v4.19.13 snapshot.
diff --git a/drivers/hid/hid-picolcd_backlight.c b/drivers/hid/hid-picolcd_backlight.c
new file mode 100644
index 0000000..808807a
--- /dev/null
+++ b/drivers/hid/hid-picolcd_backlight.c
@@ -0,0 +1,119 @@
+/***************************************************************************
+ * Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org> *
+ * *
+ * Based on Logitech G13 driver (v0.4) *
+ * Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu> *
+ * *
+ * This program is free software: you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation, version 2 of the License. *
+ * *
+ * This driver is distributed in the hope that it will be useful, but *
+ * WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
+ * General Public License for more details. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this software. If not see <http://www.gnu.org/licenses/>. *
+ ***************************************************************************/
+
+#include <linux/hid.h>
+
+#include <linux/fb.h>
+#include <linux/backlight.h>
+
+#include "hid-picolcd.h"
+
+static int picolcd_get_brightness(struct backlight_device *bdev)
+{
+ struct picolcd_data *data = bl_get_data(bdev);
+ return data->lcd_brightness;
+}
+
+static int picolcd_set_brightness(struct backlight_device *bdev)
+{
+ struct picolcd_data *data = bl_get_data(bdev);
+ struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
+ unsigned long flags;
+
+ if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
+ return -ENODEV;
+
+ data->lcd_brightness = bdev->props.brightness & 0x0ff;
+ data->lcd_power = bdev->props.power;
+ spin_lock_irqsave(&data->lock, flags);
+ hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
+ if (!(data->status & PICOLCD_FAILED))
+ hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
+ spin_unlock_irqrestore(&data->lock, flags);
+ return 0;
+}
+
+static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
+{
+ return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
+}
+
+static const struct backlight_ops picolcd_blops = {
+ .update_status = picolcd_set_brightness,
+ .get_brightness = picolcd_get_brightness,
+ .check_fb = picolcd_check_bl_fb,
+};
+
+int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
+{
+ struct device *dev = &data->hdev->dev;
+ struct backlight_device *bdev;
+ struct backlight_properties props;
+ if (!report)
+ return -ENODEV;
+ if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
+ report->field[0]->report_size != 8) {
+ dev_err(dev, "unsupported BRIGHTNESS report");
+ return -EINVAL;
+ }
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 0xff;
+ bdev = backlight_device_register(dev_name(dev), dev, data,
+ &picolcd_blops, &props);
+ if (IS_ERR(bdev)) {
+ dev_err(dev, "failed to register backlight\n");
+ return PTR_ERR(bdev);
+ }
+ bdev->props.brightness = 0xff;
+ data->lcd_brightness = 0xff;
+ data->backlight = bdev;
+ picolcd_set_brightness(bdev);
+ return 0;
+}
+
+void picolcd_exit_backlight(struct picolcd_data *data)
+{
+ struct backlight_device *bdev = data->backlight;
+
+ data->backlight = NULL;
+ backlight_device_unregister(bdev);
+}
+
+int picolcd_resume_backlight(struct picolcd_data *data)
+{
+ if (!data->backlight)
+ return 0;
+ return picolcd_set_brightness(data->backlight);
+}
+
+#ifdef CONFIG_PM
+void picolcd_suspend_backlight(struct picolcd_data *data)
+{
+ int bl_power = data->lcd_power;
+ if (!data->backlight)
+ return;
+
+ data->backlight->props.power = FB_BLANK_POWERDOWN;
+ picolcd_set_brightness(data->backlight);
+ data->lcd_power = data->backlight->props.power = bl_power;
+}
+#endif /* CONFIG_PM */
+