1// SPDX-License-Identifier: GPL-2.0+
2
3/*
4 * LCD Backlight driver for RAVE SP
5 *
6 * Copyright (C) 2018 Zodiac Inflight Innovations
7 *
8 */
9
10#include <linux/backlight.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/mfd/rave-sp.h>
14#include <linux/platform_device.h>
15
16#define	RAVE_SP_BACKLIGHT_LCD_EN	BIT(7)
17
18static int rave_sp_backlight_update_status(struct backlight_device *bd)
19{
20	const struct backlight_properties *p = &bd->props;
21	const u8 intensity =
22		(p->power == FB_BLANK_UNBLANK) ? p->brightness : 0;
23	struct rave_sp *sp = dev_get_drvdata(&bd->dev);
24	u8 cmd[] = {
25		[0] = RAVE_SP_CMD_SET_BACKLIGHT,
26		[1] = 0,
27		[2] = intensity ? RAVE_SP_BACKLIGHT_LCD_EN | intensity : 0,
28		[3] = 0,
29		[4] = 0,
30	};
31
32	return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
33}
34
35static const struct backlight_ops rave_sp_backlight_ops = {
36	.options	= BL_CORE_SUSPENDRESUME,
37	.update_status	= rave_sp_backlight_update_status,
38};
39
40static struct backlight_properties rave_sp_backlight_props = {
41	.type		= BACKLIGHT_PLATFORM,
42	.max_brightness = 100,
43	.brightness	= 50,
44};
45
46static int rave_sp_backlight_probe(struct platform_device *pdev)
47{
48	struct device *dev = &pdev->dev;
49	struct backlight_device *bd;
50
51	bd = devm_backlight_device_register(dev, pdev->name, dev,
52					    dev_get_drvdata(dev->parent),
53					    &rave_sp_backlight_ops,
54					    &rave_sp_backlight_props);
55	if (IS_ERR(bd))
56		return PTR_ERR(bd);
57
58	/*
59	 * If there is a phandle pointing to the device node we can
60	 * assume that another device will manage the status changes.
61	 * If not we make sure the backlight is in a consistent state.
62	 */
63	if (!dev->of_node->phandle)
64		backlight_update_status(bd);
65
66	return 0;
67}
68
69static const struct of_device_id rave_sp_backlight_of_match[] = {
70	{ .compatible = "zii,rave-sp-backlight" },
71	{}
72};
73
74static struct platform_driver rave_sp_backlight_driver = {
75	.probe = rave_sp_backlight_probe,
76	.driver	= {
77		.name = KBUILD_MODNAME,
78		.of_match_table = rave_sp_backlight_of_match,
79	},
80};
81module_platform_driver(rave_sp_backlight_driver);
82
83MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
84MODULE_LICENSE("GPL");
85MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
86MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
87MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
88MODULE_DESCRIPTION("RAVE SP Backlight driver");
89