nv_backlight.c

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/*
 * Backlight code for nVidia based graphic cards
 *
 * Copyright 2004 Antonino Daplas <[email protected]>
 * Copyright (c) 2006 Michael Hanselmann <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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;

    if (!par->FlatPanel)
        return 0;

    if (bd->props.power != FB_BLANK_UNBLANK ||
        bd->props.fb_blank != FB_BLANK_UNBLANK)
        level = 0;
    else
        level = bd->props.brightness;

    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 int nvidia_bl_get_brightness(struct backlight_device *bd)
{
    return bd->props.brightness;
}

static const struct backlight_ops nvidia_bl_ops = {
    .get_brightness = nvidia_bl_get_brightness,
    .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
    if (!machine_is(powermac) ||
        !pmac_has_backlight_type("mnca"))
        return;
#endif

    snprintf(name, sizeof(name), "nvidiabl%d", info->node);

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_RAW;
    props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
    bd = backlight_device_register(name, info->dev, par, &nvidia_bl_ops,
                       &props);
    if (IS_ERR(bd)) {
        info->bl_dev = NULL;
        printk(KERN_WARNING "nvidia: Backlight registration failed\n");
        goto error;
    }

    info->bl_dev = bd;
    fb_bl_default_curve(info, 0,
        0x158 * FB_BACKLIGHT_MAX / MAX_LEVEL,
        0x534 * FB_BACKLIGHT_MAX / MAX_LEVEL);

    bd->props.brightness = bd->props.max_brightness;
    bd->props.power = FB_BLANK_UNBLANK;
    backlight_update_status(bd);

    printk("nvidia: Backlight initialized (%s)\n", name);

    return;

error:
    return;
}

void nvidia_bl_exit(struct nvidia_par *par)
{
    struct fb_info *info = pci_get_drvdata(par->pci_dev);
    struct backlight_device *bd = info->bl_dev;

    backlight_device_unregister(bd);
    printk("nvidia: Backlight unloaded\n");
}