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