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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 <mach/portmux.h>

#include "pio.h"

#define MAX_NR_PIO_DEVICES          8

00026 struct pio_device {
      struct gpio_chip chip;
      void __iomem *regs;
      const struct platform_device *pdev;
      struct clk *clk;
      u32 pinmux_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 */
static DEFINE_SPINLOCK(pio_lock);

void __init at32_select_periph(unsigned int port, u32 pin_mask,
                         unsigned int periph, unsigned long flags)
{
      struct pio_device *pio;

      /* assign and verify pio */
      pio = gpio_to_pio(port);
      if (unlikely(!pio)) {
            printk(KERN_WARNING "pio: invalid port %u\n", port);
            goto fail;
      }

      /* Test if any of the requested pins is already muxed */
      spin_lock(&pio_lock);
      if (unlikely(pio->pinmux_mask & pin_mask)) {
            printk(KERN_WARNING "%s: pin(s) busy (requested 0x%x, busy 0x%x)\n",
                   pio->name, pin_mask, pio->pinmux_mask & pin_mask);
            spin_unlock(&pio_lock);
            goto fail;
      }

      pio->pinmux_mask |= pin_mask;

      /* enable pull ups */
      pio_writel(pio, PUER, pin_mask);

      /* select either peripheral A or B */
      if (periph)
            pio_writel(pio, BSR, pin_mask);
      else
            pio_writel(pio, ASR, pin_mask);

      /* enable peripheral control */
      pio_writel(pio, PDR, pin_mask);

      /* Disable pull ups if not requested. */
      if (!(flags & AT32_GPIOF_PULLUP))
            pio_writel(pio, PUDR, pin_mask);

      spin_unlock(&pio_lock);

      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);

      return;

fail:
      dump_stack();
}

/*
 * Undo a previous pin reservation. Will not affect the hardware
 * configuration.
 */
void at32_deselect_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);
            dump_stack();
            return;
      }

      clear_bit(pin_index, &pio->pinmux_mask);
}

/* 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 */

static int direction_input(struct gpio_chip *chip, unsigned offset)
{
      struct pio_device *pio = container_of(chip, struct pio_device, chip);
      u32 mask = 1 << offset;

      if (!(pio_readl(pio, PSR) & mask))
            return -EINVAL;

      pio_writel(pio, ODR, mask);
      return 0;
}

static int gpio_get(struct gpio_chip *chip, unsigned offset)
{
      struct pio_device *pio = container_of(chip, struct pio_device, chip);

      return (pio_readl(pio, PDSR) >> offset) & 1;
}

static void gpio_set(struct gpio_chip *chip, unsigned offset, int value);

static int direction_output(struct gpio_chip *chip, unsigned offset, int value)
{
      struct pio_device *pio = container_of(chip, struct pio_device, chip);
      u32 mask = 1 << offset;

      if (!(pio_readl(pio, PSR) & mask))
            return -EINVAL;

      gpio_set(chip, offset, value);
      pio_writel(pio, OER, mask);
      return 0;
}

static void gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
      struct pio_device *pio = container_of(chip, struct pio_device, chip);
      u32 mask = 1 << offset;

      if (value)
            pio_writel(pio, SODR, mask);
      else
            pio_writel(pio, CODR, mask);
}

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

/* 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);
}

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

#ifdef CONFIG_DEBUG_FS

#include <linux/seq_file.h>

/*
 * This shows more info than the generic gpio dump code:
 * pullups, deglitching, open drain drive.
 */
static void pio_bank_show(struct seq_file *s, struct gpio_chip *chip)
{
      struct pio_device *pio = container_of(chip, struct pio_device, chip);
      u32               psr, osr, imr, pdsr, pusr, ifsr, mdsr;
      unsigned          i;
      u32               mask;
      char              bank;

      psr = pio_readl(pio, PSR);
      osr = pio_readl(pio, OSR);
      imr = pio_readl(pio, IMR);
      pdsr = pio_readl(pio, PDSR);
      pusr = pio_readl(pio, PUSR);
      ifsr = pio_readl(pio, IFSR);
      mdsr = pio_readl(pio, MDSR);

      bank = 'A' + pio->pdev->id;

      for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
            const char *label;

            label = gpiochip_is_requested(chip, i);
            if (!label && (imr & mask))
                  label = "[irq]";
            if (!label)
                  continue;

            seq_printf(s, " gpio-%-3d P%c%-2d (%-12s) %s %s %s",
                  chip->base + i, bank, i,
                  label,
                  (osr & mask) ? "out" : "in ",
                  (mask & pdsr) ? "hi" : "lo",
                  (mask & pusr) ? "  " : "up");
            if (ifsr & mask)
                  seq_printf(s, " deglitch");
            if ((osr & mdsr) & mask)
                  seq_printf(s, " open-drain");
            if (imr & mask)
                  seq_printf(s, " irq-%d edge-both",
                        gpio_to_irq(chip->base + i));
            seq_printf(s, "\n");
      }
}

#else
#define pio_bank_show   NULL
#endif


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

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);

      pio->chip.label = pio->name;
      pio->chip.base = pdev->id * 32;
      pio->chip.ngpio = 32;
      pio->chip.dev = &pdev->dev;
      pio->chip.owner = THIS_MODULE;

      pio->chip.direction_input = direction_input;
      pio->chip.get = gpio_get;
      pio->chip.direction_output = direction_output;
      pio->chip.set = gpio_set;
      pio->chip.dbg_show = pio_bank_show;

      gpiochip_add(&pio->chip);

      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 = {
      .driver           = {
            .name       = "pio",
      },
};

static int __init pio_init(void)
{
      return platform_driver_probe(&pio_driver, pio_probe);
}
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);

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

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