Add bootloader reset for SMLIGHT SLZB-07 (#63)

* Find gpio chip by name

Chip number for USB gpio chips will depend on what other system gpio
chips already exist on the system. Add support to search by chip label
to find chip number.

* Add bootloader reset for SLZB-07

* Add message to avoid other USB devices

README.md

@@ -19,7 +19,7 @@ Options:
   --ezsp-baudrate NUMBERS        [default: 115200]
   --spinel-baudrate NUMBERS      [default: 460800]
   --probe-method TEXT            [default: bootloader, cpc, ezsp, spinel]
-  --bootloader-reset [yellow|ihost|sonoff]
+  --bootloader-reset [yellow|ihost|slzb07|sonoff]
   --help                         Show this message and exit.
 
 Commands:

universal_silabs_flasher/const.py

@@ -48,6 +48,7 @@ class ApplicationType(enum.Enum):
 class ResetTarget(enum.Enum):
     YELLOW = "yellow"
     IHOST = "ihost"
+    SLZB07 = "slzb07"
     SONOFF = "sonoff"
 
 
@@ -68,4 +69,12 @@ class ResetTarget(enum.Enum):
         },
         "toggle_delay": 0.1,
     },
+    ResetTarget.SLZB07: {
+        "chip_name": "cp210x",
+        "pin_states": {
+            5: [True, False, False, True],
+            4: [True, False, True, True],
+        },
+        "toggle_delay": 0.1,
+    },
 }

universal_silabs_flasher/flasher.py

@@ -22,7 +22,7 @@
 from .emberznet import connect_ezsp
 from .firmware import FirmwareImage
 from .gecko_bootloader import GeckoBootloaderProtocol, NoFirmwareError
-from .gpio import send_gpio_pattern
+from .gpio import find_gpiochip_by_label, send_gpio_pattern
 from .spinel import SpinelProtocol
 from .xmodemcrc import BLOCK_SIZE as XMODEM_BLOCK_SIZE
 
@@ -69,6 +69,12 @@ async def enter_bootloader_reset(self, target):
         _LOGGER.info(f"Triggering {target.value} bootloader")
         if target in GPIO_CONFIGS.keys():
             config = GPIO_CONFIGS[target]
+            if "chip" not in config.keys():
+                _LOGGER.warning(
+                    f"When using {target.value} bootloader reset "
+                    + "ensure no other CP2102 USB serial devices are connected."
+                )
+                config["chip"] = await find_gpiochip_by_label(config["chip_name"])
             await send_gpio_pattern(
                 config["chip"], config["pin_states"], config["toggle_delay"]
             )

universal_silabs_flasher/gpio.py

@@ -1,10 +1,14 @@
 from __future__ import annotations
 
 import asyncio
+from os import scandir
 import time
+import typing
 
 try:
     import gpiod
+
+    is_gpiod_v1 = hasattr(gpiod.chip, "OPEN_BY_PATH")
 except ImportError:
     gpiod = None
 
@@ -15,7 +19,7 @@ def _send_gpio_pattern(
     ) -> None:
         raise NotImplementedError("GPIO not supported on this platform")
 
-elif hasattr(gpiod.chip, "OPEN_BY_PATH"):
+elif is_gpiod_v1:
     # gpiod <= 1.5.4
     def _send_gpio_pattern(
         chip: str, pin_states: dict[int, list[bool]], toggle_delay: float
@@ -82,6 +86,39 @@ def _send_gpio_pattern(
                 )
 
 
+def _generate_gpio_chips() -> typing.Iterable[str]:
+    for entry in scandir("/dev/"):
+        if is_gpiod_v1:
+            if entry.name.startswith("gpiochip"):
+                yield entry.path
+        else:
+            if gpiod.is_gpiochip_device(entry.path):
+                yield entry.path
+
+
+def _find_gpiochip_by_label(label: str) -> str:
+    for path in _generate_gpio_chips():
+        try:
+            if is_gpiod_v1:
+                chip = gpiod.chip(path, gpiod.chip.OPEN_BY_PATH)
+                if chip.label == label:
+                    return path
+            else:
+                with gpiod.Chip(path) as chip:
+                    if chip.get_info().label == label:
+                        return path
+        except PermissionError:
+            pass
+    raise RuntimeError("No matching gpiochip device found")
+
+
+async def find_gpiochip_by_label(label: str) -> str:
+    result = await asyncio.get_running_loop().run_in_executor(
+        None, _find_gpiochip_by_label, label
+    )
+    return result
+
+
 async def send_gpio_pattern(
     chip: str, pin_states: dict[int, list[bool]], toggle_delay: float
 ) -> None: