diff options
Diffstat (limited to 'drivers/usb/misc/apple-mfi-fastcharge.c')
| -rw-r--r-- | drivers/usb/misc/apple-mfi-fastcharge.c | 237 |
1 files changed, 237 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 000000000000..b403094a6b3a --- /dev/null +++ b/drivers/usb/misc/apple-mfi-fastcharge.c @@ -0,0 +1,237 @@ +// 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) + 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 int mfi_fc_probe(struct usb_device *udev) +{ + struct power_supply_config battery_cfg = {}; + struct mfi_device *mfi = NULL; + int err, idProduct; + + idProduct = le16_to_cpu(udev->descriptor.idProduct); + /* See comment above mfi_fc_id_table[] */ + if (idProduct < 0x1200 || idProduct > 0x12ff) { + return -ENODEV; + } + + mfi = kzalloc(sizeof(struct mfi_device), GFP_KERNEL); + if (!mfi) { + err = -ENOMEM; + goto error; + } + + 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); + goto error; + } + + mfi->udev = usb_get_dev(udev); + dev_set_drvdata(&udev->dev, mfi); + + return 0; + +error: + kfree(mfi); + return err; +} + +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, + .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); |