linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Backlight code for via-pmu

 *

 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.

 * Copyright (C) 2001-2002 Benjamin Herrenschmidt

 * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>

 *

 */

​

#include <asm/ptrace.h>

#include <linux/adb.h>

#include <linux/pmu.h>

#include <asm/backlight.h>

#include <asm/prom.h>

​

#define MAX_PMU_LEVEL 0xFF

​

static const struct backlight_ops pmu_backlight_data;

static DEFINE_SPINLOCK(pmu_backlight_lock);

static int sleeping, uses_pmu_bl;

static u8 bl_curve[FB_BACKLIGHT_LEVELS];

​

static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)

{

    int i, flat, count, range = (max - min);

​

    bl_curve[0] = off;

​

    for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)

        bl_curve[flat] = min;

​

    count = FB_BACKLIGHT_LEVELS * 15 / 16;

    for (i = 0; i < count; ++i)

        bl_curve[flat + i] = min + (range * (i + 1) / count);

}

​

static int pmu_backlight_curve_lookup(int value)

{

    int level = (FB_BACKLIGHT_LEVELS - 1);

    int i, max = 0;

​

    /* Look for biggest value */

    for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)

        max = max((int)bl_curve[i], max);

​

    /* Look for nearest value */

    for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {

        int diff = abs(bl_curve[i] - value);

        if (diff < max) {

            max = diff;

            level = i;

        }

    }

    return level;

}

​

static int pmu_backlight_get_level_brightness(int level)

{

    int pmulevel;

​

    /* Get and convert the value */

    pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;