drivers/video/backlight/omap_bl.c

   1 /*
   2  * drivers/video/backlight/omap_bl.c
   3  *
   4  * Backlight driver for OMAP based boards.
   5  *
   6  * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
   7  *
   8  * This package is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This package is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this package; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/kernel.h>
  25 #include <linux/init.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/fb.h>
  28 #include <linux/backlight.h>
  29
  30 #include <asm/arch/hardware.h>
  31 #include <asm/arch/board.h>
  32 #include <asm/arch/mux.h>
  33
  34 #define OMAPBL_MAX_INTENSITY            0xff
  35
  36 struct omap_backlight {
  37         int powermode;
  38         int current_intensity;
  39
  40         struct device *dev;
  41         struct omap_backlight_config *pdata;
  42 };
  43
  44 static void inline omapbl_send_intensity(int intensity)
  45 {
  46         omap_writeb(intensity, OMAP_PWL_ENABLE);
  47 }
  48
  49 static void inline omapbl_send_enable(int enable)
  50 {
  51         omap_writeb(enable, OMAP_PWL_CLK_ENABLE);
  52 }
  53
  54 static void omapbl_blank(struct omap_backlight *bl, int mode)
  55 {
  56         if (bl->pdata->set_power)
  57                 bl->pdata->set_power(bl->dev, mode);
  58
  59         switch (mode) {
  60         case FB_BLANK_NORMAL:
  61         case FB_BLANK_VSYNC_SUSPEND:
  62         case FB_BLANK_HSYNC_SUSPEND:
  63         case FB_BLANK_POWERDOWN:
  64                 omapbl_send_intensity(0);
  65                 omapbl_send_enable(0);
  66                 break;
  67
  68         case FB_BLANK_UNBLANK:
  69                 omapbl_send_intensity(bl->current_intensity);
  70                 omapbl_send_enable(1);
  71                 break;
  72         }
  73 }
  74
  75 #ifdef CONFIG_PM
  76 static int omapbl_suspend(struct platform_device *pdev, pm_message_t state)
  77 {
  78         struct backlight_device *dev = platform_get_drvdata(pdev);
  79         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
  80
  81         omapbl_blank(bl, FB_BLANK_POWERDOWN);
  82         return 0;
  83 }
  84
  85 static int omapbl_resume(struct platform_device *pdev)
  86 {
  87         struct backlight_device *dev = platform_get_drvdata(pdev);
  88         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
  89
  90         omapbl_blank(bl, bl->powermode);
  91         return 0;
  92 }
  93 #else
  94 #define omapbl_suspend  NULL
  95 #define omapbl_resume   NULL
  96 #endif
  97
  98 static int omapbl_set_power(struct backlight_device *dev, int state)
  99 {
 100         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
 101
 102         omapbl_blank(bl, state);
 103         bl->powermode = state;
 104
 105         return 0;
 106 }
 107
 108 static int omapbl_update_status(struct backlight_device *dev)
 109 {
 110         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
 111
 112         if (bl->current_intensity != dev->props->brightness) {
 113                 if (dev->props->brightness < 0)
 114                         return -EPERM;  /* Leave current_intensity untouched */
 115
 116                 if (bl->powermode == FB_BLANK_UNBLANK)
 117                         omapbl_send_intensity(dev->props->brightness);
 118                 bl->current_intensity = dev->props->brightness;
 119         }
 120
 121         if (dev->props->fb_blank != bl->powermode)
 122                 omapbl_set_power(dev, dev->props->fb_blank);
 123
 124         return 0;
 125 }
 126
 127 static int omapbl_get_intensity(struct backlight_device *dev)
 128 {
 129         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
 130         return bl->current_intensity;
 131 }
 132
 133 static struct backlight_properties omapbl_data = {
 134         .owner          = THIS_MODULE,
 135         .get_brightness = omapbl_get_intensity,
 136         .update_status  = omapbl_update_status,
 137         .max_brightness = OMAPBL_MAX_INTENSITY,
 138 };
 139
 140 static int omapbl_probe(struct platform_device *pdev)
 141 {
 142         struct backlight_device *dev;
 143         struct omap_backlight *bl;
 144         struct omap_backlight_config *pdata = pdev->dev.platform_data;
 145
 146         if (!pdata)
 147                 return -ENXIO;
 148
 149         omapbl_data.check_fb = pdata->check_fb;
 150
 151         bl = kzalloc(sizeof(struct omap_backlight), GFP_KERNEL);
 152         if (unlikely(!bl))
 153                 return -ENOMEM;
 154
 155         /* REVISIT backlight API glitch:  we can't associate the
 156          * class device with "pdev" ... probably pass &pdev->dev
 157          * instead of a string.
 158          */
 159
 160         dev = backlight_device_register("omap-bl", bl, &omapbl_data);
 161         if (IS_ERR(dev)) {
 162                 kfree(bl);
 163                 return PTR_ERR(dev);
 164         }
 165
 166         bl->powermode = FB_BLANK_POWERDOWN;
 167         bl->current_intensity = 0;
 168
 169         bl->pdata = pdata;
 170         bl->dev = &pdev->dev;
 171
 172         platform_set_drvdata(pdev, dev);
 173
 174         omap_cfg_reg(PWL);      /* Conflicts with UART3 */
 175
 176         omapbl_data.fb_blank = FB_BLANK_UNBLANK;
 177         omapbl_data.brightness = pdata->default_intensity;
 178         omapbl_update_status(dev);
 179
 180         printk(KERN_INFO "OMAP LCD backlight initialised\n");
 181
 182         return 0;
 183 }
 184
 185 static int omapbl_remove(struct platform_device *pdev)
 186 {
 187         struct backlight_device *dev = platform_get_drvdata(pdev);
 188         struct omap_backlight *bl = class_get_devdata(&dev->class_dev);
 189
 190         backlight_device_unregister(dev);
 191         kfree(bl);
 192
 193         return 0;
 194 }
 195
 196 static struct platform_driver omapbl_driver = {
 197         .probe          = omapbl_probe,
 198         .remove         = omapbl_remove,
 199         .suspend        = omapbl_suspend,
 200         .resume         = omapbl_resume,
 201         .driver         = {
 202                 .name   = "omap-bl",
 203         },
 204 };
 205
 206 static int __init omapbl_init(void)
 207 {
 208         return platform_driver_register(&omapbl_driver);
 209 }
 210
 211 static void __exit omapbl_exit(void)
 212 {
 213         platform_driver_unregister(&omapbl_driver);
 214 }
 215
 216 module_init(omapbl_init);
 217 module_exit(omapbl_exit);
 218
 219 MODULE_AUTHOR("Andrzej Zaborowski <balrog@zabor.org>");
 220 MODULE_DESCRIPTION("OMAP LCD Backlight driver");
 221 MODULE_LICENSE("GPL");