rtc-bq4802.c

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/* rtc-bq4802.c: TI BQ4802 RTC driver.
 *
 * Copyright (C) 2008 David S. Miller <[email protected]>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/slab.h>

MODULE_AUTHOR("David S. Miller <[email protected]>");
MODULE_DESCRIPTION("TI BQ4802 RTC driver");
MODULE_LICENSE("GPL");

struct bq4802 {
    void __iomem        *regs;
    unsigned long       ioport;
    struct rtc_device   *rtc;
    spinlock_t      lock;
    struct resource     *r;
    u8 (*read)(struct bq4802 *, int);
    void (*write)(struct bq4802 *, int, u8);
};

static u8 bq4802_read_io(struct bq4802 *p, int off)
{
    return inb(p->ioport + off);
}

static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
{
    outb(val, p->ioport + off);
}

static u8 bq4802_read_mem(struct bq4802 *p, int off)
{
    return readb(p->regs + off);
}

static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
{
    writeb(val, p->regs + off);
}

static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct bq4802 *p = platform_get_drvdata(pdev);
    unsigned long flags;
    unsigned int century;
    u8 val;

    spin_lock_irqsave(&p->lock, flags);

    val = p->read(p, 0x0e);
    p->write(p, 0xe, val | 0x08);

    tm->tm_sec = p->read(p, 0x00);
    tm->tm_min = p->read(p, 0x02);
    tm->tm_hour = p->read(p, 0x04);
    tm->tm_mday = p->read(p, 0x06);
    tm->tm_mon = p->read(p, 0x09);
    tm->tm_year = p->read(p, 0x0a);
    tm->tm_wday = p->read(p, 0x08);
    century = p->read(p, 0x0f);

    p->write(p, 0x0e, val);

    spin_unlock_irqrestore(&p->lock, flags);

    tm->tm_sec = bcd2bin(tm->tm_sec);
    tm->tm_min = bcd2bin(tm->tm_min);
    tm->tm_hour = bcd2bin(tm->tm_hour);
    tm->tm_mday = bcd2bin(tm->tm_mday);
    tm->tm_mon = bcd2bin(tm->tm_mon);
    tm->tm_year = bcd2bin(tm->tm_year);
    tm->tm_wday = bcd2bin(tm->tm_wday);
    century = bcd2bin(century);

    tm->tm_year += (century * 100);
    tm->tm_year -= 1900;

    tm->tm_mon--;

    return 0;
}

static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct bq4802 *p = platform_get_drvdata(pdev);
    u8 sec, min, hrs, day, mon, yrs, century, val;
    unsigned long flags;
    unsigned int year;

    year = tm->tm_year + 1900;
    century = year / 100;
    yrs = year % 100;

    mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
    day = tm->tm_mday;
    hrs = tm->tm_hour;
    min = tm->tm_min;
    sec = tm->tm_sec;

    sec = bin2bcd(sec);
    min = bin2bcd(min);
    hrs = bin2bcd(hrs);
    day = bin2bcd(day);
    mon = bin2bcd(mon);
    yrs = bin2bcd(yrs);
    century = bin2bcd(century);

    spin_lock_irqsave(&p->lock, flags);

    val = p->read(p, 0x0e);
    p->write(p, 0x0e, val | 0x08);

    p->write(p, 0x00, sec);
    p->write(p, 0x02, min);
    p->write(p, 0x04, hrs);
    p->write(p, 0x06, day);
    p->write(p, 0x09, mon);
    p->write(p, 0x0a, yrs);
    p->write(p, 0x0f, century);

    p->write(p, 0x0e, val);

    spin_unlock_irqrestore(&p->lock, flags);

    return 0;
}

static const struct rtc_class_ops bq4802_ops = {
    .read_time  = bq4802_read_time,
    .set_time   = bq4802_set_time,
};

static int __devinit bq4802_probe(struct platform_device *pdev)
{
    struct bq4802 *p = kzalloc(sizeof(*p), GFP_KERNEL);
    int err = -ENOMEM;

    if (!p)
        goto out;

    spin_lock_init(&p->lock);

    p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!p->r) {
        p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
        err = -EINVAL;
        if (!p->r)
            goto out_free;
    }
    if (p->r->flags & IORESOURCE_IO) {
        p->ioport = p->r->start;
        p->read = bq4802_read_io;
        p->write = bq4802_write_io;
    } else if (p->r->flags & IORESOURCE_MEM) {
        p->regs = ioremap(p->r->start, resource_size(p->r));
        p->read = bq4802_read_mem;
        p->write = bq4802_write_mem;
    } else {
        err = -EINVAL;
        goto out_free;
    }

    platform_set_drvdata(pdev, p);

    p->rtc = rtc_device_register("bq4802", &pdev->dev,
                     &bq4802_ops, THIS_MODULE);
    if (IS_ERR(p->rtc)) {
        err = PTR_ERR(p->rtc);
        goto out_iounmap;
    }

    err = 0;
out:
    return err;

out_iounmap:
    if (p->r->flags & IORESOURCE_MEM)
        iounmap(p->regs);
out_free:
    kfree(p);
    goto out;
}

static int __devexit bq4802_remove(struct platform_device *pdev)
{
    struct bq4802 *p = platform_get_drvdata(pdev);

    rtc_device_unregister(p->rtc);
    if (p->r->flags & IORESOURCE_MEM)
        iounmap(p->regs);

    platform_set_drvdata(pdev, NULL);

    kfree(p);

    return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:rtc-bq4802");

static struct platform_driver bq4802_driver = {
    .driver     = {
        .name   = "rtc-bq4802",
        .owner  = THIS_MODULE,
    },
    .probe      = bq4802_probe,
    .remove     = __devexit_p(bq4802_remove),
};

module_platform_driver(bq4802_driver);