pio.c

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/*
 * 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/export.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

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 port, u32 pin_mask)
{
    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 (req. 0x%x, busy 0x%x)\n",
               pio->name, pin_mask, pio->pinmux_mask & pin_mask);
        spin_unlock(&pio_lock);
        goto fail;
    }

    /* Reserve pins */
    pio->pinmux_mask |= pin_mask;
    spin_unlock(&pio_lock);
    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(struct irq_data *d)
{
    unsigned        gpio = irq_to_gpio(d->irq);
    struct pio_device   *pio = &pio_dev[gpio >> 5];

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

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

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

static int gpio_irq_type(struct irq_data *d, unsigned type)
{
    if (type != IRQ_TYPE_EDGE_BOTH && type != IRQ_TYPE_NONE)
        return -EINVAL;

    return 0;
}

static struct irq_chip gpio_irqchip = {
    .name       = "gpio",
    .irq_mask   = gpio_irq_mask,
    .irq_unmask = gpio_irq_unmask,
    .irq_set_type   = gpio_irq_type,
};

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

    gpio_irq = (unsigned) irq_get_handler_data(irq);
    for (;;) {
        u32     isr;

        /* 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;
            generic_handle_irq(i);
        } while (isr);
    }
}

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

    irq_set_chip_data(irq, pio);
    irq_set_handler_data(irq, (void *)gpio_irq);

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

    irq_set_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, resource_size(regs));

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