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/backlight.h>
  13
  14 #include "hid-picolcd.h"
  15
  16 static int picolcd_get_brightness(struct backlight_device *bdev)
  17 {
  18         struct picolcd_data *data = bl_get_data(bdev);
  19         return data->lcd_brightness;
  20 }
  21
  22 static int picolcd_set_brightness(struct backlight_device *bdev)
  23 {
  24         struct picolcd_data *data = bl_get_data(bdev);
  25         struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
  26         unsigned long flags;
  27
  28         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  29                 return -ENODEV;
  30
  31         data->lcd_brightness = bdev->props.brightness & 0x0ff;
  32         data->lcd_power      = bdev->props.power;
  33         spin_lock_irqsave(&data->lock, flags);
  34         hid_set_field(report->field[0], 0,
  35                       data->lcd_power == BACKLIGHT_POWER_ON ? 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 const struct backlight_ops picolcd_blops = {
  43         .update_status  = picolcd_set_brightness,
  44         .get_brightness = picolcd_get_brightness,
  45 };
  46
  47 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
  48 {
  49         struct device *dev = &data->hdev->dev;
  50         struct backlight_device *bdev;
  51         struct backlight_properties props;
  52         if (!report)
  53                 return -ENODEV;
  54         if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  55                         report->field[0]->report_size != 8) {
  56                 dev_err(dev, "unsupported BRIGHTNESS report");
  57                 return -EINVAL;
  58         }
  59
  60         memset(&props, 0, sizeof(props));
  61         props.type = BACKLIGHT_RAW;
  62         props.max_brightness = 0xff;
  63         bdev = backlight_device_register(dev_name(dev), dev, data,
  64                         &picolcd_blops, &props);
  65         if (IS_ERR(bdev)) {
  66                 dev_err(dev, "failed to register backlight\n");
  67                 return PTR_ERR(bdev);
  68         }
  69         bdev->props.brightness     = 0xff;
  70         data->lcd_brightness       = 0xff;
  71         data->backlight            = bdev;
  72         picolcd_set_brightness(bdev);
  73         return 0;
  74 }
  75
  76 void picolcd_exit_backlight(struct picolcd_data *data)
  77 {
  78         struct backlight_device *bdev = data->backlight;
  79
  80         data->backlight = NULL;
  81         backlight_device_unregister(bdev);
  82 }
  83
  84 int picolcd_resume_backlight(struct picolcd_data *data)
  85 {
  86         if (!data->backlight)
  87                 return 0;
  88         return picolcd_set_brightness(data->backlight);
  89 }
  90
  91 #ifdef CONFIG_PM
  92 void picolcd_suspend_backlight(struct picolcd_data *data)
  93 {
  94         int bl_power = data->lcd_power;
  95         if (!data->backlight)
  96                 return;
  97
  98         data->backlight->props.power = BACKLIGHT_POWER_OFF;
  99         picolcd_set_brightness(data->backlight);
 100         data->lcd_power = data->backlight->props.power = bl_power;
 101 }
 102 #endif /* CONFIG_PM */
 103