Support BLE multiple connection in the BLE part of the esp_hid component. (IDFGH-16865)

[paul356]

Description

Since BLE supports multiple connections, it is not uncommon for a BLE hid host to support multiple connections. This PR address the need to support multiple connections in the BLE hid module. The core data struct is to add these memebers to esp_ble_hidd_dev_s. These fields help to track which connection currently is selected. I also update the handlers to use these members to respond to different events.

    // Multi-connection support
    SemaphoreHandle_t            conn_mutex;        // Mutex for protecting connection state
    hidd_connection_t           connections[ESP_HIDD_MAX_CONNECTIONS];
    uint8_t                     active_conn_index;  // Index to active connection (0xFF = broadcast mode)
    bool                        broadcast_mode;     // When true, send to all connections

Related

Testing

I have tested this change using the esp_hid_device example. For single connection the behavior stays the same. I have a keyboard project which supports multiple BLE clients. I was able to switch between different BLE clients.

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Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

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Note

Add BLE HID multi-connection support with per-connection CCC and APIs to set active connection, query connections, and toggle broadcast mode, updating send and event paths accordingly.

• API (public esp_hidd):
  • Add esp_hidd_conn_info_t and new APIs: esp_hidd_dev_set_active_conn, esp_hidd_dev_get_connections, esp_hidd_dev_set_broadcast_mode.
• BLE HID implementation (ble_hidd):
  • Introduce multi-connection state: connections[], conn_mutex, active_conn_index, broadcast_mode.
  • Track per-connection CCC for Battery; update CCC handling.
  • Update connect/disconnect to add/remove connections; adjust active connection.
  • Modify connected, battery, input, and feature report paths to support unicast to active connection or broadcast to all.
  • Initialize and free new mutex; add internal helper functions.
  • Expose BLE-specific wrappers: esp_ble_hidd_dev_set_active_conn, ...get_connections, ...set_broadcast_mode.

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[github-actions]

Warnings

⚠️

Some issues found for the commit messages in this PR: the commit message "feat(esp_hid): Enahcne esp_hid to support multiple BLE connections. Add interfaces to allow users to select which connection to use or boradcast events to all connections.": summary appears to be too long summary should not end with a period (full stop) Please fix these commit messages - here are some basic tips: follow Conventional Commits style correct format of commit message should be: <type/action>(<scope/component>): <summary>, for example fix(esp32): Fixed startup timeout issue allowed types are: change,ci,docs,feat,fix,refactor,remove,revert,test sufficiently descriptive message summary should be between 20 to 72 characters and start with upper case letter avoid Jira references in commit messages (unavailable/irrelevant for our customers) TIP: Install pre-commit hooks and run this check when committing (uses the Conventional Precommit Linter).

👋 Hello paul356, we appreciate your contribution to this project!

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[paul356]

I have trouble with pre-commit hooks. Because this fork is created years ago, I will create a new fork and fix the pre-commit hooks first, then create a new PR.