drivers/video/backlight/rave-sp-backlight.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2
   3 /*
   4  * LCD Backlight driver for RAVE SP
   5  *
   6  * Copyright (C) 2018 Zodiac Inflight Innovations
   7  *
   8  */
   9
  10 #include <linux/backlight.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mfd/rave-sp.h>
  14 #include <linux/platform_device.h>
  15
  16 #define RAVE_SP_BACKLIGHT_LCD_EN        BIT(7)
  17
  18 static int rave_sp_backlight_update_status(struct backlight_device *bd)
  19 {
  20         const struct backlight_properties *p = &bd->props;
  21         const u8 intensity =
  22                 (p->power == FB_BLANK_UNBLANK) ? p->brightness : 0;
  23         struct rave_sp *sp = dev_get_drvdata(&bd->dev);
  24         u8 cmd[] = {
  25                 [0] = RAVE_SP_CMD_SET_BACKLIGHT,
  26                 [1] = 0,
  27                 [2] = intensity ? RAVE_SP_BACKLIGHT_LCD_EN | intensity : 0,
  28                 [3] = 0,
  29                 [4] = 0,
  30         };
  31
  32         return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
  33 }
  34
  35 static const struct backlight_ops rave_sp_backlight_ops = {
  36         .options        = BL_CORE_SUSPENDRESUME,
  37         .update_status  = rave_sp_backlight_update_status,
  38 };
  39
  40 static struct backlight_properties rave_sp_backlight_props = {
  41         .type           = BACKLIGHT_PLATFORM,
  42         .max_brightness = 100,
  43         .brightness     = 50,
  44 };
  45
  46 static int rave_sp_backlight_probe(struct platform_device *pdev)
  47 {
  48         struct device *dev = &pdev->dev;
  49         struct backlight_device *bd;
  50
  51         bd = devm_backlight_device_register(dev, pdev->name, dev,
  52                                             dev_get_drvdata(dev->parent),
  53                                             &rave_sp_backlight_ops,
  54                                             &rave_sp_backlight_props);
  55         if (IS_ERR(bd))
  56                 return PTR_ERR(bd);
  57
  58         /*
  59          * If there is a phandle pointing to the device node we can
  60          * assume that another device will manage the status changes.
  61          * If not we make sure the backlight is in a consistent state.
  62          */
  63         if (!dev->of_node->phandle)
  64                 backlight_update_status(bd);
  65
  66         return 0;
  67 }
  68
  69 static const struct of_device_id rave_sp_backlight_of_match[] = {
  70         { .compatible = "zii,rave-sp-backlight" },
  71         {}
  72 };
  73
  74 static struct platform_driver rave_sp_backlight_driver = {
  75         .probe = rave_sp_backlight_probe,
  76         .driver = {
  77                 .name = KBUILD_MODNAME,
  78                 .of_match_table = rave_sp_backlight_of_match,
  79         },
  80 };
  81 module_platform_driver(rave_sp_backlight_driver);
  82
  83 MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
  84 MODULE_LICENSE("GPL");
  85 MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
  86 MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
  87 MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
  88 MODULE_DESCRIPTION("RAVE SP Backlight driver");