drivers/hid/hid-picolcd_lcd.c

   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/lcd.h>
  24
  25 #include "hid-picolcd.h"
  26
  27 /*
  28  * lcd class device
  29  */
  30 static int picolcd_get_contrast(struct lcd_device *ldev)
  31 {
  32         struct picolcd_data *data = lcd_get_data(ldev);
  33         return data->lcd_contrast;
  34 }
  35
  36 static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
  37 {
  38         struct picolcd_data *data = lcd_get_data(ldev);
  39         struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
  40         unsigned long flags;
  41
  42         if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  43                 return -ENODEV;
  44
  45         data->lcd_contrast = contrast & 0x0ff;
  46         spin_lock_irqsave(&data->lock, flags);
  47         hid_set_field(report->field[0], 0, data->lcd_contrast);
  48         if (!(data->status & PICOLCD_FAILED))
  49                 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
  50         spin_unlock_irqrestore(&data->lock, flags);
  51         return 0;
  52 }
  53
  54 static int picolcd_check_lcd_fb(struct lcd_device *ldev, struct fb_info *fb)
  55 {
  56         return fb && fb == picolcd_fbinfo((struct picolcd_data *)lcd_get_data(ldev));
  57 }
  58
  59 static struct lcd_ops picolcd_lcdops = {
  60         .get_contrast   = picolcd_get_contrast,
  61         .set_contrast   = picolcd_set_contrast,
  62         .check_fb       = picolcd_check_lcd_fb,
  63 };
  64
  65 int picolcd_init_lcd(struct picolcd_data *data, struct hid_report *report)
  66 {
  67         struct device *dev = &data->hdev->dev;
  68         struct lcd_device *ldev;
  69
  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 CONTRAST report");
  75                 return -EINVAL;
  76         }
  77
  78         ldev = lcd_device_register(dev_name(dev), dev, data, &picolcd_lcdops);
  79         if (IS_ERR(ldev)) {
  80                 dev_err(dev, "failed to register LCD\n");
  81                 return PTR_ERR(ldev);
  82         }
  83         ldev->props.max_contrast = 0x0ff;
  84         data->lcd_contrast = 0xe5;
  85         data->lcd = ldev;
  86         picolcd_set_contrast(ldev, 0xe5);
  87         return 0;
  88 }
  89
  90 void picolcd_exit_lcd(struct picolcd_data *data)
  91 {
  92         struct lcd_device *ldev = data->lcd;
  93
  94         data->lcd = NULL;
  95         if (ldev)
  96                 lcd_device_unregister(ldev);
  97 }
  98
  99 int picolcd_resume_lcd(struct picolcd_data *data)
 100 {
 101         if (!data->lcd)
 102                 return 0;
 103         return picolcd_set_contrast(data->lcd, data->lcd_contrast);
 104 }
 105