GpioEvent(event_loop, gpio, pin_params, callback)
except Exception:
logging.exception("Error Instantiating GpioEvent")
gpio.close()
raise
full_name = pin_params["full_name"]
self.reserved_gpios[full_name] = gpio_event
return gpio_event
def _request_gpio(self, pin_params: Dict[str, Any]) -> periphery.GPIO:
full_name = pin_params["full_name"]
if full_name in self.reserved_gpios:
raise self.server.error(f"GPIO {full_name} already reserved")
chip_path = pathlib.Path("/dev").joinpath(pin_params["chip_id"])
if not chip_path.exists():
raise self.server.error(f"Chip path {chip_path} does not exist")
try:
gpio = periphery.GPIO(
str(chip_path),
pin_params["pin_id"],
pin_params["direction"],
edge=pin_params.get("edge", "none"),
bias=pin_params.get("bias", "default"),
inverted=pin_params["inverted"],
label="moonraker"
)
except Exception:
logging.exception(
f"Unable to init {full_name}. Make sure the gpio is not in "
"use by another program or exported by sysfs.")
raise
return gpio
def _parse_pin(
self, pin_desc: str, initial_value: int = 0, req_type: str = "out"
) -> Dict[str, Any]:
params: Dict[str, Any] = {
"orig": pin_desc,
"inverted": False,
"request_type": req_type,
"initial_value": initial_value
}
pin_match = re.match(GPIO_PATTERN, pin_desc, re.VERBOSE)
if pin_match is None:
raise self.server.error(
f"Invalid pin format {pin_desc}. Refer to the configuration "
"documentation for details on the pin format."
)
bias_flag: Optional[str] = pin_match.group("bias")
params["inverted"] = pin_match.group("inverted") is not None
if req_type == "event":
params["direction"] = "in"
params["edge"] = "both"
params["bias"] = BIAS_FLAG_TO_DESC[bias_flag or "*"]
elif req_type == "out":
if bias_flag is not None:
raise self.server.error(
f"Invalid pin format {pin_desc}. Bias flag {bias_flag} "
"not available for output pins."
)
initial_state = bool(initial_value) ^ params["inverted"]
params["direction"] = "low" if not initial_state else "high"
chip_id: str = pin_match.group("chip_id") or "gpiochip0"
pin_name: str = pin_match.group("pin_name")
params["pin_id"] = int(pin_match.group("pin_id"))
params["chip_id"] = chip_id
params["full_name"] = f"{chip_id}:{pin_name}"
return params
def close(self) -> None:
for gpio in self.reserved_gpios.values():
gpio.close()
class GpioBase:
def __init__(
self, gpio: periphery.GPIO, pin_params: Dict[str, Any]
) -> None:
self.orig: str = pin_params["orig"]
self.name: str = pin_params["full_name"]
self.inverted: bool = pin_params["inverted"]
self.gpio = gpio
self.value: int = pin_params.get("initial_value", 0)
def close(self) -> None:
self.gpio.close()
def is_inverted(self) -> bool:
return self.inverted
def get_value(self) -> int:
return self.value
def get_name(self) -> str:
return self.name
def __str__(self) -> str:
return self.orig
class GpioOutputPin(GpioBase):
def write(self, value: int) -> None:
self.value = int(not not value)
self.gpio.write(bool(self.value))
MAX_ERRORS = 50
ERROR_RESET_TIME = 5.
class GpioEvent(GpioBase):
def __init__(
self,
event_loop: EventLoop,
gpio: periphery.GPIO,
pin_params: Dict[str, Any],
callback: GpioEventCallback
) -> None:
super().__init__(gpio, pin_params)
self.event_loop = event_loop
self.callback = callback
self.on_error: Optional[Callable[[str], None]] = None
self.debounce_period: float = 0
self.last_event_time: float = 0.
self.error_count = 0
self.last_error_reset = 0.
self.started = False
self.debounce_task: Optional[asyncio.Task] = None
os.set_blocking(self.gpio.fd, False)
def fileno(self) -> int:
return self.gpio.fd
def setup_debounce(
self, debounce_period: float, err_callback: Optional[Callable[[str], None]]
) -> None:
self.debounce_period = max(debounce_period, 0)
self.on_error = err_callback
def start(self) -> None:
if not self.started:
self.value = int(self.gpio.read())
self.last_event_time = self.event_loop.get_loop_time()
self.event_loop.add_reader(self.gpio.fd, self._on_event_trigger)
self.started = True
logging.debug(f"GPIO {self.name}: Listening for events, "
f"current state: {self.value}")
def stop(self) -> None:
if self.debounce_task is not None:
self.debounce_task.cancel()
self.debounce_task = None
if self.started:
self.event_loop.remove_reader(self.gpio.fd)
self.started = False
def close(self) -> None:
self.stop()
self.gpio.close()
def _on_event_trigger(self) -> None:
evt = self.gpio.read_event()
last_value = self.value
if evt.edge == "rising": # type: ignore
self.value = 1
elif evt.edge == "falling": # type: ignore
self.value = 0
else:
return
if self.debounce_period:
if self.debounce_task is None:
coro = self._debounce(last_value)
self.debounce_task = self.event_loop.create_task(coro)
else:
self._increment_error()
elif last_value != self.value:
# No debounce period and change detected
self._run_callback()
async def _debounce(self, last_value: int) -> None:
await asyncio.sleep(self.debounce_period)
self.debounce_task = None
if last_value != self.value:
self._run_callback()
def _run_callback(self) -> None:
eventtime = self.event_loop.get_loop_time()
evt_duration = eventtime - self.last_event_time
self.last_event_time = eventtime
ret = self.callback(eventtime, evt_duration, self.value)
if ret is not None:
self.event_loop.create_task(ret) # type: ignore
def _increment_error(self) -> None:
eventtime = self.event_loop.get_loop_time()
if eventtime - self.last_error_reset > ERROR_RESET_TIME:
self.error_count = 0
self.last_error_reset = eventtime
self.error_count += 1
if self.error_count >= MAX_ERRORS:
self.stop()
if self.on_error is not None:
self.on_error(
f"Too Many Consecutive Errors, GPIO Event Disabled on {self.name}"
)
def load_component(config: ConfigHelper) -> GpioFactory:
return GpioFactory(config)