rtc-ep93xx.c

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/*
 * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
 * Copyright (c) 2006 Tower Technologies
 *
 * Author: Alessandro Zummo <[email protected]>
 *
 * 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/module.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/gfp.h>

#define EP93XX_RTC_DATA         0x000
#define EP93XX_RTC_MATCH        0x004
#define EP93XX_RTC_STATUS       0x008
#define  EP93XX_RTC_STATUS_INTR      (1<<0)
#define EP93XX_RTC_LOAD         0x00C
#define EP93XX_RTC_CONTROL      0x010
#define  EP93XX_RTC_CONTROL_MIE      (1<<0)
#define EP93XX_RTC_SWCOMP       0x108
#define  EP93XX_RTC_SWCOMP_DEL_MASK  0x001f0000
#define  EP93XX_RTC_SWCOMP_DEL_SHIFT     16
#define  EP93XX_RTC_SWCOMP_INT_MASK  0x0000ffff
#define  EP93XX_RTC_SWCOMP_INT_SHIFT     0

#define DRV_VERSION "0.3"

/*
 * struct device dev.platform_data is used to store our private data
 * because struct rtc_device does not have a variable to hold it.
 */
struct ep93xx_rtc {
    void __iomem    *mmio_base;
    struct rtc_device *rtc;
};

static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
                unsigned short *delete)
{
    struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;
    unsigned long comp;

    comp = __raw_readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);

    if (preload)
        *preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
                >> EP93XX_RTC_SWCOMP_INT_SHIFT;

    if (delete)
        *delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
                >> EP93XX_RTC_SWCOMP_DEL_SHIFT;

    return 0;
}

static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;
    unsigned long time;

     time = __raw_readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);

    rtc_time_to_tm(time, tm);
    return 0;
}

static int ep93xx_rtc_set_mmss(struct device *dev, unsigned long secs)
{
    struct ep93xx_rtc *ep93xx_rtc = dev->platform_data;

    __raw_writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
    return 0;
}

static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
{
    unsigned short preload, delete;

    ep93xx_rtc_get_swcomp(dev, &preload, &delete);

    seq_printf(seq, "preload\t\t: %d\n", preload);
    seq_printf(seq, "delete\t\t: %d\n", delete);

    return 0;
}

static const struct rtc_class_ops ep93xx_rtc_ops = {
    .read_time  = ep93xx_rtc_read_time,
    .set_mmss   = ep93xx_rtc_set_mmss,
    .proc       = ep93xx_rtc_proc,
};

static ssize_t ep93xx_rtc_show_comp_preload(struct device *dev,
            struct device_attribute *attr, char *buf)
{
    unsigned short preload;

    ep93xx_rtc_get_swcomp(dev, &preload, NULL);

    return sprintf(buf, "%d\n", preload);
}
static DEVICE_ATTR(comp_preload, S_IRUGO, ep93xx_rtc_show_comp_preload, NULL);

static ssize_t ep93xx_rtc_show_comp_delete(struct device *dev,
            struct device_attribute *attr, char *buf)
{
    unsigned short delete;

    ep93xx_rtc_get_swcomp(dev, NULL, &delete);

    return sprintf(buf, "%d\n", delete);
}
static DEVICE_ATTR(comp_delete, S_IRUGO, ep93xx_rtc_show_comp_delete, NULL);

static struct attribute *ep93xx_rtc_attrs[] = {
    &dev_attr_comp_preload.attr,
    &dev_attr_comp_delete.attr,
    NULL
};

static const struct attribute_group ep93xx_rtc_sysfs_files = {
    .attrs  = ep93xx_rtc_attrs,
};

static int __devinit ep93xx_rtc_probe(struct platform_device *pdev)
{
    struct ep93xx_rtc *ep93xx_rtc;
    struct resource *res;
    int err;

    ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
    if (!ep93xx_rtc)
        return -ENOMEM;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res)
        return -ENXIO;

    if (!devm_request_mem_region(&pdev->dev, res->start,
                     resource_size(res), pdev->name))
        return -EBUSY;

    ep93xx_rtc->mmio_base = devm_ioremap(&pdev->dev, res->start,
                         resource_size(res));
    if (!ep93xx_rtc->mmio_base)
        return -ENXIO;

    pdev->dev.platform_data = ep93xx_rtc;
    platform_set_drvdata(pdev, ep93xx_rtc);

    ep93xx_rtc->rtc = rtc_device_register(pdev->name,
                &pdev->dev, &ep93xx_rtc_ops, THIS_MODULE);
    if (IS_ERR(ep93xx_rtc->rtc)) {
        err = PTR_ERR(ep93xx_rtc->rtc);
        goto exit;
    }

    err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_rtc_sysfs_files);
    if (err)
        goto fail;

    return 0;

fail:
    rtc_device_unregister(ep93xx_rtc->rtc);
exit:
    platform_set_drvdata(pdev, NULL);
    pdev->dev.platform_data = NULL;
    return err;
}

static int __devexit ep93xx_rtc_remove(struct platform_device *pdev)
{
    struct ep93xx_rtc *ep93xx_rtc = platform_get_drvdata(pdev);

    sysfs_remove_group(&pdev->dev.kobj, &ep93xx_rtc_sysfs_files);
    platform_set_drvdata(pdev, NULL);
    rtc_device_unregister(ep93xx_rtc->rtc);
    pdev->dev.platform_data = NULL;

    return 0;
}

static struct platform_driver ep93xx_rtc_driver = {
    .driver     = {
        .name   = "ep93xx-rtc",
        .owner  = THIS_MODULE,
    },
    .probe      = ep93xx_rtc_probe,
    .remove     = __devexit_p(ep93xx_rtc_remove),
};

module_platform_driver(ep93xx_rtc_driver);

MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
MODULE_DESCRIPTION("EP93XX RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:ep93xx-rtc");