Initial commit: Xiaoxiang Smart BMS Home Assistant integration

- BLE GATT communication via bleak (UART-over-GATT, service 0xff00)
- Parses 0x03 (general info) and 0x04 (cell voltages) frames
- Protocol verified against official RS485/UART spec V4
- DataUpdateCoordinator with 5s poll interval (configurable 2-60s)
- Auto-reconnect on BLE disconnect
- Config flow: BT auto-discovery + manual MAC entry + options flow
- Sensors: voltage, current, power, SoC, capacity, cycles, temps, cells, cell delta
- HACS-ready (hacs.json, manifest.json)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

custom_components/xiaoxiang_bms/config_flow.py

@@ -0,0 +1,130 @@
+"""Config flow for the Xiaoxiang Smart BMS integration."""
+from __future__ import annotations
+
+import voluptuous as vol
+from homeassistant import config_entries
+from homeassistant.components.bluetooth import (
+    BluetoothServiceInfoBleak,
+    async_discovered_service_info,
+)
+from homeassistant.core import callback
+from homeassistant.data_entry_flow import FlowResult
+
+from .const import (
+    CONF_ADDRESS,
+    CONF_POLL_INTERVAL,
+    DEFAULT_POLL_INTERVAL,
+    DOMAIN,
+    MAX_POLL_INTERVAL,
+    MIN_POLL_INTERVAL,
+    UART_SERVICE_UUID,
+)
+
+
+class XiaoxiangBmsConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for the Xiaoxiang Smart BMS."""
+
+    VERSION = 1
+
+    def __init__(self) -> None:
+        self._address: str | None = None
+        self._name: str | None = None
+
+    # ------------------------------------------------------------------
+    # Auto-discovery path (HA sees BMS advertising matching service UUID)
+    # ------------------------------------------------------------------
+
+    async def async_step_bluetooth(
+        self, discovery_info: BluetoothServiceInfoBleak
+    ) -> FlowResult:
+        """Handle BLE auto-discovery."""
+        self._address = discovery_info.address
+        self._name = discovery_info.name or f"Xiaoxiang BMS ({discovery_info.address})"
+
+        await self.async_set_unique_id(discovery_info.address)
+        self._abort_if_unique_id_configured()
+
+        self.context["title_placeholders"] = {"name": self._name}
+        return await self.async_step_confirm()
+
+    async def async_step_confirm(self, user_input: dict | None = None) -> FlowResult:
+        """Confirm auto-discovered device."""
+        if user_input is not None:
+            return self.async_create_entry(
+                title=self._name,
+                data={CONF_ADDRESS: self._address},
+            )
+        return self.async_show_form(
+            step_id="confirm",
+            description_placeholders={
+                "name": self._name,
+                "address": self._address,
+            },
+        )
+
+    # ------------------------------------------------------------------
+    # Manual path (user goes to Integrations → Add → Xiaoxiang BMS)
+    # ------------------------------------------------------------------
+
+    async def async_step_user(self, user_input: dict | None = None) -> FlowResult:
+        """Handle manual setup. Shows discovered BMS devices as a dropdown if found."""
+        errors: dict[str, str] = {}
+
+        if user_input is not None:
+            address = user_input[CONF_ADDRESS].upper().strip()
+            await self.async_set_unique_id(address)
+            self._abort_if_unique_id_configured()
+            return self.async_create_entry(
+                title=f"Xiaoxiang BMS ({address})",
+                data={CONF_ADDRESS: address},
+            )
+
+        # Build a dropdown of already-discovered BMS devices (filtered by service UUID)
+        discovered: dict[str, str] = {
+            info.address: f"{info.name or 'Xiaoxiang BMS'} ({info.address})"
+            for info in async_discovered_service_info(self.hass)
+            if UART_SERVICE_UUID in (info.service_uuids or [])
+        }
+
+        if discovered:
+            schema = vol.Schema({vol.Required(CONF_ADDRESS): vol.In(discovered)})
+        else:
+            schema = vol.Schema({
+                vol.Required(CONF_ADDRESS): str,
+            })
+
+        return self.async_show_form(
+            step_id="user",
+            data_schema=schema,
+            errors=errors,
+        )
+
+    # ------------------------------------------------------------------
+    # Options flow (change poll interval after setup)
+    # ------------------------------------------------------------------
+
+    @staticmethod
+    @callback
+    def async_get_options_flow(config_entry: config_entries.ConfigEntry) -> BmsOptionsFlow:
+        return BmsOptionsFlow(config_entry)
+
+
+class BmsOptionsFlow(config_entries.OptionsFlow):
+    """Allow the user to change the poll interval after initial setup."""
+
+    def __init__(self, config_entry: config_entries.ConfigEntry) -> None:
+        self._config_entry = config_entry
+
+    async def async_step_init(self, user_input: dict | None = None) -> FlowResult:
+        if user_input is not None:
+            return self.async_create_entry(title="", data=user_input)
+
+        current = self._config_entry.options.get(CONF_POLL_INTERVAL, DEFAULT_POLL_INTERVAL)
+        return self.async_show_form(
+            step_id="init",
+            data_schema=vol.Schema({
+                vol.Required(CONF_POLL_INTERVAL, default=current): vol.All(
+                    int, vol.Range(min=MIN_POLL_INTERVAL, max=MAX_POLL_INTERVAL)
+                ),
+            }),
+        )