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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;
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 = 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
98static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
99{
100 return 1;
101}
102
103static 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
109static 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
182out:
183 return ret;
184}
185
186static 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
198static 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
206static int __init aat2870_bl_init(void)
207{
208 return platform_driver_register(&aat2870_bl_driver);
209}
210subsys_initcall(aat2870_bl_init);
211
212static void __exit aat2870_bl_exit(void)
213{
214 platform_driver_unregister(&aat2870_bl_driver);
215}
216module_exit(aat2870_bl_exit);
217
218MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
219MODULE_LICENSE("GPL");
220MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
221
