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
aat2870_brightness(struct aat2870_bl_driver_data * aat2870_bl,int brightness)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
aat2870_bl_enable(struct aat2870_bl_driver_data * aat2870_bl)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
aat2870_bl_disable(struct aat2870_bl_driver_data * aat2870_bl)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
aat2870_bl_update_status(struct backlight_device * bd)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 = 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
aat2870_bl_check_fb(struct backlight_device * bd,struct fb_info * fi)93 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
94 {
95 return 1;
96 }
97
98 static 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
aat2870_bl_probe(struct platform_device * pdev)104 static 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
177 out:
178 return ret;
179 }
180
aat2870_bl_remove(struct platform_device * pdev)181 static 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
191 static 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
aat2870_bl_init(void)199 static int __init aat2870_bl_init(void)
200 {
201 return platform_driver_register(&aat2870_bl_driver);
202 }
203 subsys_initcall(aat2870_bl_init);
204
aat2870_bl_exit(void)205 static void __exit aat2870_bl_exit(void)
206 {
207 platform_driver_unregister(&aat2870_bl_driver);
208 }
209 module_exit(aat2870_bl_exit);
210
211 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
212 MODULE_LICENSE("GPL");
213 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
214