// 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
        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->device, 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 = BACKLIGHT_POWER_ON;
        backlight_update_status(bd);

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

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");
}