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/*

 * An I2C driver for the Philips PCF8563 RTC

 * Copyright 2005-06 Tower Technologies

 *

 * Author: Alessandro Zummo <a.zummo@towertech.it>

 * Maintainers: http://www.nslu2-linux.org/

 *

 * based on the other drivers in this same directory.

 *

 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf

 *

 * 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/i2c.h>

#include <linux/bcd.h>

#include <linux/rtc.h>

#define DRV_VERSION "0.4.2"

/* Addresses to scan: none

 * This chip cannot be reliably autodetected. An empty eeprom

 * located at 0x51 will pass the validation routine due to

 * the way the registers are implemented.

 */

static unsigned short normal_i2c[] = { I2C_CLIENT_END };

/* Module parameters */

I2C_CLIENT_INSMOD;

#define PCF8563_REG_ST1         0x00 /* status */

#define PCF8563_REG_ST2         0x01

#define PCF8563_REG_SC          0x02 /* datetime */

#define PCF8563_REG_MN          0x03

#define PCF8563_REG_HR          0x04

#define PCF8563_REG_DM          0x05

#define PCF8563_REG_DW          0x06

#define PCF8563_REG_MO          0x07

#define PCF8563_REG_YR          0x08

#define PCF8563_REG_AMN         0x09 /* alarm */

#define PCF8563_REG_AHR         0x0A

#define PCF8563_REG_ADM         0x0B

#define PCF8563_REG_ADW         0x0C

#define PCF8563_REG_CLKO        0x0D /* clock out */

#define PCF8563_REG_TMRC        0x0E /* timer control */

#define PCF8563_REG_TMR         0x0F /* timer */

#define PCF8563_SC_LV           0x80 /* low voltage */

#define PCF8563_MO_C            0x80 /* century */

struct pcf8563 {

        struct i2c_client client;

        /*

         * The meaning of MO_C bit varies by the chip type.

         * From PCF8563 datasheet: this bit is toggled when the years

         * register overflows from 99 to 00

         *   0 indicates the century is 20xx

         *   1 indicates the century is 19xx

         * From RTC8564 datasheet: this bit indicates change of

         * century. When the year digit data overflows from 99 to 00,

         * this bit is set. By presetting it to 0 while still in the

         * 20th century, it will be set in year 2000, ...

         * There seems no reliable way to know how the system use this

         * bit.  So let's do it heuristically, assuming we are live in

         * 1970...2069.

         */

        int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */

};

static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind);

static int pcf8563_detach(struct i2c_client *client);

/*

 * In the routines that deal directly with the pcf8563 hardware, we use

 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.

 */

static int pcf8563_get_datetime(struct i2c_client *client, struct rtc_time *tm)

{

        struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);

        unsigned char buf[13] = { PCF8563_REG_ST1 };

        struct i2c_msg msgs[] = {

                { client->addr, 0, 1, buf },     /* setup read ptr */

                { client->addr, I2C_M_RD, 13, buf },    /* read status + date */

        };

        /* read registers */

        if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {

                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

                return -EIO;

        }

        if (buf[PCF8563_REG_SC] & PCF8563_SC_LV)

                dev_info(&client->dev,

                        "low voltage detected, date/time is not reliable.\n");

        dev_dbg(&client->dev,

                "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "

                "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",

                __FUNCTION__,

                buf[0], buf[1], buf[2], buf[3],

                buf[4], buf[5], buf[6], buf[7],

                buf[8]);

        tm->tm_sec = BCD2BIN(buf[PCF8563_REG_SC] & 0x7F);

        tm->tm_min = BCD2BIN(buf[PCF8563_REG_MN] & 0x7F);

        tm->tm_hour = BCD2BIN(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */

        tm->tm_mday = BCD2BIN(buf[PCF8563_REG_DM] & 0x3F);

        tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;

        tm->tm_mon = BCD2BIN(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */

        tm->tm_year = BCD2BIN(buf[PCF8563_REG_YR]);

        if (tm->tm_year < 70)

                tm->tm_year += 100;     /* assume we are in 1970...2069 */

        /* detect the polarity heuristically. see note above. */

        pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?

                (tm->tm_year >= 100) : (tm->tm_year < 100);

        dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "

                "mday=%d, mon=%d, year=%d, wday=%d\n",

                __FUNCTION__,

                tm->tm_sec, tm->tm_min, tm->tm_hour,

                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

        /* the clock can give out invalid datetime, but we cannot return

         * -EINVAL otherwise hwclock will refuse to set the time on bootup.

         */

        if (rtc_valid_tm(tm) < 0)

                dev_err(&client->dev, "retrieved date/time is not valid.\n");

        return 0;

}

static int pcf8563_set_datetime(struct i2c_client *client, struct rtc_time *tm)

{

        struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);

        int i, err;

        unsigned char buf[9];

        dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "

                "mday=%d, mon=%d, year=%d, wday=%d\n",

                __FUNCTION__,

                tm->tm_sec, tm->tm_min, tm->tm_hour,

                tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);

        /* hours, minutes and seconds */

        buf[PCF8563_REG_SC] = BIN2BCD(tm->tm_sec);

        buf[PCF8563_REG_MN] = BIN2BCD(tm->tm_min);

        buf[PCF8563_REG_HR] = BIN2BCD(tm->tm_hour);

        buf[PCF8563_REG_DM] = BIN2BCD(tm->tm_mday);

        /* month, 1 - 12 */

        buf[PCF8563_REG_MO] = BIN2BCD(tm->tm_mon + 1);

        /* year and century */

        buf[PCF8563_REG_YR] = BIN2BCD(tm->tm_year % 100);

        if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))

                buf[PCF8563_REG_MO] |= PCF8563_MO_C;

        buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;

        /* write register's data */

        for (i = 0; i < 7; i++) {

                unsigned char data[2] = { PCF8563_REG_SC + i,

                                                buf[PCF8563_REG_SC + i] };

                err = i2c_master_send(client, data, sizeof(data));

                if (err != sizeof(data)) {

                        dev_err(&client->dev,

                                "%s: err=%d addr=%02x, data=%02x\n",

                                __FUNCTION__, err, data[0], data[1]);

                        return -EIO;

                }

        };

        return 0;

}

struct pcf8563_limit

{

        unsigned char reg;

        unsigned char mask;

        unsigned char min;

        unsigned char max;

};

static int pcf8563_validate_client(struct i2c_client *client)

{

        int i;

        static const struct pcf8563_limit pattern[] = {

                /* register, mask, min, max */

                { PCF8563_REG_SC,       0x7F,   0,       59      },

                { PCF8563_REG_MN,       0x7F,   0,       59      },

                { PCF8563_REG_HR,       0x3F,   0,       23      },

                { PCF8563_REG_DM,       0x3F,   0,       31      },

                { PCF8563_REG_MO,       0x1F,   0,       12      },

        };

        /* check limits (only registers with bcd values) */

        for (i = 0; i < ARRAY_SIZE(pattern); i++) {

                int xfer;

                unsigned char value;

                unsigned char buf = pattern[i].reg;

                struct i2c_msg msgs[] = {

                        { client->addr, 0, 1, &buf },

                        { client->addr, I2C_M_RD, 1, &buf },

                };

                xfer = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

                if (xfer != ARRAY_SIZE(msgs)) {

                        dev_err(&client->dev,

                                "%s: could not read register 0x%02X\n",

                                __FUNCTION__, pattern[i].reg);

                        return -EIO;

                }

                value = BCD2BIN(buf & pattern[i].mask);

                if (value > pattern[i].max ||

                        value < pattern[i].min) {

                        dev_dbg(&client->dev,

                                "%s: pattern=%d, reg=%x, mask=0x%02x, min=%d, "

                                "max=%d, value=%d, raw=0x%02X\n",

                                __FUNCTION__, i, pattern[i].reg, pattern[i].mask,

                                pattern[i].min, pattern[i].max,

                                value, buf);

                        return -ENODEV;

                }

        }

        return 0;

}

static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

        return pcf8563_get_datetime(to_i2c_client(dev), tm);

}

static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

        return pcf8563_set_datetime(to_i2c_client(dev), tm);

}

static const struct rtc_class_ops pcf8563_rtc_ops = {

        .read_time      = pcf8563_rtc_read_time,

        .set_time       = pcf8563_rtc_set_time,

};

static int pcf8563_attach(struct i2c_adapter *adapter)

{

        return i2c_probe(adapter, &addr_data, pcf8563_probe);

}

static struct i2c_driver pcf8563_driver = {

        .driver         = {

                .name   = "pcf8563",

        },

        .id             = I2C_DRIVERID_PCF8563,

        .attach_adapter = &pcf8563_attach,

        .detach_client  = &pcf8563_detach,

};

static int pcf8563_probe(struct i2c_adapter *adapter, int address, int kind)

{

        struct pcf8563 *pcf8563;

        struct i2c_client *client;

        struct rtc_device *rtc;

        int err = 0;

        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);

        if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {

                err = -ENODEV;

                goto exit;

        }

        if (!(pcf8563 = kzalloc(sizeof(struct pcf8563), GFP_KERNEL))) {

                err = -ENOMEM;

                goto exit;

        }

        client = &pcf8563->client;

        client->addr = address;

        client->driver = &pcf8563_driver;

        client->adapter = adapter;

        strlcpy(client->name, pcf8563_driver.driver.name, I2C_NAME_SIZE);

        /* Verify the chip is really an PCF8563 */

        if (kind < 0) {

                if (pcf8563_validate_client(client) < 0) {

                        err = -ENODEV;

                        goto exit_kfree;

                }

        }

        /* Inform the i2c layer */

        if ((err = i2c_attach_client(client)))

                goto exit_kfree;

        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");

        rtc = rtc_device_register(pcf8563_driver.driver.name, &client->dev,

                                &pcf8563_rtc_ops, THIS_MODULE);

        if (IS_ERR(rtc)) {

                err = PTR_ERR(rtc);

                goto exit_detach;

        }

        i2c_set_clientdata(client, rtc);

        return 0;

exit_detach:

        i2c_detach_client(client);

exit_kfree:

        kfree(pcf8563);

exit:

        return err;

}

static int pcf8563_detach(struct i2c_client *client)

{

        struct pcf8563 *pcf8563 = container_of(client, struct pcf8563, client);

        int err;

        struct rtc_device *rtc = i2c_get_clientdata(client);

        if (rtc)

                rtc_device_unregister(rtc);

        if ((err = i2c_detach_client(client)))

                return err;

        kfree(pcf8563);

        return 0;

}

static int __init pcf8563_init(void)

{

        return i2c_add_driver(&pcf8563_driver);

}

static void __exit pcf8563_exit(void)

{

        i2c_del_driver(&pcf8563_driver);

}

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");

MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(DRV_VERSION);

module_init(pcf8563_init);

module_exit(pcf8563_exit);