HID: lg-g15: Add keyboard and LCD backlight control

Register a led_classdev for the keyboard backlight and another one for
the LCD backlight.

This commit also includes LED_BRIGHT_HW_CHANGED support, which together
with a desktop-environment which supports this, such as GNOME3 leads to
the kbd-backlight OSD being show with the new level when changing the
backlight setting through the hotkey on the keyboard.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-lg-g15.c b/drivers/hid/hid-lg-g15.c
index 724dc06..1b6af52 100644 (file)
--- a/drivers/hid/hid-lg-g15.c
+++ b/drivers/hid/hid-lg-g15.c
@@ -17,19 +17,134 @@
 
 #define LG_G15_TRANSFER_BUF_SIZE       20
 
+#define LG_G15_FEATURE_REPORT          0x02
+
 enum lg_g15_model {
        LG_G15,
        LG_G15_V2,
 };
 
+enum lg_g15_led_type {
+       LG_G15_KBD_BRIGHTNESS,
+       LG_G15_LCD_BRIGHTNESS,
+       LG_G15_BRIGHTNESS_MAX,
+};
+
+struct lg_g15_led {
+       struct led_classdev cdev;
+       enum led_brightness brightness;
+       enum lg_g15_led_type led;
+};
+
 struct lg_g15_data {
        /* Must be first for proper dma alignment */
        u8 transfer_buf[LG_G15_TRANSFER_BUF_SIZE];
+       /* Protects the transfer_buf and led brightness */
+       struct mutex mutex;
+       struct work_struct work;
        struct input_dev *input;
        struct hid_device *hdev;
        enum lg_g15_model model;
+       struct lg_g15_led leds[LG_G15_BRIGHTNESS_MAX];
 };
 
+static int lg_g15_update_led_brightness(struct lg_g15_data *g15)
+{
+       int ret;
+
+       ret = hid_hw_raw_request(g15->hdev, LG_G15_FEATURE_REPORT,
+                                g15->transfer_buf, 4,
+                                HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+       if (ret != 4) {
+               hid_err(g15->hdev, "Error getting LED brightness: %d\n", ret);
+               return (ret < 0) ? ret : -EIO;
+       }
+
+       g15->leds[LG_G15_KBD_BRIGHTNESS].brightness = g15->transfer_buf[1];
+       g15->leds[LG_G15_LCD_BRIGHTNESS].brightness = g15->transfer_buf[2];
+       return 0;
+}
+
+static enum led_brightness lg_g15_led_get(struct led_classdev *led_cdev)
+{
+       struct lg_g15_led *g15_led =
+               container_of(led_cdev, struct lg_g15_led, cdev);
+       struct lg_g15_data *g15 = dev_get_drvdata(led_cdev->dev->parent);
+       enum led_brightness brightness;
+
+       mutex_lock(&g15->mutex);
+       lg_g15_update_led_brightness(g15);
+       brightness = g15->leds[g15_led->led].brightness;
+       mutex_unlock(&g15->mutex);
+
+       return brightness;
+}
+
+static int lg_g15_led_set(struct led_classdev *led_cdev,
+                         enum led_brightness brightness)
+{
+       struct lg_g15_led *g15_led =
+               container_of(led_cdev, struct lg_g15_led, cdev);
+       struct lg_g15_data *g15 = dev_get_drvdata(led_cdev->dev->parent);
+       int ret;
+
+       /* Ignore LED off on unregister / keyboard unplug */
+       if (led_cdev->flags & LED_UNREGISTERING)
+               return 0;
+
+       mutex_lock(&g15->mutex);
+
+       g15->transfer_buf[0] = LG_G15_FEATURE_REPORT;
+       g15->transfer_buf[1] = g15_led->led + 1;
+       g15->transfer_buf[2] = brightness << (g15_led->led * 4);
+       g15->transfer_buf[3] = 0;
+
+       ret = hid_hw_raw_request(g15->hdev, LG_G15_FEATURE_REPORT,
+                                g15->transfer_buf, 4,
+                                HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+       if (ret == 4) {
+               /* Success */
+               g15_led->brightness = brightness;
+               ret = 0;
+       } else {
+               hid_err(g15->hdev, "Error setting LED brightness: %d\n", ret);
+               ret = (ret < 0) ? ret : -EIO;
+       }
+
+       mutex_unlock(&g15->mutex);
+
+       return ret;
+}
+
+static void lg_g15_leds_changed_work(struct work_struct *work)
+{
+       struct lg_g15_data *g15 = container_of(work, struct lg_g15_data, work);
+       enum led_brightness old_brightness[LG_G15_BRIGHTNESS_MAX];
+       enum led_brightness brightness[LG_G15_BRIGHTNESS_MAX];
+       int i, ret;
+
+       mutex_lock(&g15->mutex);
+       for (i = 0; i < LG_G15_BRIGHTNESS_MAX; i++)
+               old_brightness[i] = g15->leds[i].brightness;
+
+       ret = lg_g15_update_led_brightness(g15);
+
+       for (i = 0; i < LG_G15_BRIGHTNESS_MAX; i++)
+               brightness[i] = g15->leds[i].brightness;
+       mutex_unlock(&g15->mutex);
+
+       if (ret)
+               return;
+
+       for (i = 0; i < LG_G15_BRIGHTNESS_MAX; i++) {
+               if (brightness[i] == old_brightness[i])
+                       continue;
+
+               led_classdev_notify_brightness_hw_changed(&g15->leds[i].cdev,
+                                                         brightness[i]);
+       }
+}
+
 /* On the G15 Mark I Logitech has been quite creative with which bit is what */
 static int lg_g15_event(struct lg_g15_data *g15, u8 *data, int size)
 {
@@ -69,6 +184,10 @@ static int lg_g15_event(struct lg_g15_data *g15, u8 *data, int size)
                input_report_key(g15->input, KEY_KBD_LCD_MENU2 + i, val);
        }
 
+       /* Backlight cycle button pressed? */
+       if (data[1] & 0x80)
+               schedule_work(&g15->work);
+
        input_sync(g15->input);
        return 0;
 }
@@ -97,6 +216,10 @@ static int lg_g15_v2_event(struct lg_g15_data *g15, u8 *data, int size)
                input_report_key(g15->input, KEY_KBD_LCD_MENU2 + i, val);
        }
 
+       /* Backlight cycle button pressed? */
+       if (data[2] & 0x01)
+               schedule_work(&g15->work);
+
        input_sync(g15->input);
        return 0;
 }
@@ -129,6 +252,23 @@ static void lg_g15_input_close(struct input_dev *dev)
        hid_hw_close(hdev);
 }
 
+static int lg_g15_register_led(struct lg_g15_data *g15, int i)
+{
+       const char * const led_names[] = {
+               "g15::kbd_backlight",
+               "g15::lcd_backlight",
+       };
+
+       g15->leds[i].led = i;
+       g15->leds[i].cdev.name = led_names[i];
+       g15->leds[i].cdev.brightness_set_blocking = lg_g15_led_set;
+       g15->leds[i].cdev.brightness_get = lg_g15_led_get;
+       g15->leds[i].cdev.flags = LED_BRIGHT_HW_CHANGED;
+       g15->leds[i].cdev.max_brightness = 2;
+
+       return devm_led_classdev_register(&g15->hdev->dev, &g15->leds[i].cdev);
+}
+
 static int lg_g15_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
        u8 gkeys_settings_output_report = 0;
@@ -145,12 +285,15 @@ static int lg_g15_probe(struct hid_device *hdev, const struct hid_device_id *id)
        if (!g15)
                return -ENOMEM;
 
+       mutex_init(&g15->mutex);
+
        input = devm_input_allocate_device(&hdev->dev);
        if (!input)
                return -ENOMEM;
 
        g15->hdev = hdev;
        g15->model = id->driver_data;
+       INIT_WORK(&g15->work, lg_g15_leds_changed_work);
        hid_set_drvdata(hdev, (void *)g15);
 
        switch (g15->model) {
@@ -196,6 +339,12 @@ static int lg_g15_probe(struct hid_device *hdev, const struct hid_device_id *id)
                goto error_hw_stop;
        }
 
+       /* Get initial brightness levels */
+       ret = lg_g15_update_led_brightness(g15);
+       if (ret)
+               goto error_hw_stop;
+
+       /* Setup and register input device */
        input->name = "Logitech Gaming Keyboard Gaming Keys";
        input->phys = hdev->phys;
        input->uniq = hdev->uniq;
@@ -227,6 +376,13 @@ static int lg_g15_probe(struct hid_device *hdev, const struct hid_device_id *id)
        if (ret)
                goto error_hw_stop;
 
+       /* Register LED devices */
+       for (i = 0; i < LG_G15_BRIGHTNESS_MAX; i++) {
+               ret = lg_g15_register_led(g15, i);
+               if (ret)
+                       goto error_hw_stop;
+       }
+
        return 0;
 
 error_hw_stop: