/*
* 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 = {
.driver = {
.owner = THIS_MODULE,
.name = "x1205",
},
.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, ® },
};
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);
