drivers/video/backlight/ipaq_micro_bl.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * iPAQ microcontroller backlight support
   7  * Author : Linus Walleij <linus.walleij@linaro.org>
   8  */
   9
  10 #include <linux/backlight.h>
  11 #include <linux/err.h>
  12 #include <linux/fb.h>
  13 #include <linux/init.h>
  14 #include <linux/mfd/ipaq-micro.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17
  18 static int micro_bl_update_status(struct backlight_device *bd)
  19 {
  20         struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
  21         int intensity = bd->props.brightness;
  22         struct ipaq_micro_msg msg = {
  23                 .id = MSG_BACKLIGHT,
  24                 .tx_len = 3,
  25         };
  26
  27         if (bd->props.power != FB_BLANK_UNBLANK)
  28                 intensity = 0;
  29         if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED))
  30                 intensity = 0;
  31
  32         /*
  33          * Message format:
  34          * Byte 0: backlight instance (usually 1)
  35          * Byte 1: on/off
  36          * Byte 2: intensity, 0-255
  37          */
  38         msg.tx_data[0] = 0x01;
  39         msg.tx_data[1] = intensity > 0 ? 1 : 0;
  40         msg.tx_data[2] = intensity;
  41         return ipaq_micro_tx_msg_sync(micro, &msg);
  42 }
  43
  44 static const struct backlight_ops micro_bl_ops = {
  45         .options = BL_CORE_SUSPENDRESUME,
  46         .update_status  = micro_bl_update_status,
  47 };
  48
  49 static struct backlight_properties micro_bl_props = {
  50         .type = BACKLIGHT_RAW,
  51         .max_brightness = 255,
  52         .power = FB_BLANK_UNBLANK,
  53         .brightness = 64,
  54 };
  55
  56 static int micro_backlight_probe(struct platform_device *pdev)
  57 {
  58         struct backlight_device *bd;
  59         struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
  60
  61         bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
  62                                             &pdev->dev, micro, &micro_bl_ops,
  63                                             &micro_bl_props);
  64         if (IS_ERR(bd))
  65                 return PTR_ERR(bd);
  66
  67         platform_set_drvdata(pdev, bd);
  68         backlight_update_status(bd);
  69
  70         return 0;
  71 }
  72
  73 static struct platform_driver micro_backlight_device_driver = {
  74         .driver = {
  75                 .name    = "ipaq-micro-backlight",
  76         },
  77         .probe   = micro_backlight_probe,
  78 };
  79 module_platform_driver(micro_backlight_device_driver);
  80
  81 MODULE_LICENSE("GPL v2");
  82 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
  83 MODULE_ALIAS("platform:ipaq-micro-backlight");