ipaq_micro_bl.c

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