drivers/video/backlight/ipaq_micro_bl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  * iPAQ microcontroller backlight support
   5  * Author : Linus Walleij <linus.walleij@linaro.org>
   6  */
   7
   8 #include <linux/backlight.h>
   9 #include <linux/err.h>
  10 #include <linux/fb.h>
  11 #include <linux/init.h>
  12 #include <linux/mfd/ipaq-micro.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15
  16 static int micro_bl_update_status(struct backlight_device *bd)
  17 {
  18         struct ipaq_micro *micro = dev_get_drvdata(&bd->dev);
  19         int intensity = bd->props.brightness;
  20         struct ipaq_micro_msg msg = {
  21                 .id = MSG_BACKLIGHT,
  22                 .tx_len = 3,
  23         };
  24
  25         if (bd->props.power != FB_BLANK_UNBLANK)
  26                 intensity = 0;
  27         if (bd->props.state & (BL_CORE_FBBLANK | BL_CORE_SUSPENDED))
  28                 intensity = 0;
  29
  30         /*
  31          * Message format:
  32          * Byte 0: backlight instance (usually 1)
  33          * Byte 1: on/off
  34          * Byte 2: intensity, 0-255
  35          */
  36         msg.tx_data[0] = 0x01;
  37         msg.tx_data[1] = intensity > 0 ? 1 : 0;
  38         msg.tx_data[2] = intensity;
  39         return ipaq_micro_tx_msg_sync(micro, &msg);
  40 }
  41
  42 static const struct backlight_ops micro_bl_ops = {
  43         .options = BL_CORE_SUSPENDRESUME,
  44         .update_status  = micro_bl_update_status,
  45 };
  46
  47 static const struct backlight_properties micro_bl_props = {
  48         .type = BACKLIGHT_RAW,
  49         .max_brightness = 255,
  50         .power = FB_BLANK_UNBLANK,
  51         .brightness = 64,
  52 };
  53
  54 static int micro_backlight_probe(struct platform_device *pdev)
  55 {
  56         struct backlight_device *bd;
  57         struct ipaq_micro *micro = dev_get_drvdata(pdev->dev.parent);
  58
  59         bd = devm_backlight_device_register(&pdev->dev, "ipaq-micro-backlight",
  60                                             &pdev->dev, micro, &micro_bl_ops,
  61                                             &micro_bl_props);
  62         if (IS_ERR(bd))
  63                 return PTR_ERR(bd);
  64
  65         platform_set_drvdata(pdev, bd);
  66         backlight_update_status(bd);
  67
  68         return 0;
  69 }
  70
  71 static struct platform_driver micro_backlight_device_driver = {
  72         .driver = {
  73                 .name    = "ipaq-micro-backlight",
  74         },
  75         .probe   = micro_backlight_probe,
  76 };
  77 module_platform_driver(micro_backlight_device_driver);
  78
  79 MODULE_LICENSE("GPL v2");
  80 MODULE_DESCRIPTION("driver for iPAQ Atmel micro backlight");
  81 MODULE_ALIAS("platform:ipaq-micro-backlight");