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