via-pmu-backlight.c

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/*
 * Backlight code for via-pmu
 *
 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
 * Copyright (C) 2001-2002 Benjamin Herrenschmidt
 * Copyright (C) 2006      Michael Hanselmann <[email protected]>
 *
 */

#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;
    if (pmulevel < 0)
        pmulevel = 0;
    else if (pmulevel > MAX_PMU_LEVEL)
        pmulevel = MAX_PMU_LEVEL;

    return pmulevel;
}

static int __pmu_backlight_update_status(struct backlight_device *bd)
{
    struct adb_request req;
    int level = bd->props.brightness;


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

    if (level > 0) {
        int pmulevel = pmu_backlight_get_level_brightness(level);

        pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
        pmu_wait_complete(&req);

        pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
            PMU_POW_BACKLIGHT | PMU_POW_ON);
        pmu_wait_complete(&req);
    } else {
        pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
            PMU_POW_BACKLIGHT | PMU_POW_OFF);
        pmu_wait_complete(&req);
    }

    return 0;
}

static int pmu_backlight_update_status(struct backlight_device *bd)
{
    unsigned long flags;
    int rc = 0;

    spin_lock_irqsave(&pmu_backlight_lock, flags);
    /* Don't update brightness when sleeping */
    if (!sleeping)
        rc = __pmu_backlight_update_status(bd);
    spin_unlock_irqrestore(&pmu_backlight_lock, flags);
    return rc;
}


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

static const struct backlight_ops pmu_backlight_data = {
    .get_brightness = pmu_backlight_get_brightness,
    .update_status  = pmu_backlight_update_status,

};

#ifdef CONFIG_PM
void pmu_backlight_set_sleep(int sleep)
{
    unsigned long flags;

    spin_lock_irqsave(&pmu_backlight_lock, flags);
    sleeping = sleep;
    if (pmac_backlight && uses_pmu_bl) {
        if (sleep) {
            struct adb_request req;

            pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
                    PMU_POW_BACKLIGHT | PMU_POW_OFF);
            pmu_wait_complete(&req);
        } else
            __pmu_backlight_update_status(pmac_backlight);
    }
    spin_unlock_irqrestore(&pmu_backlight_lock, flags);
}
#endif /* CONFIG_PM */

void __init pmu_backlight_init()
{
    struct backlight_properties props;
    struct backlight_device *bd;
    char name[10];
    int level, autosave;

    /* Special case for the old PowerBook since I can't test on it */
    autosave =
        of_machine_is_compatible("AAPL,3400/2400") ||
        of_machine_is_compatible("AAPL,3500");

    if (!autosave &&
        !pmac_has_backlight_type("pmu") &&
        !of_machine_is_compatible("AAPL,PowerBook1998") &&
        !of_machine_is_compatible("PowerBook1,1"))
        return;

    snprintf(name, sizeof(name), "pmubl");

    memset(&props, 0, sizeof(struct backlight_properties));
    props.type = BACKLIGHT_PLATFORM;
    props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
    bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
                       &props);
    if (IS_ERR(bd)) {
        printk(KERN_ERR "PMU Backlight registration failed\n");
        return;
    }
    uses_pmu_bl = 1;
    pmu_backlight_init_curve(0x7F, 0x46, 0x0E);

    level = bd->props.max_brightness;

    if (autosave) {
        /* read autosaved value if available */
        struct adb_request req;
        pmu_request(&req, NULL, 2, 0xd9, 0);
        pmu_wait_complete(&req);

        level = pmu_backlight_curve_lookup(
                (req.reply[0] >> 4) *
                bd->props.max_brightness / 15);
    }

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

    printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
}