drivers/hid/hid-picolcd_lcd.c

   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  */
  20 static 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
  26 static 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
  44 static 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
  49 static 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
  55 int 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
  80 void 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
  88 int 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