Quelle  aat2870_bl.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/video/backlight/aat2870_bl.c
 *
 * Copyright (c) 2011, NVIDIA Corporation.
 * Author: Jin Park <jinyoungp@nvidia.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/backlight.h>
#include <linux/mfd/aat2870.h>

struct aat2870_bl_driver_data {
 struct platform_device *pdev;
 struct backlight_device *bd;

 int channels;
 int max_current;
 int brightness; /* current brightness */
};

static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
         int brightness)
{
 struct backlight_device *bd = aat2870_bl->bd;
 int val;

 val = brightness * (aat2870_bl->max_current - 1);
 val /= bd->props.max_brightness;

 return val;
}

static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
{
 struct aat2870_data *aat2870
   = dev_get_drvdata(aat2870_bl->pdev->dev.parent);

 return aat2870->write(aat2870, AAT2870_BL_CH_EN,
         (u8)aat2870_bl->channels);
}

static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
{
 struct aat2870_data *aat2870
   = dev_get_drvdata(aat2870_bl->pdev->dev.parent);

 return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
}

static int aat2870_bl_update_status(struct backlight_device *bd)
{
 struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
 struct aat2870_data *aat2870 =
   dev_get_drvdata(aat2870_bl->pdev->dev.parent);
 int brightness = backlight_get_brightness(bd);
 int ret;

 if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
  dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
  return -EINVAL;
 }

 dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
   bd->props.brightness, bd->props.power, bd->props.state);

 ret = aat2870->write(aat2870, AAT2870_BLM,
        (u8)aat2870_brightness(aat2870_bl, brightness));
 if (ret < 0)
  return ret;

 if (brightness == 0) {
  ret = aat2870_bl_disable(aat2870_bl);
  if (ret < 0)
   return ret;
 } else if (aat2870_bl->brightness == 0) {
  ret = aat2870_bl_enable(aat2870_bl);
  if (ret < 0)
   return ret;
 }

 aat2870_bl->brightness = brightness;

 return 0;
}

static const struct backlight_ops aat2870_bl_ops = {
 .options = BL_CORE_SUSPENDRESUME,
 .update_status = aat2870_bl_update_status,
};

static int aat2870_bl_probe(struct platform_device *pdev)
{
 struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
 struct aat2870_bl_driver_data *aat2870_bl;
 struct backlight_device *bd;
 struct backlight_properties props;
 int ret = 0;

 if (!pdata) {
  dev_err(&pdev->dev, "No platform data\n");
  ret = -ENXIO;
  goto out;
 }

 if (pdev->id != AAT2870_ID_BL) {
  dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
  ret = -EINVAL;
  goto out;
 }

 aat2870_bl = devm_kzalloc(&pdev->dev,
      sizeof(struct aat2870_bl_driver_data),
      GFP_KERNEL);
 if (!aat2870_bl) {
  ret = -ENOMEM;
  goto out;
 }

 memset(&props, 0, sizeof(struct backlight_properties));

 props.type = BACKLIGHT_RAW;
 bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
     &pdev->dev, aat2870_bl, &aat2870_bl_ops,
     &props);
 if (IS_ERR(bd)) {
  dev_err(&pdev->dev,
   "Failed allocate memory for backlight device\n");
  ret = PTR_ERR(bd);
  goto out;
 }

 aat2870_bl->pdev = pdev;
 platform_set_drvdata(pdev, aat2870_bl);

 aat2870_bl->bd = bd;

 if (pdata->channels > 0)
  aat2870_bl->channels = pdata->channels;
 else
  aat2870_bl->channels = AAT2870_BL_CH_ALL;

 if (pdata->max_current > 0)
  aat2870_bl->max_current = pdata->max_current;
 else
  aat2870_bl->max_current = AAT2870_CURRENT_27_9;

 if (pdata->max_brightness > 0)
  bd->props.max_brightness = pdata->max_brightness;
 else
  bd->props.max_brightness = 255;

 aat2870_bl->brightness = 0;
 bd->props.power = BACKLIGHT_POWER_ON;
 bd->props.brightness = bd->props.max_brightness;

 ret = aat2870_bl_update_status(bd);
 if (ret < 0) {
  dev_err(&pdev->dev, "Failed to initialize\n");
  return ret;
 }

 return 0;

out:
 return ret;
}

static void aat2870_bl_remove(struct platform_device *pdev)
{
 struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
 struct backlight_device *bd = aat2870_bl->bd;

 bd->props.power = BACKLIGHT_POWER_OFF;
 bd->props.brightness = 0;
 backlight_update_status(bd);
}

static struct platform_driver aat2870_bl_driver = {
 .driver = {
  .name = "aat2870-backlight",
 },
 .probe  = aat2870_bl_probe,
 .remove  = aat2870_bl_remove,
};

static int __init aat2870_bl_init(void)
{
 return platform_driver_register(&aat2870_bl_driver);
}
subsys_initcall(aat2870_bl_init);

static void __exit aat2870_bl_exit(void)
{
 platform_driver_unregister(&aat2870_bl_driver);
}
module_exit(aat2870_bl_exit);

MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jin Park ");