pm-gpio.c

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/* linux/arch/arm/plat-s3c/pm-gpio.c
 *
 * Copyright 2008 Openmoko, Inc.
 * Copyright 2008 Simtec Electronics
 *  Ben Dooks <[email protected]>
 *  http://armlinux.simtec.co.uk/
 *
 * S3C series GPIO PM code
 *
 * 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/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/gpio.h>

#include <plat/gpio-core.h>
#include <plat/pm.h>

/* PM GPIO helpers */

#define OFFS_CON    (0x00)
#define OFFS_DAT    (0x04)
#define OFFS_UP     (0x08)

static void samsung_gpio_pm_1bit_save(struct samsung_gpio_chip *chip)
{
    chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
    chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
}

static void samsung_gpio_pm_1bit_resume(struct samsung_gpio_chip *chip)
{
    void __iomem *base = chip->base;
    u32 old_gpcon = __raw_readl(base + OFFS_CON);
    u32 old_gpdat = __raw_readl(base + OFFS_DAT);
    u32 gps_gpcon = chip->pm_save[0];
    u32 gps_gpdat = chip->pm_save[1];
    u32 gpcon;

    /* GPACON only has one bit per control / data and no PULLUPs.
     * GPACON[x] = 0 => Output, 1 => SFN */

    /* first set all SFN bits to SFN */

    gpcon = old_gpcon | gps_gpcon;
    __raw_writel(gpcon, base + OFFS_CON);

    /* now set all the other bits */

    __raw_writel(gps_gpdat, base + OFFS_DAT);
    __raw_writel(gps_gpcon, base + OFFS_CON);

    S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
          chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
}

struct samsung_gpio_pm samsung_gpio_pm_1bit = {
    .save   = samsung_gpio_pm_1bit_save,
    .resume = samsung_gpio_pm_1bit_resume,
};

static void samsung_gpio_pm_2bit_save(struct samsung_gpio_chip *chip)
{
    chip->pm_save[0] = __raw_readl(chip->base + OFFS_CON);
    chip->pm_save[1] = __raw_readl(chip->base + OFFS_DAT);
    chip->pm_save[2] = __raw_readl(chip->base + OFFS_UP);
}

/* Test whether the given masked+shifted bits of an GPIO configuration
 * are one of the SFN (special function) modes. */

static inline int is_sfn(unsigned long con)
{
    return con >= 2;
}

/* Test if the given masked+shifted GPIO configuration is an input */

static inline int is_in(unsigned long con)
{
    return con == 0;
}

/* Test if the given masked+shifted GPIO configuration is an output */

static inline int is_out(unsigned long con)
{
    return con == 1;
}

static void samsung_gpio_pm_2bit_resume(struct samsung_gpio_chip *chip)
{
    void __iomem *base = chip->base;
    u32 old_gpcon = __raw_readl(base + OFFS_CON);
    u32 old_gpdat = __raw_readl(base + OFFS_DAT);
    u32 gps_gpcon = chip->pm_save[0];
    u32 gps_gpdat = chip->pm_save[1];
    u32 gpcon, old, new, mask;
    u32 change_mask = 0x0;
    int nr;

    /* restore GPIO pull-up settings */
    __raw_writel(chip->pm_save[2], base + OFFS_UP);

    /* Create a change_mask of all the items that need to have
     * their CON value changed before their DAT value, so that
     * we minimise the work between the two settings.
     */

    for (nr = 0, mask = 0x03; nr < 32; nr += 2, mask <<= 2) {
        old = (old_gpcon & mask) >> nr;
        new = (gps_gpcon & mask) >> nr;

        /* If there is no change, then skip */

        if (old == new)
            continue;

        /* If both are special function, then skip */

        if (is_sfn(old) && is_sfn(new))
            continue;

        /* Change is IN => OUT, do not change now */

        if (is_in(old) && is_out(new))
            continue;

        /* Change is SFN => OUT, do not change now */

        if (is_sfn(old) && is_out(new))
            continue;

        /* We should now be at the case of IN=>SFN,
         * OUT=>SFN, OUT=>IN, SFN=>IN. */

        change_mask |= mask;
    }


    /* Write the new CON settings */

    gpcon = old_gpcon & ~change_mask;
    gpcon |= gps_gpcon & change_mask;

    __raw_writel(gpcon, base + OFFS_CON);

    /* Now change any items that require DAT,CON */

    __raw_writel(gps_gpdat, base + OFFS_DAT);
    __raw_writel(gps_gpcon, base + OFFS_CON);

    S3C_PMDBG("%s: CON %08x => %08x, DAT %08x => %08x\n",
          chip->chip.label, old_gpcon, gps_gpcon, old_gpdat, gps_gpdat);
}

struct samsung_gpio_pm samsung_gpio_pm_2bit = {
    .save   = samsung_gpio_pm_2bit_save,
    .resume = samsung_gpio_pm_2bit_resume,
};

#if defined(CONFIG_ARCH_S3C64XX) || defined(CONFIG_PLAT_S5P)
static void samsung_gpio_pm_4bit_save(struct samsung_gpio_chip *chip)
{
    chip->pm_save[1] = __raw_readl(chip->base + OFFS_CON);
    chip->pm_save[2] = __raw_readl(chip->base + OFFS_DAT);
    chip->pm_save[3] = __raw_readl(chip->base + OFFS_UP);

    if (chip->chip.ngpio > 8)
        chip->pm_save[0] = __raw_readl(chip->base - 4);
}

static u32 samsung_gpio_pm_4bit_mask(u32 old_gpcon, u32 gps_gpcon)
{
    u32 old, new, mask;
    u32 change_mask = 0x0;
    int nr;

    for (nr = 0, mask = 0x0f; nr < 16; nr += 4, mask <<= 4) {
        old = (old_gpcon & mask) >> nr;
        new = (gps_gpcon & mask) >> nr;

        /* If there is no change, then skip */

        if (old == new)
            continue;

        /* If both are special function, then skip */

        if (is_sfn(old) && is_sfn(new))
            continue;

        /* Change is IN => OUT, do not change now */

        if (is_in(old) && is_out(new))
            continue;

        /* Change is SFN => OUT, do not change now */

        if (is_sfn(old) && is_out(new))
            continue;

        /* We should now be at the case of IN=>SFN,
         * OUT=>SFN, OUT=>IN, SFN=>IN. */

        change_mask |= mask;
    }

    return change_mask;
}

static void samsung_gpio_pm_4bit_con(struct samsung_gpio_chip *chip, int index)
{
    void __iomem *con = chip->base + (index * 4);
    u32 old_gpcon = __raw_readl(con);
    u32 gps_gpcon = chip->pm_save[index + 1];
    u32 gpcon, mask;

    mask = samsung_gpio_pm_4bit_mask(old_gpcon, gps_gpcon);

    gpcon = old_gpcon & ~mask;
    gpcon |= gps_gpcon & mask;

    __raw_writel(gpcon, con);
}

static void samsung_gpio_pm_4bit_resume(struct samsung_gpio_chip *chip)
{
    void __iomem *base = chip->base;
    u32 old_gpcon[2];
    u32 old_gpdat = __raw_readl(base + OFFS_DAT);
    u32 gps_gpdat = chip->pm_save[2];

    /* First, modify the CON settings */

    old_gpcon[0] = 0;
    old_gpcon[1] = __raw_readl(base + OFFS_CON);

    samsung_gpio_pm_4bit_con(chip, 0);
    if (chip->chip.ngpio > 8) {
        old_gpcon[0] = __raw_readl(base - 4);
        samsung_gpio_pm_4bit_con(chip, -1);
    }

    /* Now change the configurations that require DAT,CON */

    __raw_writel(chip->pm_save[2], base + OFFS_DAT);
    __raw_writel(chip->pm_save[1], base + OFFS_CON);
    if (chip->chip.ngpio > 8)
        __raw_writel(chip->pm_save[0], base - 4);

    __raw_writel(chip->pm_save[2], base + OFFS_DAT);
    __raw_writel(chip->pm_save[3], base + OFFS_UP);

    if (chip->chip.ngpio > 8) {
        S3C_PMDBG("%s: CON4 %08x,%08x => %08x,%08x, DAT %08x => %08x\n",
              chip->chip.label, old_gpcon[0], old_gpcon[1],
              __raw_readl(base - 4),
              __raw_readl(base + OFFS_CON),
              old_gpdat, gps_gpdat);
    } else
        S3C_PMDBG("%s: CON4 %08x => %08x, DAT %08x => %08x\n",
              chip->chip.label, old_gpcon[1],
              __raw_readl(base + OFFS_CON),
              old_gpdat, gps_gpdat);
}

struct samsung_gpio_pm samsung_gpio_pm_4bit = {
    .save   = samsung_gpio_pm_4bit_save,
    .resume = samsung_gpio_pm_4bit_resume,
};
#endif /* CONFIG_ARCH_S3C64XX || CONFIG_PLAT_S5P */

static void samsung_pm_save_gpio(struct samsung_gpio_chip *ourchip)
{
    struct samsung_gpio_pm *pm = ourchip->pm;

    if (pm == NULL || pm->save == NULL)
        S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
    else
        pm->save(ourchip);
}

void samsung_pm_save_gpios(void)
{
    struct samsung_gpio_chip *ourchip;
    unsigned int gpio_nr;

    for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
        ourchip = samsung_gpiolib_getchip(gpio_nr);
        if (!ourchip) {
            gpio_nr++;
            continue;
        }

        samsung_pm_save_gpio(ourchip);

        S3C_PMDBG("%s: save %08x,%08x,%08x,%08x\n",
              ourchip->chip.label,
              ourchip->pm_save[0],
              ourchip->pm_save[1],
              ourchip->pm_save[2],
              ourchip->pm_save[3]);

        gpio_nr += ourchip->chip.ngpio;
        gpio_nr += CONFIG_S3C_GPIO_SPACE;
    }
}

static void samsung_pm_resume_gpio(struct samsung_gpio_chip *ourchip)
{
    struct samsung_gpio_pm *pm = ourchip->pm;

    if (pm == NULL || pm->resume == NULL)
        S3C_PMDBG("%s: no pm for %s\n", __func__, ourchip->chip.label);
    else
        pm->resume(ourchip);
}

void samsung_pm_restore_gpios(void)
{
    struct samsung_gpio_chip *ourchip;
    unsigned int gpio_nr;

    for (gpio_nr = 0; gpio_nr < S3C_GPIO_END;) {
        ourchip = samsung_gpiolib_getchip(gpio_nr);
        if (!ourchip) {
            gpio_nr++;
            continue;
        }

        samsung_pm_resume_gpio(ourchip);

        gpio_nr += ourchip->chip.ngpio;
        gpio_nr += CONFIG_S3C_GPIO_SPACE;
    }
}