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_lcd.c (2724B)

      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/lcd.h>
     14
     15#include "hid-picolcd.h"
     16
     17/*
     18 * lcd class device
     19 */
     20static int picolcd_get_contrast(struct lcd_device *ldev)
     21{
     22	struct picolcd_data *data = lcd_get_data(ldev);
     23	return data->lcd_contrast;
     24}
     25
     26static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
     27{
     28	struct picolcd_data *data = lcd_get_data(ldev);
     29	struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
     30	unsigned long flags;
     31
     32	if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
     33		return -ENODEV;
     34
     35	data->lcd_contrast = contrast & 0x0ff;
     36	spin_lock_irqsave(&data->lock, flags);
     37	hid_set_field(report->field[0], 0, data->lcd_contrast);
     38	if (!(data->status & PICOLCD_FAILED))
     39		hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
     40	spin_unlock_irqrestore(&data->lock, flags);
     41	return 0;
     42}
     43
     44static int picolcd_check_lcd_fb(struct lcd_device *ldev, struct fb_info *fb)
     45{
     46	return fb && fb == picolcd_fbinfo((struct picolcd_data *)lcd_get_data(ldev));
     47}
     48
     49static struct lcd_ops picolcd_lcdops = {
     50	.get_contrast   = picolcd_get_contrast,
     51	.set_contrast   = picolcd_set_contrast,
     52	.check_fb       = picolcd_check_lcd_fb,
     53};
     54
     55int picolcd_init_lcd(struct picolcd_data *data, struct hid_report *report)
     56{
     57	struct device *dev = &data->hdev->dev;
     58	struct lcd_device *ldev;
     59
     60	if (!report)
     61		return -ENODEV;
     62	if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
     63			report->field[0]->report_size != 8) {
     64		dev_err(dev, "unsupported CONTRAST report");
     65		return -EINVAL;
     66	}
     67
     68	ldev = lcd_device_register(dev_name(dev), dev, data, &picolcd_lcdops);
     69	if (IS_ERR(ldev)) {
     70		dev_err(dev, "failed to register LCD\n");
     71		return PTR_ERR(ldev);
     72	}
     73	ldev->props.max_contrast = 0x0ff;
     74	data->lcd_contrast = 0xe5;
     75	data->lcd = ldev;
     76	picolcd_set_contrast(ldev, 0xe5);
     77	return 0;
     78}
     79
     80void picolcd_exit_lcd(struct picolcd_data *data)
     81{
     82	struct lcd_device *ldev = data->lcd;
     83
     84	data->lcd = NULL;
     85	lcd_device_unregister(ldev);
     86}
     87
     88int picolcd_resume_lcd(struct picolcd_data *data)
     89{
     90	if (!data->lcd)
     91		return 0;
     92	return picolcd_set_contrast(data->lcd, data->lcd_contrast);
     93}
     94