tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/mod_devicetable.h>
13#include <linux/module.h>
14#include <linux/mfd/rave-sp.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17
18#define RAVE_SP_BACKLIGHT_LCD_EN BIT(7)
19
20static int rave_sp_backlight_update_status(struct backlight_device *bd)
21{
22 const struct backlight_properties *p = &bd->props;
23 const u8 intensity =
24 (p->power == BACKLIGHT_POWER_ON) ? p->brightness : 0;
25 struct rave_sp *sp = dev_get_drvdata(&bd->dev);
26 u8 cmd[] = {
27 [0] = RAVE_SP_CMD_SET_BACKLIGHT,
28 [1] = 0,
29 [2] = intensity ? RAVE_SP_BACKLIGHT_LCD_EN | intensity : 0,
30 [3] = 0,
31 [4] = 0,
32 };
33
34 return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
35}
36
37static const struct backlight_ops rave_sp_backlight_ops = {
38 .options = BL_CORE_SUSPENDRESUME,
39 .update_status = rave_sp_backlight_update_status,
40};
41
42static struct backlight_properties rave_sp_backlight_props = {
43 .type = BACKLIGHT_PLATFORM,
44 .max_brightness = 100,
45 .brightness = 50,
46};
47
48static int rave_sp_backlight_probe(struct platform_device *pdev)
49{
50 struct device *dev = &pdev->dev;
51 struct backlight_device *bd;
52
53 bd = devm_backlight_device_register(dev, pdev->name, dev,
54 dev_get_drvdata(dev->parent),
55 &rave_sp_backlight_ops,
56 &rave_sp_backlight_props);
57 if (IS_ERR(bd))
58 return PTR_ERR(bd);
59
60 /*
61 * If there is a phandle pointing to the device node we can
62 * assume that another device will manage the status changes.
63 * If not we make sure the backlight is in a consistent state.
64 */
65 if (!dev->of_node->phandle)
66 backlight_update_status(bd);
67
68 return 0;
69}
70
71static const struct of_device_id rave_sp_backlight_of_match[] = {
72 { .compatible = "zii,rave-sp-backlight" },
73 {}
74};
75
76static struct platform_driver rave_sp_backlight_driver = {
77 .probe = rave_sp_backlight_probe,
78 .driver = {
79 .name = KBUILD_MODNAME,
80 .of_match_table = rave_sp_backlight_of_match,
81 },
82};
83module_platform_driver(rave_sp_backlight_driver);
84
85MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
86MODULE_LICENSE("GPL");
87MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
88MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
89MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
90MODULE_DESCRIPTION("RAVE SP Backlight driver");