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/backlight.h>
24 
25 #include "hid-picolcd.h"
26 
27 static int picolcd_get_brightness(struct backlight_device *bdev)
28 {
29 	struct picolcd_data *data = bl_get_data(bdev);
30 	return data->lcd_brightness;
31 }
32 
33 static int picolcd_set_brightness(struct backlight_device *bdev)
34 {
35 	struct picolcd_data *data = bl_get_data(bdev);
36 	struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
37 	unsigned long flags;
38 
39 	if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
40 		return -ENODEV;
41 
42 	data->lcd_brightness = bdev->props.brightness & 0x0ff;
43 	data->lcd_power      = bdev->props.power;
44 	spin_lock_irqsave(&data->lock, flags);
45 	hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
46 	if (!(data->status & PICOLCD_FAILED))
47 		hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
48 	spin_unlock_irqrestore(&data->lock, flags);
49 	return 0;
50 }
51 
52 static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
53 {
54 	return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
55 }
56 
57 static const struct backlight_ops picolcd_blops = {
58 	.update_status  = picolcd_set_brightness,
59 	.get_brightness = picolcd_get_brightness,
60 	.check_fb       = picolcd_check_bl_fb,
61 };
62 
63 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
64 {
65 	struct device *dev = &data->hdev->dev;
66 	struct backlight_device *bdev;
67 	struct backlight_properties props;
68 	if (!report)
69 		return -ENODEV;
70 	if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
71 			report->field[0]->report_size != 8) {
72 		dev_err(dev, "unsupported BRIGHTNESS report");
73 		return -EINVAL;
74 	}
75 
76 	memset(&props, 0, sizeof(props));
77 	props.type = BACKLIGHT_RAW;
78 	props.max_brightness = 0xff;
79 	bdev = backlight_device_register(dev_name(dev), dev, data,
80 			&picolcd_blops, &props);
81 	if (IS_ERR(bdev)) {
82 		dev_err(dev, "failed to register backlight\n");
83 		return PTR_ERR(bdev);
84 	}
85 	bdev->props.brightness     = 0xff;
86 	data->lcd_brightness       = 0xff;
87 	data->backlight            = bdev;
88 	picolcd_set_brightness(bdev);
89 	return 0;
90 }
91 
92 void picolcd_exit_backlight(struct picolcd_data *data)
93 {
94 	struct backlight_device *bdev = data->backlight;
95 
96 	data->backlight = NULL;
97 	if (bdev)
98 		backlight_device_unregister(bdev);
99 }
100 
101 int picolcd_resume_backlight(struct picolcd_data *data)
102 {
103 	if (!data->backlight)
104 		return 0;
105 	return picolcd_set_brightness(data->backlight);
106 }
107 
108 #ifdef CONFIG_PM
109 void picolcd_suspend_backlight(struct picolcd_data *data)
110 {
111 	int bl_power = data->lcd_power;
112 	if (!data->backlight)
113 		return;
114 
115 	data->backlight->props.power = FB_BLANK_POWERDOWN;
116 	picolcd_set_brightness(data->backlight);
117 	data->lcd_power = data->backlight->props.power = bl_power;
118 }
119 #endif /* CONFIG_PM */
120 
121