kernel-ark/drivers/i2c/chips/ds1337.c
Dirk Eibach 763d9c046a i2c: fix broken ds1337 initialization
On a custom board with ds1337 RTC I found that upgrade from 2.6.15 to
2.6.18 broke RTC support.

The main problem are changes to ds1337_init_client().
When a ds1337 recognizes a problem (e.g. power or clock failure) bit 7
in status register is set. This has to be reset by writing 0 to status
register. But since there are only 16 byte written to the chip and the
first byte is interpreted as an address, the status register (which is
the 16th) is never written.
The other problem is, that initializing all registers to zero is not
valid for day, date and month register. Funny enough this is checked by
ds1337_detect(), which depends on this values not being zero. So then
treated by ds1337_init_client() the ds1337 is not detected anymore,
whereas the failure bit in the status register is still set.

Signed-off-by: Dirk Stieler <stieler@gdsys.de>
Signed-off-by: Dirk Eibach <eibach@gdsys.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:31 +01:00

411 lines
9.9 KiB
C

/*
* 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 = {
.driver = {
.name = "ds1337",
},
.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 = kzalloc(sizeof(struct ds1337_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
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)
{
u8 status, control;
/* On some boards, the RTC isn't configured by boot firmware.
* Handle that case by starting/configuring the RTC now.
*/
status = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
if ((status & 0x80) || (control & 0x80)) {
/* RTC not running */
u8 buf[1+16]; /* First byte is interpreted as address */
struct i2c_msg msg[1];
dev_dbg(&client->dev, "%s: RTC not running!\n", __FUNCTION__);
/* Initialize all, including STATUS and CONTROL to zero */
memset(buf, 0, sizeof(buf));
/* Write valid values in the date/time registers */
buf[1+DS1337_REG_DAY] = 1;
buf[1+DS1337_REG_DATE] = 1;
buf[1+DS1337_REG_MONTH] = 1;
msg[0].addr = client->addr;
msg[0].flags = 0;
msg[0].len = sizeof(buf);
msg[0].buf = &buf[0];
i2c_transfer(client->adapter, msg, 1);
} else {
/* Running: ensure that device is set in 24-hour mode */
s32 val;
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);