drivers/hid/hid-picolcd_backlight.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /***************************************************************************
   3  *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
   4  *                                                                         *
   5  *   Based on Logitech G13 driver (v0.4)                                   *
   6  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
   7  *                                                                         *
   8  ***************************************************************************/
   9
  10 #include <linux/hid.h>
  11
  12 #include <linux/fb.h>
  13 #include <linux/backlight.h>
  14
  15 #include "hid-picolcd.h"
  16
  17 static int picolcd_get_brightness(struct backlight_device *bdev)
  18 {
  19         struct picolcd_data *data = bl_get_data(bdev);
  20         return data->lcd_brightness;
  21 }
  22
  23 static int picolcd_set_brightness(struct backlight_device *bdev)
  24 {
  25         struct picolcd_data *data = bl_get_data(bdev);
  26         struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
  27         unsigned long flags;
  28
  29         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  30                 return -ENODEV;
  31
  32         data->lcd_brightness = bdev->props.brightness & 0x0ff;
  33         data->lcd_power      = bdev->props.power;
  34         spin_lock_irqsave(&data->lock, flags);
  35         hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
  36         if (!(data->status & PICOLCD_FAILED))
  37                 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
  38         spin_unlock_irqrestore(&data->lock, flags);
  39         return 0;
  40 }
  41
  42 static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
  43 {
  44         return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
  45 }
  46
  47 static const struct backlight_ops picolcd_blops = {
  48         .update_status  = picolcd_set_brightness,
  49         .get_brightness = picolcd_get_brightness,
  50         .check_fb       = picolcd_check_bl_fb,
  51 };
  52
  53 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
  54 {
  55         struct device *dev = &data->hdev->dev;
  56         struct backlight_device *bdev;
  57         struct backlight_properties props;
  58         if (!report)
  59                 return -ENODEV;
  60         if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  61                         report->field[0]->report_size != 8) {
  62                 dev_err(dev, "unsupported BRIGHTNESS report");
  63                 return -EINVAL;
  64         }
  65
  66         memset(&props, 0, sizeof(props));
  67         props.type = BACKLIGHT_RAW;
  68         props.max_brightness = 0xff;
  69         bdev = backlight_device_register(dev_name(dev), dev, data,
  70                         &picolcd_blops, &props);
  71         if (IS_ERR(bdev)) {
  72                 dev_err(dev, "failed to register backlight\n");
  73                 return PTR_ERR(bdev);
  74         }
  75         bdev->props.brightness     = 0xff;
  76         data->lcd_brightness       = 0xff;
  77         data->backlight            = bdev;
  78         picolcd_set_brightness(bdev);
  79         return 0;
  80 }
  81
  82 void picolcd_exit_backlight(struct picolcd_data *data)
  83 {
  84         struct backlight_device *bdev = data->backlight;
  85
  86         data->backlight = NULL;
  87         backlight_device_unregister(bdev);
  88 }
  89
  90 int picolcd_resume_backlight(struct picolcd_data *data)
  91 {
  92         if (!data->backlight)
  93                 return 0;
  94         return picolcd_set_brightness(data->backlight);
  95 }
  96
  97 #ifdef CONFIG_PM
  98 void picolcd_suspend_backlight(struct picolcd_data *data)
  99 {
 100         int bl_power = data->lcd_power;
 101         if (!data->backlight)
 102                 return;
 103
 104         data->backlight->props.power = FB_BLANK_POWERDOWN;
 105         picolcd_set_brightness(data->backlight);
 106         data->lcd_power = data->backlight->props.power = bl_power;
 107 }
 108 #endif /* CONFIG_PM */
 109