kernel/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_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
 111 static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
 112 {
 113         return 1;
 114 }
 115
 116 static 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
 122 static 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
 195 out:
 196         return ret;
 197 }
 198
 199 static 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
 211 static 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
 219 static int __init aat2870_bl_init(void)
 220 {
 221         return platform_driver_register(&aat2870_bl_driver);
 222 }
 223 subsys_initcall(aat2870_bl_init);
 224
 225 static void __exit aat2870_bl_exit(void)
 226 {
 227         platform_driver_unregister(&aat2870_bl_driver);
 228 }
 229 module_exit(aat2870_bl_exit);
 230
 231 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
 232 MODULE_LICENSE("GPL");
 233 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");