1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License version 2 as
4  * published by the Free Software Foundation.
5  *
6  * iPAQ microcontroller backlight support
7  * Author : Linus Walleij <linus.walleij@linaro.org>
8  */
9 
10 #include <linux/backlight.h>
11 #include <linux/err.h>
12 #include <linux/fb.h>
13 #include <linux/init.h>
14 #include <linux/mfd/ipaq-micro.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 
18 static int micro_bl_update_status(struct backlight_device *bd)
19 {
20 	struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
21 	int intensity = bd->props.brightness;
22 	struct ipaq_micro_msg msg = {
23 		.id = MSG_BACKLIGHT,
24 		.tx_len = 3,
25 	};
26 
27 	if (bd->props.power != FB_BLANK_UNBLANK)
28 		intensity = 0;
29 	if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED))
30 		intensity = 0;
31 
32 	/*
33 	 * Message format:
34 	 * Byte 0: backlight instance (usually 1)
35 	 * Byte 1: on/off
36 	 * Byte 2: intensity, 0-255
37 	 */
38 	msg.tx_data[0] = 0x01;
39 	msg.tx_data[1] = intensity > 0 ? 1 : 0;
40 	msg.tx_data[2] = intensity;
41 	return ipaq_micro_tx_msg_sync(micro, &msg);
42 }
43 
44 static const struct backlight_ops micro_bl_ops = {
45 	.options = BL_CORE_SUSPENDRESUME,
46 	.update_status  = micro_bl_update_status,
47 };
48 
49 static struct backlight_properties micro_bl_props = {
50 	.type = BACKLIGHT_RAW,
51 	.max_brightness = 255,
52 	.power = FB_BLANK_UNBLANK,
53 	.brightness = 64,
54 };
55 
56 static int micro_backlight_probe(struct platform_device *pdev)
57 {
58 	struct backlight_device *bd;
59 	struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
60 
61 	bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
62 					    &pdev->dev, micro, &micro_bl_ops,
63 					    &micro_bl_props);
64 	if (IS_ERR(bd))
65 		return PTR_ERR(bd);
66 
67 	platform_set_drvdata(pdev, bd);
68 	backlight_update_status(bd);
69 
70 	return 0;
71 }
72 
73 static struct platform_driver micro_backlight_device_driver = {
74 	.driver = {
75 		.name    = "ipaq-micro-backlight",
76 	},
77 	.probe   = micro_backlight_probe,
78 };
79 module_platform_driver(micro_backlight_device_driver);
80 
81 MODULE_LICENSE("GPL v2");
82 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
83 MODULE_ALIAS("platform:ipaq-micro-backlight");
84