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gpio.c

/*
 * TI DaVinci GPIO Support
 *
 * Copyright (c) 2006-2007 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.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>

#include <mach/gpio.h>

#include <asm/mach/irq.h>

00023 struct davinci_gpio_regs {
      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;
};

#define chip2controller(chip) \
      container_of(chip, struct davinci_gpio_controller, chip)

static struct davinci_gpio_controller chips[DIV_ROUND_UP(DAVINCI_N_GPIO, 32)];
static void __iomem *gpio_base;

static struct davinci_gpio_regs __iomem __init *gpio2regs(unsigned gpio)
{
      void __iomem *ptr;

      if (gpio < 32 * 1)
            ptr = gpio_base + 0x10;
      else if (gpio < 32 * 2)
            ptr = gpio_base + 0x38;
      else if (gpio < 32 * 3)
            ptr = gpio_base + 0x60;
      else if (gpio < 32 * 4)
            ptr = gpio_base + 0x88;
      else if (gpio < 32 * 5)
            ptr = gpio_base + 0xb0;
      else
            ptr = NULL;
      return ptr;
}

static inline struct davinci_gpio_regs __iomem *irq2regs(int irq)
{
      struct davinci_gpio_regs __iomem *g;

      g = (__force struct davinci_gpio_regs __iomem *)get_irq_chip_data(irq);

      return g;
}

static int __init davinci_gpio_irq_setup(void);

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

/* board setup code *MUST* setup pinmux and enable the GPIO clock. */
static inline int __davinci_direction(struct gpio_chip *chip,
                  unsigned offset, bool out, int value)
{
      struct davinci_gpio_controller *d = chip2controller(chip);
      struct davinci_gpio_regs __iomem *g = d->regs;
      unsigned long flags;
      u32 temp;
      u32 mask = 1 << offset;

      spin_lock_irqsave(&d->lock, flags);
      temp = __raw_readl(&g->dir);
      if (out) {
            temp &= ~mask;
            __raw_writel(mask, value ? &g->set_data : &g->clr_data);
      } else {
            temp |= mask;
      }
      __raw_writel(temp, &g->dir);
      spin_unlock_irqrestore(&d->lock, flags);

      return 0;
}

static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
{
      return __davinci_direction(chip, offset, false, 0);
}

static int
davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
      return __davinci_direction(chip, offset, true, value);
}

/*
 * Read the pin's value (works even if it's set up as output);
 * returns zero/nonzero.
 *
 * Note that changes are synched to the GPIO clock, so reading values back
 * right after you've set them may give old values.
 */
static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
{
      struct davinci_gpio_controller *d = chip2controller(chip);
      struct davinci_gpio_regs __iomem *g = d->regs;

      return (1 << offset) & __raw_readl(&g->in_data);
}

/*
 * Assuming the pin is muxed as a gpio output, set its output value.
 */
static void
davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
      struct davinci_gpio_controller *d = chip2controller(chip);
      struct davinci_gpio_regs __iomem *g = d->regs;

      __raw_writel((1 << offset), value ? &g->set_data : &g->clr_data);
}

static int __init davinci_gpio_setup(void)
{
      int i, base;
      unsigned ngpio;
      struct davinci_soc_info *soc_info = &davinci_soc_info;
      struct davinci_gpio_regs *regs;

      if (soc_info->gpio_type != GPIO_TYPE_DAVINCI)
            return 0;

      /*
       * The gpio banks conceptually expose a segmented bitmap,
       * and "ngpio" is one more than the largest zero-based
       * bit index that's valid.
       */
      ngpio = soc_info->gpio_num;
      if (ngpio == 0) {
            pr_err("GPIO setup:  how many GPIOs?\n");
            return -EINVAL;
      }

      if (WARN_ON(DAVINCI_N_GPIO < ngpio))
            ngpio = DAVINCI_N_GPIO;

      gpio_base = ioremap(soc_info->gpio_base, SZ_4K);
      if (WARN_ON(!gpio_base))
            return -ENOMEM;

      for (i = 0, base = 0; base < ngpio; i++, base += 32) {
            chips[i].chip.label = "DaVinci";

            chips[i].chip.direction_input = davinci_direction_in;
            chips[i].chip.get = davinci_gpio_get;
            chips[i].chip.direction_output = davinci_direction_out;
            chips[i].chip.set = davinci_gpio_set;

            chips[i].chip.base = base;
            chips[i].chip.ngpio = ngpio - base;
            if (chips[i].chip.ngpio > 32)
                  chips[i].chip.ngpio = 32;

            spin_lock_init(&chips[i].lock);

            regs = gpio2regs(base);
            chips[i].regs = regs;
            chips[i].set_data = &regs->set_data;
            chips[i].clr_data = &regs->clr_data;
            chips[i].in_data = &regs->in_data;

            gpiochip_add(&chips[i].chip);
      }

      soc_info->gpio_ctlrs = chips;
      soc_info->gpio_ctlrs_num = DIV_ROUND_UP(ngpio, 32);

      davinci_gpio_irq_setup();
      return 0;
}
pure_initcall(davinci_gpio_setup);

/*--------------------------------------------------------------------------*/
/*
 * We expect irqs will normally be set up as input pins, but they can also be
 * used as output pins ... which is convenient for testing.
 *
 * NOTE:  The first few GPIOs also have direct INTC hookups in addition
 * to their GPIOBNK0 irq, with a bit less overhead.
 *
 * All those INTC hookups (direct, plus several IRQ banks) can also
 * serve as EDMA event triggers.
 */

static void gpio_irq_disable(struct irq_data *d)
{
      struct davinci_gpio_regs __iomem *g = irq2regs(d->irq);
      u32 mask = (u32) irq_data_get_irq_data(d);

      __raw_writel(mask, &g->clr_falling);
      __raw_writel(mask, &g->clr_rising);
}

static void gpio_irq_enable(struct irq_data *d)
{
      struct davinci_gpio_regs __iomem *g = irq2regs(d->irq);
      u32 mask = (u32) irq_data_get_irq_data(d);
      unsigned status = irq_desc[d->irq].status;

      status &= IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;
      if (!status)
            status = IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING;

      if (status & IRQ_TYPE_EDGE_FALLING)
            __raw_writel(mask, &g->set_falling);
      if (status & IRQ_TYPE_EDGE_RISING)
            __raw_writel(mask, &g->set_rising);
}

static int gpio_irq_type(struct irq_data *d, unsigned trigger)
{
      struct davinci_gpio_regs __iomem *g = irq2regs(d->irq);
      u32 mask = (u32) irq_data_get_irq_data(d);

      if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
            return -EINVAL;

      irq_desc[d->irq].status &= ~IRQ_TYPE_SENSE_MASK;
      irq_desc[d->irq].status |= trigger;

      /* don't enable the IRQ if it's currently disabled */
      if (irq_desc[d->irq].depth == 0) {
            __raw_writel(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
                       ? &g->set_falling : &g->clr_falling);
            __raw_writel(mask, (trigger & IRQ_TYPE_EDGE_RISING)
                       ? &g->set_rising : &g->clr_rising);
      }
      return 0;
}

static struct irq_chip gpio_irqchip = {
      .name       = "GPIO",
      .irq_enable = gpio_irq_enable,
      .irq_disable      = gpio_irq_disable,
      .irq_set_type     = gpio_irq_type,
};

static void
gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
      struct davinci_gpio_regs __iomem *g = irq2regs(irq);
      u32 mask = 0xffff;

      /* we only care about one bank */
      if (irq & 1)
            mask <<= 16;

      /* temporarily mask (level sensitive) parent IRQ */
      desc->irq_data.chip->irq_mask(&desc->irq_data);
      desc->irq_data.chip->irq_ack(&desc->irq_data);
      while (1) {
            u32         status;
            int         n;
            int         res;

            /* ack any irqs */
            status = __raw_readl(&g->intstat) & mask;
            if (!status)
                  break;
            __raw_writel(status, &g->intstat);
            if (irq & 1)
                  status >>= 16;

            /* now demux them to the right lowlevel handler */
            n = (int)get_irq_data(irq);
            while (status) {
                  res = ffs(status);
                  n += res;
                  generic_handle_irq(n - 1);
                  status >>= res;
            }
      }
      desc->irq_data.chip->irq_unmask(&desc->irq_data);
      /* now it may re-trigger */
}

static int gpio_to_irq_banked(struct gpio_chip *chip, unsigned offset)
{
      struct davinci_gpio_controller *d = chip2controller(chip);

      if (d->irq_base >= 0)
            return d->irq_base + offset;
      else
            return -ENODEV;
}

static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
{
      struct davinci_soc_info *soc_info = &davinci_soc_info;

      /* NOTE:  we assume for now that only irqs in the first gpio_chip
       * can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
       */
      if (offset < soc_info->gpio_unbanked)
            return soc_info->gpio_irq + offset;
      else
            return -ENODEV;
}

static int gpio_irq_type_unbanked(struct irq_data *d, unsigned trigger)
{
      struct davinci_gpio_regs __iomem *g = irq2regs(d->irq);
      u32 mask = (u32) irq_data_get_irq_data(d);

      if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
            return -EINVAL;

      __raw_writel(mask, (trigger & IRQ_TYPE_EDGE_FALLING)
                 ? &g->set_falling : &g->clr_falling);
      __raw_writel(mask, (trigger & IRQ_TYPE_EDGE_RISING)
                 ? &g->set_rising : &g->clr_rising);

      return 0;
}

/*
 * NOTE:  for suspend/resume, probably best to make a platform_device with
 * suspend_late/resume_resume calls hooking into results of the set_wake()
 * calls ... so if no gpios are wakeup events the clock can be disabled,
 * with outputs left at previously set levels, and so that VDD3P3V.IOPWDN0
 * (dm6446) can be set appropriately for GPIOV33 pins.
 */

static int __init davinci_gpio_irq_setup(void)
{
      unsigned    gpio, irq, bank;
      struct clk  *clk;
      u32         binten = 0;
      unsigned    ngpio, bank_irq;
      struct davinci_soc_info *soc_info = &davinci_soc_info;
      struct davinci_gpio_regs      __iomem *g;

      ngpio = soc_info->gpio_num;

      bank_irq = soc_info->gpio_irq;
      if (bank_irq == 0) {
            printk(KERN_ERR "Don't know first GPIO bank IRQ.\n");
            return -EINVAL;
      }

      clk = clk_get(NULL, "gpio");
      if (IS_ERR(clk)) {
            printk(KERN_ERR "Error %ld getting gpio clock?\n",
                   PTR_ERR(clk));
            return PTR_ERR(clk);
      }
      clk_enable(clk);

      /* Arrange gpio_to_irq() support, handling either direct IRQs or
       * banked IRQs.  Having GPIOs in the first GPIO bank use direct
       * IRQs, while the others use banked IRQs, would need some setup
       * tweaks to recognize hardware which can do that.
       */
      for (gpio = 0, bank = 0; gpio < ngpio; bank++, gpio += 32) {
            chips[bank].chip.to_irq = gpio_to_irq_banked;
            chips[bank].irq_base = soc_info->gpio_unbanked
                  ? -EINVAL
                  : (soc_info->intc_irq_num + gpio);
      }

      /*
       * AINTC can handle direct/unbanked IRQs for GPIOs, with the GPIO
       * controller only handling trigger modes.  We currently assume no
       * IRQ mux conflicts; gpio_irq_type_unbanked() is only for GPIOs.
       */
      if (soc_info->gpio_unbanked) {
            static struct irq_chip gpio_irqchip_unbanked;

            /* pass "bank 0" GPIO IRQs to AINTC */
            chips[0].chip.to_irq = gpio_to_irq_unbanked;
            binten = BIT(0);

            /* AINTC handles mask/unmask; GPIO handles triggering */
            irq = bank_irq;
            gpio_irqchip_unbanked = *get_irq_desc_chip(irq_to_desc(irq));
            gpio_irqchip_unbanked.name = "GPIO-AINTC";
            gpio_irqchip_unbanked.irq_set_type = gpio_irq_type_unbanked;

            /* default trigger: both edges */
            g = gpio2regs(0);
            __raw_writel(~0, &g->set_falling);
            __raw_writel(~0, &g->set_rising);

            /* set the direct IRQs up to use that irqchip */
            for (gpio = 0; gpio < soc_info->gpio_unbanked; gpio++, irq++) {
                  set_irq_chip(irq, &gpio_irqchip_unbanked);
                  set_irq_data(irq, (void *) __gpio_mask(gpio));
                  set_irq_chip_data(irq, (__force void *) g);
                  irq_desc[irq].status |= IRQ_TYPE_EDGE_BOTH;
            }

            goto done;
      }

      /*
       * Or, AINTC can handle IRQs for banks of 16 GPIO IRQs, which we
       * then chain through our own handler.
       */
      for (gpio = 0, irq = gpio_to_irq(0), bank = 0;
                  gpio < ngpio;
                  bank++, bank_irq++) {
            unsigned          i;

            /* disabled by default, enabled only as needed */
            g = gpio2regs(gpio);
            __raw_writel(~0, &g->clr_falling);
            __raw_writel(~0, &g->clr_rising);

            /* set up all irqs in this bank */
            set_irq_chained_handler(bank_irq, gpio_irq_handler);
            set_irq_chip_data(bank_irq, (__force void *) g);
            set_irq_data(bank_irq, (void *) irq);

            for (i = 0; i < 16 && gpio < ngpio; i++, irq++, gpio++) {
                  set_irq_chip(irq, &gpio_irqchip);
                  set_irq_chip_data(irq, (__force void *) g);
                  set_irq_data(irq, (void *) __gpio_mask(gpio));
                  set_irq_handler(irq, handle_simple_irq);
                  set_irq_flags(irq, IRQF_VALID);
            }

            binten |= BIT(bank);
      }

done:
      /* BINTEN -- per-bank interrupt enable. genirq would also let these
       * bits be set/cleared dynamically.
       */
      __raw_writel(binten, gpio_base + 0x08);

      printk(KERN_INFO "DaVinci: %d gpio irqs\n", irq - gpio_to_irq(0));

      return 0;
}

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