[PATCH v2 3/5] HID: magicmouse: Magic Trackpad 2 USB battery capacity

From: José Expósito
Date: Sat May 22 2021 - 14:06:46 EST


Report the battery capacity percentage for the Apple Magic Trackpad 2
when it is connected over USB.

Signed-off-by: José Expósito <jose.exposito89@xxxxxxxxx>
---
drivers/hid/Kconfig | 2 +-
drivers/hid/hid-magicmouse.c | 136 +++++++++++++++++++++++++++++++++++
2 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 4bf263c2d61a..f4856e5f5aa4 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -640,7 +640,7 @@ config LOGIWHEELS_FF

config HID_MAGICMOUSE
tristate "Apple Magic Mouse/Trackpad multi-touch support"
- depends on HID
+ depends on USB_HID
help
Support for the Apple Magic Mouse/Trackpad multi-touch.

diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
index d4a58dd6d2b8..ea8a85767c39 100644
--- a/drivers/hid/hid-magicmouse.c
+++ b/drivers/hid/hid-magicmouse.c
@@ -16,6 +16,7 @@
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/usb.h>
#include <linux/workqueue.h>

#include "hid-ids.h"
@@ -58,6 +59,7 @@ MODULE_PARM_DESC(report_undeciphered, "Report undeciphered multi-touch state fie
#define MOUSE2_REPORT_ID 0x12
#define DOUBLE_REPORT_ID 0xf7
#define BT_BATTERY_REPORT_ID 0x90
+#define USB_BATTERY_EP_ADDR 0x81

/* These definitions are not precise, but they're close enough. (Bits
* 0x03 seem to indicate the aspect ratio of the touch, bits 0x70 seem
@@ -142,6 +144,10 @@ struct magicmouse_sc {
struct power_supply *ps;
struct power_supply_desc ps_desc;
int capacity;
+ struct urb *urb;
+ u8 *urb_buf;
+ int urb_buf_size;
+ dma_addr_t urb_buf_dma;
} battery;
};

@@ -231,6 +237,112 @@ static int magicmouse_battery_get_property(struct power_supply *psy,
return ret;
}

+static void magicmouse_battery_usb_urb_complete(struct urb *urb)
+{
+ struct magicmouse_sc *msc = urb->context;
+ int ret;
+
+ switch (urb->status) {
+ case 0:
+ msc->battery.capacity = msc->battery.urb_buf[2];
+ break;
+ case -EOVERFLOW:
+ hid_err(msc->hdev, "URB overflow\n");
+ fallthrough;
+ case -ECONNRESET:
+ case -ENOENT:
+ case -ESHUTDOWN:
+ return;
+ default:
+ break;
+ }
+
+ ret = usb_submit_urb(msc->battery.urb, GFP_ATOMIC);
+ if (ret)
+ hid_err(msc->hdev, "unable to submit URB, %d\n", ret);
+}
+
+static int magicmouse_battery_usb_probe(struct magicmouse_sc *msc)
+{
+ struct usb_interface *iface = to_usb_interface(msc->hdev->dev.parent);
+ struct usb_device *usbdev = interface_to_usbdev(iface);
+ struct usb_host_endpoint *endpoint = NULL;
+ u8 ep_address;
+ unsigned int pipe = 0;
+ int i, ret;
+
+ if (!magicmouse_can_report_battery_vendor(msc, USB_VENDOR_ID_APPLE))
+ return -EINVAL;
+
+ for (i = 0; i < sizeof(usbdev->ep_in); i++) {
+ endpoint = usbdev->ep_in[i];
+ if (endpoint) {
+ ep_address = endpoint->desc.bEndpointAddress;
+ if (ep_address == USB_BATTERY_EP_ADDR)
+ break;
+ }
+ }
+
+ if (!endpoint) {
+ hid_err(msc->hdev, "endpoint with address %d not found\n",
+ USB_BATTERY_EP_ADDR);
+ ret = -EIO;
+ goto exit;
+ }
+
+ msc->battery.urb = usb_alloc_urb(0, GFP_ATOMIC);
+ if (!msc->battery.urb) {
+ hid_err(msc->hdev, "unable to alloc URB, ENOMEM\n");
+ ret = -ENOMEM;
+ goto exit;
+ }
+
+ pipe = usb_rcvintpipe(usbdev, endpoint->desc.bEndpointAddress);
+ if (pipe == 0) {
+ hid_err(msc->hdev, "unable to create USB rcvintpipe\n");
+ ret = -EIO;
+ goto err_free_urb;
+ }
+
+ msc->battery.urb_buf_size = endpoint->desc.wMaxPacketSize;
+ msc->battery.urb_buf_dma = msc->battery.urb->transfer_dma;
+ msc->battery.urb_buf = usb_alloc_coherent(usbdev,
+ msc->battery.urb_buf_size, GFP_ATOMIC,
+ &msc->battery.urb_buf_dma);
+ if (!msc->battery.urb_buf) {
+ hid_err(msc->hdev, "unable to alloc URB buffer, ENOMEM\n");
+ ret = -ENOMEM;
+ goto err_free_urb;
+ }
+
+ usb_fill_int_urb(msc->battery.urb, usbdev, pipe, msc->battery.urb_buf,
+ msc->battery.urb_buf_size,
+ magicmouse_battery_usb_urb_complete, msc,
+ endpoint->desc.bInterval);
+
+ ret = usb_submit_urb(msc->battery.urb, GFP_ATOMIC);
+ if (ret) {
+ hid_err(msc->hdev, "unable to submit URB, %d\n", ret);
+ goto err_free_urb_buf;
+ }
+
+ return 0;
+
+err_free_urb_buf:
+ usb_free_coherent(usbdev, msc->battery.urb_buf_size,
+ msc->battery.urb_buf, msc->battery.urb_buf_dma);
+
+err_free_urb:
+ usb_free_urb(msc->battery.urb);
+
+exit:
+ msc->battery.urb = NULL;
+ msc->battery.urb_buf = NULL;
+ msc->battery.urb_buf_size = 0;
+
+ return ret;
+}
+
static int magicmouse_battery_probe(struct hid_device *hdev)
{
struct magicmouse_sc *msc = hid_get_drvdata(hdev);
@@ -269,6 +381,12 @@ static int magicmouse_battery_probe(struct hid_device *hdev)
return ret;
}

+ if (msc->input->id.vendor == USB_VENDOR_ID_APPLE) {
+ ret = magicmouse_battery_usb_probe(msc);
+ if (ret)
+ return ret;
+ }
+
return 0;
}

@@ -923,7 +1041,25 @@ static int magicmouse_probe(struct hid_device *hdev,
static void magicmouse_remove(struct hid_device *hdev)
{
struct magicmouse_sc *msc = hid_get_drvdata(hdev);
+ struct usb_interface *iface;
+ struct usb_device *usbdev;
cancel_delayed_work_sync(&msc->work);
+
+ if (msc &&
+ magicmouse_can_report_battery_vendor(msc, USB_VENDOR_ID_APPLE) &&
+ msc->battery.urb && msc->battery.urb_buf) {
+ iface = to_usb_interface(hdev->dev.parent);
+ usbdev = interface_to_usbdev(iface);
+
+ usb_kill_urb(msc->battery.urb);
+
+ usb_free_coherent(usbdev, msc->battery.urb_buf_size,
+ msc->battery.urb_buf,
+ msc->battery.urb_buf_dma);
+
+ usb_free_urb(msc->battery.urb);
+ }
+
hid_hw_stop(hdev);
}

--
2.25.1