+struct wacom_sysfs_group_devres {
+ struct attribute_group *group;
+ struct kobject *root;
+};
+
+static void wacom_devm_sysfs_group_release(struct device *dev, void *res)
+{
+ struct wacom_sysfs_group_devres *devres = res;
+ struct kobject *kobj = devres->root;
+
+ dev_dbg(dev, "%s: dropping reference to %s\n",
+ __func__, devres->group->name);
+ sysfs_remove_group(kobj, devres->group);
+}
+
+static int __wacom_devm_sysfs_create_group(struct wacom *wacom,
+ struct kobject *root,
+ struct attribute_group *group)
+{
+ struct wacom_sysfs_group_devres *devres;
+ int error;
+
+ devres = devres_alloc(wacom_devm_sysfs_group_release,
+ sizeof(struct wacom_sysfs_group_devres),
+ GFP_KERNEL);
+ if (!devres)
+ return -ENOMEM;
+
+ devres->group = group;
+ devres->root = root;
+
+ error = sysfs_create_group(devres->root, group);
+ if (error)
+ return error;
+
+ devres_add(&wacom->hdev->dev, devres);
+
+ return 0;
+}
+
+static int wacom_devm_sysfs_create_group(struct wacom *wacom,
+ struct attribute_group *group)
+{
+ return __wacom_devm_sysfs_create_group(wacom, &wacom->hdev->dev.kobj,
+ group);
+}
+
+enum led_brightness wacom_leds_brightness_get(struct wacom_led *led)
+{
+ struct wacom *wacom = led->wacom;
+
+ if (wacom->led.max_hlv)
+ return led->hlv * LED_FULL / wacom->led.max_hlv;
+
+ if (wacom->led.max_llv)
+ return led->llv * LED_FULL / wacom->led.max_llv;
+
+ /* device doesn't support brightness tuning */
+ return LED_FULL;
+}
+
+static enum led_brightness __wacom_led_brightness_get(struct led_classdev *cdev)
+{
+ struct wacom_led *led = container_of(cdev, struct wacom_led, cdev);
+ struct wacom *wacom = led->wacom;
+
+ if (wacom->led.groups[led->group].select != led->id)
+ return LED_OFF;
+
+ return wacom_leds_brightness_get(led);
+}
+
+static int wacom_led_brightness_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct wacom_led *led = container_of(cdev, struct wacom_led, cdev);
+ struct wacom *wacom = led->wacom;
+ int error;
+
+ mutex_lock(&wacom->lock);
+
+ if (!wacom->led.groups || (brightness == LED_OFF &&
+ wacom->led.groups[led->group].select != led->id)) {
+ error = 0;
+ goto out;
+ }
+
+ led->llv = wacom->led.llv = wacom->led.max_llv * brightness / LED_FULL;
+ led->hlv = wacom->led.hlv = wacom->led.max_hlv * brightness / LED_FULL;
+
+ wacom->led.groups[led->group].select = led->id;
+
+ error = wacom_led_control(wacom);
+
+out:
+ mutex_unlock(&wacom->lock);
+
+ return error;
+}
+
+static void wacom_led_readonly_brightness_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+}
+
+static int wacom_led_register_one(struct device *dev, struct wacom *wacom,
+ struct wacom_led *led, unsigned int group,
+ unsigned int id, bool read_only)
+{
+ int error;
+ char *name;
+
+ name = devm_kasprintf(dev, GFP_KERNEL,
+ "%s::wacom-%d.%d",
+ dev_name(dev),
+ group,
+ id);
+ if (!name)
+ return -ENOMEM;
+
+ if (!read_only) {
+ led->trigger.name = name;
+ error = devm_led_trigger_register(dev, &led->trigger);
+ if (error) {
+ hid_err(wacom->hdev,
+ "failed to register LED trigger %s: %d\n",
+ led->cdev.name, error);
+ return error;
+ }
+ }
+
+ led->group = group;
+ led->id = id;
+ led->wacom = wacom;
+ led->llv = wacom->led.llv;
+ led->hlv = wacom->led.hlv;
+ led->cdev.name = name;
+ led->cdev.max_brightness = LED_FULL;
+ led->cdev.flags = LED_HW_PLUGGABLE;
+ led->cdev.brightness_get = __wacom_led_brightness_get;
+ if (!read_only) {
+ led->cdev.brightness_set_blocking = wacom_led_brightness_set;
+ led->cdev.default_trigger = led->cdev.name;
+ } else {
+ led->cdev.brightness_set = wacom_led_readonly_brightness_set;
+ }
+
+ error = devm_led_classdev_register(dev, &led->cdev);
+ if (error) {
+ hid_err(wacom->hdev,
+ "failed to register LED %s: %d\n",
+ led->cdev.name, error);
+ led->cdev.name = NULL;
+ return error;
+ }
+
+ return 0;
+}
+
+static void wacom_led_groups_release_one(void *data)
+{
+ struct wacom_group_leds *group = data;
+
+ devres_release_group(group->dev, group);
+}
+
+static int wacom_led_groups_alloc_and_register_one(struct device *dev,
+ struct wacom *wacom,
+ int group_id, int count,
+ bool read_only)
+{
+ struct wacom_led *leds;
+ int i, error;
+
+ if (group_id >= wacom->led.count || count <= 0)
+ return -EINVAL;
+
+ if (!devres_open_group(dev, &wacom->led.groups[group_id], GFP_KERNEL))
+ return -ENOMEM;
+
+ leds = devm_kzalloc(dev, sizeof(struct wacom_led) * count, GFP_KERNEL);
+ if (!leds) {
+ error = -ENOMEM;
+ goto err;
+ }
+
+ wacom->led.groups[group_id].leds = leds;
+ wacom->led.groups[group_id].count = count;
+
+ for (i = 0; i < count; i++) {
+ error = wacom_led_register_one(dev, wacom, &leds[i],
+ group_id, i, read_only);
+ if (error)
+ goto err;
+ }
+
+ wacom->led.groups[group_id].dev = dev;
+
+ devres_close_group(dev, &wacom->led.groups[group_id]);
+
+ /*
+ * There is a bug (?) in devm_led_classdev_register() in which its
+ * increments the refcount of the parent. If the parent is an input
+ * device, that means the ref count never reaches 0 when
+ * devm_input_device_release() gets called.
+ * This means that the LEDs are still there after disconnect.
+ * Manually force the release of the group so that the leds are released
+ * once we are done using them.
+ */
+ error = devm_add_action_or_reset(&wacom->hdev->dev,
+ wacom_led_groups_release_one,
+ &wacom->led.groups[group_id]);
+ if (error)
+ return error;
+
+ return 0;
+
+err:
+ devres_release_group(dev, &wacom->led.groups[group_id]);
+ return error;
+}
+
+struct wacom_led *wacom_led_find(struct wacom *wacom, unsigned int group_id,
+ unsigned int id)
+{
+ struct wacom_group_leds *group;
+
+ if (group_id >= wacom->led.count)
+ return NULL;
+
+ group = &wacom->led.groups[group_id];
+
+ if (!group->leds)
+ return NULL;
+
+ id %= group->count;
+
+ return &group->leds[id];
+}
+
+/**
+ * wacom_led_next: gives the next available led with a wacom trigger.
+ *
+ * returns the next available struct wacom_led which has its default trigger
+ * or the current one if none is available.
+ */
+struct wacom_led *wacom_led_next(struct wacom *wacom, struct wacom_led *cur)
+{
+ struct wacom_led *next_led;
+ int group, next;
+
+ if (!wacom || !cur)
+ return NULL;
+
+ group = cur->group;
+ next = cur->id;
+
+ do {
+ next_led = wacom_led_find(wacom, group, ++next);
+ if (!next_led || next_led == cur)
+ return next_led;
+ } while (next_led->cdev.trigger != &next_led->trigger);
+
+ return next_led;
+}
+
+static void wacom_led_groups_release(void *data)
+{
+ struct wacom *wacom = data;
+
+ wacom->led.groups = NULL;
+ wacom->led.count = 0;
+}
+
+static int wacom_led_groups_allocate(struct wacom *wacom, int count)
+{
+ struct device *dev = &wacom->hdev->dev;
+ struct wacom_group_leds *groups;
+ int error;
+
+ groups = devm_kzalloc(dev, sizeof(struct wacom_group_leds) * count,
+ GFP_KERNEL);
+ if (!groups)
+ return -ENOMEM;
+
+ error = devm_add_action_or_reset(dev, wacom_led_groups_release, wacom);
+ if (error)
+ return error;
+
+ wacom->led.groups = groups;
+ wacom->led.count = count;
+
+ return 0;
+}
+
+static int wacom_leds_alloc_and_register(struct wacom *wacom, int group_count,
+ int led_per_group, bool read_only)
+{
+ struct device *dev;
+ int i, error;
+
+ if (!wacom->wacom_wac.pad_input)
+ return -EINVAL;
+
+ dev = &wacom->wacom_wac.pad_input->dev;
+
+ error = wacom_led_groups_allocate(wacom, group_count);
+ if (error)
+ return error;
+
+ for (i = 0; i < group_count; i++) {
+ error = wacom_led_groups_alloc_and_register_one(dev, wacom, i,
+ led_per_group,
+ read_only);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+