1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
4 *      PCF50633 backlight device driver
5 */
6
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/platform_device.h>
11
12#include <linux/backlight.h>
13#include <linux/fb.h>
14
15#include <linux/mfd/pcf50633/core.h>
16#include <linux/mfd/pcf50633/backlight.h>
17
18struct pcf50633_bl {
19	struct pcf50633 *pcf;
20	struct backlight_device *bl;
21
22	unsigned int brightness;
23	unsigned int brightness_limit;
24};
25
26/*
27 * pcf50633_bl_set_brightness_limit
28 *
29 * Update the brightness limit for the pc50633 backlight. The actual brightness
30 * will not go above the limit. This is useful to limit power drain for example
31 * on low battery.
32 *
33 * @dev: Pointer to a pcf50633 device
34 * @limit: The brightness limit. Valid values are 0-63
35 */
36int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
37{
38	struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);
39
40	if (!pcf_bl)
41		return -ENODEV;
42
43	pcf_bl->brightness_limit = limit & 0x3f;
44	backlight_update_status(pcf_bl->bl);
45
46	return 0;
47}
48
49static int pcf50633_bl_update_status(struct backlight_device *bl)
50{
51	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
52	unsigned int new_brightness;
53
54
55	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||
56		bl->props.power != FB_BLANK_UNBLANK)
57		new_brightness = 0;
58	else if (bl->props.brightness < pcf_bl->brightness_limit)
59		new_brightness = bl->props.brightness;
60	else
61		new_brightness = pcf_bl->brightness_limit;
62
63
64	if (pcf_bl->brightness == new_brightness)
65		return 0;
66
67	if (new_brightness) {
68		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
69					new_brightness);
70		if (!pcf_bl->brightness)
71			pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
72	} else {
73		pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
74	}
75
76	pcf_bl->brightness = new_brightness;
77
78	return 0;
79}
80
81static int pcf50633_bl_get_brightness(struct backlight_device *bl)
82{
83	struct pcf50633_bl *pcf_bl = bl_get_data(bl);
84
85	return pcf_bl->brightness;
86}
87
88static const struct backlight_ops pcf50633_bl_ops = {
89	.get_brightness = pcf50633_bl_get_brightness,
90	.update_status	= pcf50633_bl_update_status,
91	.options	= BL_CORE_SUSPENDRESUME,
92};
93
94static int pcf50633_bl_probe(struct platform_device *pdev)
95{
96	struct pcf50633_bl *pcf_bl;
97	struct device *parent = pdev->dev.parent;
98	struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent);
99	struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
100	struct backlight_properties bl_props;
101
102	pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
103	if (!pcf_bl)
104		return -ENOMEM;
105
106	memset(&bl_props, 0, sizeof(bl_props));
107	bl_props.type = BACKLIGHT_RAW;
108	bl_props.max_brightness = 0x3f;
109	bl_props.power = FB_BLANK_UNBLANK;
110
111	if (pdata) {
112		bl_props.brightness = pdata->default_brightness;
113		pcf_bl->brightness_limit = pdata->default_brightness_limit;
114	} else {
115		bl_props.brightness = 0x3f;
116		pcf_bl->brightness_limit = 0x3f;
117	}
118
119	pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);
120
121	pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
122						&pdev->dev, pcf_bl,
123						&pcf50633_bl_ops, &bl_props);
124
125	if (IS_ERR(pcf_bl->bl))
126		return PTR_ERR(pcf_bl->bl);
127
128	platform_set_drvdata(pdev, pcf_bl);
129
130	pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
131
132	/*
133	 * Should be different from bl_props.brightness, so we do not exit
134	 * update_status early the first time it's called
135	 */
136	pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;
137
138	backlight_update_status(pcf_bl->bl);
139
140	return 0;
141}
142
143static struct platform_driver pcf50633_bl_driver = {
144	.probe =	pcf50633_bl_probe,
145	.driver = {
146		.name = "pcf50633-backlight",
147	},
148};
149
150module_platform_driver(pcf50633_bl_driver);
151
152MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
153MODULE_DESCRIPTION("PCF50633 backlight driver");
154MODULE_LICENSE("GPL");
155MODULE_ALIAS("platform:pcf50633-backlight");
156