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
  22 #include <linux/fb.h>
  23 #include <linux/backlight.h>
  24
  25 #include "hid-picolcd.h"
  26
  27 static int picolcd_get_brightness(struct backlight_device *bdev)
  28 {
  29         struct picolcd_data *data = bl_get_data(bdev);
  30         return data->lcd_brightness;
  31 }
  32
  33 static int picolcd_set_brightness(struct backlight_device *bdev)
  34 {
  35         struct picolcd_data *data = bl_get_data(bdev);
  36         struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
  37         unsigned long flags;
  38
  39         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  40                 return -ENODEV;
  41
  42         data->lcd_brightness = bdev->props.brightness & 0x0ff;
  43         data->lcd_power      = bdev->props.power;
  44         spin_lock_irqsave(&data->lock, flags);
  45         hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
  46         if (!(data->status & PICOLCD_FAILED))
  47                 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
  48         spin_unlock_irqrestore(&data->lock, flags);
  49         return 0;
  50 }
  51
  52 static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
  53 {
  54         return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
  55 }
  56
  57 static const struct backlight_ops picolcd_blops = {
  58         .update_status  = picolcd_set_brightness,
  59         .get_brightness = picolcd_get_brightness,
  60         .check_fb       = picolcd_check_bl_fb,
  61 };
  62
  63 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
  64 {
  65         struct device *dev = &data->hdev->dev;
  66         struct backlight_device *bdev;
  67         struct backlight_properties props;
  68         if (!report)
  69                 return -ENODEV;
  70         if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  71                         report->field[0]->report_size != 8) {
  72                 dev_err(dev, "unsupported BRIGHTNESS report");
  73                 return -EINVAL;
  74         }
  75
  76         memset(&props, 0, sizeof(props));
  77         props.type = BACKLIGHT_RAW;
  78         props.max_brightness = 0xff;
  79         bdev = backlight_device_register(dev_name(dev), dev, data,
  80                         &picolcd_blops, &props);
  81         if (IS_ERR(bdev)) {
  82                 dev_err(dev, "failed to register backlight\n");
  83                 return PTR_ERR(bdev);
  84         }
  85         bdev->props.brightness     = 0xff;
  86         data->lcd_brightness       = 0xff;
  87         data->backlight            = bdev;
  88         picolcd_set_brightness(bdev);
  89         return 0;
  90 }
  91
  92 void picolcd_exit_backlight(struct picolcd_data *data)
  93 {
  94         struct backlight_device *bdev = data->backlight;
  95
  96         data->backlight = NULL;
  97         if (bdev)
  98                 backlight_device_unregister(bdev);
  99 }
 100
 101 int picolcd_resume_backlight(struct picolcd_data *data)
 102 {
 103         if (!data->backlight)
 104                 return 0;
 105         return picolcd_set_brightness(data->backlight);
 106 }
 107
 108 #ifdef CONFIG_PM
 109 void picolcd_suspend_backlight(struct picolcd_data *data)
 110 {
 111         int bl_power = data->lcd_power;
 112         if (!data->backlight)
 113                 return;
 114
 115         data->backlight->props.power = FB_BLANK_POWERDOWN;
 116         picolcd_set_brightness(data->backlight);
 117         data->lcd_power = data->backlight->props.power = bl_power;
 118 }
 119 #endif /* CONFIG_PM */
 120