mfp.c

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/*
 * linux/arch/arm/plat-pxa/mfp.c
 *
 *   Multi-Function Pin Support
 *
 * Copyright (C) 2007 Marvell Internation Ltd.
 *
 * 2007-08-21: eric miao <[email protected]>
 *             initial version
 *
 *  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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>

#include <plat/mfp.h>

#define MFPR_SIZE   (PAGE_SIZE)

/* MFPR register bit definitions */
#define MFPR_PULL_SEL       (0x1 << 15)
#define MFPR_PULLUP_EN      (0x1 << 14)
#define MFPR_PULLDOWN_EN    (0x1 << 13)
#define MFPR_SLEEP_SEL      (0x1 << 9)
#define MFPR_SLEEP_OE_N     (0x1 << 7)
#define MFPR_EDGE_CLEAR     (0x1 << 6)
#define MFPR_EDGE_FALL_EN   (0x1 << 5)
#define MFPR_EDGE_RISE_EN   (0x1 << 4)

#define MFPR_SLEEP_DATA(x)  ((x) << 8)
#define MFPR_DRIVE(x)       (((x) & 0x7) << 10)
#define MFPR_AF_SEL(x)      (((x) & 0x7) << 0)

#define MFPR_EDGE_NONE      (0)
#define MFPR_EDGE_RISE      (MFPR_EDGE_RISE_EN)
#define MFPR_EDGE_FALL      (MFPR_EDGE_FALL_EN)
#define MFPR_EDGE_BOTH      (MFPR_EDGE_RISE | MFPR_EDGE_FALL)

/*
 * Table that determines the low power modes outputs, with actual settings
 * used in parentheses for don't-care values. Except for the float output,
 * the configured driven and pulled levels match, so if there is a need for
 * non-LPM pulled output, the same configuration could probably be used.
 *
 * Output value  sleep_oe_n  sleep_data  pullup_en  pulldown_en  pull_sel
 *                 (bit 7)    (bit 8)    (bit 14)     (bit 13)   (bit 15)
 *
 * Input            0          X(0)        X(0)        X(0)       0
 * Drive 0          0          0           0           X(1)       0
 * Drive 1          0          1           X(1)        0      0
 * Pull hi (1)      1          X(1)        1           0      0
 * Pull lo (0)      1          X(0)        0           1      0
 * Z (float)        1          X(0)        0           0      0
 */
#define MFPR_LPM_INPUT      (0)
#define MFPR_LPM_DRIVE_LOW  (MFPR_SLEEP_DATA(0) | MFPR_PULLDOWN_EN)
#define MFPR_LPM_DRIVE_HIGH     (MFPR_SLEEP_DATA(1) | MFPR_PULLUP_EN)
#define MFPR_LPM_PULL_LOW       (MFPR_LPM_DRIVE_LOW  | MFPR_SLEEP_OE_N)
#define MFPR_LPM_PULL_HIGH      (MFPR_LPM_DRIVE_HIGH | MFPR_SLEEP_OE_N)
#define MFPR_LPM_FLOAT          (MFPR_SLEEP_OE_N)
#define MFPR_LPM_MASK       (0xe080)

/*
 * The pullup and pulldown state of the MFP pin at run mode is by default
 * determined by the selected alternate function. In case that some buggy
 * devices need to override this default behavior,  the definitions below
 * indicates the setting of corresponding MFPR bits
 *
 * Definition       pull_sel  pullup_en  pulldown_en
 * MFPR_PULL_NONE       0         0        0
 * MFPR_PULL_LOW        1         0        1
 * MFPR_PULL_HIGH       1         1        0
 * MFPR_PULL_BOTH       1         1        1
 * MFPR_PULL_FLOAT  1         0        0
 */
#define MFPR_PULL_NONE      (0)
#define MFPR_PULL_LOW       (MFPR_PULL_SEL | MFPR_PULLDOWN_EN)
#define MFPR_PULL_BOTH      (MFPR_PULL_LOW | MFPR_PULLUP_EN)
#define MFPR_PULL_HIGH      (MFPR_PULL_SEL | MFPR_PULLUP_EN)
#define MFPR_PULL_FLOAT     (MFPR_PULL_SEL)

/* mfp_spin_lock is used to ensure that MFP register configuration
 * (most likely a read-modify-write operation) is atomic, and that
 * mfp_table[] is consistent
 */
static DEFINE_SPINLOCK(mfp_spin_lock);

static void __iomem *mfpr_mmio_base;

struct mfp_pin {
    unsigned long   config;     /* -1 for not configured */
    unsigned long   mfpr_off;   /* MFPRxx Register offset */
    unsigned long   mfpr_run;   /* Run-Mode Register Value */
    unsigned long   mfpr_lpm;   /* Low Power Mode Register Value */
};

static struct mfp_pin mfp_table[MFP_PIN_MAX];

/* mapping of MFP_LPM_* definitions to MFPR_LPM_* register bits */
static const unsigned long mfpr_lpm[] = {
    MFPR_LPM_INPUT,
    MFPR_LPM_DRIVE_LOW,
    MFPR_LPM_DRIVE_HIGH,
    MFPR_LPM_PULL_LOW,
    MFPR_LPM_PULL_HIGH,
    MFPR_LPM_FLOAT,
    MFPR_LPM_INPUT,
};

/* mapping of MFP_PULL_* definitions to MFPR_PULL_* register bits */
static const unsigned long mfpr_pull[] = {
    MFPR_PULL_NONE,
    MFPR_PULL_LOW,
    MFPR_PULL_HIGH,
    MFPR_PULL_BOTH,
    MFPR_PULL_FLOAT,
};

/* mapping of MFP_LPM_EDGE_* definitions to MFPR_EDGE_* register bits */
static const unsigned long mfpr_edge[] = {
    MFPR_EDGE_NONE,
    MFPR_EDGE_RISE,
    MFPR_EDGE_FALL,
    MFPR_EDGE_BOTH,
};

#define mfpr_readl(off)         \
    __raw_readl(mfpr_mmio_base + (off))

#define mfpr_writel(off, val)       \
    __raw_writel(val, mfpr_mmio_base + (off))

#define mfp_configured(p)   ((p)->config != -1)

/*
 * perform a read-back of any valid MFPR register to make sure the
 * previous writings are finished
 */
static unsigned long mfpr_off_readback;
#define mfpr_sync() (void)__raw_readl(mfpr_mmio_base + mfpr_off_readback)

static inline void __mfp_config_run(struct mfp_pin *p)
{
    if (mfp_configured(p))
        mfpr_writel(p->mfpr_off, p->mfpr_run);
}

static inline void __mfp_config_lpm(struct mfp_pin *p)
{
    if (mfp_configured(p)) {
        unsigned long mfpr_clr = (p->mfpr_run & ~MFPR_EDGE_BOTH) | MFPR_EDGE_CLEAR;
        if (mfpr_clr != p->mfpr_run)
            mfpr_writel(p->mfpr_off, mfpr_clr);
        if (p->mfpr_lpm != mfpr_clr)
            mfpr_writel(p->mfpr_off, p->mfpr_lpm);
    }
}

void mfp_config(unsigned long *mfp_cfgs, int num)
{
    unsigned long flags;
    int i;

    spin_lock_irqsave(&mfp_spin_lock, flags);

    for (i = 0; i < num; i++, mfp_cfgs++) {
        unsigned long tmp, c = *mfp_cfgs;
        struct mfp_pin *p;
        int pin, af, drv, lpm, edge, pull;

        pin = MFP_PIN(c);
        BUG_ON(pin >= MFP_PIN_MAX);
        p = &mfp_table[pin];

        af  = MFP_AF(c);
        drv = MFP_DS(c);
        lpm = MFP_LPM_STATE(c);
        edge = MFP_LPM_EDGE(c);
        pull = MFP_PULL(c);

        /* run-mode pull settings will conflict with MFPR bits of
         * low power mode state,  calculate mfpr_run and mfpr_lpm
         * individually if pull != MFP_PULL_NONE
         */
        tmp = MFPR_AF_SEL(af) | MFPR_DRIVE(drv);

        if (likely(pull == MFP_PULL_NONE)) {
            p->mfpr_run = tmp | mfpr_lpm[lpm] | mfpr_edge[edge];
            p->mfpr_lpm = p->mfpr_run;
        } else {
            p->mfpr_lpm = tmp | mfpr_lpm[lpm] | mfpr_edge[edge];
            p->mfpr_run = tmp | mfpr_pull[pull];
        }

        p->config = c; __mfp_config_run(p);
    }

    mfpr_sync();
    spin_unlock_irqrestore(&mfp_spin_lock, flags);
}

unsigned long mfp_read(int mfp)
{
    unsigned long val, flags;

    BUG_ON(mfp < 0 || mfp >= MFP_PIN_MAX);

    spin_lock_irqsave(&mfp_spin_lock, flags);
    val = mfpr_readl(mfp_table[mfp].mfpr_off);
    spin_unlock_irqrestore(&mfp_spin_lock, flags);

    return val;
}

void mfp_write(int mfp, unsigned long val)
{
    unsigned long flags;

    BUG_ON(mfp < 0 || mfp >= MFP_PIN_MAX);

    spin_lock_irqsave(&mfp_spin_lock, flags);
    mfpr_writel(mfp_table[mfp].mfpr_off, val);
    mfpr_sync();
    spin_unlock_irqrestore(&mfp_spin_lock, flags);
}

void __init mfp_init_base(void __iomem *mfpr_base)
{
    int i;

    /* initialize the table with default - unconfigured */
    for (i = 0; i < ARRAY_SIZE(mfp_table); i++)
        mfp_table[i].config = -1;

    mfpr_mmio_base = mfpr_base;
}

void __init mfp_init_addr(struct mfp_addr_map *map)
{
    struct mfp_addr_map *p;
    unsigned long offset, flags;
    int i;

    spin_lock_irqsave(&mfp_spin_lock, flags);

    /* mfp offset for readback */
    mfpr_off_readback = map[0].offset;

    for (p = map; p->start != MFP_PIN_INVALID; p++) {
        offset = p->offset;
        i = p->start;

        do {
            mfp_table[i].mfpr_off = offset;
            mfp_table[i].mfpr_run = 0;
            mfp_table[i].mfpr_lpm = 0;
            offset += 4; i++;
        } while ((i <= p->end) && (p->end != -1));
    }

    spin_unlock_irqrestore(&mfp_spin_lock, flags);
}

void mfp_config_lpm(void)
{
    struct mfp_pin *p = &mfp_table[0];
    int pin;

    for (pin = 0; pin < ARRAY_SIZE(mfp_table); pin++, p++)
        __mfp_config_lpm(p);
}

void mfp_config_run(void)
{
    struct mfp_pin *p = &mfp_table[0];
    int pin;

    for (pin = 0; pin < ARRAY_SIZE(mfp_table); pin++, p++)
        __mfp_config_run(p);
}