[PATCH] i2c: New Xicor X1205 RTC driver

New driver for the Xicor X1205 RTC chip.

Signed-off-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 708 insertions, 0 deletions

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 6bd44a44cd28..f9fae28f5612 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -126,4 +126,13 @@ config SENSORS_MAX6875
           This driver can also be built as a module.  If so, the module
           will be called max6875.
 
+config RTC_X1205_I2C
+        tristate "Xicor X1205 RTC chip"
+        depends on I2C && EXPERIMENTAL
+        help
+          If you say yes here you get support for the Xicor X1205 RTC chip.
+
+          This driver can also be built as a module. If so, the module
+          will be called x1205.
+
 endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index a876dd42b860..46178b57b1f1 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
 obj-$(CONFIG_SENSORS_RTC8564)   += rtc8564.o
 obj-$(CONFIG_ISP1301_OMAP)      += isp1301_omap.o
 obj-$(CONFIG_TPS65010)          += tps65010.o
+obj-$(CONFIG_RTC_X1205_I2C)     += x1205.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/x1205.c b/drivers/i2c/chips/x1205.c
new file mode 100644
index 000000000000..7da366cdc18c
--- /dev/null
+++ b/drivers/i2c/chips/x1205.c
@@ -0,0 +1,698 @@
+/*
+ *  x1205.c - An i2c driver for the Xicor X1205 RTC
+ *  Copyright 2004 Karen Spearel
+ *  Copyright 2005 Alessandro Zummo
+ *
+ *  please send all reports to:
+ *      kas11 at tampabay dot rr dot com
+ *      a dot zummo at towertech dot it
+ *
+ *  based on the other drivers in this same directory.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/string.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/list.h>
+
+#include <linux/x1205.h>
+
+#define DRV_VERSION "0.9.9"
+
+/* Addresses to scan: none. This chip is located at
+ * 0x6f and uses a two bytes register addressing.
+ * Two bytes need to be written to read a single register,
+ * while most other chips just require one and take the second
+ * one as the data to be written. To prevent corrupting
+ * unknown chips, the user must explicitely set the probe parameter.
+ */
+
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD;
+I2C_CLIENT_MODULE_PARM(hctosys,
+        "Set the system time from the hardware clock upon initialization");
+
+/* offsets into CCR area */
+
+#define CCR_SEC                 0
+#define CCR_MIN                 1
+#define CCR_HOUR                2
+#define CCR_MDAY                3
+#define CCR_MONTH               4
+#define CCR_YEAR                5
+#define CCR_WDAY                6
+#define CCR_Y2K                 7
+
+#define X1205_REG_SR            0x3F    /* status register */
+#define X1205_REG_Y2K           0x37
+#define X1205_REG_DW            0x36
+#define X1205_REG_YR            0x35
+#define X1205_REG_MO            0x34
+#define X1205_REG_DT            0x33
+#define X1205_REG_HR            0x32
+#define X1205_REG_MN            0x31
+#define X1205_REG_SC            0x30
+#define X1205_REG_DTR           0x13
+#define X1205_REG_ATR           0x12
+#define X1205_REG_INT           0x11
+#define X1205_REG_0             0x10
+#define X1205_REG_Y2K1          0x0F
+#define X1205_REG_DWA1          0x0E
+#define X1205_REG_YRA1          0x0D
+#define X1205_REG_MOA1          0x0C
+#define X1205_REG_DTA1          0x0B
+#define X1205_REG_HRA1          0x0A
+#define X1205_REG_MNA1          0x09
+#define X1205_REG_SCA1          0x08
+#define X1205_REG_Y2K0          0x07
+#define X1205_REG_DWA0          0x06
+#define X1205_REG_YRA0          0x05
+#define X1205_REG_MOA0          0x04
+#define X1205_REG_DTA0          0x03
+#define X1205_REG_HRA0          0x02
+#define X1205_REG_MNA0          0x01
+#define X1205_REG_SCA0          0x00
+
+#define X1205_CCR_BASE          0x30    /* Base address of CCR */
+#define X1205_ALM0_BASE         0x00    /* Base address of ALARM0 */
+
+#define X1205_SR_RTCF           0x01    /* Clock failure */
+#define X1205_SR_WEL            0x02    /* Write Enable Latch */
+#define X1205_SR_RWEL           0x04    /* Register Write Enable */
+
+#define X1205_DTR_DTR0          0x01
+#define X1205_DTR_DTR1          0x02
+#define X1205_DTR_DTR2          0x04
+
+#define X1205_HR_MIL            0x80    /* Set in ccr.hour for 24 hr mode */
+
+/* Prototypes */
+static int x1205_attach(struct i2c_adapter *adapter);
+static int x1205_detach(struct i2c_client *client);
+static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);
+static int x1205_command(struct i2c_client *client, unsigned int cmd,
+        void *arg);
+
+static struct i2c_driver x1205_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "x1205",
+        .flags          = I2C_DF_NOTIFY,
+        .attach_adapter = &x1205_attach,
+        .detach_client  = &x1205_detach,
+};
+
+struct x1205_data {
+        struct i2c_client client;
+        struct list_head list;
+        unsigned int epoch;
+};
+
+static const unsigned char days_in_mo[] =
+        { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+static LIST_HEAD(x1205_clients);
+
+/* Workaround until the I2C subsytem will allow to send
+ * commands to a specific client. This function will send the command
+ * to the first client.
+ */
+int x1205_do_command(unsigned int cmd, void *arg)
+{
+        struct list_head *walk;
+        struct list_head *tmp;
+        struct x1205_data *data;
+
+        list_for_each_safe(walk, tmp, &x1205_clients) {
+                data = list_entry(walk, struct x1205_data, list);
+                return x1205_command(&data->client, cmd, arg);
+        }
+
+        return -ENODEV;
+}
+
+#define is_leap(year) \
+        ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
+
+/* make sure the rtc_time values are in bounds */
+static int x1205_validate_tm(struct rtc_time *tm)
+{
+        int year = tm->tm_year + 1900;
+
+        if ((tm->tm_year < 70) || (tm->tm_year > 255))
+                return -EINVAL;
+
+        if ((tm->tm_mon > 11) || (tm->tm_mday == 0))
+                return -EINVAL;
+
+        if (tm->tm_mday > days_in_mo[tm->tm_mon]
+                + ((tm->tm_mon == 1) && is_leap(year)))
+                return -EINVAL;
+
+        if ((tm->tm_hour >= 24) || (tm->tm_min >= 60) || (tm->tm_sec >= 60))
+                return -EINVAL;
+
+        return 0;
+}
+
+/*
+ * In the routines that deal directly with the x1205 hardware, we use
+ * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch
+ * Epoch is initialized as 2000. Time is set to UTC.
+ */
+static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,
+                                u8 reg_base)
+{
+        unsigned char dt_addr[2] = { 0, reg_base };
+        static unsigned char sr_addr[2] = { 0, X1205_REG_SR };
+
+        unsigned char buf[8], sr;
+
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 2, sr_addr },        /* setup read ptr */
+                { client->addr, I2C_M_RD, 1, &sr },     /* read status */
+                { client->addr, 0, 2, dt_addr },        /* setup read ptr */
+                { client->addr, I2C_M_RD, 8, buf },     /* read date */
+        };
+
+        struct x1205_data *data = i2c_get_clientdata(client);
+
+        /* read status register */
+        if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        /* check for battery failure */
+        if (sr & X1205_SR_RTCF) {
+                dev_warn(&client->dev,
+                        "Clock had a power failure, you must set the date.\n");
+                return -EINVAL;
+        }
+
+        /* read date registers */
+        if ((i2c_transfer(client->adapter, &msgs[2], 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        dev_dbg(&client->dev,
+                "%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
+                "mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
+                __FUNCTION__,
+                buf[0], buf[1], buf[2], buf[3],
+                buf[4], buf[5], buf[6], buf[7]);
+
+        tm->tm_sec = BCD2BIN(buf[CCR_SEC]);
+        tm->tm_min = BCD2BIN(buf[CCR_MIN]);
+        tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */
+        tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);
+        tm->tm_mon = BCD2BIN(buf[CCR_MONTH]);
+        data->epoch = BCD2BIN(buf[CCR_Y2K]) * 100;
+        tm->tm_year = BCD2BIN(buf[CCR_YEAR]) + data->epoch - 1900;
+        tm->tm_wday = buf[CCR_WDAY];
+
+        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);
+
+        return 0;
+}
+
+static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,
+                                int datetoo, u8 reg_base)
+{
+        int i, err, xfer;
+
+        unsigned char buf[8];
+
+        static const unsigned char wel[3] = { 0, X1205_REG_SR,
+                                                X1205_SR_WEL };
+
+        static const unsigned char rwel[3] = { 0, X1205_REG_SR,
+                                                X1205_SR_WEL | X1205_SR_RWEL };
+
+        static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };
+
+        struct x1205_data *data = i2c_get_clientdata(client);
+
+        /* check if all values in the tm struct are correct */
+        if ((err = x1205_validate_tm(tm)) < 0)
+                return err;
+
+        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);
+
+        buf[CCR_SEC] = BIN2BCD(tm->tm_sec);
+        buf[CCR_MIN] = BIN2BCD(tm->tm_min);
+
+        /* set hour and 24hr bit */
+        buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;
+
+        /* should we also set the date? */
+        if (datetoo) {
+                buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);
+
+                /* month, 0 - 11 */
+                buf[CCR_MONTH] = BIN2BCD(tm->tm_mon);
+
+                /* year, since 1900 */
+                buf[CCR_YEAR] = BIN2BCD(tm->tm_year + 1900 - data->epoch);
+                buf[CCR_WDAY] = tm->tm_wday & 0x07;
+                buf[CCR_Y2K] = BIN2BCD(data->epoch / 100);
+        }
+
+        /* this sequence is required to unlock the chip */
+        xfer = i2c_master_send(client, wel, 3);
+        if (xfer != 3) {
+                dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);
+                return -EIO;
+        }
+
+        xfer = i2c_master_send(client, rwel, 3);
+        if (xfer != 3) {
+                dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);
+                return -EIO;
+        }
+
+        /* write register's data */
+        for (i = 0; i < (datetoo ? 8 : 3); i++) {
+                unsigned char rdata[3] = { 0, reg_base + i, buf[i] };
+
+                xfer = i2c_master_send(client, rdata, 3);
+                if (xfer != 3) {
+                        dev_err(&client->dev,
+                                "%s: xfer=%d addr=%02x, data=%02x\n",
+                                __FUNCTION__,
+                                 xfer, rdata[1], rdata[2]);
+                        return -EIO;
+                }
+        };
+
+        /* disable further writes */
+        xfer = i2c_master_send(client, diswe, 3);
+        if (xfer != 3) {
+                dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);
+                return -EIO;
+        }
+
+        return 0;
+}
+
+static int x1205_get_dtrim(struct i2c_client *client, int *trim)
+{
+        unsigned char dtr;
+        static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };
+
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 2, dtr_addr },       /* setup read ptr */
+                { client->addr, I2C_M_RD, 1, &dtr },    /* read dtr */
+        };
+
+        /* read dtr register */
+        if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);
+
+        *trim = 0;
+
+        if (dtr & X1205_DTR_DTR0)
+                *trim += 20;
+
+        if (dtr & X1205_DTR_DTR1)
+                *trim += 10;
+
+        if (dtr & X1205_DTR_DTR2)
+                *trim = -*trim;
+
+        return 0;
+}
+
+static int x1205_get_atrim(struct i2c_client *client, int *trim)
+{
+        s8 atr;
+        static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };
+
+        struct i2c_msg msgs[] = {
+                { client->addr, 0, 2, atr_addr },       /* setup read ptr */
+                { client->addr, I2C_M_RD, 1, &atr },    /* read atr */
+        };
+
+        /* read atr register */
+        if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+                dev_err(&client->dev, "%s: read error\n", __FUNCTION__);
+                return -EIO;
+        }
+
+        dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);
+
+        /* atr is a two's complement value on 6 bits,
+         * perform sign extension. The formula is
+         * Catr = (atr * 0.25pF) + 11.00pF.
+         */
+        if (atr & 0x20)
+                atr |= 0xC0;
+
+        dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);
+
+        *trim = (atr * 250) + 11000;
+
+        dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);
+
+        return 0;
+}
+
+static int x1205_hctosys(struct i2c_client *client)
+{
+        int err;
+
+        struct rtc_time tm;
+        struct timespec tv;
+
+        err = x1205_command(client, X1205_CMD_GETDATETIME, &tm);
+
+        if (err) {
+                dev_err(&client->dev,
+                        "Unable to set the system clock\n");
+                return err;
+        }
+
+        /* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
+         * whether it stores the most close value or the value with partial
+         * seconds truncated. However, it is important that we use it to store
+         * the truncated value. This is because otherwise it is necessary,
+         * in an rtc sync function, to read both xtime.tv_sec and
+         * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
+         * of >32bits is not possible. So storing the most close value would
+         * slow down the sync API. So here we have the truncated value and
+         * the best guess is to add 0.5s.
+         */
+
+        tv.tv_nsec = NSEC_PER_SEC >> 1;
+
+        /* WARNING: this is not the C library 'mktime' call, it is a built in
+         * inline function from include/linux/time.h.  It expects (requires)
+         * the month to be in the range 1-12
+         */
+
+        tv.tv_sec  = mktime(tm.tm_year + 1900, tm.tm_mon + 1,
+                                tm.tm_mday, tm.tm_hour,
+                                tm.tm_min, tm.tm_sec);
+
+        do_settimeofday(&tv);
+
+        dev_info(&client->dev,
+                "setting the system clock to %d-%d-%d %d:%d:%d\n",
+                tm.tm_year + 1900, tm.tm_mon + 1,
+                tm.tm_mday, tm.tm_hour, tm.tm_min,
+                tm.tm_sec);
+
+        return 0;
+}
+
+struct x1205_limit
+{
+        unsigned char reg;
+        unsigned char mask;
+        unsigned char min;
+        unsigned char max;
+};
+
+static int x1205_validate_client(struct i2c_client *client)
+{
+        int i, xfer;
+
+        /* Probe array. We will read the register at the specified
+         * address and check if the given bits are zero.
+         */
+        static const unsigned char probe_zero_pattern[] = {
+                /* register, mask */
+                X1205_REG_SR,   0x18,
+                X1205_REG_DTR,  0xF8,
+                X1205_REG_ATR,  0xC0,
+                X1205_REG_INT,  0x18,
+                X1205_REG_0,    0xFF,
+        };
+
+        static const struct x1205_limit probe_limits_pattern[] = {
+                /* register, mask, min, max */
+                { X1205_REG_Y2K,        0xFF,   19,     20      },
+                { X1205_REG_DW,         0xFF,   0,      6       },
+                { X1205_REG_YR,         0xFF,   0,      99      },
+                { X1205_REG_MO,         0xFF,   0,      12      },
+                { X1205_REG_DT,         0xFF,   0,      31      },
+                { X1205_REG_HR,         0x7F,   0,      23      },
+                { X1205_REG_MN,         0xFF,   0,      59      },
+                { X1205_REG_SC,         0xFF,   0,      59      },
+                { X1205_REG_Y2K1,       0xFF,   19,     20      },
+                { X1205_REG_Y2K0,       0xFF,   19,     20      },
+        };
+
+        /* check that registers have bits a 0 where expected */
+        for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {
+                unsigned char buf;
+
+                unsigned char addr[2] = { 0, probe_zero_pattern[i] };
+
+                struct i2c_msg msgs[2] = {
+                        { client->addr, 0, 2, addr },
+                        { client->addr, I2C_M_RD, 1, &buf },
+                };
+
+                xfer = i2c_transfer(client->adapter, msgs, 2);
+                if (xfer != 2) {
+                        dev_err(&client->adapter->dev,
+                                "%s: could not read register %x\n",
+                                __FUNCTION__, addr[1]);
+
+                        return -EIO;
+                }
+
+                if ((buf & probe_zero_pattern[i+1]) != 0) {
+                        dev_err(&client->adapter->dev,
+                                "%s: register=%02x, zero pattern=%d, value=%x\n",
+                                __FUNCTION__, addr[1], i, buf);
+
+                        return -ENODEV;
+                }
+        }
+
+        /* check limits (only registers with bcd values) */
+        for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {
+                unsigned char reg, value;
+
+                unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };
+
+                struct i2c_msg msgs[2] = {
+                        { client->addr, 0, 2, addr },
+                        { client->addr, I2C_M_RD, 1, &reg },
+                };
+
+                xfer = i2c_transfer(client->adapter, msgs, 2);
+
+                if (xfer != 2) {
+                        dev_err(&client->adapter->dev,
+                                "%s: could not read register %x\n",
+                                __FUNCTION__, addr[1]);
+
+                        return -EIO;
+                }
+
+                value = BCD2BIN(reg & probe_limits_pattern[i].mask);
+
+                if (value > probe_limits_pattern[i].max ||
+                        value < probe_limits_pattern[i].min) {
+                        dev_dbg(&client->adapter->dev,
+                                "%s: register=%x, lim pattern=%d, value=%d\n",
+                                __FUNCTION__, addr[1], i, value);
+
+                        return -ENODEV;
+                }
+        }
+
+        return 0;
+}
+
+static int x1205_attach(struct i2c_adapter *adapter)
+{
+        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+
+        return i2c_probe(adapter, &addr_data, x1205_probe);
+}
+
+int x1205_direct_attach(int adapter_id,
+        struct i2c_client_address_data *address_data)
+{
+        int err;
+        struct i2c_adapter *adapter = i2c_get_adapter(adapter_id);
+
+        if (adapter) {
+                err = i2c_probe(adapter,
+                        address_data, x1205_probe);
+
+                i2c_put_adapter(adapter);
+
+                return err;
+        }
+
+        return -ENODEV;
+}
+
+static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)
+{
+        struct i2c_client *client;
+        struct x1205_data *data;
+
+        int err = 0;
+
+        dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+                err = -ENODEV;
+                goto exit;
+        }
+
+        if (!(data = kzalloc(sizeof(struct x1205_data), GFP_KERNEL))) {
+                err = -ENOMEM;
+                goto exit;
+        }
+
+        /* Initialize our structures */
+        data->epoch = 2000;
+
+        client = &data->client;
+        client->addr = address;
+        client->driver = &x1205_driver;
+        client->adapter = adapter;
+
+        strlcpy(client->name, "x1205", I2C_NAME_SIZE);
+
+        i2c_set_clientdata(client, data);
+
+        /* Verify the chip is really an X1205 */
+        if (kind < 0) {
+                if (x1205_validate_client(client) < 0) {
+                        err = -ENODEV;
+                        goto exit_kfree;
+                }
+        }
+
+        /* Inform the i2c layer */
+        if ((err = i2c_attach_client(client)))
+                goto exit_kfree;
+
+        list_add(&data->list, &x1205_clients);
+
+        dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
+
+        /* If requested, set the system time */
+        if (hctosys)
+                x1205_hctosys(client);
+
+        return 0;
+
+exit_kfree:
+        kfree(data);
+
+exit:
+        return err;
+}
+
+static int x1205_detach(struct i2c_client *client)
+{
+        int err;
+        struct x1205_data *data = i2c_get_clientdata(client);
+
+        dev_dbg(&client->dev, "%s\n", __FUNCTION__);
+
+        if ((err = i2c_detach_client(client)))
+                return err;
+
+        list_del(&data->list);
+
+        kfree(data);
+
+        return 0;
+}
+
+static int x1205_command(struct i2c_client *client, unsigned int cmd,
+        void *param)
+{
+        if (param == NULL)
+                return -EINVAL;
+
+        if (!capable(CAP_SYS_TIME))
+                return -EACCES;
+
+        dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
+
+        switch (cmd) {
+        case X1205_CMD_GETDATETIME:
+                return x1205_get_datetime(client, param, X1205_CCR_BASE);
+
+        case X1205_CMD_SETTIME:
+                return x1205_set_datetime(client, param, 0,
+                                X1205_CCR_BASE);
+
+        case X1205_CMD_SETDATETIME:
+                return x1205_set_datetime(client, param, 1,
+                                X1205_CCR_BASE);
+
+        case X1205_CMD_GETALARM:
+                return x1205_get_datetime(client, param, X1205_ALM0_BASE);
+
+        case X1205_CMD_SETALARM:
+                return x1205_set_datetime(client, param, 1,
+                                X1205_ALM0_BASE);
+
+        case X1205_CMD_GETDTRIM:
+                return x1205_get_dtrim(client, param);
+
+        case X1205_CMD_GETATRIM:
+                return x1205_get_atrim(client, param);
+
+        default:
+                return -EINVAL;
+        }
+}
+
+static int __init x1205_init(void)
+{
+        return i2c_add_driver(&x1205_driver);
+}
+
+static void __exit x1205_exit(void)
+{
+        i2c_del_driver(&x1205_driver);
+}
+
+MODULE_AUTHOR(
+        "Karen Spearel <kas11@tampabay.rr.com>, "
+        "Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("Xicor X1205 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+
+EXPORT_SYMBOL_GPL(x1205_do_command);
+EXPORT_SYMBOL_GPL(x1205_direct_attach);
+
+module_init(x1205_init);
+module_exit(x1205_exit);