1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * USB port LED trigger
4 *
5 * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
6 */
7
8 #include <linux/device.h>
9 #include <linux/leds.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/slab.h>
13 #include <linux/usb.h>
14 #include <linux/usb/of.h>
15
16 struct usbport_trig_data {
17 struct led_classdev *led_cdev;
18 struct list_head ports;
19 struct notifier_block nb;
20 int count; /* Amount of connected matching devices */
21 };
22
23 struct usbport_trig_port {
24 struct usbport_trig_data *data;
25 struct usb_device *hub;
26 int portnum;
27 char *port_name;
28 bool observed;
29 struct device_attribute attr;
30 struct list_head list;
31 };
32
33 /***************************************
34 * Helpers
35 ***************************************/
36
37 /*
38 * usbport_trig_usb_dev_observed - Check if dev is connected to observed port
39 */
usbport_trig_usb_dev_observed(struct usbport_trig_data * usbport_data,struct usb_device * usb_dev)40 static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data,
41 struct usb_device *usb_dev)
42 {
43 struct usbport_trig_port *port;
44
45 if (!usb_dev->parent)
46 return false;
47
48 list_for_each_entry(port, &usbport_data->ports, list) {
49 if (usb_dev->parent == port->hub &&
50 usb_dev->portnum == port->portnum)
51 return port->observed;
52 }
53
54 return false;
55 }
56
usbport_trig_usb_dev_check(struct usb_device * usb_dev,void * data)57 static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data)
58 {
59 struct usbport_trig_data *usbport_data = data;
60
61 if (usbport_trig_usb_dev_observed(usbport_data, usb_dev))
62 usbport_data->count++;
63
64 return 0;
65 }
66
67 /*
68 * usbport_trig_update_count - Recalculate amount of connected matching devices
69 */
usbport_trig_update_count(struct usbport_trig_data * usbport_data)70 static void usbport_trig_update_count(struct usbport_trig_data *usbport_data)
71 {
72 struct led_classdev *led_cdev = usbport_data->led_cdev;
73
74 usbport_data->count = 0;
75 usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check);
76 led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF);
77 }
78
79 /***************************************
80 * Device attr
81 ***************************************/
82
usbport_trig_port_show(struct device * dev,struct device_attribute * attr,char * buf)83 static ssize_t usbport_trig_port_show(struct device *dev,
84 struct device_attribute *attr, char *buf)
85 {
86 struct usbport_trig_port *port = container_of(attr,
87 struct usbport_trig_port,
88 attr);
89
90 return sprintf(buf, "%d\n", port->observed) + 1;
91 }
92
usbport_trig_port_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)93 static ssize_t usbport_trig_port_store(struct device *dev,
94 struct device_attribute *attr,
95 const char *buf, size_t size)
96 {
97 struct usbport_trig_port *port = container_of(attr,
98 struct usbport_trig_port,
99 attr);
100
101 if (!strcmp(buf, "0") || !strcmp(buf, "0\n"))
102 port->observed = 0;
103 else if (!strcmp(buf, "1") || !strcmp(buf, "1\n"))
104 port->observed = 1;
105 else
106 return -EINVAL;
107
108 usbport_trig_update_count(port->data);
109
110 return size;
111 }
112
113 static struct attribute *ports_attrs[] = {
114 NULL,
115 };
116
117 static const struct attribute_group ports_group = {
118 .name = "ports",
119 .attrs = ports_attrs,
120 };
121
122 /***************************************
123 * Adding & removing ports
124 ***************************************/
125
126 /*
127 * usbport_trig_port_observed - Check if port should be observed
128 */
usbport_trig_port_observed(struct usbport_trig_data * usbport_data,struct usb_device * usb_dev,int port1)129 static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data,
130 struct usb_device *usb_dev, int port1)
131 {
132 struct device *dev = usbport_data->led_cdev->dev;
133 struct device_node *led_np = dev->of_node;
134 struct of_phandle_args args;
135 struct device_node *port_np;
136 int count, i;
137
138 if (!led_np)
139 return false;
140
141 /*
142 * Get node of port being added
143 *
144 * FIXME: This is really the device node of the connected device
145 */
146 port_np = usb_of_get_device_node(usb_dev, port1);
147 if (!port_np)
148 return false;
149
150 of_node_put(port_np);
151
152 /* Amount of trigger sources for this LED */
153 count = of_count_phandle_with_args(led_np, "trigger-sources",
154 "#trigger-source-cells");
155 if (count < 0) {
156 dev_warn(dev, "Failed to get trigger sources for %pOF\n",
157 led_np);
158 return false;
159 }
160
161 /* Check list of sources for this specific port */
162 for (i = 0; i < count; i++) {
163 int err;
164
165 err = of_parse_phandle_with_args(led_np, "trigger-sources",
166 "#trigger-source-cells", i,
167 &args);
168 if (err) {
169 dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n",
170 i, err);
171 continue;
172 }
173
174 of_node_put(args.np);
175
176 if (args.np == port_np)
177 return true;
178 }
179
180 return false;
181 }
182
usbport_trig_add_port(struct usbport_trig_data * usbport_data,struct usb_device * usb_dev,const char * hub_name,int portnum)183 static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
184 struct usb_device *usb_dev,
185 const char *hub_name, int portnum)
186 {
187 struct led_classdev *led_cdev = usbport_data->led_cdev;
188 struct usbport_trig_port *port;
189 size_t len;
190 int err;
191
192 port = kzalloc(sizeof(*port), GFP_KERNEL);
193 if (!port) {
194 err = -ENOMEM;
195 goto err_out;
196 }
197
198 port->data = usbport_data;
199 port->hub = usb_dev;
200 port->portnum = portnum;
201 port->observed = usbport_trig_port_observed(usbport_data, usb_dev,
202 portnum);
203
204 len = strlen(hub_name) + 8;
205 port->port_name = kzalloc(len, GFP_KERNEL);
206 if (!port->port_name) {
207 err = -ENOMEM;
208 goto err_free_port;
209 }
210 snprintf(port->port_name, len, "%s-port%d", hub_name, portnum);
211
212 sysfs_attr_init(&port->attr.attr);
213 port->attr.attr.name = port->port_name;
214 port->attr.attr.mode = S_IRUSR | S_IWUSR;
215 port->attr.show = usbport_trig_port_show;
216 port->attr.store = usbport_trig_port_store;
217
218 err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr,
219 ports_group.name);
220 if (err)
221 goto err_free_port_name;
222
223 list_add_tail(&port->list, &usbport_data->ports);
224
225 return 0;
226
227 err_free_port_name:
228 kfree(port->port_name);
229 err_free_port:
230 kfree(port);
231 err_out:
232 return err;
233 }
234
usbport_trig_add_usb_dev_ports(struct usb_device * usb_dev,void * data)235 static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev,
236 void *data)
237 {
238 struct usbport_trig_data *usbport_data = data;
239 int i;
240
241 for (i = 1; i <= usb_dev->maxchild; i++)
242 usbport_trig_add_port(usbport_data, usb_dev,
243 dev_name(&usb_dev->dev), i);
244
245 return 0;
246 }
247
usbport_trig_remove_port(struct usbport_trig_data * usbport_data,struct usbport_trig_port * port)248 static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data,
249 struct usbport_trig_port *port)
250 {
251 struct led_classdev *led_cdev = usbport_data->led_cdev;
252
253 list_del(&port->list);
254 sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr,
255 ports_group.name);
256 kfree(port->port_name);
257 kfree(port);
258 }
259
usbport_trig_remove_usb_dev_ports(struct usbport_trig_data * usbport_data,struct usb_device * usb_dev)260 static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data,
261 struct usb_device *usb_dev)
262 {
263 struct usbport_trig_port *port, *tmp;
264
265 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
266 if (port->hub == usb_dev)
267 usbport_trig_remove_port(usbport_data, port);
268 }
269 }
270
271 /***************************************
272 * Init, exit, etc.
273 ***************************************/
274
usbport_trig_notify(struct notifier_block * nb,unsigned long action,void * data)275 static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
276 void *data)
277 {
278 struct usbport_trig_data *usbport_data =
279 container_of(nb, struct usbport_trig_data, nb);
280 struct led_classdev *led_cdev = usbport_data->led_cdev;
281 struct usb_device *usb_dev = data;
282 bool observed;
283
284 observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev);
285
286 switch (action) {
287 case USB_DEVICE_ADD:
288 usbport_trig_add_usb_dev_ports(usb_dev, usbport_data);
289 if (observed && usbport_data->count++ == 0)
290 led_set_brightness(led_cdev, LED_FULL);
291 return NOTIFY_OK;
292 case USB_DEVICE_REMOVE:
293 usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev);
294 if (observed && --usbport_data->count == 0)
295 led_set_brightness(led_cdev, LED_OFF);
296 return NOTIFY_OK;
297 }
298
299 return NOTIFY_DONE;
300 }
301
usbport_trig_activate(struct led_classdev * led_cdev)302 static int usbport_trig_activate(struct led_classdev *led_cdev)
303 {
304 struct usbport_trig_data *usbport_data;
305 int err;
306
307 usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
308 if (!usbport_data)
309 return -ENOMEM;
310 usbport_data->led_cdev = led_cdev;
311
312 /* List of ports */
313 INIT_LIST_HEAD(&usbport_data->ports);
314 err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group);
315 if (err)
316 goto err_free;
317 usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
318 usbport_trig_update_count(usbport_data);
319
320 /* Notifications */
321 usbport_data->nb.notifier_call = usbport_trig_notify;
322 led_set_trigger_data(led_cdev, usbport_data);
323 usb_register_notify(&usbport_data->nb);
324 return 0;
325
326 err_free:
327 kfree(usbport_data);
328 return err;
329 }
330
usbport_trig_deactivate(struct led_classdev * led_cdev)331 static void usbport_trig_deactivate(struct led_classdev *led_cdev)
332 {
333 struct usbport_trig_data *usbport_data = led_get_trigger_data(led_cdev);
334 struct usbport_trig_port *port, *tmp;
335
336 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
337 usbport_trig_remove_port(usbport_data, port);
338 }
339
340 sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
341
342 usb_unregister_notify(&usbport_data->nb);
343
344 kfree(usbport_data);
345 }
346
347 static struct led_trigger usbport_led_trigger = {
348 .name = "usbport",
349 .activate = usbport_trig_activate,
350 .deactivate = usbport_trig_deactivate,
351 };
352
353 module_led_trigger(usbport_led_trigger);
354
355 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
356 MODULE_DESCRIPTION("USB port trigger");
357 MODULE_LICENSE("GPL v2");
358