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gpio.c

/*
 * Generic GPIO driver for logic cells found in the Nomadik SoC
 *
 * Copyright (C) 2008,2009 STMicroelectronics
 * Copyright (C) 2009 Alessandro Rubini <rubini@unipv.it>
 *   Rewritten based on work by Prafulla WADASKAR <prafulla.wadaskar@st.com>
 *
 * 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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/amba/bus.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <mach/hardware.h>
#include <mach/gpio.h>

/*
 * The GPIO module in the Nomadik family of Systems-on-Chip is an
 * AMBA device, managing 32 pins and alternate functions.  The logic block
 * is currently only used in the Nomadik.
 *
 * Symbols in this file are called "nmk_gpio" for "nomadik gpio"
 */

#define NMK_GPIO_PER_CHIP 32
00035 struct nmk_gpio_chip {
      struct gpio_chip chip;
      void __iomem *addr;
      unsigned int parent_irq;
      spinlock_t *lock;
      /* Keep track of configured edges */
      u32 edge_rising;
      u32 edge_falling;
};

/* Mode functions */
int nmk_gpio_set_mode(int gpio, int gpio_mode)
{
      struct nmk_gpio_chip *nmk_chip;
      unsigned long flags;
      u32 afunc, bfunc, bit;

      nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
      if (!nmk_chip)
            return -EINVAL;

      bit = 1 << (gpio - nmk_chip->chip.base);

      spin_lock_irqsave(&nmk_chip->lock, flags);
      afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & ~bit;
      bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & ~bit;
      if (gpio_mode & NMK_GPIO_ALT_A)
            afunc |= bit;
      if (gpio_mode & NMK_GPIO_ALT_B)
            bfunc |= bit;
      writel(afunc, nmk_chip->addr + NMK_GPIO_AFSLA);
      writel(bfunc, nmk_chip->addr + NMK_GPIO_AFSLB);
      spin_unlock_irqrestore(&nmk_chip->lock, flags);

      return 0;
}
EXPORT_SYMBOL(nmk_gpio_set_mode);

int nmk_gpio_get_mode(int gpio)
{
      struct nmk_gpio_chip *nmk_chip;
      u32 afunc, bfunc, bit;

      nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
      if (!nmk_chip)
            return -EINVAL;

      bit = 1 << (gpio - nmk_chip->chip.base);

      afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & bit;
      bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & bit;

      return (afunc ? NMK_GPIO_ALT_A : 0) | (bfunc ? NMK_GPIO_ALT_B : 0);
}
EXPORT_SYMBOL(nmk_gpio_get_mode);


/* IRQ functions */
static inline int nmk_gpio_get_bitmask(int gpio)
{
      return 1 << (gpio % 32);
}

static void nmk_gpio_irq_ack(unsigned int irq)
{
      int gpio;
      struct nmk_gpio_chip *nmk_chip;

      gpio = NOMADIK_IRQ_TO_GPIO(irq);
      nmk_chip = get_irq_chip_data(irq);
      if (!nmk_chip)
            return;
      writel(nmk_gpio_get_bitmask(gpio), nmk_chip->addr + NMK_GPIO_IC);
}

static void nmk_gpio_irq_mask(unsigned int irq)
{
      int gpio;
      struct nmk_gpio_chip *nmk_chip;
      unsigned long flags;
      u32 bitmask, reg;

      gpio = NOMADIK_IRQ_TO_GPIO(irq);
      nmk_chip = get_irq_chip_data(irq);
      bitmask = nmk_gpio_get_bitmask(gpio);
      if (!nmk_chip)
            return;

      /* we must individually clear the two edges */
      spin_lock_irqsave(&nmk_chip->lock, flags);
      if (nmk_chip->edge_rising & bitmask) {
            reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
            reg &= ~bitmask;
            writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
      }
      if (nmk_chip->edge_falling & bitmask) {
            reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
            reg &= ~bitmask;
            writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
      }
      spin_unlock_irqrestore(&nmk_chip->lock, flags);
};

static void nmk_gpio_irq_unmask(unsigned int irq)
{
      int gpio;
      struct nmk_gpio_chip *nmk_chip;
      unsigned long flags;
      u32 bitmask, reg;

      gpio = NOMADIK_IRQ_TO_GPIO(irq);
      nmk_chip = get_irq_chip_data(irq);
      bitmask = nmk_gpio_get_bitmask(gpio);
      if (!nmk_chip)
            return;

      /* we must individually set the two edges */
      spin_lock_irqsave(&nmk_chip->lock, flags);
      if (nmk_chip->edge_rising & bitmask) {
            reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
            reg |= bitmask;
            writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
      }
      if (nmk_chip->edge_falling & bitmask) {
            reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
            reg |= bitmask;
            writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
      }
      spin_unlock_irqrestore(&nmk_chip->lock, flags);
}

static int nmk_gpio_irq_set_type(unsigned int irq, unsigned int type)
{
      int gpio;
      struct nmk_gpio_chip *nmk_chip;
      unsigned long flags;
      u32 bitmask;

      gpio = NOMADIK_IRQ_TO_GPIO(irq);
      nmk_chip = get_irq_chip_data(irq);
      bitmask = nmk_gpio_get_bitmask(gpio);
      if (!nmk_chip)
            return -EINVAL;

      if (type & IRQ_TYPE_LEVEL_HIGH)
            return -EINVAL;
      if (type & IRQ_TYPE_LEVEL_LOW)
            return -EINVAL;

      spin_lock_irqsave(&nmk_chip->lock, flags);

      nmk_chip->edge_rising &= ~bitmask;
      if (type & IRQ_TYPE_EDGE_RISING)
            nmk_chip->edge_rising |= bitmask;
      writel(nmk_chip->edge_rising, nmk_chip->addr + NMK_GPIO_RIMSC);

      nmk_chip->edge_falling &= ~bitmask;
      if (type & IRQ_TYPE_EDGE_FALLING)
            nmk_chip->edge_falling |= bitmask;
      writel(nmk_chip->edge_falling, nmk_chip->addr + NMK_GPIO_FIMSC);

      spin_unlock_irqrestore(&nmk_chip->lock, flags);

      nmk_gpio_irq_unmask(irq);

      return 0;
}

static struct irq_chip nmk_gpio_irq_chip = {
      .name       = "Nomadik-GPIO",
      .ack        = nmk_gpio_irq_ack,
      .mask       = nmk_gpio_irq_mask,
      .unmask           = nmk_gpio_irq_unmask,
      .set_type   = nmk_gpio_irq_set_type,
};

static void nmk_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
{
      struct nmk_gpio_chip *nmk_chip;
      struct irq_chip *host_chip;
      unsigned int gpio_irq;
      u32 pending;
      unsigned int first_irq;

      nmk_chip = get_irq_data(irq);
      first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
      while ( (pending = readl(nmk_chip->addr + NMK_GPIO_IS)) ) {
            gpio_irq = first_irq + __ffs(pending);
            generic_handle_irq(gpio_irq);
      }
      if (0) {/* don't ack parent irq, as ack == disable */
            host_chip = get_irq_chip(irq);
            host_chip->ack(irq);
      }
}

static int nmk_gpio_init_irq(struct nmk_gpio_chip *nmk_chip)
{
      unsigned int first_irq;
      int i;

      first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
      for (i = first_irq; i < first_irq + NMK_GPIO_PER_CHIP; i++) {
            set_irq_chip(i, &nmk_gpio_irq_chip);
            set_irq_handler(i, handle_edge_irq);
            set_irq_flags(i, IRQF_VALID);
            set_irq_chip_data(i, nmk_chip);
      }
      set_irq_chained_handler(nmk_chip->parent_irq, nmk_gpio_irq_handler);
      set_irq_data(nmk_chip->parent_irq, nmk_chip);
      return 0;
}

/* I/O Functions */
static int nmk_gpio_make_input(struct gpio_chip *chip, unsigned offset)
{
      struct nmk_gpio_chip *nmk_chip =
            container_of(chip, struct nmk_gpio_chip, chip);

      writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRC);
      return 0;
}

static int nmk_gpio_make_output(struct gpio_chip *chip, unsigned offset,
                        int val)
{
      struct nmk_gpio_chip *nmk_chip =
            container_of(chip, struct nmk_gpio_chip, chip);

      writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRS);
      return 0;
}

static int nmk_gpio_get_input(struct gpio_chip *chip, unsigned offset)
{
      struct nmk_gpio_chip *nmk_chip =
            container_of(chip, struct nmk_gpio_chip, chip);
      u32 bit = 1 << offset;

      return (readl(nmk_chip->addr + NMK_GPIO_DAT) & bit) != 0;
}

static void nmk_gpio_set_output(struct gpio_chip *chip, unsigned offset,
                        int val)
{
      struct nmk_gpio_chip *nmk_chip =
            container_of(chip, struct nmk_gpio_chip, chip);
      u32 bit = 1 << offset;

      if (val)
            writel(bit, nmk_chip->addr + NMK_GPIO_DATS);
      else
            writel(bit, nmk_chip->addr + NMK_GPIO_DATC);
}

/* This structure is replicated for each GPIO block allocated at probe time */
static struct gpio_chip nmk_gpio_template = {
      .direction_input  = nmk_gpio_make_input,
      .get              = nmk_gpio_get_input,
      .direction_output = nmk_gpio_make_output,
      .set              = nmk_gpio_set_output,
      .ngpio                  = NMK_GPIO_PER_CHIP,
      .can_sleep        = 0,
};

static int __init nmk_gpio_probe(struct amba_device *dev, struct amba_id *id)
{
      struct nmk_gpio_platform_data *pdata;
      struct nmk_gpio_chip *nmk_chip;
      struct gpio_chip *chip;
      int ret;

      pdata = dev->dev.platform_data;
      ret = amba_request_regions(dev, pdata->name);
      if (ret)
            return ret;

      nmk_chip = kzalloc(sizeof(*nmk_chip), GFP_KERNEL);
      if (!nmk_chip) {
            ret = -ENOMEM;
            goto out_amba;
      }
      /*
       * The virt address in nmk_chip->addr is in the nomadik register space,
       * so we can simply convert the resource address, without remapping
       */
      nmk_chip->addr = io_p2v(dev->res.start);
      nmk_chip->chip = nmk_gpio_template;
      nmk_chip->parent_irq = pdata->parent_irq;

      chip = &nmk_chip->chip;
      chip->base = pdata->first_gpio;
      chip->label = pdata->name;
      chip->dev = &dev->dev;
      chip->owner = THIS_MODULE;

      ret = gpiochip_add(&nmk_chip->chip);
      if (ret)
            goto out_free;

      amba_set_drvdata(dev, nmk_chip);

      nmk_gpio_init_irq(nmk_chip);

      dev_info(&dev->dev, "Bits %i-%i at address %p\n",
             nmk_chip->chip.base, nmk_chip->chip.base+31, nmk_chip->addr);
      return 0;

 out_free:
      kfree(nmk_chip);
 out_amba:
      amba_release_regions(dev);
      dev_err(&dev->dev, "Failure %i for GPIO %i-%i\n", ret,
              pdata->first_gpio, pdata->first_gpio+31);
      return ret;
}

static int nmk_gpio_remove(struct amba_device *dev)
{
      struct nmk_gpio_chip *nmk_chip;

      nmk_chip = amba_get_drvdata(dev);
      gpiochip_remove(&nmk_chip->chip);
      kfree(nmk_chip);
      amba_release_regions(dev);
      return 0;
}


/* We have 0x1f080060 and 0x1f180060, accept both using the mask */
static struct amba_id nmk_gpio_ids[] = {
      {
            .id   = 0x1f080060,
            .mask = 0xffefffff,
      },
      {0, 0},
};

static struct amba_driver nmk_gpio_driver = {
      .drv = {
            .owner = THIS_MODULE,
            .name = "gpio",
            },
      .probe = nmk_gpio_probe,
      .remove = nmk_gpio_remove,
      .suspend = NULL, /* to be done */
      .resume = NULL,
      .id_table = nmk_gpio_ids,
};

static int __init nmk_gpio_init(void)
{
      return amba_driver_register(&nmk_gpio_driver);
}

arch_initcall(nmk_gpio_init);

MODULE_AUTHOR("Prafulla WADASKAR and Alessandro Rubini");
MODULE_DESCRIPTION("Nomadik GPIO Driver");
MODULE_LICENSE("GPL");



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