drivers/hid/hid-picolcd_lcd.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /***************************************************************************
0003  *   Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org>  *
0004  *                                                                         *
0005  *   Based on Logitech G13 driver (v0.4)                                   *
0006  *     Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu>   *
0007  *                                                                         *
0008  ***************************************************************************/
0009
0010 #include <linux/hid.h>
0011
0012 #include <linux/fb.h>
0013 #include <linux/lcd.h>
0014
0015 #include "hid-picolcd.h"
0016
0017 /*
0018  * lcd class device
0019  */
0020 static int picolcd_get_contrast(struct lcd_device *ldev)
0021 {
0022     struct picolcd_data *data = lcd_get_data(ldev);
0023     return data->lcd_contrast;
0024 }
0025
0026 static int picolcd_set_contrast(struct lcd_device *ldev, int contrast)
0027 {
0028     struct picolcd_data *data = lcd_get_data(ldev);
0029     struct hid_report *report = picolcd_out_report(REPORT_CONTRAST, data->hdev);
0030     unsigned long flags;
0031
0032     if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
0033         return -ENODEV;
0034
0035     data->lcd_contrast = contrast & 0x0ff;
0036     spin_lock_irqsave(&data->lock, flags);
0037     hid_set_field(report->field[0], 0, data->lcd_contrast);
0038     if (!(data->status & PICOLCD_FAILED))
0039         hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
0040     spin_unlock_irqrestore(&data->lock, flags);
0041     return 0;
0042 }
0043
0044 static int picolcd_check_lcd_fb(struct lcd_device *ldev, struct fb_info *fb)
0045 {
0046     return fb && fb == picolcd_fbinfo((struct picolcd_data *)lcd_get_data(ldev));
0047 }
0048
0049 static struct lcd_ops picolcd_lcdops = {
0050     .get_contrast   = picolcd_get_contrast,
0051     .set_contrast   = picolcd_set_contrast,
0052     .check_fb       = picolcd_check_lcd_fb,
0053 };
0054
0055 int picolcd_init_lcd(struct picolcd_data *data, struct hid_report *report)
0056 {
0057     struct device *dev = &data->hdev->dev;
0058     struct lcd_device *ldev;
0059
0060     if (!report)
0061         return -ENODEV;
0062     if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
0063             report->field[0]->report_size != 8) {
0064         dev_err(dev, "unsupported CONTRAST report");
0065         return -EINVAL;
0066     }
0067
0068     ldev = lcd_device_register(dev_name(dev), dev, data, &picolcd_lcdops);
0069     if (IS_ERR(ldev)) {
0070         dev_err(dev, "failed to register LCD\n");
0071         return PTR_ERR(ldev);
0072     }
0073     ldev->props.max_contrast = 0x0ff;
0074     data->lcd_contrast = 0xe5;
0075     data->lcd = ldev;
0076     picolcd_set_contrast(ldev, 0xe5);
0077     return 0;
0078 }
0079
0080 void picolcd_exit_lcd(struct picolcd_data *data)
0081 {
0082     struct lcd_device *ldev = data->lcd;
0083
0084     data->lcd = NULL;
0085     lcd_device_unregister(ldev);
0086 }
0087
0088 int picolcd_resume_lcd(struct picolcd_data *data)
0089 {
0090     if (!data->lcd)
0091         return 0;
0092     return picolcd_set_contrast(data->lcd, data->lcd_contrast);
0093 }
0094