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/backlight.h>
13
14 #include "hid-picolcd.h"
15
picolcd_get_brightness(struct backlight_device * bdev)16 static int picolcd_get_brightness(struct backlight_device *bdev)
17 {
18 struct picolcd_data *data = bl_get_data(bdev);
19 return data->lcd_brightness;
20 }
21
picolcd_set_brightness(struct backlight_device * bdev)22 static int picolcd_set_brightness(struct backlight_device *bdev)
23 {
24 struct picolcd_data *data = bl_get_data(bdev);
25 struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
26 unsigned long flags;
27
28 if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
29 return -ENODEV;
30
31 data->lcd_brightness = bdev->props.brightness & 0x0ff;
32 data->lcd_power = bdev->props.power;
33 spin_lock_irqsave(&data->lock, flags);
34 hid_set_field(report->field[0], 0,
35 data->lcd_power == BACKLIGHT_POWER_ON ? data->lcd_brightness : 0);
36 if (!(data->status & PICOLCD_FAILED))
37 hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
38 spin_unlock_irqrestore(&data->lock, flags);
39 return 0;
40 }
41
42 static const struct backlight_ops picolcd_blops = {
43 .update_status = picolcd_set_brightness,
44 .get_brightness = picolcd_get_brightness,
45 };
46
picolcd_init_backlight(struct picolcd_data * data,struct hid_report * report)47 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
48 {
49 struct device *dev = &data->hdev->dev;
50 struct backlight_device *bdev;
51 struct backlight_properties props;
52 if (!report)
53 return -ENODEV;
54 if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
55 report->field[0]->report_size != 8) {
56 dev_err(dev, "unsupported BRIGHTNESS report");
57 return -EINVAL;
58 }
59
60 memset(&props, 0, sizeof(props));
61 props.type = BACKLIGHT_RAW;
62 props.max_brightness = 0xff;
63 bdev = backlight_device_register(dev_name(dev), dev, data,
64 &picolcd_blops, &props);
65 if (IS_ERR(bdev)) {
66 dev_err(dev, "failed to register backlight\n");
67 return PTR_ERR(bdev);
68 }
69 bdev->props.brightness = 0xff;
70 data->lcd_brightness = 0xff;
71 data->backlight = bdev;
72 picolcd_set_brightness(bdev);
73 return 0;
74 }
75
picolcd_exit_backlight(struct picolcd_data * data)76 void picolcd_exit_backlight(struct picolcd_data *data)
77 {
78 struct backlight_device *bdev = data->backlight;
79
80 data->backlight = NULL;
81 backlight_device_unregister(bdev);
82 }
83
picolcd_resume_backlight(struct picolcd_data * data)84 int picolcd_resume_backlight(struct picolcd_data *data)
85 {
86 if (!data->backlight)
87 return 0;
88 return picolcd_set_brightness(data->backlight);
89 }
90
91 #ifdef CONFIG_PM
picolcd_suspend_backlight(struct picolcd_data * data)92 void picolcd_suspend_backlight(struct picolcd_data *data)
93 {
94 int bl_power = data->lcd_power;
95 if (!data->backlight)
96 return;
97
98 data->backlight->props.power = BACKLIGHT_POWER_OFF;
99 picolcd_set_brightness(data->backlight);
100 data->lcd_power = data->backlight->props.power = bl_power;
101 }
102 #endif /* CONFIG_PM */
103
104