From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F2BFC27B358 for ; Fri, 21 Nov 2025 13:16:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763730967; cv=none; b=lI2uIa3d2Sw2kWakPxBkRb9iYzvPD/CDZk/t08No88fBNNZSe/Q/spnzXvnNzQFKIPOITMk4JjR924RVTwoRFurCTLCROhgKc2zhNxYnFq1D9cX3LuXyiJS8BYCEsGfrF0WzjJjiS/PiPrd8dzVgy2N4JjP/fv0NSiit1e0SUbg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763730967; c=relaxed/simple; bh=/BkkE594fUsCyhqJeALSYkKt+a5AF64RFZhX/SXHyvE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=k3LiBI2bsKFdgjQt8NNopvbBf8ypq9WezVOSm0Kdajo1/gr/zF1GmfzC4GUgATRA/mNEHLHGQPtUVGtnONGCN0vUHPlTIbujR/75weNmU+WfbVITjgIhbbfL9BeYRdMGn6i+cdfKN65hyZ5CG0p7XM31hNFblzCZeiBMVTJuREE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=hYRuqCtX; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=aUtc+pIc; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hYRuqCtX"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="aUtc+pIc" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763730964; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=NoV13vPmiMrtALSrh3dg+PL4CWMVhykeafbLwPzqoD0=; b=hYRuqCtXizqG+8HwmXfjYDJo3M6lnBJB9QGU0sXfxoHIeuKOau+s1x8x8y2cNUvSiBJI1m 8v6I/8dJQ1G50nmC9NKodguyJA5mjFFl/N7PxTqK5WpXw1+gZ1hSPoyB+KhcxM1bmUoO9Q dznZfyXYd+1SsND/pNIe+wbR43+or0I= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-547-kBEQROYdMDGfbRKcaek64Q-1; Fri, 21 Nov 2025 08:16:03 -0500 X-MC-Unique: kBEQROYdMDGfbRKcaek64Q-1 X-Mimecast-MFC-AGG-ID: kBEQROYdMDGfbRKcaek64Q_1763730962 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-47106720618so18883165e9.1 for ; Fri, 21 Nov 2025 05:16:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1763730961; x=1764335761; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=NoV13vPmiMrtALSrh3dg+PL4CWMVhykeafbLwPzqoD0=; b=aUtc+pIcA0AuETAKeGRz2ebFkgGweztCMKL3DUVaKbmfmsrO3kK6V+RRQdtqoxGAN4 6YjAn+nrG96+JNreU+gJPgzVyIn6DFyIlTcZuCSQPj9r4g1AjUu43Y6lXBYqtoMFFFZw SdLn6c1p1kZCuKcygimew4pb8zo7qIDcmkLK90ov1sNA3nCbKKsH2jaklokkfLJy7acJ xK4stUMlKU/0UU8xPv8KM7BocAfuaIqa1P/WzUJCptIDP6aqUvYY1h8IfpwCKG1VLnin oP/EYTMi767yi0m4gtp254R0pVx56BwLwYwCKoPd57PZWFuhd17kssh6Msdk5b7GvAtM iJHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763730961; x=1764335761; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=NoV13vPmiMrtALSrh3dg+PL4CWMVhykeafbLwPzqoD0=; b=uWrJkgYrCDhzVQIsic2TjzmKP7LH91o1/5PfE2ePYlqqMEZq2ApSVr7BTHajxkFpD3 7+ECOwK7CwnY7QOUipQhWPWKqpCIWzAri6ITVQRsCBBq6AFwvLoyD1EHHB3NW8UQmroj VemrGjKPnvotWQRw60ItzUksC2oF7KISeOhSpzSrRg1xWaOpzTQnFp8tRxJsMGJCsmlb pvS6thd9XmKdzNj5JC070kvBRS4w9+50fCx1CHNcwZSiNFVg98k88I0BglMCNFIiYHbj 8PqcCmsqsp++NFRLODxmI6itVpgx625f3R9sagN8eQVD5KDeuSk/Jpn8nbny5ogxgGV6 WIpg== X-Gm-Message-State: AOJu0YxJsnSkr/eR5XzTD6bwJD2LZkXsXXccQkfGwLoU87+u/trpIqbv ZVy/GosmA6f8paAJM0gIpJwQWEVYOARaxZFJEx3tFKpORmGSblFW6VXeCML4xXrsZJl5PxRm4dz 3Yn7y7Kq8Naa3oaKJNxbVwYhTuNDLBX/q6hKijLxIY0BD9i0QyITtIn8i9KfBYDLMh4aJI6U+A2 T/vP1yJ/AfHUJHs1P8eeGl7eLsW4V5kBiofZDfSEJwvq/qQgA1 X-Gm-Gg: ASbGncv5Z0GGb/YDlNpjKit4L9hfdmxyxTApbhEGyKWjsFpOsvrOziqkyY9SGLuZeLh bAHyjZsJz4sSUKqjnmQRtx8gLuPlhoSEr0HlAowOPQpiNrX0pB8Uz9RZr8Rt4Q/6UOGp3wd7ZWh eFtzzV332vC71eimAM3c70w53w2uWdDSonafrtjcA5e4fdt0ueuP5oEqVyyVhBmpJlM2OZNkqsq YmSjRI8uF0a+XClEC0OSQFlfBZCQWwK/CYkttsoE3DzoWyg/oLQQ9qDC3KPpsDasozFCmdX2LL7 v34E8Q3V3OFzJCTPoS2b+ohs+p7KvKdFBGKDGBjdAj/yflpUtrVoV/Z/pBdWB5F38A8BmRpHVnb 1oE3xgRjyPl1xsuZsRH0Raz89+TivcGLx90YkJdcV8AKMq09PiFSKZ/iv2kLqN83FSDuZWV4GO0 Jc7y4OLJk= X-Received: by 2002:a05:600c:524d:b0:477:c71:1fc1 with SMTP id 5b1f17b1804b1-477c01d44b4mr23367175e9.19.1763730961380; Fri, 21 Nov 2025 05:16:01 -0800 (PST) X-Google-Smtp-Source: AGHT+IH38SwZ2eHrnA/qn6RywfYYxZgssOuXSgUXr55RXUG+E7Ys6uTWIB70tz3uWlfOu0NYvDj5qA== X-Received: by 2002:a05:600c:524d:b0:477:c71:1fc1 with SMTP id 5b1f17b1804b1-477c01d44b4mr23365825e9.19.1763730959338; Fri, 21 Nov 2025 05:15:59 -0800 (PST) Received: from sissix.redhat.com ([2a06:5900:814a:ab00:3725:2991:6cf3:b3aa]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477bf3ba1b4sm43077435e9.15.2025.11.21.05.15.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Nov 2025 05:15:59 -0800 (PST) From: Lucas Zampieri To: linux-input@vger.kernel.org Cc: Lucas Zampieri , linux-kernel@vger.kernel.org, Jiri Kosina , Benjamin Tissoires , Sebastian Reichel , Bastien Nocera , linux-pm@vger.kernel.org Subject: [PATCH v5 0/2] HID: Add support for multiple batteries per device Date: Fri, 21 Nov 2025 13:15:52 +0000 Message-ID: <20251121131556.601130-1-lzampier@redhat.com> X-Mailer: git-send-email 2.51.1 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This series adds support for HID devices with multiple batteries. Currently, the HID battery reporting subsystem only supports one battery per device. There are several devices with multiple batteries that would benefit from this support: - Gaming headsets with batteries in both the headset and charging dock - Wireless earbuds with per-earbud batteries plus charging case - Split keyboards with per-side batteries ## Proposed Solution This series introduces struct hid_battery to encapsulate individual battery state, replaces the old battery fields with a list-based approach, and adds support for multiple batteries tracked within struct hid_device. Batteries are identified by report ID and named as hid-{uniq}-battery-{id}. The implementation is fully backwards compatible with single-battery devices through a helper function. The series first converts the battery code to devm_* as preparatory cleanup, which simplifies the subsequent refactoring and reduces risk of memory management bugs. ## Testing Tested with split keyboard hardware (Dactyl 5x6) using custom ZMK firmware that implements per-side HID battery reporting. Each battery (left and right keyboard halves) reports independently through the power supply interface with distinct report IDs (0x05 and 0x06). Test firmware available on my personal fork at: https://github.com/zampierilucas/zmk/tree/feat/individual-hid-battery-reporting If this series gets merged, these changes will be proposed to upstream ZMK. HID descriptor and recording captured with hid-recorder: D: 0 R: 162 05 01 09 06 a1 01 85 01 05 07 19 e0 29 e7 15 00 25 01 75 01 95 08 81 02 05 07 75 08 95 01 81 03 05 07 15 00 25 01 19 00 29 67 75 01 95 68 81 02 c0 05 0c 09 01 a1 01 85 02 05 0c 15 00 26 ff 0f 19 00 2a ff 0f 75 10 95 06 81 00 c0 05 84 09 05 a1 01 05 85 85 05 09 44 15 00 25 01 35 00 45 01 75 08 95 01 81 02 09 65 15 00 25 64 35 00 45 64 75 08 95 01 81 02 c0 05 84 09 05 a1 01 05 85 85 06 09 44 15 00 25 01 35 00 45 01 75 08 95 01 81 02 09 65 15 00 25 64 35 00 45 64 75 08 95 01 81 02 c0 N: ZMK Project Dactyl 5x6 P: usb-0000:2d:00.3-4.2/input2 I: 3 1d50 615e D: 0 E: 0.000000 3 05 00 56 E: 0.000977 3 05 00 56 E: 1.490974 3 06 00 52 E: 1.491958 3 06 00 52 E: 6.492979 3 06 00 53 E: 6.493962 3 06 00 53 The recording shows both batteries reporting with different charge levels (Report ID 05: 86%, Report ID 06: 82%-83%), demonstrating the multi-battery functionality. This can be used to verify UPower compatibility. ## Future Work: Userspace Integration As suggested by Bastien, semantic battery differentiation (e.g., "left earbud" vs "right earbud") requires userspace coordination, as HID reports typically lack role metadata. This will require: 1. systemd/hwdb entries for device-specific battery role mappings 2. UPower updates to enumerate and group multi-battery devices 3. Desktop environment changes to display batteries with meaningful labels This kernel infrastructure is a prerequisite for that userspace work. Lucas Zampieri (2): HID: input: Convert battery code to devm_* HID: Refactor battery code to use struct hid_battery and add multi-battery support Signed-off-by: Lucas Zampieri Changes in v5: - Split the monolithic v4 patch into two logical patches as suggested by Benjamin, devm_* conversion, then struct refactor and multi-battery support combined Changes in v4: - Added missing hidinput_update_battery() stub in #else block for CONFIG_HID_BATTERY_STRENGTH=n builds - Reported-by: kernel test robot - Closes: https://lore.kernel.org/oe-kbuild-all/202511201624.yUv4VtBv-lkp@intel.com/ Changes in v3: - Squashed the three v2 patches into a single patch as suggested by Benjamin - Removed all legacy dev->battery_* fields, using list-based storage only - Changed battery naming to include report ID: hid-{uniq}-battery-{report_id} - Converted battery memory management to devm_* for automatic cleanup - Updated hidinput_update_battery() to take struct hid_battery directly - Added hid_get_first_battery() helper for external driver compatibility - Updated hid-apple.c and hid-magicmouse.c to use new battery API - Simplified cover letter based on feedback Changes in v2: - Split the monolithic v1 patch into three logical patches for easier review: 1. Introduce struct hid_battery (pure structure addition) 2. Refactor existing code to use the new structure (internal changes) 3. Add multi-battery support (new functionality) - Added detailed testing section with hardware specifics - Added hid-recorder output (dactyl-hid-recording.txt) demonstrating two-battery HID descriptor for UPower validation - Added "Future Work: Userspace Integration" section addressing Bastien's feedback about semantic battery differentiation - Added hardware examples with product links to commit messages (per Bastien's suggestion) - No functional changes from v1, only improved patch organization and documentation drivers/hid/hid-apple.c | 10 +- drivers/hid/hid-core.c | 4 + drivers/hid/hid-input-test.c | 39 ++++--- drivers/hid/hid-input.c | 196 ++++++++++++++++++----------------- drivers/hid/hid-magicmouse.c | 10 +- include/linux/hid.h | 54 +++++++--- 6 files changed, 180 insertions(+), 133 deletions(-) base-commit: 8b690556d8fe0ee15151cc37ec49c5bbfe41d5b1 -- 2.51.1