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