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 
19 struct 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 
28 static 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 
40 static 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 
49 static 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 
57 static 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 = bd->props.brightness;
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 	if ((bd->props.power != FB_BLANK_UNBLANK) ||
74 			(bd->props.state & BL_CORE_FBBLANK) ||
75 			(bd->props.state & BL_CORE_SUSPENDED))
76 		brightness = 0;
77 
78 	ret = aat2870->write(aat2870, AAT2870_BLM,
79 			     (u8)aat2870_brightness(aat2870_bl, brightness));
80 	if (ret < 0)
81 		return ret;
82 
83 	if (brightness == 0) {
84 		ret = aat2870_bl_disable(aat2870_bl);
85 		if (ret < 0)
86 			return ret;
87 	} else if (aat2870_bl->brightness == 0) {
88 		ret = aat2870_bl_enable(aat2870_bl);
89 		if (ret < 0)
90 			return ret;
91 	}
92 
93 	aat2870_bl->brightness = brightness;
94 
95 	return 0;
96 }
97 
98 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
99 {
100 	return 1;
101 }
102 
103 static const struct backlight_ops aat2870_bl_ops = {
104 	.options = BL_CORE_SUSPENDRESUME,
105 	.update_status = aat2870_bl_update_status,
106 	.check_fb = aat2870_bl_check_fb,
107 };
108 
109 static int aat2870_bl_probe(struct platform_device *pdev)
110 {
111 	struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
112 	struct aat2870_bl_driver_data *aat2870_bl;
113 	struct backlight_device *bd;
114 	struct backlight_properties props;
115 	int ret = 0;
116 
117 	if (!pdata) {
118 		dev_err(&pdev->dev, "No platform data\n");
119 		ret = -ENXIO;
120 		goto out;
121 	}
122 
123 	if (pdev->id != AAT2870_ID_BL) {
124 		dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
125 		ret = -EINVAL;
126 		goto out;
127 	}
128 
129 	aat2870_bl = devm_kzalloc(&pdev->dev,
130 				  sizeof(struct aat2870_bl_driver_data),
131 				  GFP_KERNEL);
132 	if (!aat2870_bl) {
133 		ret = -ENOMEM;
134 		goto out;
135 	}
136 
137 	memset(&props, 0, sizeof(struct backlight_properties));
138 
139 	props.type = BACKLIGHT_RAW;
140 	bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
141 					&pdev->dev, aat2870_bl, &aat2870_bl_ops,
142 					&props);
143 	if (IS_ERR(bd)) {
144 		dev_err(&pdev->dev,
145 			"Failed allocate memory for backlight device\n");
146 		ret = PTR_ERR(bd);
147 		goto out;
148 	}
149 
150 	aat2870_bl->pdev = pdev;
151 	platform_set_drvdata(pdev, aat2870_bl);
152 
153 	aat2870_bl->bd = bd;
154 
155 	if (pdata->channels > 0)
156 		aat2870_bl->channels = pdata->channels;
157 	else
158 		aat2870_bl->channels = AAT2870_BL_CH_ALL;
159 
160 	if (pdata->max_current > 0)
161 		aat2870_bl->max_current = pdata->max_current;
162 	else
163 		aat2870_bl->max_current = AAT2870_CURRENT_27_9;
164 
165 	if (pdata->max_brightness > 0)
166 		bd->props.max_brightness = pdata->max_brightness;
167 	else
168 		bd->props.max_brightness = 255;
169 
170 	aat2870_bl->brightness = 0;
171 	bd->props.power = FB_BLANK_UNBLANK;
172 	bd->props.brightness = bd->props.max_brightness;
173 
174 	ret = aat2870_bl_update_status(bd);
175 	if (ret < 0) {
176 		dev_err(&pdev->dev, "Failed to initialize\n");
177 		return ret;
178 	}
179 
180 	return 0;
181 
182 out:
183 	return ret;
184 }
185 
186 static int aat2870_bl_remove(struct platform_device *pdev)
187 {
188 	struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
189 	struct backlight_device *bd = aat2870_bl->bd;
190 
191 	bd->props.power = FB_BLANK_POWERDOWN;
192 	bd->props.brightness = 0;
193 	backlight_update_status(bd);
194 
195 	return 0;
196 }
197 
198 static struct platform_driver aat2870_bl_driver = {
199 	.driver = {
200 		.name	= "aat2870-backlight",
201 	},
202 	.probe		= aat2870_bl_probe,
203 	.remove		= aat2870_bl_remove,
204 };
205 
206 static int __init aat2870_bl_init(void)
207 {
208 	return platform_driver_register(&aat2870_bl_driver);
209 }
210 subsys_initcall(aat2870_bl_init);
211 
212 static void __exit aat2870_bl_exit(void)
213 {
214 	platform_driver_unregister(&aat2870_bl_driver);
215 }
216 module_exit(aat2870_bl_exit);
217 
218 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
219 MODULE_LICENSE("GPL");
220 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
221