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22#include <linux/module.h>
23#include <linux/kernel.h>
24#include <linux/init.h>
25#include <linux/platform_device.h>
26#include <linux/mutex.h>
27#include <linux/delay.h>
28#include <linux/fb.h>
29#include <linux/backlight.h>
30#include <linux/mfd/aat2870.h>
31
32struct aat2870_bl_driver_data {
33 struct platform_device *pdev;
34 struct backlight_device *bd;
35
36 int channels;
37 int max_current;
38 int brightness;
39};
40
41static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
42 int brightness)
43{
44 struct backlight_device *bd = aat2870_bl->bd;
45 int val;
46
47 val = brightness * (aat2870_bl->max_current - 1);
48 val /= bd->props.max_brightness;
49
50 return val;
51}
52
53static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
54{
55 struct aat2870_data *aat2870
56 = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
57
58 return aat2870->write(aat2870, AAT2870_BL_CH_EN,
59 (u8)aat2870_bl->channels);
60}
61
62static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
63{
64 struct aat2870_data *aat2870
65 = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
66
67 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
68}
69
70static int aat2870_bl_update_status(struct backlight_device *bd)
71{
72 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
73 struct aat2870_data *aat2870 =
74 dev_get_drvdata(aat2870_bl->pdev->dev.parent);
75 int brightness = bd->props.brightness;
76 int ret;
77
78 if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
79 dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
80 return -EINVAL;
81 }
82
83 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
84 bd->props.brightness, bd->props.power, bd->props.state);
85
86 if ((bd->props.power != FB_BLANK_UNBLANK) ||
87 (bd->props.state & BL_CORE_FBBLANK) ||
88 (bd->props.state & BL_CORE_SUSPENDED))
89 brightness = 0;
90
91 ret = aat2870->write(aat2870, AAT2870_BLM,
92 (u8)aat2870_brightness(aat2870_bl, brightness));
93 if (ret < 0)
94 return ret;
95
96 if (brightness == 0) {
97 ret = aat2870_bl_disable(aat2870_bl);
98 if (ret < 0)
99 return ret;
100 } else if (aat2870_bl->brightness == 0) {
101 ret = aat2870_bl_enable(aat2870_bl);
102 if (ret < 0)
103 return ret;
104 }
105
106 aat2870_bl->brightness = brightness;
107
108 return 0;
109}
110
111static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
112{
113 return 1;
114}
115
116static const struct backlight_ops aat2870_bl_ops = {
117 .options = BL_CORE_SUSPENDRESUME,
118 .update_status = aat2870_bl_update_status,
119 .check_fb = aat2870_bl_check_fb,
120};
121
122static int aat2870_bl_probe(struct platform_device *pdev)
123{
124 struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
125 struct aat2870_bl_driver_data *aat2870_bl;
126 struct backlight_device *bd;
127 struct backlight_properties props;
128 int ret = 0;
129
130 if (!pdata) {
131 dev_err(&pdev->dev, "No platform data\n");
132 ret = -ENXIO;
133 goto out;
134 }
135
136 if (pdev->id != AAT2870_ID_BL) {
137 dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
138 ret = -EINVAL;
139 goto out;
140 }
141
142 aat2870_bl = devm_kzalloc(&pdev->dev,
143 sizeof(struct aat2870_bl_driver_data),
144 GFP_KERNEL);
145 if (!aat2870_bl) {
146 ret = -ENOMEM;
147 goto out;
148 }
149
150 memset(&props, 0, sizeof(struct backlight_properties));
151
152 props.type = BACKLIGHT_RAW;
153 bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
154 &pdev->dev, aat2870_bl, &aat2870_bl_ops,
155 &props);
156 if (IS_ERR(bd)) {
157 dev_err(&pdev->dev,
158 "Failed allocate memory for backlight device\n");
159 ret = PTR_ERR(bd);
160 goto out;
161 }
162
163 aat2870_bl->pdev = pdev;
164 platform_set_drvdata(pdev, aat2870_bl);
165
166 aat2870_bl->bd = bd;
167
168 if (pdata->channels > 0)
169 aat2870_bl->channels = pdata->channels;
170 else
171 aat2870_bl->channels = AAT2870_BL_CH_ALL;
172
173 if (pdata->max_current > 0)
174 aat2870_bl->max_current = pdata->max_current;
175 else
176 aat2870_bl->max_current = AAT2870_CURRENT_27_9;
177
178 if (pdata->max_brightness > 0)
179 bd->props.max_brightness = pdata->max_brightness;
180 else
181 bd->props.max_brightness = 255;
182
183 aat2870_bl->brightness = 0;
184 bd->props.power = FB_BLANK_UNBLANK;
185 bd->props.brightness = bd->props.max_brightness;
186
187 ret = aat2870_bl_update_status(bd);
188 if (ret < 0) {
189 dev_err(&pdev->dev, "Failed to initialize\n");
190 return ret;
191 }
192
193 return 0;
194
195out:
196 return ret;
197}
198
199static int aat2870_bl_remove(struct platform_device *pdev)
200{
201 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
202 struct backlight_device *bd = aat2870_bl->bd;
203
204 bd->props.power = FB_BLANK_POWERDOWN;
205 bd->props.brightness = 0;
206 backlight_update_status(bd);
207
208 return 0;
209}
210
211static struct platform_driver aat2870_bl_driver = {
212 .driver = {
213 .name = "aat2870-backlight",
214 },
215 .probe = aat2870_bl_probe,
216 .remove = aat2870_bl_remove,
217};
218
219static int __init aat2870_bl_init(void)
220{
221 return platform_driver_register(&aat2870_bl_driver);
222}
223subsys_initcall(aat2870_bl_init);
224
225static void __exit aat2870_bl_exit(void)
226{
227 platform_driver_unregister(&aat2870_bl_driver);
228}
229module_exit(aat2870_bl_exit);
230
231MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
232MODULE_LICENSE("GPL");
233MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
234
