drivers/gpu/drm/gma500/backlight.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/gma500/backlight.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/gma500/backlight.c
Extension
.c
Size
2864 bytes
Lines
120
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
/*
 * GMA500 Backlight Interface
 *
 * Copyright (c) 2009-2011, Intel Corporation.
 *
 * Authors: Eric Knopp
 */

#include <linux/backlight.h>

#include <acpi/video.h>

#include <drm/drm_print.h>

#include "psb_drv.h"
#include "psb_intel_reg.h"
#include "psb_intel_drv.h"
#include "intel_bios.h"
#include "power.h"

void gma_backlight_enable(struct drm_device *dev)
{
	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);

	dev_priv->backlight_enabled = true;
	dev_priv->ops->backlight_set(dev, dev_priv->backlight_level);
}

void gma_backlight_disable(struct drm_device *dev)
{
	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);

	dev_priv->backlight_enabled = false;
	dev_priv->ops->backlight_set(dev, 0);
}

void gma_backlight_set(struct drm_device *dev, int v)
{
	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);

	dev_priv->backlight_level = v;
	if (dev_priv->backlight_enabled)
		dev_priv->ops->backlight_set(dev, v);
}

static int gma_backlight_get_brightness(struct backlight_device *bd)
{
	struct drm_device *dev = bl_get_data(bd);
	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);

	if (dev_priv->ops->backlight_get)
		return dev_priv->ops->backlight_get(dev);

	return dev_priv->backlight_level;
}

static int gma_backlight_update_status(struct backlight_device *bd)
{
	struct drm_device *dev = bl_get_data(bd);
	int level = backlight_get_brightness(bd);

	/* Percentage 1-100% being valid */
	if (level < 1)
		level = 1;

	gma_backlight_set(dev, level);
	return 0;
}

static const struct backlight_ops gma_backlight_ops __maybe_unused = {
	.get_brightness = gma_backlight_get_brightness,
	.update_status  = gma_backlight_update_status,
};

int gma_backlight_init(struct drm_device *dev)
{
	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
	struct backlight_properties props __maybe_unused = {};
	int ret;

	dev_priv->backlight_enabled = true;
	dev_priv->backlight_level = 100;

	ret = dev_priv->ops->backlight_init(dev);
	if (ret)
		return ret;

	if (!acpi_video_backlight_use_native()) {
		drm_info(dev, "Skipping %s backlight registration\n",

Annotation

Implementation Notes