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([37.100.201.144]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488ede1df12sm315334375e9.4.2026.04.15.08.56.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 08:56:07 -0700 (PDT) From: Damiano Gragnaniello To: Jiri Kosina , Benjamin Tissoires Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Damiano Gragnaniello , Jiri Kosina , Benjamin Tissoires Subject: [PATCH] HID: magicmouse: add battery reporting for Magic Trackpad v1 Date: Wed, 15 Apr 2026 17:55:48 +0200 Message-ID: <20260415155548.927385-1-damianogragnaniello@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The Magic Trackpad v1 (USB_DEVICE_ID_APPLE_MAGICTRACKPAD, 0x030e) connects over Bluetooth and uses two AA batteries. When the device sends Report ID 0x47, byte 1 carries the battery level as a percentage (0-100) already expressed in firmware units. This patch: - Registers a power_supply instance via devm_power_supply_register() during probe() for the v1 trackpad only (BT, vendor 0x05ac). - Parses Report ID 0x47 in magicmouse_raw_event() and calls power_supply_changed() to propagate the value to userspace. - Exposes PRESENT, CAPACITY, SCOPE and STATUS properties, consistent with how hid-sony and hid-logitech-hidpp expose battery data. - Registration failure is treated as non-fatal so the input device continues to work even if power_supply cannot be allocated. Tested on Linux Mint / kernel 6.17 with an Apple Magic Trackpad A1339 (first generation, AA cells, firmware 0x0291). Note: Technical analysis and initial boilerplate structure were assisted by=20 Claude (Anthropic AI). The logic has been manually verified against hardwar= e=20 descriptors (rdesc) and tested on physical A1339 hardware. Cc: Jiri Kosina Cc: Benjamin Tissoires Signed-off-by: Damiano Gragnaniello --- --- /home/claude/hid-patch/hid-magicmouse.c.orig 2026-04-15 13:34:50.358612= 695 +0000 +++ /home/claude/hid-patch/hid-magicmouse.c 2026-04-15 13:35:39.402309524 += 0000 @@ -15,6 +15,7 @@ #include #include #include +#include #include #include =20 @@ -60,6 +61,7 @@ #define MOUSE_REPORT_ID 0x29 #define MOUSE2_REPORT_ID 0x12 #define DOUBLE_REPORT_ID 0xf7 +#define TRACKPAD_V1_BATTERY_REPORT_ID 0x47 #define USB_BATTERY_TIMEOUT_SEC 60 =20 /* These definitions are not precise, but they're close enough. (Bits @@ -124,6 +126,10 @@ * @hdev: Pointer to the underlying HID device. * @work: Workqueue to handle initialization retry for quirky devices. * @battery_timer: Timer for obtaining battery level information. + * @battery: Power supply instance for Magic Trackpad v1 AA battery report= ing. + * @battery_desc: Descriptor for the power_supply registration. + * @battery_name: Name buffer for the power_supply instance. + * @battery_capacity: Last known battery level (0-100%) for Magic Trackpad= v1. */ struct magicmouse_sc { struct input_dev *input; @@ -149,8 +155,46 @@ struct hid_device *hdev; struct delayed_work work; struct timer_list battery_timer; + + /* Magic Trackpad v1 (AA battery) power_supply support */ + struct power_supply *battery; + struct power_supply_desc battery_desc; + char battery_name[64]; + int battery_capacity; +}; + +static const enum power_supply_property magicmouse_v1_battery_props[] =3D { + POWER_SUPPLY_PROP_PRESENT, + POWER_SUPPLY_PROP_CAPACITY, + POWER_SUPPLY_PROP_SCOPE, + POWER_SUPPLY_PROP_STATUS, }; =20 +static int magicmouse_v1_battery_get_property(struct power_supply *psy, + enum power_supply_property psp, + union power_supply_propval *val) +{ + struct magicmouse_sc *msc =3D power_supply_get_drvdata(psy); + + switch (psp) { + case POWER_SUPPLY_PROP_PRESENT: + val->intval =3D 1; + break; + case POWER_SUPPLY_PROP_CAPACITY: + val->intval =3D msc->battery_capacity; + break; + case POWER_SUPPLY_PROP_SCOPE: + val->intval =3D POWER_SUPPLY_SCOPE_DEVICE; + break; + case POWER_SUPPLY_PROP_STATUS: + val->intval =3D POWER_SUPPLY_STATUS_DISCHARGING; + break; + default: + return -EINVAL; + } + return 0; +} + static int magicmouse_firm_touch(struct magicmouse_sc *msc) { int touch =3D -1; @@ -391,6 +435,19 @@ int x =3D 0, y =3D 0, ii, clicks =3D 0, npoints; =20 switch (data[0]) { + case TRACKPAD_V1_BATTERY_REPORT_ID: + /* + * Magic Trackpad v1 (AA battery, 0x030e) sends battery level + * in byte 1, already expressed as a percentage (0-100). + * Clamp defensively and notify the power_supply framework. + */ + if (size < 2) + return 0; + if (msc->battery) { + msc->battery_capacity =3D clamp_val((int)data[1], 0, 100); + power_supply_changed(msc->battery); + } + return 0; case TRACKPAD_REPORT_ID: case TRACKPAD2_BT_REPORT_ID: /* Expect four bytes of prefix, and N*9 bytes of touch data. */ @@ -890,6 +947,38 @@ magicmouse_fetch_battery(hdev); } =20 + /* Register power_supply for Magic Trackpad v1 (AA battery, BT only) */ + if (id->product =3D=3D USB_DEVICE_ID_APPLE_MAGICTRACKPAD && + id->vendor =3D=3D USB_VENDOR_ID_APPLE) { + struct power_supply_config psy_cfg =3D {}; + + msc->battery_capacity =3D 0; + snprintf(msc->battery_name, sizeof(msc->battery_name), + "hid-magictrackpad-v1-%s", dev_name(&hdev->dev)); + + msc->battery_desc.name =3D msc->battery_name; + msc->battery_desc.type =3D POWER_SUPPLY_TYPE_BATTERY; + msc->battery_desc.properties =3D magicmouse_v1_battery_props; + msc->battery_desc.num_properties =3D + ARRAY_SIZE(magicmouse_v1_battery_props); + msc->battery_desc.get_property =3D + magicmouse_v1_battery_get_property; + + psy_cfg.drv_data =3D msc; + + msc->battery =3D devm_power_supply_register(&hdev->dev, + &msc->battery_desc, + &psy_cfg); + if (IS_ERR(msc->battery)) { + ret =3D PTR_ERR(msc->battery); + hid_err(hdev, + "unable to register trackpad v1 battery: %d\n", + ret); + msc->battery =3D NULL; + /* Non-fatal: continue without battery reporting */ + } + } + if (is_usb_magicmouse2(id->vendor, id->product) || (is_usb_magictrackpad2(id->vendor, id->product) && hdev->type !=3D HID_TYPE_USBMOUSE))