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gpio.c

/*
 * linux/arch/arm/mach-at91/gpio.c
 *
 * Copyright (C) 2005 HP Labs
 *
 * 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.
 */

#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>

#include <asm/io.h>
#include <asm/hardware.h>
#include <asm/arch/at91_pio.h>
#include <asm/arch/gpio.h>

#include "generic.h"


static struct at91_gpio_bank *gpio;
static int gpio_banks;


static inline void __iomem *pin_to_controller(unsigned pin)
{
      void __iomem *sys_base = (void __iomem *) AT91_VA_BASE_SYS;

      pin -= PIN_BASE;
      pin /= 32;
      if (likely(pin < gpio_banks))
            return sys_base + gpio[pin].offset;

      return NULL;
}

static inline unsigned pin_to_mask(unsigned pin)
{
      pin -= PIN_BASE;
      return 1 << (pin % 32);
}


/*--------------------------------------------------------------------------*/

/* Not all hardware capabilities are exposed through these calls; they
 * only encapsulate the most common features and modes.  (So if you
 * want to change signals in groups, do it directly.)
 *
 * Bootloaders will usually handle some of the pin multiplexing setup.
 * The intent is certainly that by the time Linux is fully booted, all
 * pins should have been fully initialized.  These setup calls should
 * only be used by board setup routines, or possibly in driver probe().
 *
 * For bootloaders doing all that setup, these calls could be inlined
 * as NOPs so Linux won't duplicate any setup code
 */


/*
 * mux the pin to the "GPIO" peripheral role.
 */
int __init_or_module at91_set_GPIO_periph(unsigned pin, int use_pullup)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;
      __raw_writel(mask, pio + PIO_IDR);
      __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
      __raw_writel(mask, pio + PIO_PER);
      return 0;
}
EXPORT_SYMBOL(at91_set_GPIO_periph);


/*
 * mux the pin to the "A" internal peripheral role.
 */
int __init_or_module at91_set_A_periph(unsigned pin, int use_pullup)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;

      __raw_writel(mask, pio + PIO_IDR);
      __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
      __raw_writel(mask, pio + PIO_ASR);
      __raw_writel(mask, pio + PIO_PDR);
      return 0;
}
EXPORT_SYMBOL(at91_set_A_periph);


/*
 * mux the pin to the "B" internal peripheral role.
 */
int __init_or_module at91_set_B_periph(unsigned pin, int use_pullup)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;

      __raw_writel(mask, pio + PIO_IDR);
      __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
      __raw_writel(mask, pio + PIO_BSR);
      __raw_writel(mask, pio + PIO_PDR);
      return 0;
}
EXPORT_SYMBOL(at91_set_B_periph);


/*
 * mux the pin to the gpio controller (instead of "A" or "B" peripheral), and
 * configure it for an input.
 */
int __init_or_module at91_set_gpio_input(unsigned pin, int use_pullup)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;

      __raw_writel(mask, pio + PIO_IDR);
      __raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
      __raw_writel(mask, pio + PIO_ODR);
      __raw_writel(mask, pio + PIO_PER);
      return 0;
}
EXPORT_SYMBOL(at91_set_gpio_input);


/*
 * mux the pin to the gpio controller (instead of "A" or "B" peripheral),
 * and configure it for an output.
 */
int __init_or_module at91_set_gpio_output(unsigned pin, int value)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;

      __raw_writel(mask, pio + PIO_IDR);
      __raw_writel(mask, pio + PIO_PUDR);
      __raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
      __raw_writel(mask, pio + PIO_OER);
      __raw_writel(mask, pio + PIO_PER);
      return 0;
}
EXPORT_SYMBOL(at91_set_gpio_output);


/*
 * enable/disable the glitch filter; mostly used with IRQ handling.
 */
int __init_or_module at91_set_deglitch(unsigned pin, int is_on)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;
      __raw_writel(mask, pio + (is_on ? PIO_IFER : PIO_IFDR));
      return 0;
}
EXPORT_SYMBOL(at91_set_deglitch);

/*
 * enable/disable the multi-driver; This is only valid for output and
 * allows the output pin to run as an open collector output.
 */
int __init_or_module at91_set_multi_drive(unsigned pin, int is_on)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;

      __raw_writel(mask, pio + (is_on ? PIO_MDER : PIO_MDDR));
      return 0;
}
EXPORT_SYMBOL(at91_set_multi_drive);

/*--------------------------------------------------------------------------*/

/* new-style GPIO calls; these expect at91_set_GPIO_periph to have been
 * called, and maybe at91_set_multi_drive() for putout pins.
 */

int gpio_direction_input(unsigned pin)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio || !(__raw_readl(pio + PIO_PSR) & mask))
            return -EINVAL;
      __raw_writel(mask, pio + PIO_ODR);
      return 0;
}
EXPORT_SYMBOL(gpio_direction_input);

int gpio_direction_output(unsigned pin, int value)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio || !(__raw_readl(pio + PIO_PSR) & mask))
            return -EINVAL;
      __raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
      __raw_writel(mask, pio + PIO_OER);
      return 0;
}
EXPORT_SYMBOL(gpio_direction_output);

/*--------------------------------------------------------------------------*/

/*
 * assuming the pin is muxed as a gpio output, set its value.
 */
int at91_set_gpio_value(unsigned pin, int value)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (!pio)
            return -EINVAL;
      __raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
      return 0;
}
EXPORT_SYMBOL(at91_set_gpio_value);


/*
 * read the pin's value (works even if it's not muxed as a gpio).
 */
int at91_get_gpio_value(unsigned pin)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);
      u32         pdsr;

      if (!pio)
            return -EINVAL;
      pdsr = __raw_readl(pio + PIO_PDSR);
      return (pdsr & mask) != 0;
}
EXPORT_SYMBOL(at91_get_gpio_value);

/*--------------------------------------------------------------------------*/

#ifdef CONFIG_PM

static u32 wakeups[MAX_GPIO_BANKS];
static u32 backups[MAX_GPIO_BANKS];

static int gpio_irq_set_wake(unsigned pin, unsigned state)
{
      unsigned    mask = pin_to_mask(pin);
      unsigned    bank = (pin - PIN_BASE) / 32;

      if (unlikely(bank >= MAX_GPIO_BANKS))
            return -EINVAL;

      if (state)
            wakeups[bank] |= mask;
      else
            wakeups[bank] &= ~mask;

      set_irq_wake(gpio[bank].id, state);

      return 0;
}

void at91_gpio_suspend(void)
{
      int i;

      for (i = 0; i < gpio_banks; i++) {
            u32 pio = gpio[i].offset;

            backups[i] = at91_sys_read(pio + PIO_IMR);
            at91_sys_write(pio + PIO_IDR, backups[i]);
            at91_sys_write(pio + PIO_IER, wakeups[i]);

            if (!wakeups[i])
                  clk_disable(gpio[i].clock);
            else {
#ifdef CONFIG_PM_DEBUG
                  printk(KERN_DEBUG "GPIO-%c may wake for %08x\n", 'A'+i, wakeups[i]);
#endif
            }
      }
}

void at91_gpio_resume(void)
{
      int i;

      for (i = 0; i < gpio_banks; i++) {
            u32 pio = gpio[i].offset;

            if (!wakeups[i])
                  clk_enable(gpio[i].clock);

            at91_sys_write(pio + PIO_IDR, wakeups[i]);
            at91_sys_write(pio + PIO_IER, backups[i]);
      }
}

#else
#define gpio_irq_set_wake     NULL
#endif


/* Several AIC controller irqs are dispatched through this GPIO handler.
 * To use any AT91_PIN_* as an externally triggered IRQ, first call
 * at91_set_gpio_input() then maybe enable its glitch filter.
 * Then just request_irq() with the pin ID; it works like any ARM IRQ
 * handler, though it always triggers on rising and falling edges.
 *
 * Alternatively, certain pins may be used directly as IRQ0..IRQ6 after
 * configuring them with at91_set_a_periph() or at91_set_b_periph().
 * IRQ0..IRQ6 should be configurable, e.g. level vs edge triggering.
 */

static void gpio_irq_mask(unsigned pin)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (pio)
            __raw_writel(mask, pio + PIO_IDR);
}

static void gpio_irq_unmask(unsigned pin)
{
      void __iomem      *pio = pin_to_controller(pin);
      unsigned    mask = pin_to_mask(pin);

      if (pio)
            __raw_writel(mask, pio + PIO_IER);
}

static int gpio_irq_type(unsigned pin, unsigned type)
{
      return (type == IRQT_BOTHEDGE) ? 0 : -EINVAL;
}

static struct irq_chip gpio_irqchip = {
      .name       = "GPIO",
      .mask       = gpio_irq_mask,
      .unmask           = gpio_irq_unmask,
      .set_type   = gpio_irq_type,
      .set_wake   = gpio_irq_set_wake,
};

static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
      unsigned    pin;
      struct irq_desc   *gpio;
      void __iomem      *pio;
      u32         isr;

      pio = get_irq_chip_data(irq);

      /* temporarily mask (level sensitive) parent IRQ */
      desc->chip->ack(irq);
      for (;;) {
            /* reading ISR acks the pending (edge triggered) GPIO interrupt */
            isr = __raw_readl(pio + PIO_ISR) & __raw_readl(pio + PIO_IMR);
            if (!isr)
                  break;

            pin = (unsigned) get_irq_data(irq);
            gpio = &irq_desc[pin];

            while (isr) {
                  if (isr & 1) {
                        if (unlikely(gpio->depth)) {
                              /*
                               * The core ARM interrupt handler lazily disables IRQs so
                               * another IRQ must be generated before it actually gets
                               * here to be disabled on the GPIO controller.
                               */
                              gpio_irq_mask(pin);
                        }
                        else
                              desc_handle_irq(pin, gpio);
                  }
                  pin++;
                  gpio++;
                  isr >>= 1;
            }
      }
      desc->chip->unmask(irq);
      /* now it may re-trigger */
}

/*--------------------------------------------------------------------------*/

/*
 * Called from the processor-specific init to enable GPIO interrupt support.
 */
void __init at91_gpio_irq_setup(void)
{
      unsigned    pioc, pin;

      for (pioc = 0, pin = PIN_BASE;
                  pioc < gpio_banks;
                  pioc++) {
            void __iomem      *controller;
            unsigned    id = gpio[pioc].id;
            unsigned    i;

            clk_enable(gpio[pioc].clock); /* enable PIO controller's clock */

            controller = (void __iomem *) AT91_VA_BASE_SYS + gpio[pioc].offset;
            __raw_writel(~0, controller + PIO_IDR);

            set_irq_data(id, (void *) pin);
            set_irq_chip_data(id, controller);

            for (i = 0; i < 32; i++, pin++) {
                  /*
                   * Can use the "simple" and not "edge" handler since it's
                   * shorter, and the AIC handles interrupts sanely.
                   */
                  set_irq_chip(pin, &gpio_irqchip);
                  set_irq_handler(pin, handle_simple_irq);
                  set_irq_flags(pin, IRQF_VALID);
            }

            set_irq_chained_handler(id, gpio_irq_handler);
      }
      pr_info("AT91: %d gpio irqs in %d banks\n", pin - PIN_BASE, gpio_banks);
}

/*
 * Called from the processor-specific init to enable GPIO pin support.
 */
void __init at91_gpio_init(struct at91_gpio_bank *data, int nr_banks)
{
      BUG_ON(nr_banks > MAX_GPIO_BANKS);

      gpio = data;
      gpio_banks = nr_banks;
}

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