LXR linux/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
  18static 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
  35static const struct backlight_ops rave_sp_backlight_ops = {
  36        .options        = BL_CORE_SUSPENDRESUME,
  37        .update_status  = rave_sp_backlight_update_status,
  38};
  39
  40static struct backlight_properties rave_sp_backlight_props = {
  41        .type           = BACKLIGHT_PLATFORM,
  42        .max_brightness = 100,
  43        .brightness     = 50,
  44};
  45
  46static 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
  69static const struct of_device_id rave_sp_backlight_of_match[] = {
  70        { .compatible = "zii,rave-sp-backlight" },
  71        {}
  72};
  73
  74static 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};
  81module_platform_driver(rave_sp_backlight_driver);
  82
  83MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
  84MODULE_LICENSE("GPL");
  85MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");
  86MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");
  87MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
  88MODULE_DESCRIPTION("RAVE SP Backlight driver");
  89