linux/drivers/hid/hid-picolcd_backlight.c
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   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
  27static 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
  33static 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
  52static 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
  57static 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
  63int 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
  92void 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
 101int 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
 109void 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
 121
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