]> git.openfabrics.org - ~shefty/rdma-dev.git/blob - drivers/video/backlight/aat2870_bl.c
drivers/video/backlight/aat2870_bl.c: fix setting max_current
[~shefty/rdma-dev.git] / drivers / video / backlight / aat2870_bl.c
1 /*
2  * linux/drivers/video/backlight/aat2870_bl.c
3  *
4  * Copyright (c) 2011, NVIDIA Corporation.
5  * Author: Jin Park <jinyoungp@nvidia.com>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * version 2 as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19  * 02110-1301 USA
20  */
21
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
32 struct 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; /* current brightness */
39 };
40
41 static 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
53 static 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
62 static 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
70 static int aat2870_bl_get_brightness(struct backlight_device *bd)
71 {
72         return bd->props.brightness;
73 }
74
75 static int aat2870_bl_update_status(struct backlight_device *bd)
76 {
77         struct aat2870_bl_driver_data *aat2870_bl = dev_get_drvdata(&bd->dev);
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
116 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
117 {
118         return 1;
119 }
120
121 static 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
128 static 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 = kzalloc(sizeof(struct aat2870_bl_driver_data), GFP_KERNEL);
149         if (!aat2870_bl) {
150                 dev_err(&pdev->dev,
151                         "Failed to allocate memory for aat2870 backlight\n");
152                 ret = -ENOMEM;
153                 goto out;
154         }
155
156         memset(&props, 0, sizeof(struct backlight_properties));
157
158         props.type = BACKLIGHT_RAW;
159         bd = backlight_device_register("aat2870-backlight", &pdev->dev,
160                                        aat2870_bl, &aat2870_bl_ops, &props);
161         if (IS_ERR(bd)) {
162                 dev_err(&pdev->dev,
163                         "Failed allocate memory for backlight device\n");
164                 ret = PTR_ERR(bd);
165                 goto out_kfree;
166         }
167
168         aat2870_bl->pdev = pdev;
169         platform_set_drvdata(pdev, aat2870_bl);
170
171         aat2870_bl->bd = bd;
172
173         if (pdata->channels > 0)
174                 aat2870_bl->channels = pdata->channels;
175         else
176                 aat2870_bl->channels = AAT2870_BL_CH_ALL;
177
178         if (pdata->max_current > 0)
179                 aat2870_bl->max_current = pdata->max_current;
180         else
181                 aat2870_bl->max_current = AAT2870_CURRENT_27_9;
182
183         if (pdata->max_brightness > 0)
184                 bd->props.max_brightness = pdata->max_brightness;
185         else
186                 bd->props.max_brightness = 255;
187
188         aat2870_bl->brightness = 0;
189         bd->props.power = FB_BLANK_UNBLANK;
190         bd->props.brightness = bd->props.max_brightness;
191
192         ret = aat2870_bl_update_status(bd);
193         if (ret < 0) {
194                 dev_err(&pdev->dev, "Failed to initialize\n");
195                 goto out_bl_dev_unregister;
196         }
197
198         return 0;
199
200 out_bl_dev_unregister:
201         backlight_device_unregister(bd);
202 out_kfree:
203         kfree(aat2870_bl);
204 out:
205         return ret;
206 }
207
208 static 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         kfree(aat2870_bl);
219
220         return 0;
221 }
222
223 static struct platform_driver aat2870_bl_driver = {
224         .driver = {
225                 .name   = "aat2870-backlight",
226                 .owner  = THIS_MODULE,
227         },
228         .probe          = aat2870_bl_probe,
229         .remove         = aat2870_bl_remove,
230 };
231
232 static int __init aat2870_bl_init(void)
233 {
234         return platform_driver_register(&aat2870_bl_driver);
235 }
236 subsys_initcall(aat2870_bl_init);
237
238 static void __exit aat2870_bl_exit(void)
239 {
240         platform_driver_unregister(&aat2870_bl_driver);
241 }
242 module_exit(aat2870_bl_exit);
243
244 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
245 MODULE_LICENSE("GPL");
246 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");