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gpio.h

/*
 * TI DaVinci GPIO Support
 *
 * Copyright (c) 2006 David Brownell
 * Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#ifndef     __DAVINCI_GPIO_H
#define     __DAVINCI_GPIO_H

#include <linux/io.h>
#include <linux/spinlock.h>

#include <asm-generic/gpio.h>

#include <mach/irqs.h>
#include <mach/common.h>

#define DAVINCI_GPIO_BASE 0x01C67000

enum davinci_gpio_type {
      GPIO_TYPE_DAVINCI = 0,
      GPIO_TYPE_TNETV107X,
};

/*
 * basic gpio routines
 *
 * board-specific init should be done by arch/.../.../board-XXX.c (maybe
 * initializing banks together) rather than boot loaders; kexec() won't
 * go through boot loaders.
 *
 * the gpio clock will be turned on when gpios are used, and you may also
 * need to pay attention to PINMUX registers to be sure those pins are
 * used as gpios, not with other peripherals.
 *
 * On-chip GPIOs are numbered 0..(DAVINCI_N_GPIO-1).  For documentation,
 * and maybe for later updates, code may write GPIO(N).  These may be
 * all 1.8V signals, all 3.3V ones, or a mix of the two.  A given chip
 * may not support all the GPIOs in that range.
 *
 * GPIOs can also be on external chips, numbered after the ones built-in
 * to the DaVinci chip.  For now, they won't be usable as IRQ sources.
 */
#define     GPIO(X)           (X)         /* 0 <= X <= (DAVINCI_N_GPIO - 1) */

/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio)     (16 * (bank) + (gpio))

00055 struct davinci_gpio_controller {
      struct gpio_chip  chip;
      int               irq_base;
      spinlock_t        lock;
      void __iomem            *regs;
      void __iomem            *set_data;
      void __iomem            *clr_data;
      void __iomem            *in_data;
};

/* The __gpio_to_controller() and __gpio_mask() functions inline to constants
 * with constant parameters; or in outlined code they execute at runtime.
 *
 * You'd access the controller directly when reading or writing more than
 * one gpio value at a time, and to support wired logic where the value
 * being driven by the cpu need not match the value read back.
 *
 * These are NOT part of the cross-platform GPIO interface
 */
static inline struct davinci_gpio_controller *
__gpio_to_controller(unsigned gpio)
{
      struct davinci_gpio_controller *ctlrs = davinci_soc_info.gpio_ctlrs;
      int index = gpio / 32;

      if (!ctlrs || index >= davinci_soc_info.gpio_ctlrs_num)
            return NULL;

      return ctlrs + index;
}

static inline u32 __gpio_mask(unsigned gpio)
{
      return 1 << (gpio % 32);
}

/*
 * The get/set/clear functions will inline when called with constant
 * parameters referencing built-in GPIOs, for low-overhead bitbanging.
 *
 * gpio_set_value() will inline only on traditional Davinci style controllers
 * with distinct set/clear registers.
 *
 * Otherwise, calls with variable parameters or referencing external
 * GPIOs (e.g. on GPIO expander chips) use outlined functions.
 */
static inline void gpio_set_value(unsigned gpio, int value)
{
      if (__builtin_constant_p(value) && gpio < davinci_soc_info.gpio_num) {
            struct davinci_gpio_controller *ctlr;
            u32                     mask;

            ctlr = __gpio_to_controller(gpio);

            if (ctlr->set_data != ctlr->clr_data) {
                  mask = __gpio_mask(gpio);
                  if (value)
                        __raw_writel(mask, ctlr->set_data);
                  else
                        __raw_writel(mask, ctlr->clr_data);
                  return;
            }
      }

      __gpio_set_value(gpio, value);
}

/* Returns zero or nonzero; works for gpios configured as inputs OR
 * as outputs, at least for built-in GPIOs.
 *
 * NOTE: for built-in GPIOs, changes in reported values are synchronized
 * to the GPIO clock.  This is easily seen after calling gpio_set_value()
 * and then immediately gpio_get_value(), where the gpio_get_value() will
 * return the old value until the GPIO clock ticks and the new value gets
 * latched.
 */
static inline int gpio_get_value(unsigned gpio)
{
      struct davinci_gpio_controller *ctlr;

      if (!__builtin_constant_p(gpio) || gpio >= davinci_soc_info.gpio_num)
            return __gpio_get_value(gpio);

      ctlr = __gpio_to_controller(gpio);
      return __gpio_mask(gpio) & __raw_readl(ctlr->in_data);
}

static inline int gpio_cansleep(unsigned gpio)
{
      if (__builtin_constant_p(gpio) && gpio < davinci_soc_info.gpio_num)
            return 0;
      else
            return __gpio_cansleep(gpio);
}

static inline int gpio_to_irq(unsigned gpio)
{
      return __gpio_to_irq(gpio);
}

static inline int irq_to_gpio(unsigned irq)
{
      /* don't support the reverse mapping */
      return -ENOSYS;
}

#endif                        /* __DAVINCI_GPIO_H */

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