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(ld_dev: 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(ld_dev: 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(lock: &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(name: dev_name(dev), parent: dev, devdata: data, ops: &picolcd_lcdops);
69 if (IS_ERR(ptr: ldev)) {
70 dev_err(dev, "failed to register LCD\n");
71 return PTR_ERR(ptr: ldev);
72 }
73 ldev->props.max_contrast = 0x0ff;
74 data->lcd_contrast = 0xe5;
75 data->lcd = ldev;
76 picolcd_set_contrast(ldev, contrast: 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(ld: ldev);
86}
87
88int picolcd_resume_lcd(struct picolcd_data *data)
89{
90 if (!data->lcd)
91 return 0;
92 return picolcd_set_contrast(ldev: data->lcd, contrast: data->lcd_contrast);
93}
94
95

source code of linux/drivers/hid/hid-picolcd_lcd.c