1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * iPAQ microcontroller backlight support
5 * Author : Linus Walleij <linus.walleij@linaro.org>
6 */
7
8#include <linux/backlight.h>
9#include <linux/err.h>
10#include <linux/fb.h>
11#include <linux/init.h>
12#include <linux/mfd/ipaq-micro.h>
13#include <linux/module.h>
14#include <linux/platform_device.h>
15
16static int micro_bl_update_status(struct backlight_device *bd)
17{
18	struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
19	int intensity = bd->props.brightness;
20	struct ipaq_micro_msg msg = {
21		.id = MSG_BACKLIGHT,
22		.tx_len = 3,
23	};
24
25	if (bd->props.power != FB_BLANK_UNBLANK)
26		intensity = 0;
27	if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED))
28		intensity = 0;
29
30	/*
31	 * Message format:
32	 * Byte 0: backlight instance (usually 1)
33	 * Byte 1: on/off
34	 * Byte 2: intensity, 0-255
35	 */
36	msg.tx_data[0] = 0x01;
37	msg.tx_data[1] = intensity > 0 ? 1 : 0;
38	msg.tx_data[2] = intensity;
39	return ipaq_micro_tx_msg_sync(micro, &msg);
40}
41
42static const struct backlight_ops micro_bl_ops = {
43	.options = BL_CORE_SUSPENDRESUME,
44	.update_status  = micro_bl_update_status,
45};
46
47static const struct backlight_properties micro_bl_props = {
48	.type = BACKLIGHT_RAW,
49	.max_brightness = 255,
50	.power = FB_BLANK_UNBLANK,
51	.brightness = 64,
52};
53
54static int micro_backlight_probe(struct platform_device *pdev)
55{
56	struct backlight_device *bd;
57	struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
58
59	bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
60					    &pdev->dev, micro, &micro_bl_ops,
61					    &micro_bl_props);
62	if (IS_ERR(bd))
63		return PTR_ERR(bd);
64
65	platform_set_drvdata(pdev, bd);
66	backlight_update_status(bd);
67
68	return 0;
69}
70
71static struct platform_driver micro_backlight_device_driver = {
72	.driver = {
73		.name    = "ipaq-micro-backlight",
74	},
75	.probe   = micro_backlight_probe,
76};
77module_platform_driver(micro_backlight_device_driver);
78
79MODULE_LICENSE("GPL v2");
80MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
81MODULE_ALIAS("platform:ipaq-micro-backlight");
82