The USB HID spec describes a number of LEDs that are currently
unsupported. For now, add only the micmute LED since this one is proven
to exist in actual devices. Since LED support via input-leds is
grandfathered, the new LED is added directly in hid-input.
Signed-off-by: Bernhard Seibold <mail@xxxxxxxxxxxxxxxxxxx>
---
drivers/hid/Kconfig | 11 +++++
drivers/hid/hid-input.c | 92 +++++++++++++++++++++++++++++++++++++++++
include/linux/hid.h | 1 +
3 files changed, 104 insertions(+)
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 4c682c650704..f8ed13d9740a 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -42,6 +42,17 @@ config HID_BATTERY_STRENGTH
that support this feature) through power_supply class so that userspace
tools, such as upower, can display it.
+config HID_LEDS
+ bool "LED support for HID devices"
+ select LEDS_CLASS
+ default y
+ help
+ This option adds support for LEDs on HID devices. Currently, the
+ only supported LED is microphone mute. For all other LEDs,
+ enable CONFIG_INPUT_LEDS.
+
+ If unsure, say Y.
+
config HIDRAW
bool "/dev/hidraw raw HID device support"
help
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index c8b20d44b147..32d3e6a2ac44 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -16,6 +16,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kernel.h>
+#include <linux/leds.h>
#include <linux/hid.h>
#include <linux/hid-debug.h>
@@ -104,6 +105,9 @@ static const struct usage_priority hidinput_usages_priorities[] = {
#define map_key_clear(c) hid_map_usage_clear(hidinput, usage, &bit, \
&max, EV_KEY, (c))
+#define setup_led(name, trigger) \
+ hidinput_setup_led(device, field, usage_index, name, trigger)
+
static bool match_scancode(struct hid_usage *usage,
unsigned int cur_idx, unsigned int scancode)
{
@@ -674,6 +678,88 @@ static bool hidinput_set_battery_charge_status(struct hid_device *dev,
}
#endif /* CONFIG_HID_BATTERY_STRENGTH */
+#ifdef CONFIG_HID_LEDS
+
+struct hid_led {
+ struct list_head list;
+ struct led_classdev cdev;
+ struct hid_field *field;
+ unsigned int offset;
+ char *name;
+};
+
+static int hidinput_led_brightness_set(struct led_classdev *cdev,
+ enum led_brightness value)
+{
+ struct device *dev = cdev->dev->parent;
+ struct hid_device *device = to_hid_device(dev);
+ struct hid_led *led = container_of(cdev, struct hid_led, cdev);
+
+ hid_set_field(led->field, led->offset, !!value);
+ schedule_work(&device->led_work);
+
+ return 0;
+}
+
+static void hidinput_setup_led(struct hid_device *device,
+ struct hid_field *field, unsigned int offset,
+ const char *name, const char *trigger)
+{
+ struct hid_led *led;
+ struct device *dev = &device->dev;
+ struct device *idev = &field->hidinput->input->dev;
+
+ led = kzalloc(sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return;
+
+ led->name = kasprintf(GFP_KERNEL, "%s::%s", dev_name(idev), name);
+ if (!led->name) {
+ kfree(led);
+ return;
+ }
+
+ led->cdev.name = led->name;
+ led->cdev.default_trigger = trigger;
+ led->cdev.max_brightness = 1;
+ led->cdev.brightness_set_blocking = hidinput_led_brightness_set;
+ led->field = field;
+ led->offset = offset;
+
+ if (led_classdev_register(dev, &led->cdev)) {
+ kfree(name);
+ kfree(led);
+ return;
+ }
+
+ list_add_tail(&led->list, &device->leds);
+}
+
+static void hidinput_cleanup_leds(struct hid_device *device)
+{
+ struct hid_led *led, *tmp;
+
+ list_for_each_entry_safe(led, tmp, &device->leds, list) {
+ led_classdev_unregister(&led->cdev);
+ kfree(led->name);
+ kfree(led);
+ }
+}
+
+#else /* !CONFIG_HID_LEDS */
+
+static void hidinput_setup_led(struct hid_device *device,
+ struct hid_field *field, unsigned int offset,
+ const char *name, const char *trigger)
+{
+}
+
+static void hidinput_cleanup_leds(struct hid_device *device)
+{
+}
+
+#endif /* CONFIG_HID_LEDS */
+
static bool hidinput_field_in_collection(struct hid_device *device, struct hid_field *field,
unsigned int type, unsigned int usage)
{
@@ -935,6 +1021,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
case 0x19: map_led (LED_MAIL); break; /* "Message Waiting" */
case 0x4d: map_led (LED_CHARGING); break; /* "External Power Connected" */
+ case 0x21: /* "Microphone" */
+ setup_led("micmute", "audio-micmute");
+ break;
+
default: goto ignore;
}
break;
@@ -2282,6 +2372,7 @@ int hidinput_connect(struct hid_device *hid, unsigned int force)
int i, k;
INIT_LIST_HEAD(&hid->inputs);
+ INIT_LIST_HEAD(&hid->leds);
INIT_WORK(&hid->led_work, hidinput_led_worker);
hid->status &= ~HID_STAT_DUP_DETECTED;
@@ -2380,6 +2471,7 @@ void hidinput_disconnect(struct hid_device *hid)
{
struct hid_input *hidinput, *next;
+ hidinput_cleanup_leds(hid);
hidinput_cleanup_battery(hid);
list_for_each_entry_safe(hidinput, next, &hid->inputs, list) {
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 7c26db874ff0..7c0e2789755f 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -617,6 +617,7 @@ struct hid_device { /* device report descriptor */
unsigned country; /* HID country */
struct hid_report_enum report_enum[HID_REPORT_TYPES];
struct work_struct led_work; /* delayed LED worker */
+ struct list_head leds; /* List of associated LEDs */
struct semaphore driver_input_lock; /* protects the current driver */
struct device dev; /* device */
--
2.43.0
