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 
16 static int micro_bl_update_status(struct backlight_device *bd)
17 {
18 	struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
19 	int intensity = backlight_get_brightness(bd);
20 	struct ipaq_micro_msg msg = {
21 		.id = MSG_BACKLIGHT,
22 		.tx_len = 3,
23 	};
24 
25 	/*
26 	 * Message format:
27 	 * Byte 0: backlight instance (usually 1)
28 	 * Byte 1: on/off
29 	 * Byte 2: intensity, 0-255
30 	 */
31 	msg.tx_data[0] = 0x01;
32 	msg.tx_data[1] = intensity > 0 ? 1 : 0;
33 	msg.tx_data[2] = intensity;
34 	return ipaq_micro_tx_msg_sync(micro, &msg);
35 }
36 
37 static const struct backlight_ops micro_bl_ops = {
38 	.options = BL_CORE_SUSPENDRESUME,
39 	.update_status  = micro_bl_update_status,
40 };
41 
42 static const struct backlight_properties micro_bl_props = {
43 	.type = BACKLIGHT_RAW,
44 	.max_brightness = 255,
45 	.power = FB_BLANK_UNBLANK,
46 	.brightness = 64,
47 };
48 
49 static int micro_backlight_probe(struct platform_device *pdev)
50 {
51 	struct backlight_device *bd;
52 	struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
53 
54 	bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
55 					    &pdev->dev, micro, &micro_bl_ops,
56 					    &micro_bl_props);
57 	if (IS_ERR(bd))
58 		return PTR_ERR(bd);
59 
60 	platform_set_drvdata(pdev, bd);
61 	backlight_update_status(bd);
62 
63 	return 0;
64 }
65 
66 static struct platform_driver micro_backlight_device_driver = {
67 	.driver = {
68 		.name    = "ipaq-micro-backlight",
69 	},
70 	.probe   = micro_backlight_probe,
71 };
72 module_platform_driver(micro_backlight_device_driver);
73 
74 MODULE_LICENSE("GPL v2");
75 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
76 MODULE_ALIAS("platform:ipaq-micro-backlight");
77