gpio.c

Go to the documentation of this file.

/*
 * arch/sh/boards/mach-x3proto/gpio.c
 *
 * Renesas SH-X3 Prototype Baseboard GPIO Support.
 *
 * Copyright (C) 2010 - 2012  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/irqdomain.h>
#include <linux/io.h>
#include <mach/ilsel.h>
#include <mach/hardware.h>

#define KEYCTLR 0xb81c0000
#define KEYOUTR 0xb81c0002
#define KEYDETR 0xb81c0004

static DEFINE_SPINLOCK(x3proto_gpio_lock);
static struct irq_domain *x3proto_irq_domain;

static int x3proto_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
    unsigned long flags;
    unsigned int data;

    spin_lock_irqsave(&x3proto_gpio_lock, flags);
    data = __raw_readw(KEYCTLR);
    data |= (1 << gpio);
    __raw_writew(data, KEYCTLR);
    spin_unlock_irqrestore(&x3proto_gpio_lock, flags);

    return 0;
}

static int x3proto_gpio_get(struct gpio_chip *chip, unsigned gpio)
{
    return !!(__raw_readw(KEYDETR) & (1 << gpio));
}

static int x3proto_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
{
    int virq;

    if (gpio < chip->ngpio)
        virq = irq_create_mapping(x3proto_irq_domain, gpio);
    else
        virq = -ENXIO;

    return virq;
}

static void x3proto_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
{
    struct irq_data *data = irq_get_irq_data(irq);
    struct irq_chip *chip = irq_data_get_irq_chip(data);
    unsigned long mask;
    int pin;

    chip->irq_mask_ack(data);

    mask = __raw_readw(KEYDETR);
    for_each_set_bit(pin, &mask, NR_BASEBOARD_GPIOS)
        generic_handle_irq(irq_linear_revmap(x3proto_irq_domain, pin));

    chip->irq_unmask(data);
}

struct gpio_chip x3proto_gpio_chip = {
    .label          = "x3proto-gpio",
    .direction_input    = x3proto_gpio_direction_input,
    .get            = x3proto_gpio_get,
    .to_irq         = x3proto_gpio_to_irq,
    .base           = -1,
    .ngpio          = NR_BASEBOARD_GPIOS,
};

static int x3proto_gpio_irq_map(struct irq_domain *domain, unsigned int virq,
                irq_hw_number_t hwirq)
{
    irq_set_chip_and_handler_name(virq, &dummy_irq_chip, handle_simple_irq,
                      "gpio");

    return 0;
}

static struct irq_domain_ops x3proto_gpio_irq_ops = {
    .map    = x3proto_gpio_irq_map,
    .xlate  = irq_domain_xlate_twocell,
};

int __init x3proto_gpio_setup(void)
{
    int ilsel, ret;

    ilsel = ilsel_enable(ILSEL_KEY);
    if (unlikely(ilsel < 0))
        return ilsel;

    ret = gpiochip_add(&x3proto_gpio_chip);
    if (unlikely(ret))
        goto err_gpio;

    x3proto_irq_domain = irq_domain_add_linear(NULL, NR_BASEBOARD_GPIOS,
                           &x3proto_gpio_irq_ops, NULL);
    if (unlikely(!x3proto_irq_domain))
        goto err_irq;

    pr_info("registering '%s' support, handling GPIOs %u -> %u, "
        "bound to IRQ %u\n",
        x3proto_gpio_chip.label, x3proto_gpio_chip.base,
        x3proto_gpio_chip.base + x3proto_gpio_chip.ngpio,
        ilsel);

    irq_set_chained_handler(ilsel, x3proto_gpio_irq_handler);
    irq_set_irq_wake(ilsel, 1);

    return 0;

err_irq:
    ret = gpiochip_remove(&x3proto_gpio_chip);
    if (unlikely(ret))
        pr_err("Failed deregistering GPIO\n");

err_gpio:
    synchronize_irq(ilsel);

    ilsel_disable(ILSEL_KEY);

    return ret;
}