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 = 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
 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 = dev_get_platdata(&pdev->dev);
 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 = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
 162                                         &pdev->dev, aat2870_bl, &aat2870_bl_ops,
 163                                         &props);
 164         if (IS_ERR(bd)) {
 165                 dev_err(&pdev->dev,
 166                         "Failed allocate memory for backlight device\n");
 167                 ret = PTR_ERR(bd);
 168                 goto out;
 169         }
 170
 171         aat2870_bl->pdev = pdev;
 172         platform_set_drvdata(pdev, aat2870_bl);
 173
 174         aat2870_bl->bd = bd;
 175
 176         if (pdata->channels > 0)
 177                 aat2870_bl->channels = pdata->channels;
 178         else
 179                 aat2870_bl->channels = AAT2870_BL_CH_ALL;
 180
 181         if (pdata->max_current > 0)
 182                 aat2870_bl->max_current = pdata->max_current;
 183         else
 184                 aat2870_bl->max_current = AAT2870_CURRENT_27_9;
 185
 186         if (pdata->max_brightness > 0)
 187                 bd->props.max_brightness = pdata->max_brightness;
 188         else
 189                 bd->props.max_brightness = 255;
 190
 191         aat2870_bl->brightness = 0;
 192         bd->props.power = FB_BLANK_UNBLANK;
 193         bd->props.brightness = bd->props.max_brightness;
 194
 195         ret = aat2870_bl_update_status(bd);
 196         if (ret < 0) {
 197                 dev_err(&pdev->dev, "Failed to initialize\n");
 198                 return ret;
 199         }
 200
 201         return 0;
 202
 203 out:
 204         return ret;
 205 }
 206
 207 static int aat2870_bl_remove(struct platform_device *pdev)
 208 {
 209         struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
 210         struct backlight_device *bd = aat2870_bl->bd;
 211
 212         bd->props.power = FB_BLANK_POWERDOWN;
 213         bd->props.brightness = 0;
 214         backlight_update_status(bd);
 215
 216         return 0;
 217 }
 218
 219 static struct platform_driver aat2870_bl_driver = {
 220         .driver = {
 221                 .name   = "aat2870-backlight",
 222                 .owner  = THIS_MODULE,
 223         },
 224         .probe          = aat2870_bl_probe,
 225         .remove         = aat2870_bl_remove,
 226 };
 227
 228 static int __init aat2870_bl_init(void)
 229 {
 230         return platform_driver_register(&aat2870_bl_driver);
 231 }
 232 subsys_initcall(aat2870_bl_init);
 233
 234 static void __exit aat2870_bl_exit(void)
 235 {
 236         platform_driver_unregister(&aat2870_bl_driver);
 237 }
 238 module_exit(aat2870_bl_exit);
 239
 240 MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
 241 MODULE_LICENSE("GPL");
 242 MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");