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path: root/drivers/usb/misc/apple-mfi-fastcharge.c
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Diffstat (limited to 'drivers/usb/misc/apple-mfi-fastcharge.c')
-rw-r--r--drivers/usb/misc/apple-mfi-fastcharge.c241
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/usb/misc/apple-mfi-fastcharge.c b/drivers/usb/misc/apple-mfi-fastcharge.c
new file mode 100644
index 000000000..ac8695195
--- /dev/null
+++ b/drivers/usb/misc/apple-mfi-fastcharge.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Fast-charge control for Apple "MFi" devices
+ *
+ * Copyright (C) 2019 Bastien Nocera <hadess@hadess.net>
+ */
+
+/* Standard include files */
+#include <linux/module.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
+MODULE_DESCRIPTION("Fast-charge control for Apple \"MFi\" devices");
+MODULE_LICENSE("GPL");
+
+#define TRICKLE_CURRENT_MA 0
+#define FAST_CURRENT_MA 2500
+
+#define APPLE_VENDOR_ID 0x05ac /* Apple */
+
+/* The product ID is defined as starting with 0x12nn, as per the
+ * "Choosing an Apple Device USB Configuration" section in
+ * release R9 (2012) of the "MFi Accessory Hardware Specification"
+ *
+ * To distinguish an Apple device, a USB host can check the device
+ * descriptor of attached USB devices for the following fields:
+ * ■ Vendor ID: 0x05AC
+ * ■ Product ID: 0x12nn
+ *
+ * Those checks will be done in .match() and .probe().
+ */
+
+static const struct usb_device_id mfi_fc_id_table[] = {
+ { .idVendor = APPLE_VENDOR_ID,
+ .match_flags = USB_DEVICE_ID_MATCH_VENDOR },
+ {},
+};
+
+MODULE_DEVICE_TABLE(usb, mfi_fc_id_table);
+
+/* Driver-local specific stuff */
+struct mfi_device {
+ struct usb_device *udev;
+ struct power_supply *battery;
+ int charge_type;
+};
+
+static int apple_mfi_fc_set_charge_type(struct mfi_device *mfi,
+ const union power_supply_propval *val)
+{
+ int current_ma;
+ int retval;
+ __u8 request_type;
+
+ if (mfi->charge_type == val->intval) {
+ dev_dbg(&mfi->udev->dev, "charge type %d already set\n",
+ mfi->charge_type);
+ return 0;
+ }
+
+ switch (val->intval) {
+ case POWER_SUPPLY_CHARGE_TYPE_TRICKLE:
+ current_ma = TRICKLE_CURRENT_MA;
+ break;
+ case POWER_SUPPLY_CHARGE_TYPE_FAST:
+ current_ma = FAST_CURRENT_MA;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ request_type = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE;
+ retval = usb_control_msg(mfi->udev, usb_sndctrlpipe(mfi->udev, 0),
+ 0x40, /* Vendor‐defined power request */
+ request_type,
+ current_ma, /* wValue, current offset */
+ current_ma, /* wIndex, current offset */
+ NULL, 0, USB_CTRL_GET_TIMEOUT);
+ if (retval) {
+ dev_dbg(&mfi->udev->dev, "retval = %d\n", retval);
+ return retval;
+ }
+
+ mfi->charge_type = val->intval;
+
+ return 0;
+}
+
+static int apple_mfi_fc_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct mfi_device *mfi = power_supply_get_drvdata(psy);
+
+ dev_dbg(&mfi->udev->dev, "prop: %d\n", psp);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_TYPE:
+ val->intval = mfi->charge_type;
+ break;
+ case POWER_SUPPLY_PROP_SCOPE:
+ val->intval = POWER_SUPPLY_SCOPE_DEVICE;
+ break;
+ default:
+ return -ENODATA;
+ }
+
+ return 0;
+}
+
+static int apple_mfi_fc_set_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ const union power_supply_propval *val)
+{
+ struct mfi_device *mfi = power_supply_get_drvdata(psy);
+ int ret;
+
+ dev_dbg(&mfi->udev->dev, "prop: %d\n", psp);
+
+ ret = pm_runtime_get_sync(&mfi->udev->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(&mfi->udev->dev);
+ return ret;
+ }
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_TYPE:
+ ret = apple_mfi_fc_set_charge_type(mfi, val);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ pm_runtime_mark_last_busy(&mfi->udev->dev);
+ pm_runtime_put_autosuspend(&mfi->udev->dev);
+
+ return ret;
+}
+
+static int apple_mfi_fc_property_is_writeable(struct power_supply *psy,
+ enum power_supply_property psp)
+{
+ switch (psp) {
+ case POWER_SUPPLY_PROP_CHARGE_TYPE:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static enum power_supply_property apple_mfi_fc_properties[] = {
+ POWER_SUPPLY_PROP_CHARGE_TYPE,
+ POWER_SUPPLY_PROP_SCOPE
+};
+
+static const struct power_supply_desc apple_mfi_fc_desc = {
+ .name = "apple_mfi_fastcharge",
+ .type = POWER_SUPPLY_TYPE_BATTERY,
+ .properties = apple_mfi_fc_properties,
+ .num_properties = ARRAY_SIZE(apple_mfi_fc_properties),
+ .get_property = apple_mfi_fc_get_property,
+ .set_property = apple_mfi_fc_set_property,
+ .property_is_writeable = apple_mfi_fc_property_is_writeable
+};
+
+static bool mfi_fc_match(struct usb_device *udev)
+{
+ int idProduct;
+
+ idProduct = le16_to_cpu(udev->descriptor.idProduct);
+ /* See comment above mfi_fc_id_table[] */
+ return (idProduct >= 0x1200 && idProduct <= 0x12ff);
+}
+
+static int mfi_fc_probe(struct usb_device *udev)
+{
+ struct power_supply_config battery_cfg = {};
+ struct mfi_device *mfi = NULL;
+ int err;
+
+ if (!mfi_fc_match(udev))
+ return -ENODEV;
+
+ mfi = kzalloc(sizeof(struct mfi_device), GFP_KERNEL);
+ if (!mfi)
+ return -ENOMEM;
+
+ battery_cfg.drv_data = mfi;
+
+ mfi->charge_type = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
+ mfi->battery = power_supply_register(&udev->dev,
+ &apple_mfi_fc_desc,
+ &battery_cfg);
+ if (IS_ERR(mfi->battery)) {
+ dev_err(&udev->dev, "Can't register battery\n");
+ err = PTR_ERR(mfi->battery);
+ kfree(mfi);
+ return err;
+ }
+
+ mfi->udev = usb_get_dev(udev);
+ dev_set_drvdata(&udev->dev, mfi);
+
+ return 0;
+}
+
+static void mfi_fc_disconnect(struct usb_device *udev)
+{
+ struct mfi_device *mfi;
+
+ mfi = dev_get_drvdata(&udev->dev);
+ if (mfi->battery)
+ power_supply_unregister(mfi->battery);
+ dev_set_drvdata(&udev->dev, NULL);
+ usb_put_dev(mfi->udev);
+ kfree(mfi);
+}
+
+static struct usb_device_driver mfi_fc_driver = {
+ .name = "apple-mfi-fastcharge",
+ .probe = mfi_fc_probe,
+ .disconnect = mfi_fc_disconnect,
+ .id_table = mfi_fc_id_table,
+ .match = mfi_fc_match,
+ .generic_subclass = 1,
+};
+
+static int __init mfi_fc_driver_init(void)
+{
+ return usb_register_device_driver(&mfi_fc_driver, THIS_MODULE);
+}
+
+static void __exit mfi_fc_driver_exit(void)
+{
+ usb_deregister_device_driver(&mfi_fc_driver);
+}
+
+module_init(mfi_fc_driver_init);
+module_exit(mfi_fc_driver_exit);