1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Fast-charge control for Apple "MFi" devices |
4 | * |
5 | * Copyright (C) 2019 Bastien Nocera <hadess@hadess.net> |
6 | */ |
7 | |
8 | /* Standard include files */ |
9 | #include <linux/module.h> |
10 | #include <linux/power_supply.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/usb.h> |
13 | |
14 | MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>" ); |
15 | MODULE_DESCRIPTION("Fast-charge control for Apple \"MFi\" devices" ); |
16 | MODULE_LICENSE("GPL" ); |
17 | |
18 | #define TRICKLE_CURRENT_MA 0 |
19 | #define FAST_CURRENT_MA 2500 |
20 | |
21 | #define APPLE_VENDOR_ID 0x05ac /* Apple */ |
22 | |
23 | /* The product ID is defined as starting with 0x12nn, as per the |
24 | * "Choosing an Apple Device USB Configuration" section in |
25 | * release R9 (2012) of the "MFi Accessory Hardware Specification" |
26 | * |
27 | * To distinguish an Apple device, a USB host can check the device |
28 | * descriptor of attached USB devices for the following fields: |
29 | * ■ Vendor ID: 0x05AC |
30 | * ■ Product ID: 0x12nn |
31 | * |
32 | * Those checks will be done in .match() and .probe(). |
33 | */ |
34 | |
35 | static const struct usb_device_id mfi_fc_id_table[] = { |
36 | { .idVendor = APPLE_VENDOR_ID, |
37 | .match_flags = USB_DEVICE_ID_MATCH_VENDOR }, |
38 | {}, |
39 | }; |
40 | |
41 | MODULE_DEVICE_TABLE(usb, mfi_fc_id_table); |
42 | |
43 | /* Driver-local specific stuff */ |
44 | struct mfi_device { |
45 | struct usb_device *udev; |
46 | struct power_supply *battery; |
47 | int charge_type; |
48 | }; |
49 | |
50 | static int apple_mfi_fc_set_charge_type(struct mfi_device *mfi, |
51 | const union power_supply_propval *val) |
52 | { |
53 | int current_ma; |
54 | int retval; |
55 | __u8 request_type; |
56 | |
57 | if (mfi->charge_type == val->intval) { |
58 | dev_dbg(&mfi->udev->dev, "charge type %d already set\n" , |
59 | mfi->charge_type); |
60 | return 0; |
61 | } |
62 | |
63 | switch (val->intval) { |
64 | case POWER_SUPPLY_CHARGE_TYPE_TRICKLE: |
65 | current_ma = TRICKLE_CURRENT_MA; |
66 | break; |
67 | case POWER_SUPPLY_CHARGE_TYPE_FAST: |
68 | current_ma = FAST_CURRENT_MA; |
69 | break; |
70 | default: |
71 | return -EINVAL; |
72 | } |
73 | |
74 | request_type = USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE; |
75 | retval = usb_control_msg(dev: mfi->udev, usb_sndctrlpipe(mfi->udev, 0), |
76 | request: 0x40, /* Vendor‐defined power request */ |
77 | requesttype: request_type, |
78 | value: current_ma, /* wValue, current offset */ |
79 | index: current_ma, /* wIndex, current offset */ |
80 | NULL, size: 0, USB_CTRL_GET_TIMEOUT); |
81 | if (retval) { |
82 | dev_dbg(&mfi->udev->dev, "retval = %d\n" , retval); |
83 | return retval; |
84 | } |
85 | |
86 | mfi->charge_type = val->intval; |
87 | |
88 | return 0; |
89 | } |
90 | |
91 | static int apple_mfi_fc_get_property(struct power_supply *psy, |
92 | enum power_supply_property psp, |
93 | union power_supply_propval *val) |
94 | { |
95 | struct mfi_device *mfi = power_supply_get_drvdata(psy); |
96 | |
97 | dev_dbg(&mfi->udev->dev, "prop: %d\n" , psp); |
98 | |
99 | switch (psp) { |
100 | case POWER_SUPPLY_PROP_CHARGE_TYPE: |
101 | val->intval = mfi->charge_type; |
102 | break; |
103 | case POWER_SUPPLY_PROP_SCOPE: |
104 | val->intval = POWER_SUPPLY_SCOPE_DEVICE; |
105 | break; |
106 | default: |
107 | return -ENODATA; |
108 | } |
109 | |
110 | return 0; |
111 | } |
112 | |
113 | static int apple_mfi_fc_set_property(struct power_supply *psy, |
114 | enum power_supply_property psp, |
115 | const union power_supply_propval *val) |
116 | { |
117 | struct mfi_device *mfi = power_supply_get_drvdata(psy); |
118 | int ret; |
119 | |
120 | dev_dbg(&mfi->udev->dev, "prop: %d\n" , psp); |
121 | |
122 | ret = pm_runtime_get_sync(dev: &mfi->udev->dev); |
123 | if (ret < 0) { |
124 | pm_runtime_put_noidle(dev: &mfi->udev->dev); |
125 | return ret; |
126 | } |
127 | |
128 | switch (psp) { |
129 | case POWER_SUPPLY_PROP_CHARGE_TYPE: |
130 | ret = apple_mfi_fc_set_charge_type(mfi, val); |
131 | break; |
132 | default: |
133 | ret = -EINVAL; |
134 | } |
135 | |
136 | pm_runtime_mark_last_busy(dev: &mfi->udev->dev); |
137 | pm_runtime_put_autosuspend(dev: &mfi->udev->dev); |
138 | |
139 | return ret; |
140 | } |
141 | |
142 | static int apple_mfi_fc_property_is_writeable(struct power_supply *psy, |
143 | enum power_supply_property psp) |
144 | { |
145 | switch (psp) { |
146 | case POWER_SUPPLY_PROP_CHARGE_TYPE: |
147 | return 1; |
148 | default: |
149 | return 0; |
150 | } |
151 | } |
152 | |
153 | static enum power_supply_property apple_mfi_fc_properties[] = { |
154 | POWER_SUPPLY_PROP_CHARGE_TYPE, |
155 | POWER_SUPPLY_PROP_SCOPE |
156 | }; |
157 | |
158 | static const struct power_supply_desc apple_mfi_fc_desc = { |
159 | .name = "apple_mfi_fastcharge" , |
160 | .type = POWER_SUPPLY_TYPE_BATTERY, |
161 | .properties = apple_mfi_fc_properties, |
162 | .num_properties = ARRAY_SIZE(apple_mfi_fc_properties), |
163 | .get_property = apple_mfi_fc_get_property, |
164 | .set_property = apple_mfi_fc_set_property, |
165 | .property_is_writeable = apple_mfi_fc_property_is_writeable |
166 | }; |
167 | |
168 | static bool mfi_fc_match(struct usb_device *udev) |
169 | { |
170 | int idProduct; |
171 | |
172 | idProduct = le16_to_cpu(udev->descriptor.idProduct); |
173 | /* See comment above mfi_fc_id_table[] */ |
174 | return (idProduct >= 0x1200 && idProduct <= 0x12ff); |
175 | } |
176 | |
177 | static int mfi_fc_probe(struct usb_device *udev) |
178 | { |
179 | struct power_supply_config battery_cfg = {}; |
180 | struct mfi_device *mfi = NULL; |
181 | int err; |
182 | |
183 | if (!mfi_fc_match(udev)) |
184 | return -ENODEV; |
185 | |
186 | mfi = kzalloc(size: sizeof(struct mfi_device), GFP_KERNEL); |
187 | if (!mfi) |
188 | return -ENOMEM; |
189 | |
190 | battery_cfg.drv_data = mfi; |
191 | |
192 | mfi->charge_type = POWER_SUPPLY_CHARGE_TYPE_TRICKLE; |
193 | mfi->battery = power_supply_register(parent: &udev->dev, |
194 | desc: &apple_mfi_fc_desc, |
195 | cfg: &battery_cfg); |
196 | if (IS_ERR(ptr: mfi->battery)) { |
197 | dev_err(&udev->dev, "Can't register battery\n" ); |
198 | err = PTR_ERR(ptr: mfi->battery); |
199 | kfree(objp: mfi); |
200 | return err; |
201 | } |
202 | |
203 | mfi->udev = usb_get_dev(dev: udev); |
204 | dev_set_drvdata(dev: &udev->dev, data: mfi); |
205 | |
206 | return 0; |
207 | } |
208 | |
209 | static void mfi_fc_disconnect(struct usb_device *udev) |
210 | { |
211 | struct mfi_device *mfi; |
212 | |
213 | mfi = dev_get_drvdata(dev: &udev->dev); |
214 | if (mfi->battery) |
215 | power_supply_unregister(psy: mfi->battery); |
216 | dev_set_drvdata(dev: &udev->dev, NULL); |
217 | usb_put_dev(dev: mfi->udev); |
218 | kfree(objp: mfi); |
219 | } |
220 | |
221 | static struct usb_device_driver mfi_fc_driver = { |
222 | .name = "apple-mfi-fastcharge" , |
223 | .probe = mfi_fc_probe, |
224 | .disconnect = mfi_fc_disconnect, |
225 | .id_table = mfi_fc_id_table, |
226 | .match = mfi_fc_match, |
227 | .generic_subclass = 1, |
228 | }; |
229 | |
230 | static int __init mfi_fc_driver_init(void) |
231 | { |
232 | return usb_register_device_driver(&mfi_fc_driver, THIS_MODULE); |
233 | } |
234 | |
235 | static void __exit mfi_fc_driver_exit(void) |
236 | { |
237 | usb_deregister_device_driver(&mfi_fc_driver); |
238 | } |
239 | |
240 | module_init(mfi_fc_driver_init); |
241 | module_exit(mfi_fc_driver_exit); |
242 | |