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linux/drivers/i2c/chips/ds1337.c

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/*
* linux/drivers/i2c/chips/ds1337.c
*
* Copyright (C) 2005 James Chapman <jchapman@katalix.com>
*
* based on linux/drivers/acorn/char/pcf8583.c
* Copyright (C) 2000 Russell King
*
* 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 Dallas Semiconductor DS1337 and DS1339 real time clock chip
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h> /* get the user-level API */
#include <linux/bcd.h>
#include <linux/list.h>
/* Device registers */
#define DS1337_REG_HOUR 2
#define DS1337_REG_DAY 3
#define DS1337_REG_DATE 4
#define DS1337_REG_MONTH 5
#define DS1337_REG_CONTROL 14
#define DS1337_REG_STATUS 15
/* FIXME - how do we export these interface constants? */
#define DS1337_GET_DATE 0
#define DS1337_SET_DATE 1
/*
* Functions declaration
*/
static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };
I2C_CLIENT_INSMOD_1(ds1337);
static int ds1337_attach_adapter(struct i2c_adapter *adapter);
static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind);
static void ds1337_init_client(struct i2c_client *client);
static int ds1337_detach_client(struct i2c_client *client);
static int ds1337_command(struct i2c_client *client, unsigned int cmd,
void *arg);
/*
* Driver data (common to all clients)
*/
static struct i2c_driver ds1337_driver = {
.owner = THIS_MODULE,
.name = "ds1337",
.flags = I2C_DF_NOTIFY,
.attach_adapter = ds1337_attach_adapter,
.detach_client = ds1337_detach_client,
.command = ds1337_command,
};
/*
* Client data (each client gets its own)
*/
struct ds1337_data {
struct i2c_client client;
struct list_head list;
};
/*
* Internal variables
*/
static LIST_HEAD(ds1337_clients);
static inline int ds1337_read(struct i2c_client *client, u8 reg, u8 *value)
{
s32 tmp = i2c_smbus_read_byte_data(client, reg);
if (tmp < 0)
return -EIO;
*value = tmp;
return 0;
}
/*
* Chip access functions
*/
static int ds1337_get_datetime(struct i2c_client *client, struct rtc_time *dt)
{
int result;
u8 buf[7];
u8 val;
struct i2c_msg msg[2];
u8 offs = 0;
if (!dt) {
dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
return -EINVAL;
}
msg[0].addr = client->addr;
msg[0].flags = 0;
msg[0].len = 1;
msg[0].buf = &offs;
msg[1].addr = client->addr;
msg[1].flags = I2C_M_RD;
msg[1].len = sizeof(buf);
msg[1].buf = &buf[0];
result = i2c_transfer(client->adapter, msg, 2);
dev_dbg(&client->dev, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
__FUNCTION__, result, buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6]);
if (result == 2) {
dt->tm_sec = BCD2BIN(buf[0]);
dt->tm_min = BCD2BIN(buf[1]);
val = buf[2] & 0x3f;
dt->tm_hour = BCD2BIN(val);
dt->tm_wday = BCD2BIN(buf[3]) - 1;
dt->tm_mday = BCD2BIN(buf[4]);
val = buf[5] & 0x7f;
dt->tm_mon = BCD2BIN(val) - 1;
dt->tm_year = BCD2BIN(buf[6]);
if (buf[5] & 0x80)
dt->tm_year += 100;
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
__FUNCTION__, dt->tm_sec, dt->tm_min,
dt->tm_hour, dt->tm_mday,
dt->tm_mon, dt->tm_year, dt->tm_wday);
return 0;
}
dev_err(&client->dev, "error reading data! %d\n", result);
return -EIO;
}
static int ds1337_set_datetime(struct i2c_client *client, struct rtc_time *dt)
{
int result;
u8 buf[8];
u8 val;
struct i2c_msg msg[1];
if (!dt) {
dev_dbg(&client->dev, "%s: EINVAL: dt=NULL\n", __FUNCTION__);
return -EINVAL;
}
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__,
dt->tm_sec, dt->tm_min, dt->tm_hour,
dt->tm_mday, dt->tm_mon, dt->tm_year, dt->tm_wday);
buf[0] = 0; /* reg offset */
buf[1] = BIN2BCD(dt->tm_sec);
buf[2] = BIN2BCD(dt->tm_min);
buf[3] = BIN2BCD(dt->tm_hour);
buf[4] = BIN2BCD(dt->tm_wday) + 1;
buf[5] = BIN2BCD(dt->tm_mday);
buf[6] = BIN2BCD(dt->tm_mon) + 1;
val = dt->tm_year;
if (val >= 100) {
val -= 100;
buf[6] |= (1 << 7);
}
buf[7] = BIN2BCD(val);
msg[0].addr = client->addr;
msg[0].flags = 0;
msg[0].len = sizeof(buf);
msg[0].buf = &buf[0];
result = i2c_transfer(client->adapter, msg, 1);
if (result == 1)
return 0;
dev_err(&client->dev, "error writing data! %d\n", result);
return -EIO;
}
static int ds1337_command(struct i2c_client *client, unsigned int cmd,
void *arg)
{
dev_dbg(&client->dev, "%s: cmd=%d\n", __FUNCTION__, cmd);
switch (cmd) {
case DS1337_GET_DATE:
return ds1337_get_datetime(client, arg);
case DS1337_SET_DATE:
return ds1337_set_datetime(client, arg);
default:
return -EINVAL;
}
}
/*
* Public API for access to specific device. Useful for low-level
* RTC access from kernel code.
*/
int ds1337_do_command(int bus, int cmd, void *arg)
{
struct list_head *walk;
struct list_head *tmp;
struct ds1337_data *data;
list_for_each_safe(walk, tmp, &ds1337_clients) {
data = list_entry(walk, struct ds1337_data, list);
if (data->client.adapter->nr == bus)
return ds1337_command(&data->client, cmd, arg);
}
return -ENODEV;
}
static int ds1337_attach_adapter(struct i2c_adapter *adapter)
{
return i2c_probe(adapter, &addr_data, ds1337_detect);
}
/*
* The following function does more than just detection. If detection
* succeeds, it also registers the new chip.
*/
static int ds1337_detect(struct i2c_adapter *adapter, int address, int kind)
{
struct i2c_client *new_client;
struct ds1337_data *data;
int err = 0;
const char *name = "";
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_I2C))
goto exit;
if (!(data = kmalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
memset(data, 0, sizeof(struct ds1337_data));
INIT_LIST_HEAD(&data->list);
/* The common I2C client data is placed right before the
* DS1337-specific data.
*/
new_client = &data->client;
i2c_set_clientdata(new_client, data);
new_client->addr = address;
new_client->adapter = adapter;
new_client->driver = &ds1337_driver;
new_client->flags = 0;
/*
* Now we do the remaining detection. A negative kind means that
* the driver was loaded with no force parameter (default), so we
* must both detect and identify the chip. A zero kind means that
* the driver was loaded with the force parameter, the detection
* step shall be skipped. A positive kind means that the driver
* was loaded with the force parameter and a given kind of chip is
* requested, so both the detection and the identification steps
* are skipped.
*
* For detection, we read registers that are most likely to cause
* detection failure, i.e. those that have more bits with fixed
* or reserved values.
*/
/* Default to an DS1337 if forced */
if (kind == 0)
kind = ds1337;
if (kind < 0) { /* detection and identification */
u8 data;
/* Check that status register bits 6-2 are zero */
if ((ds1337_read(new_client, DS1337_REG_STATUS, &data) < 0) ||
(data & 0x7c))
goto exit_free;
/* Check for a valid day register value */
if ((ds1337_read(new_client, DS1337_REG_DAY, &data) < 0) ||
(data == 0) || (data & 0xf8))
goto exit_free;
/* Check for a valid date register value */
if ((ds1337_read(new_client, DS1337_REG_DATE, &data) < 0) ||
(data == 0) || (data & 0xc0) || ((data & 0x0f) > 9) ||
(data >= 0x32))
goto exit_free;
/* Check for a valid month register value */
if ((ds1337_read(new_client, DS1337_REG_MONTH, &data) < 0) ||
(data == 0) || (data & 0x60) || ((data & 0x0f) > 9) ||
((data >= 0x13) && (data <= 0x19)))
goto exit_free;
/* Check that control register bits 6-5 are zero */
if ((ds1337_read(new_client, DS1337_REG_CONTROL, &data) < 0) ||
(data & 0x60))
goto exit_free;
kind = ds1337;
}
if (kind == ds1337)
name = "ds1337";
/* We can fill in the remaining client fields */
strlcpy(new_client->name, name, I2C_NAME_SIZE);
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(new_client)))
goto exit_free;
/* Initialize the DS1337 chip */
ds1337_init_client(new_client);
/* Add client to local list */
list_add(&data->list, &ds1337_clients);
return 0;
exit_free:
kfree(data);
exit:
return err;
}
static void ds1337_init_client(struct i2c_client *client)
{
s32 val;
/* Ensure that device is set in 24-hour mode */
val = i2c_smbus_read_byte_data(client, DS1337_REG_HOUR);
if ((val >= 0) && (val & (1 << 6)))
i2c_smbus_write_byte_data(client, DS1337_REG_HOUR,
val & 0x3f);
}
static int ds1337_detach_client(struct i2c_client *client)
{
int err;
struct ds1337_data *data = i2c_get_clientdata(client);
if ((err = i2c_detach_client(client)))
return err;
list_del(&data->list);
kfree(data);
return 0;
}
static int __init ds1337_init(void)
{
return i2c_add_driver(&ds1337_driver);
}
static void __exit ds1337_exit(void)
{
i2c_del_driver(&ds1337_driver);
}
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("DS1337 RTC driver");
MODULE_LICENSE("GPL");
EXPORT_SYMBOL_GPL(ds1337_do_command);
module_init(ds1337_init);
module_exit(ds1337_exit);
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