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mfp.c

/*
 * linux/arch/arm/plat-pxa/mfp.c
 *
 *   Multi-Function Pin Support
 *
 * Copyright (C) 2007 Marvell Internation Ltd.
 *
 * 2007-08-21: eric miao <eric.miao@marvell.com>
 *             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 <linux/sysdev.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;

00096 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,
};

/* 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 MFPR register to make sure the
 * previous writings are finished
 */
#define mfpr_sync()     (void)__raw_readl(mfpr_mmio_base + 0)

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(unsigned long 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 = (void __iomem *)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);

      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);
}

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