cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hid-picolcd_backlight.c (3369B)

      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/fb.h>
     13#include <linux/backlight.h>
     14
     15#include "hid-picolcd.h"
     16
     17static int picolcd_get_brightness(struct backlight_device *bdev)
     18{
     19	struct picolcd_data *data = bl_get_data(bdev);
     20	return data->lcd_brightness;
     21}
     22
     23static int picolcd_set_brightness(struct backlight_device *bdev)
     24{
     25	struct picolcd_data *data = bl_get_data(bdev);
     26	struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
     27	unsigned long flags;
     28
     29	if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
     30		return -ENODEV;
     31
     32	data->lcd_brightness = bdev->props.brightness & 0x0ff;
     33	data->lcd_power      = bdev->props.power;
     34	spin_lock_irqsave(&data->lock, flags);
     35	hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? 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
     42static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
     43{
     44	return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
     45}
     46
     47static const struct backlight_ops picolcd_blops = {
     48	.update_status  = picolcd_set_brightness,
     49	.get_brightness = picolcd_get_brightness,
     50	.check_fb       = picolcd_check_bl_fb,
     51};
     52
     53int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
     54{
     55	struct device *dev = &data->hdev->dev;
     56	struct backlight_device *bdev;
     57	struct backlight_properties props;
     58	if (!report)
     59		return -ENODEV;
     60	if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
     61			report->field[0]->report_size != 8) {
     62		dev_err(dev, "unsupported BRIGHTNESS report");
     63		return -EINVAL;
     64	}
     65
     66	memset(&props, 0, sizeof(props));
     67	props.type = BACKLIGHT_RAW;
     68	props.max_brightness = 0xff;
     69	bdev = backlight_device_register(dev_name(dev), dev, data,
     70			&picolcd_blops, &props);
     71	if (IS_ERR(bdev)) {
     72		dev_err(dev, "failed to register backlight\n");
     73		return PTR_ERR(bdev);
     74	}
     75	bdev->props.brightness     = 0xff;
     76	data->lcd_brightness       = 0xff;
     77	data->backlight            = bdev;
     78	picolcd_set_brightness(bdev);
     79	return 0;
     80}
     81
     82void picolcd_exit_backlight(struct picolcd_data *data)
     83{
     84	struct backlight_device *bdev = data->backlight;
     85
     86	data->backlight = NULL;
     87	backlight_device_unregister(bdev);
     88}
     89
     90int picolcd_resume_backlight(struct picolcd_data *data)
     91{
     92	if (!data->backlight)
     93		return 0;
     94	return picolcd_set_brightness(data->backlight);
     95}
     96
     97#ifdef CONFIG_PM
     98void picolcd_suspend_backlight(struct picolcd_data *data)
     99{
    100	int bl_power = data->lcd_power;
    101	if (!data->backlight)
    102		return;
    103
    104	data->backlight->props.power = FB_BLANK_POWERDOWN;
    105	picolcd_set_brightness(data->backlight);
    106	data->lcd_power = data->backlight->props.power = bl_power;
    107}
    108#endif /* CONFIG_PM */
    109