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#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
  29static 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
  35static 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
  54static 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
  59static 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
  65int 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
  94void 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
 103int 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
 111void 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
 123
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