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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 <asm-generic/gpio.h>
#include <mach/hardware.h>

/*
 * 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 PINMUX0 and PINMUX1 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 should write GPIO(N) or:
 *  - GPIOV18(N) for 1.8V pins, N in 0..53; same as GPIO(0)..GPIO(53)
 *  - GPIOV33(N) for 3.3V pins, N in 0..17; same as GPIO(54)..GPIO(70)
 *
 * For GPIO IRQs use gpio_to_irq(GPIO(N)) or gpio_to_irq(GPIOV33(N)) etc
 * for now, that's != GPIO(N)
 *
 * 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 <= 70 */
#define     GPIOV18(X)  (X)         /* 1.8V i/o; 0 <= X <= 53 */
#define     GPIOV33(X)  ((X)+54)    /* 3.3V i/o; 0 <= X <= 17 */

struct gpio_controller {
      u32   dir;
      u32   out_data;
      u32   set_data;
      u32   clr_data;
      u32   in_data;
      u32   set_rising;
      u32   clr_rising;
      u32   set_falling;
      u32   clr_falling;
      u32   intstat;
};

/* 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 gpio_controller *__iomem
__gpio_to_controller(unsigned gpio)
{
      void *__iomem ptr;

      if (gpio < 32)
            ptr = IO_ADDRESS(DAVINCI_GPIO_BASE + 0x10);
      else if (gpio < 64)
            ptr = IO_ADDRESS(DAVINCI_GPIO_BASE + 0x38);
      else if (gpio < DAVINCI_N_GPIO)
            ptr = IO_ADDRESS(DAVINCI_GPIO_BASE + 0x60);
      else
            ptr = NULL;
      return ptr;
}

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.
 *
 * 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_N_GPIO) {
            struct gpio_controller  *__iomem g;
            u32               mask;

            g = __gpio_to_controller(gpio);
            mask = __gpio_mask(gpio);
            if (value)
                  __raw_writel(mask, &g->set_data);
            else
                  __raw_writel(mask, &g->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 gpio_controller  *__iomem g;

      if (!__builtin_constant_p(gpio) || gpio >= DAVINCI_N_GPIO)
            return __gpio_get_value(gpio);

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

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

static inline int gpio_to_irq(unsigned gpio)
{
      if (gpio >= DAVINCI_N_GPIO)
            return -EINVAL;
      return DAVINCI_N_AINTC_IRQ + gpio;
}

static inline int irq_to_gpio(unsigned irq)
{
      /* caller guarantees gpio_to_irq() succeeded */
      return irq - DAVINCI_N_AINTC_IRQ;
}

#endif                        /* __DAVINCI_GPIO_H */

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