drivers/hid/hid-picolcd_backlight.c

   1 /***************************************************************************
   2  *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
   3  *                                                                         *
   4  *   Based on Logitech G13 driver (v0.4)                                   *
   5  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
   6  *                                                                         *
   7  *   This program is free software: you can redistribute it and/or modify  *
   8  *   it under the terms of the GNU General Public License as published by  *
   9  *   the Free Software Foundation, version 2 of the License.               *
  10  *                                                                         *
  11  *   This driver is distributed in the hope that it will be useful, but    *
  12  *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
  14  *   General Public License for more details.                              *
  15  *                                                                         *
  16  *   You should have received a copy of the GNU General Public License     *
  17  *   along with this software. If not see <http://www.gnu.org/licenses/>.  *
  18  ***************************************************************************/
  19
  20 #include <linux/hid.h>
  21 #include "usbhid/usbhid.h"
  22 #include <linux/usb.h>
  23
  24 #include <linux/fb.h>
  25 #include <linux/backlight.h>
  26
  27 #include "hid-picolcd.h"
  28
  29 static int picolcd_get_brightness(struct backlight_device *bdev)
  30 {
  31         struct picolcd_data *data = bl_get_data(bdev);
  32         return data->lcd_brightness;
  33 }
  34
  35 static int picolcd_set_brightness(struct backlight_device *bdev)
  36 {
  37         struct picolcd_data *data = bl_get_data(bdev);
  38         struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
  39         unsigned long flags;
  40
  41         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  42                 return -ENODEV;
  43
  44         data->lcd_brightness = bdev->props.brightness & 0x0ff;
  45         data->lcd_power      = bdev->props.power;
  46         spin_lock_irqsave(&data->lock, flags);
  47         hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
  48         if (!(data->status & PICOLCD_FAILED))
  49                 usbhid_submit_report(data->hdev, report, USB_DIR_OUT);
  50         spin_unlock_irqrestore(&data->lock, flags);
  51         return 0;
  52 }
  53
  54 static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
  55 {
  56         return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
  57 }
  58
  59 static const struct backlight_ops picolcd_blops = {
  60         .update_status  = picolcd_set_brightness,
  61         .get_brightness = picolcd_get_brightness,
  62         .check_fb       = picolcd_check_bl_fb,
  63 };
  64
  65 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
  66 {
  67         struct device *dev = &data->hdev->dev;
  68         struct backlight_device *bdev;
  69         struct backlight_properties props;
  70         if (!report)
  71                 return -ENODEV;
  72         if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  73                         report->field[0]->report_size != 8) {
  74                 dev_err(dev, "unsupported BRIGHTNESS report");
  75                 return -EINVAL;
  76         }
  77
  78         memset(&props, 0, sizeof(props));
  79         props.type = BACKLIGHT_RAW;
  80         props.max_brightness = 0xff;
  81         bdev = backlight_device_register(dev_name(dev), dev, data,
  82                         &picolcd_blops, &props);
  83         if (IS_ERR(bdev)) {
  84                 dev_err(dev, "failed to register backlight\n");
  85                 return PTR_ERR(bdev);
  86         }
  87         bdev->props.brightness     = 0xff;
  88         data->lcd_brightness       = 0xff;
  89         data->backlight            = bdev;
  90         picolcd_set_brightness(bdev);
  91         return 0;
  92 }
  93
  94 void picolcd_exit_backlight(struct picolcd_data *data)
  95 {
  96         struct backlight_device *bdev = data->backlight;
  97
  98         data->backlight = NULL;
  99         if (bdev)
 100                 backlight_device_unregister(bdev);
 101 }
 102
 103 int picolcd_resume_backlight(struct picolcd_data *data)
 104 {
 105         if (!data->backlight)
 106                 return 0;
 107         return picolcd_set_brightness(data->backlight);
 108 }
 109
 110 #ifdef CONFIG_PM
 111 void picolcd_suspend_backlight(struct picolcd_data *data)
 112 {
 113         int bl_power = data->lcd_power;
 114         if (!data->backlight)
 115                 return;
 116
 117         data->backlight->props.power = FB_BLANK_POWERDOWN;
 118         picolcd_set_brightness(data->backlight);
 119         data->lcd_power = data->backlight->props.power = bl_power;
 120 }
 121 #endif /* CONFIG_PM */
 122