drivers/video/fbdev/nvidia/nv_backlight.c

Source file repositories/reference/linux-study-clean/drivers/video/fbdev/nvidia/nv_backlight.c

File Facts

System
Linux kernel
Corpus path
drivers/video/fbdev/nvidia/nv_backlight.c
Extension
.c
Size
3218 bytes
Lines
132
Domain
Driver Families
Bucket
drivers/video
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
/*
 * Backlight code for nVidia based graphic cards
 *
 * Copyright 2004 Antonino Daplas <adaplas@pol.net>
 * Copyright (c) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
 */

#include <linux/backlight.h>
#include <linux/fb.h>
#include <linux/pci.h>

#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif

#include "nv_local.h"
#include "nv_type.h"
#include "nv_proto.h"

/* We do not have any information about which values are allowed, thus
 * we used safe values.
 */
#define MIN_LEVEL 0x158
#define MAX_LEVEL 0x534
#define LEVEL_STEP ((MAX_LEVEL - MIN_LEVEL) / FB_BACKLIGHT_MAX)

static int nvidia_bl_get_level_brightness(struct nvidia_par *par,
		int level)
{
	struct fb_info *info = pci_get_drvdata(par->pci_dev);
	int nlevel;

	/* Get and convert the value */
	/* No locking of bl_curve since we read a single value */
	nlevel = MIN_LEVEL + info->bl_curve[level] * LEVEL_STEP;

	if (nlevel < 0)
		nlevel = 0;
	else if (nlevel < MIN_LEVEL)
		nlevel = MIN_LEVEL;
	else if (nlevel > MAX_LEVEL)
		nlevel = MAX_LEVEL;

	return nlevel;
}

static int nvidia_bl_update_status(struct backlight_device *bd)
{
	struct nvidia_par *par = bl_get_data(bd);
	u32 tmp_pcrt, tmp_pmc, fpcontrol;
	int level = backlight_get_brightness(bd);

	if (!par->FlatPanel)
		return 0;

	tmp_pmc = NV_RD32(par->PMC, 0x10F0) & 0x0000FFFF;
	tmp_pcrt = NV_RD32(par->PCRTC0, 0x081C) & 0xFFFFFFFC;
	fpcontrol = NV_RD32(par->PRAMDAC, 0x0848) & 0xCFFFFFCC;

	if (level > 0) {
		tmp_pcrt |= 0x1;
		tmp_pmc |= (1 << 31); /* backlight bit */
		tmp_pmc |= nvidia_bl_get_level_brightness(par, level) << 16;
		fpcontrol |= par->fpSyncs;
	} else
		fpcontrol |= 0x20000022;

	NV_WR32(par->PCRTC0, 0x081C, tmp_pcrt);
	NV_WR32(par->PMC, 0x10F0, tmp_pmc);
	NV_WR32(par->PRAMDAC, 0x848, fpcontrol);

	return 0;
}

static const struct backlight_ops nvidia_bl_ops = {
	.update_status	= nvidia_bl_update_status,
};

void nvidia_bl_init(struct nvidia_par *par)
{
	struct backlight_properties props;
	struct fb_info *info = pci_get_drvdata(par->pci_dev);
	struct backlight_device *bd;
	char name[12];

	if (!par->FlatPanel)
		return;

#ifdef CONFIG_PMAC_BACKLIGHT

Annotation

Implementation Notes