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/* drivers/rtc/rtc-v3020.c

 *

 * Copyright (C) 2006 8D Technologies inc.

 * Copyright (C) 2004 Compulab Ltd.

 *

 * 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.

 *

 * Driver for the V3020 RTC

 *

 * Changelog:

 *

 *  10-May-2006: Raphael Assenat <raph@8d.com>

 *                              - Converted to platform driver

 *                              - Use the generic rtc class

 *

 *  ??-???-2004: Someone at Compulab

 *                      - Initial driver creation.

 *

 */

#include <linux/platform_device.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/rtc.h>

#include <linux/types.h>

#include <linux/bcd.h>

#include <linux/rtc-v3020.h>

#include <linux/delay.h>

#include <asm/io.h>

#undef DEBUG

struct v3020 {

        void __iomem *ioaddress;

        int leftshift;

        struct rtc_device *rtc;

};

static void v3020_set_reg(struct v3020 *chip, unsigned char address,

                        unsigned char data)

{

        int i;

        unsigned char tmp;

        tmp = address;

        for (i = 0; i < 4; i++) {

                writel((tmp & 1) << chip->leftshift, chip->ioaddress);

                tmp >>= 1;

                udelay(1);

        }

        /* Commands dont have data */

        if (!V3020_IS_COMMAND(address)) {

                for (i = 0; i < 8; i++) {

                        writel((data & 1) << chip->leftshift, chip->ioaddress);

                        data >>= 1;

                        udelay(1);

                }

        }

}

static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)

{

        unsigned int data=0;

        int i;

        for (i = 0; i < 4; i++) {

                writel((address & 1) << chip->leftshift, chip->ioaddress);

                address >>= 1;

                udelay(1);

        }

        for (i = 0; i < 8; i++) {

                data >>= 1;

                if (readl(chip->ioaddress) & (1 << chip->leftshift))

                        data |= 0x80;

                udelay(1);

        }

        return data;

}

static int v3020_read_time(struct device *dev, struct rtc_time *dt)

{

        struct v3020 *chip = dev_get_drvdata(dev);

        int tmp;

        /* Copy the current time to ram... */

        v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);

        /* ...and then read constant values. */

        tmp = v3020_get_reg(chip, V3020_SECONDS);

        dt->tm_sec      = BCD2BIN(tmp);

        tmp = v3020_get_reg(chip, V3020_MINUTES);

        dt->tm_min      = BCD2BIN(tmp);

        tmp = v3020_get_reg(chip, V3020_HOURS);

        dt->tm_hour     = BCD2BIN(tmp);

        tmp = v3020_get_reg(chip, V3020_MONTH_DAY);

        dt->tm_mday     = BCD2BIN(tmp);

        tmp = v3020_get_reg(chip, V3020_MONTH);

        dt->tm_mon    = BCD2BIN(tmp) - 1;

        tmp = v3020_get_reg(chip, V3020_WEEK_DAY);

        dt->tm_wday     = BCD2BIN(tmp);

        tmp = v3020_get_reg(chip, V3020_YEAR);

        dt->tm_year = BCD2BIN(tmp)+100;

#ifdef DEBUG

        printk("\n%s : Read RTC values\n",__FUNCTION__);

        printk("tm_hour: %i\n",dt->tm_hour);

        printk("tm_min : %i\n",dt->tm_min);

        printk("tm_sec : %i\n",dt->tm_sec);

        printk("tm_year: %i\n",dt->tm_year);

        printk("tm_mon : %i\n",dt->tm_mon);

        printk("tm_mday: %i\n",dt->tm_mday);

        printk("tm_wday: %i\n",dt->tm_wday);

#endif

        return 0;

}

static int v3020_set_time(struct device *dev, struct rtc_time *dt)

{

        struct v3020 *chip = dev_get_drvdata(dev);

#ifdef DEBUG

        printk("\n%s : Setting RTC values\n",__FUNCTION__);

        printk("tm_sec : %i\n",dt->tm_sec);

        printk("tm_min : %i\n",dt->tm_min);

        printk("tm_hour: %i\n",dt->tm_hour);

        printk("tm_mday: %i\n",dt->tm_mday);

        printk("tm_wday: %i\n",dt->tm_wday);

        printk("tm_year: %i\n",dt->tm_year);

#endif

        /* Write all the values to ram... */

        v3020_set_reg(chip, V3020_SECONDS,      BIN2BCD(dt->tm_sec));

        v3020_set_reg(chip, V3020_MINUTES,      BIN2BCD(dt->tm_min));

        v3020_set_reg(chip, V3020_HOURS,        BIN2BCD(dt->tm_hour));

        v3020_set_reg(chip, V3020_MONTH_DAY,    BIN2BCD(dt->tm_mday));

        v3020_set_reg(chip, V3020_MONTH,     BIN2BCD(dt->tm_mon + 1));

        v3020_set_reg(chip, V3020_WEEK_DAY,     BIN2BCD(dt->tm_wday));

        v3020_set_reg(chip, V3020_YEAR,         BIN2BCD(dt->tm_year % 100));

        /* ...and set the clock. */

        v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);

        /* Compulab used this delay here. I dont know why,

         * the datasheet does not specify a delay. */

        /*mdelay(5);*/

        return 0;

}

static const struct rtc_class_ops v3020_rtc_ops = {

        .read_time      = v3020_read_time,

        .set_time       = v3020_set_time,

};

static int rtc_probe(struct platform_device *pdev)

{

        struct v3020_platform_data *pdata = pdev->dev.platform_data;

        struct v3020 *chip;

        struct rtc_device *rtc;

        int retval = -EBUSY;

        int i;

        int temp;

        if (pdev->num_resources != 1)

                return -EBUSY;

        if (pdev->resource[0].flags != IORESOURCE_MEM)

                return -EBUSY;

        chip = kzalloc(sizeof *chip, GFP_KERNEL);

        if (!chip)

                return -ENOMEM;

        chip->leftshift = pdata->leftshift;

        chip->ioaddress = ioremap(pdev->resource[0].start, 1);

        if (chip->ioaddress == NULL)

                goto err_chip;

        /* Make sure the v3020 expects a communication cycle

         * by reading 8 times */

        for (i = 0; i < 8; i++)

                temp = readl(chip->ioaddress);

        /* Test chip by doing a write/read sequence

         * to the chip ram */

        v3020_set_reg(chip, V3020_SECONDS, 0x33);

        if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {

                retval = -ENODEV;

                goto err_io;

        }

        /* Make sure frequency measurment mode, test modes, and lock

         * are all disabled */

        v3020_set_reg(chip, V3020_STATUS_0, 0x0);

        dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"

                "data connected to D%d\n",

                (unsigned long long)pdev->resource[0].start,

                chip->leftshift);

        platform_set_drvdata(pdev, chip);

        rtc = rtc_device_register("v3020",

                                &pdev->dev, &v3020_rtc_ops, THIS_MODULE);

        if (IS_ERR(rtc)) {

                retval = PTR_ERR(rtc);

                goto err_io;

        }

        chip->rtc = rtc;

        return 0;

err_io:

        iounmap(chip->ioaddress);

err_chip:

        kfree(chip);

        return retval;

}

static int rtc_remove(struct platform_device *dev)

{

        struct v3020 *chip = platform_get_drvdata(dev);

        struct rtc_device *rtc = chip->rtc;

        if (rtc)

                rtc_device_unregister(rtc);

        iounmap(chip->ioaddress);

        kfree(chip);

        return 0;

}

static struct platform_driver rtc_device_driver = {

        .probe  = rtc_probe,

        .remove = rtc_remove,

        .driver = {

                .name   = "v3020",

                .owner  = THIS_MODULE,

        },

};

static __init int v3020_init(void)

{

        return platform_driver_register(&rtc_device_driver);

}

static __exit void v3020_exit(void)

{

        platform_driver_unregister(&rtc_device_driver);

}

module_init(v3020_init);

module_exit(v3020_exit);

MODULE_DESCRIPTION("V3020 RTC");

MODULE_AUTHOR("Raphael Assenat");

MODULE_LICENSE("GPL");