hid-picolcd_backlight.c

  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
 16static 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
 22static 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
 42static const struct backlight_ops picolcd_blops = {
 43	.update_status  = picolcd_set_brightness,
 44	.get_brightness = picolcd_get_brightness,
 45};
 46
 47int 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
 76void 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
 84int 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
 92void 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