1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Backlight driver for HP Jornada 700 series (710/720/728)
5 * Copyright (C) 2006-2009 Kristoffer Ericson <kristoffer.ericson@gmail.com>
6 */
7
8#include <linux/backlight.h>
9#include <linux/device.h>
10#include <linux/fb.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14
15#include <mach/jornada720.h>
16#include <mach/hardware.h>
17
18#include <video/s1d13xxxfb.h>
19
20#define BL_MAX_BRIGHT	255
21#define BL_DEF_BRIGHT	25
22
23static int jornada_bl_get_brightness(struct backlight_device *bd)
24{
25	int ret;
26
27	/* check if backlight is on */
28	if (!(PPSR & PPC_LDD1))
29		return 0;
30
31	jornada_ssp_start();
32
33	/* cmd should return txdummy */
34	ret = jornada_ssp_byte(GETBRIGHTNESS);
35
36	if (jornada_ssp_byte(GETBRIGHTNESS) != TXDUMMY) {
37		dev_err(&bd->dev, "get brightness timeout\n");
38		jornada_ssp_end();
39		return -ETIMEDOUT;
40	}
41
42	/* exchange txdummy for value */
43	ret = jornada_ssp_byte(TXDUMMY);
44
45	jornada_ssp_end();
46
47	return BL_MAX_BRIGHT - ret;
48}
49
50static int jornada_bl_update_status(struct backlight_device *bd)
51{
52	int ret = 0;
53
54	jornada_ssp_start();
55
56	/* If backlight is off then really turn it off */
57	if (backlight_is_blank(bd)) {
58		ret = jornada_ssp_byte(BRIGHTNESSOFF);
59		if (ret != TXDUMMY) {
60			dev_info(&bd->dev, "brightness off timeout\n");
61			/* turn off backlight */
62			PPSR &= ~PPC_LDD1;
63			PPDR |= PPC_LDD1;
64			ret = -ETIMEDOUT;
65		}
66	} else  /* turn on backlight */
67		PPSR |= PPC_LDD1;
68
69	/* send command to our mcu */
70	if (jornada_ssp_byte(SETBRIGHTNESS) != TXDUMMY) {
71		dev_info(&bd->dev, "failed to set brightness\n");
72		ret = -ETIMEDOUT;
73		goto out;
74	}
75
76	/*
77	 * at this point we expect that the mcu has accepted
78	 * our command and is waiting for our new value
79	 * please note that maximum brightness is 255,
80	 * but due to physical layout it is equal to 0, so we simply
81	 * invert the value (MAX VALUE - NEW VALUE).
82	 */
83	if (jornada_ssp_byte(BL_MAX_BRIGHT - bd->props.brightness)
84		!= TXDUMMY) {
85		dev_err(&bd->dev, "set brightness failed\n");
86		ret = -ETIMEDOUT;
87	}
88
89	/*
90	 * If infact we get an TXDUMMY as output we are happy and dont
91	 * make any further comments about it
92	 */
93out:
94	jornada_ssp_end();
95
96	return ret;
97}
98
99static const struct backlight_ops jornada_bl_ops = {
100	.get_brightness = jornada_bl_get_brightness,
101	.update_status = jornada_bl_update_status,
102	.options = BL_CORE_SUSPENDRESUME,
103};
104
105static int jornada_bl_probe(struct platform_device *pdev)
106{
107	struct backlight_properties props;
108	int ret;
109	struct backlight_device *bd;
110
111	memset(&props, 0, sizeof(struct backlight_properties));
112	props.type = BACKLIGHT_RAW;
113	props.max_brightness = BL_MAX_BRIGHT;
114
115	bd = devm_backlight_device_register(&pdev->dev, S1D_DEVICENAME,
116					&pdev->dev, NULL, &jornada_bl_ops,
117					&props);
118	if (IS_ERR(bd)) {
119		ret = PTR_ERR(bd);
120		dev_err(&pdev->dev, "failed to register device, err=%x\n", ret);
121		return ret;
122	}
123
124	bd->props.power = FB_BLANK_UNBLANK;
125	bd->props.brightness = BL_DEF_BRIGHT;
126	/*
127	 * note. make sure max brightness is set otherwise
128	 * you will get seemingly non-related errors when
129	 * trying to change brightness
130	 */
131	jornada_bl_update_status(bd);
132
133	platform_set_drvdata(pdev, bd);
134	dev_info(&pdev->dev, "HP Jornada 700 series backlight driver\n");
135
136	return 0;
137}
138
139static struct platform_driver jornada_bl_driver = {
140	.probe		= jornada_bl_probe,
141	.driver	= {
142		.name	= "jornada_bl",
143	},
144};
145
146module_platform_driver(jornada_bl_driver);
147
148MODULE_AUTHOR("Kristoffer Ericson <kristoffer.ericson>");
149MODULE_DESCRIPTION("HP Jornada 710/720/728 Backlight driver");
150MODULE_LICENSE("GPL");
151