drivers/hid/hid-picolcd_backlight.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/backlight.h>
0014
0015 #include "hid-picolcd.h"
0016
0017 static int picolcd_get_brightness(struct backlight_device *bdev)
0018 {
0019     struct picolcd_data *data = bl_get_data(bdev);
0020     return data->lcd_brightness;
0021 }
0022
0023 static int picolcd_set_brightness(struct backlight_device *bdev)
0024 {
0025     struct picolcd_data *data = bl_get_data(bdev);
0026     struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
0027     unsigned long flags;
0028
0029     if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
0030         return -ENODEV;
0031
0032     data->lcd_brightness = bdev->props.brightness & 0x0ff;
0033     data->lcd_power      = bdev->props.power;
0034     spin_lock_irqsave(&data->lock, flags);
0035     hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
0036     if (!(data->status & PICOLCD_FAILED))
0037         hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
0038     spin_unlock_irqrestore(&data->lock, flags);
0039     return 0;
0040 }
0041
0042 static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
0043 {
0044     return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
0045 }
0046
0047 static const struct backlight_ops picolcd_blops = {
0048     .update_status  = picolcd_set_brightness,
0049     .get_brightness = picolcd_get_brightness,
0050     .check_fb       = picolcd_check_bl_fb,
0051 };
0052
0053 int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
0054 {
0055     struct device *dev = &data->hdev->dev;
0056     struct backlight_device *bdev;
0057     struct backlight_properties props;
0058     if (!report)
0059         return -ENODEV;
0060     if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
0061             report->field[0]->report_size != 8) {
0062         dev_err(dev, "unsupported BRIGHTNESS report");
0063         return -EINVAL;
0064     }
0065
0066     memset(&props, 0, sizeof(props));
0067     props.type = BACKLIGHT_RAW;
0068     props.max_brightness = 0xff;
0069     bdev = backlight_device_register(dev_name(dev), dev, data,
0070             &picolcd_blops, &props);
0071     if (IS_ERR(bdev)) {
0072         dev_err(dev, "failed to register backlight\n");
0073         return PTR_ERR(bdev);
0074     }
0075     bdev->props.brightness     = 0xff;
0076     data->lcd_brightness       = 0xff;
0077     data->backlight            = bdev;
0078     picolcd_set_brightness(bdev);
0079     return 0;
0080 }
0081
0082 void picolcd_exit_backlight(struct picolcd_data *data)
0083 {
0084     struct backlight_device *bdev = data->backlight;
0085
0086     data->backlight = NULL;
0087     backlight_device_unregister(bdev);
0088 }
0089
0090 int picolcd_resume_backlight(struct picolcd_data *data)
0091 {
0092     if (!data->backlight)
0093         return 0;
0094     return picolcd_set_brightness(data->backlight);
0095 }
0096
0097 #ifdef CONFIG_PM
0098 void picolcd_suspend_backlight(struct picolcd_data *data)
0099 {
0100     int bl_power = data->lcd_power;
0101     if (!data->backlight)
0102         return;
0103
0104     data->backlight->props.power = FB_BLANK_POWERDOWN;
0105     picolcd_set_brightness(data->backlight);
0106     data->lcd_power = data->backlight->props.power = bl_power;
0107 }
0108 #endif /* CONFIG_PM */
0109