1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/drivers/video/backlight/aat2870_bl.c
4 *
5 * Copyright (c) 2011, NVIDIA Corporation.
6 * Author: Jin Park <jinyoungp@nvidia.com>
7 */
8
9#include <linux/module.h>
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/platform_device.h>
13#include <linux/mutex.h>
14#include <linux/delay.h>
15#include <linux/fb.h>
16#include <linux/backlight.h>
17#include <linux/mfd/aat2870.h>
18
19struct aat2870_bl_driver_data {
20	struct platform_device *pdev;
21	struct backlight_device *bd;
22
23	int channels;
24	int max_current;
25	int brightness; /* current brightness */
26};
27
28static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
29				     int brightness)
30{
31	struct backlight_device *bd = aat2870_bl->bd;
32	int val;
33
34	val = brightness * (aat2870_bl->max_current - 1);
35	val /= bd->props.max_brightness;
36
37	return val;
38}
39
40static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
41{
42	struct aat2870_data *aat2870
43			= dev_get_drvdata(aat2870_bl->pdev->dev.parent);
44
45	return aat2870->write(aat2870, AAT2870_BL_CH_EN,
46			      (u8)aat2870_bl->channels);
47}
48
49static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
50{
51	struct aat2870_data *aat2870
52			= dev_get_drvdata(aat2870_bl->pdev->dev.parent);
53
54	return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
55}
56
57static int aat2870_bl_update_status(struct backlight_device *bd)
58{
59	struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
60	struct aat2870_data *aat2870 =
61			dev_get_drvdata(aat2870_bl->pdev->dev.parent);
62	int brightness = backlight_get_brightness(bd);
63	int ret;
64
65	if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
66		dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
67		return -EINVAL;
68	}
69
70	dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
71		 bd->props.brightness, bd->props.power, bd->props.state);
72
73	ret = aat2870->write(aat2870, AAT2870_BLM,
74			     (u8)aat2870_brightness(aat2870_bl, brightness));
75	if (ret < 0)
76		return ret;
77
78	if (brightness == 0) {
79		ret = aat2870_bl_disable(aat2870_bl);
80		if (ret < 0)
81			return ret;
82	} else if (aat2870_bl->brightness == 0) {
83		ret = aat2870_bl_enable(aat2870_bl);
84		if (ret < 0)
85			return ret;
86	}
87
88	aat2870_bl->brightness = brightness;
89
90	return 0;
91}
92
93static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
94{
95	return 1;
96}
97
98static const struct backlight_ops aat2870_bl_ops = {
99	.options = BL_CORE_SUSPENDRESUME,
100	.update_status = aat2870_bl_update_status,
101	.check_fb = aat2870_bl_check_fb,
102};
103
104static int aat2870_bl_probe(struct platform_device *pdev)
105{
106	struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
107	struct aat2870_bl_driver_data *aat2870_bl;
108	struct backlight_device *bd;
109	struct backlight_properties props;
110	int ret = 0;
111
112	if (!pdata) {
113		dev_err(&pdev->dev, "No platform data\n");
114		ret = -ENXIO;
115		goto out;
116	}
117
118	if (pdev->id != AAT2870_ID_BL) {
119		dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
120		ret = -EINVAL;
121		goto out;
122	}
123
124	aat2870_bl = devm_kzalloc(&pdev->dev,
125				  sizeof(struct aat2870_bl_driver_data),
126				  GFP_KERNEL);
127	if (!aat2870_bl) {
128		ret = -ENOMEM;
129		goto out;
130	}
131
132	memset(&props, 0, sizeof(struct backlight_properties));
133
134	props.type = BACKLIGHT_RAW;
135	bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
136					&pdev->dev, aat2870_bl, &aat2870_bl_ops,
137					&props);
138	if (IS_ERR(bd)) {
139		dev_err(&pdev->dev,
140			"Failed allocate memory for backlight device\n");
141		ret = PTR_ERR(bd);
142		goto out;
143	}
144
145	aat2870_bl->pdev = pdev;
146	platform_set_drvdata(pdev, aat2870_bl);
147
148	aat2870_bl->bd = bd;
149
150	if (pdata->channels > 0)
151		aat2870_bl->channels = pdata->channels;
152	else
153		aat2870_bl->channels = AAT2870_BL_CH_ALL;
154
155	if (pdata->max_current > 0)
156		aat2870_bl->max_current = pdata->max_current;
157	else
158		aat2870_bl->max_current = AAT2870_CURRENT_27_9;
159
160	if (pdata->max_brightness > 0)
161		bd->props.max_brightness = pdata->max_brightness;
162	else
163		bd->props.max_brightness = 255;
164
165	aat2870_bl->brightness = 0;
166	bd->props.power = FB_BLANK_UNBLANK;
167	bd->props.brightness = bd->props.max_brightness;
168
169	ret = aat2870_bl_update_status(bd);
170	if (ret < 0) {
171		dev_err(&pdev->dev, "Failed to initialize\n");
172		return ret;
173	}
174
175	return 0;
176
177out:
178	return ret;
179}
180
181static void aat2870_bl_remove(struct platform_device *pdev)
182{
183	struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
184	struct backlight_device *bd = aat2870_bl->bd;
185
186	bd->props.power = FB_BLANK_POWERDOWN;
187	bd->props.brightness = 0;
188	backlight_update_status(bd);
189}
190
191static struct platform_driver aat2870_bl_driver = {
192	.driver = {
193		.name	= "aat2870-backlight",
194	},
195	.probe		= aat2870_bl_probe,
196	.remove_new	= aat2870_bl_remove,
197};
198
199static int __init aat2870_bl_init(void)
200{
201	return platform_driver_register(&aat2870_bl_driver);
202}
203subsys_initcall(aat2870_bl_init);
204
205static void __exit aat2870_bl_exit(void)
206{
207	platform_driver_unregister(&aat2870_bl_driver);
208}
209module_exit(aat2870_bl_exit);
210
211MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
212MODULE_LICENSE("GPL");
213MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
214