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pio.c

/*
 * Atmel PIO2 Port Multiplexer support
 *
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * 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/clk.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/platform_device.h>
#include <linux/irq.h>

#include <asm/gpio.h>
#include <asm/io.h>

#include <asm/arch/portmux.h>

#include "pio.h"

#define MAX_NR_PIO_DEVICES          8

struct pio_device {
      void __iomem *regs;
      const struct platform_device *pdev;
      struct clk *clk;
      u32 pinmux_mask;
      u32 gpio_mask;
      char name[8];
};

static struct pio_device pio_dev[MAX_NR_PIO_DEVICES];

static struct pio_device *gpio_to_pio(unsigned int gpio)
{
      struct pio_device *pio;
      unsigned int index;

      index = gpio >> 5;
      if (index >= MAX_NR_PIO_DEVICES)
            return NULL;
      pio = &pio_dev[index];
      if (!pio->regs)
            return NULL;

      return pio;
}

/* Pin multiplexing API */

void __init at32_select_periph(unsigned int pin, unsigned int periph,
                         unsigned long flags)
{
      struct pio_device *pio;
      unsigned int pin_index = pin & 0x1f;
      u32 mask = 1 << pin_index;

      pio = gpio_to_pio(pin);
      if (unlikely(!pio)) {
            printk("pio: invalid pin %u\n", pin);
            goto fail;
      }

      if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
            printk("%s: pin %u is busy\n", pio->name, pin_index);
            goto fail;
      }

      pio_writel(pio, PUER, mask);
      if (periph)
            pio_writel(pio, BSR, mask);
      else
            pio_writel(pio, ASR, mask);

      pio_writel(pio, PDR, mask);
      if (!(flags & AT32_GPIOF_PULLUP))
            pio_writel(pio, PUDR, mask);

      /* gpio_request NOT allowed */
      set_bit(pin_index, &pio->gpio_mask);

      return;

fail:
      dump_stack();
}

void __init at32_select_gpio(unsigned int pin, unsigned long flags)
{
      struct pio_device *pio;
      unsigned int pin_index = pin & 0x1f;
      u32 mask = 1 << pin_index;

      pio = gpio_to_pio(pin);
      if (unlikely(!pio)) {
            printk("pio: invalid pin %u\n", pin);
            goto fail;
      }

      if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
            printk("%s: pin %u is busy\n", pio->name, pin_index);
            goto fail;
      }

      if (flags & AT32_GPIOF_OUTPUT) {
            if (flags & AT32_GPIOF_HIGH)
                  pio_writel(pio, SODR, mask);
            else
                  pio_writel(pio, CODR, mask);
            if (flags & AT32_GPIOF_MULTIDRV)
                  pio_writel(pio, MDER, mask);
            else
                  pio_writel(pio, MDDR, mask);
            pio_writel(pio, PUDR, mask);
            pio_writel(pio, OER, mask);
      } else {
            if (flags & AT32_GPIOF_PULLUP)
                  pio_writel(pio, PUER, mask);
            else
                  pio_writel(pio, PUDR, mask);
            if (flags & AT32_GPIOF_DEGLITCH)
                  pio_writel(pio, IFER, mask);
            else
                  pio_writel(pio, IFDR, mask);
            pio_writel(pio, ODR, mask);
      }

      pio_writel(pio, PER, mask);

      /* gpio_request now allowed */
      clear_bit(pin_index, &pio->gpio_mask);

      return;

fail:
      dump_stack();
}

/* Reserve a pin, preventing anyone else from changing its configuration. */
void __init at32_reserve_pin(unsigned int pin)
{
      struct pio_device *pio;
      unsigned int pin_index = pin & 0x1f;

      pio = gpio_to_pio(pin);
      if (unlikely(!pio)) {
            printk("pio: invalid pin %u\n", pin);
            goto fail;
      }

      if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
            printk("%s: pin %u is busy\n", pio->name, pin_index);
            goto fail;
      }

      return;

fail:
      dump_stack();
}

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

/* GPIO API */

int gpio_request(unsigned int gpio, const char *label)
{
      struct pio_device *pio;
      unsigned int pin;

      pio = gpio_to_pio(gpio);
      if (!pio)
            return -ENODEV;

      pin = gpio & 0x1f;
      if (test_and_set_bit(pin, &pio->gpio_mask))
            return -EBUSY;

      return 0;
}
EXPORT_SYMBOL(gpio_request);

void gpio_free(unsigned int gpio)
{
      struct pio_device *pio;
      unsigned int pin;

      pio = gpio_to_pio(gpio);
      if (!pio) {
            printk(KERN_ERR
                   "gpio: attempted to free invalid pin %u\n", gpio);
            return;
      }

      pin = gpio & 0x1f;
      if (!test_and_clear_bit(pin, &pio->gpio_mask))
            printk(KERN_ERR "gpio: freeing free or non-gpio pin %s-%u\n",
                   pio->name, pin);
}
EXPORT_SYMBOL(gpio_free);

int gpio_direction_input(unsigned int gpio)
{
      struct pio_device *pio;
      unsigned int pin;

      pio = gpio_to_pio(gpio);
      if (!pio)
            return -ENODEV;

      pin = gpio & 0x1f;
      pio_writel(pio, ODR, 1 << pin);

      return 0;
}
EXPORT_SYMBOL(gpio_direction_input);

int gpio_direction_output(unsigned int gpio, int value)
{
      struct pio_device *pio;
      unsigned int pin;

      pio = gpio_to_pio(gpio);
      if (!pio)
            return -ENODEV;

      gpio_set_value(gpio, value);

      pin = gpio & 0x1f;
      pio_writel(pio, OER, 1 << pin);

      return 0;
}
EXPORT_SYMBOL(gpio_direction_output);

int gpio_get_value(unsigned int gpio)
{
      struct pio_device *pio = &pio_dev[gpio >> 5];

      return (pio_readl(pio, PDSR) >> (gpio & 0x1f)) & 1;
}
EXPORT_SYMBOL(gpio_get_value);

void gpio_set_value(unsigned int gpio, int value)
{
      struct pio_device *pio = &pio_dev[gpio >> 5];
      u32 mask;

      mask = 1 << (gpio & 0x1f);
      if (value)
            pio_writel(pio, SODR, mask);
      else
            pio_writel(pio, CODR, mask);
}
EXPORT_SYMBOL(gpio_set_value);

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

/* GPIO IRQ support */

static void gpio_irq_mask(unsigned irq)
{
      unsigned          gpio = irq_to_gpio(irq);
      struct pio_device *pio = &pio_dev[gpio >> 5];

      pio_writel(pio, IDR, 1 << (gpio & 0x1f));
}

static void gpio_irq_unmask(unsigned irq)
{
      unsigned          gpio = irq_to_gpio(irq);
      struct pio_device *pio = &pio_dev[gpio >> 5];

      pio_writel(pio, IER, 1 << (gpio & 0x1f));
}

static int gpio_irq_type(unsigned irq, unsigned type)
{
      if (type != IRQ_TYPE_EDGE_BOTH && type != IRQ_TYPE_NONE)
            return -EINVAL;

      return 0;
}

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

static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
      struct pio_device *pio = get_irq_chip_data(irq);
      unsigned          gpio_irq;

      gpio_irq = (unsigned) get_irq_data(irq);
      for (;;) {
            u32         isr;
            struct irq_desc   *d;

            /* ack pending GPIO interrupts */
            isr = pio_readl(pio, ISR) & pio_readl(pio, IMR);
            if (!isr)
                  break;
            do {
                  int i;

                  i = ffs(isr) - 1;
                  isr &= ~(1 << i);

                  i += gpio_irq;
                  d = &irq_desc[i];

                  d->handle_irq(i, d);
            } while (isr);
      }
}

static void __init
gpio_irq_setup(struct pio_device *pio, int irq, int gpio_irq)
{
      unsigned    i;

      set_irq_chip_data(irq, pio);
      set_irq_data(irq, (void *) gpio_irq);

      for (i = 0; i < 32; i++, gpio_irq++) {
            set_irq_chip_data(gpio_irq, pio);
            set_irq_chip_and_handler(gpio_irq, &gpio_irqchip,
                        handle_simple_irq);
      }

      set_irq_chained_handler(irq, gpio_irq_handler);
}

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

static int __init pio_probe(struct platform_device *pdev)
{
      struct pio_device *pio = NULL;
      int irq = platform_get_irq(pdev, 0);
      int gpio_irq_base = GPIO_IRQ_BASE + pdev->id * 32;

      BUG_ON(pdev->id >= MAX_NR_PIO_DEVICES);
      pio = &pio_dev[pdev->id];
      BUG_ON(!pio->regs);

      gpio_irq_setup(pio, irq, gpio_irq_base);

      platform_set_drvdata(pdev, pio);

      printk(KERN_DEBUG "%s: base 0x%p, irq %d chains %d..%d\n",
             pio->name, pio->regs, irq, gpio_irq_base, gpio_irq_base + 31);

      return 0;
}

static struct platform_driver pio_driver = {
      .probe            = pio_probe,
      .driver           = {
            .name       = "pio",
      },
};

static int __init pio_init(void)
{
      return platform_driver_register(&pio_driver);
}
postcore_initcall(pio_init);

void __init at32_init_pio(struct platform_device *pdev)
{
      struct resource *regs;
      struct pio_device *pio;

      if (pdev->id > MAX_NR_PIO_DEVICES) {
            dev_err(&pdev->dev, "only %d PIO devices supported\n",
                  MAX_NR_PIO_DEVICES);
            return;
      }

      pio = &pio_dev[pdev->id];
      snprintf(pio->name, sizeof(pio->name), "pio%d", pdev->id);

      regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
      if (!regs) {
            dev_err(&pdev->dev, "no mmio resource defined\n");
            return;
      }

      pio->clk = clk_get(&pdev->dev, "mck");
      if (IS_ERR(pio->clk))
            /*
             * This is a fatal error, but if we continue we might
             * be so lucky that we manage to initialize the
             * console and display this message...
             */
            dev_err(&pdev->dev, "no mck clock defined\n");
      else
            clk_enable(pio->clk);

      pio->pdev = pdev;
      pio->regs = ioremap(regs->start, regs->end - regs->start + 1);

      /*
       * request_gpio() is only valid for pins that have been
       * explicitly configured as GPIO and not previously requested
       */
      pio->gpio_mask = ~0UL;

      /* start with irqs disabled and acked */
      pio_writel(pio, IDR, ~0UL);
      (void) pio_readl(pio, ISR);
}

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