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
micro_bl_update_status(struct backlight_device * bd)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
micro_backlight_probe(struct platform_device * pdev)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, µ_bl_ops,
56 µ_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