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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_get_brightness(struct backlight_device *bd)
71{
72 return bd->props.brightness;
73}
74
75static int aat2870_bl_update_status(struct backlight_device *bd)
76{
77 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
78 struct aat2870_data *aat2870 =
79 dev_get_drvdata(aat2870_bl->pdev->dev.parent);
80 int brightness = bd->props.brightness;
81 int ret;
82
83 if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
84 dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
85 return -EINVAL;
86 }
87
88 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
89 bd->props.brightness, bd->props.power, bd->props.state);
90
91 if ((bd->props.power != FB_BLANK_UNBLANK) ||
92 (bd->props.state & BL_CORE_FBBLANK) ||
93 (bd->props.state & BL_CORE_SUSPENDED))
94 brightness = 0;
95
96 ret = aat2870->write(aat2870, AAT2870_BLM,
97 (u8)aat2870_brightness(aat2870_bl, brightness));
98 if (ret < 0)
99 return ret;
100
101 if (brightness == 0) {
102 ret = aat2870_bl_disable(aat2870_bl);
103 if (ret < 0)
104 return ret;
105 } else if (aat2870_bl->brightness == 0) {
106 ret = aat2870_bl_enable(aat2870_bl);
107 if (ret < 0)
108 return ret;
109 }
110
111 aat2870_bl->brightness = brightness;
112
113 return 0;
114}
115
116static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
117{
118 return 1;
119}
120
121static const struct backlight_ops aat2870_bl_ops = {
122 .options = BL_CORE_SUSPENDRESUME,
123 .get_brightness = aat2870_bl_get_brightness,
124 .update_status = aat2870_bl_update_status,
125 .check_fb = aat2870_bl_check_fb,
126};
127
128static int aat2870_bl_probe(struct platform_device *pdev)
129{
130 struct aat2870_bl_platform_data *pdata = pdev->dev.platform_data;
131 struct aat2870_bl_driver_data *aat2870_bl;
132 struct backlight_device *bd;
133 struct backlight_properties props;
134 int ret = 0;
135
136 if (!pdata) {
137 dev_err(&pdev->dev, "No platform data\n");
138 ret = -ENXIO;
139 goto out;
140 }
141
142 if (pdev->id != AAT2870_ID_BL) {
143 dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
144 ret = -EINVAL;
145 goto out;
146 }
147
148 aat2870_bl = devm_kzalloc(&pdev->dev,
149 sizeof(struct aat2870_bl_driver_data),
150 GFP_KERNEL);
151 if (!aat2870_bl) {
152 dev_err(&pdev->dev,
153 "Failed to allocate memory for aat2870 backlight\n");
154 ret = -ENOMEM;
155 goto out;
156 }
157
158 memset(&props, 0, sizeof(struct backlight_properties));
159
160 props.type = BACKLIGHT_RAW;
161 bd = backlight_device_register("aat2870-backlight", &pdev->dev,
162 aat2870_bl, &aat2870_bl_ops, &props);
163 if (IS_ERR(bd)) {
164 dev_err(&pdev->dev,
165 "Failed allocate memory for backlight device\n");
166 ret = PTR_ERR(bd);
167 goto out;
168 }
169
170 aat2870_bl->pdev = pdev;
171 platform_set_drvdata(pdev, aat2870_bl);
172
173 aat2870_bl->bd = bd;
174
175 if (pdata->channels > 0)
176 aat2870_bl->channels = pdata->channels;
177 else
178 aat2870_bl->channels = AAT2870_BL_CH_ALL;
179
180 if (pdata->max_current > 0)
181 aat2870_bl->max_current = pdata->max_current;
182 else
183 aat2870_bl->max_current = AAT2870_CURRENT_27_9;
184
185 if (pdata->max_brightness > 0)
186 bd->props.max_brightness = pdata->max_brightness;
187 else
188 bd->props.max_brightness = 255;
189
190 aat2870_bl->brightness = 0;
191 bd->props.power = FB_BLANK_UNBLANK;
192 bd->props.brightness = bd->props.max_brightness;
193
194 ret = aat2870_bl_update_status(bd);
195 if (ret < 0) {
196 dev_err(&pdev->dev, "Failed to initialize\n");
197 goto out_bl_dev_unregister;
198 }
199
200 return 0;
201
202out_bl_dev_unregister:
203 backlight_device_unregister(bd);
204out:
205 return ret;
206}
207
208static int aat2870_bl_remove(struct platform_device *pdev)
209{
210 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
211 struct backlight_device *bd = aat2870_bl->bd;
212
213 bd->props.power = FB_BLANK_POWERDOWN;
214 bd->props.brightness = 0;
215 backlight_update_status(bd);
216
217 backlight_device_unregister(bd);
218
219 return 0;
220}
221
222static struct platform_driver aat2870_bl_driver = {
223 .driver = {
224 .name = "aat2870-backlight",
225 .owner = THIS_MODULE,
226 },
227 .probe = aat2870_bl_probe,
228 .remove = aat2870_bl_remove,
229};
230
231static int __init aat2870_bl_init(void)
232{
233 return platform_driver_register(&aat2870_bl_driver);
234}
235subsys_initcall(aat2870_bl_init);
236
237static void __exit aat2870_bl_exit(void)
238{
239 platform_driver_unregister(&aat2870_bl_driver);
240}
241module_exit(aat2870_bl_exit);
242
243MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
244MODULE_LICENSE("GPL");
245MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");
246
