Commit 5162b75b authored by Grant Likely's avatar Grant Likely Committed by Jean Delvare
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i2c: New DS1682 chip driver



A driver for the Dallas DS1682 elapsed time recorder chip.

Tested on a MPC5200 based board using the integrated i2c adapter.
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 4b2643d7
......@@ -30,6 +30,16 @@ config SENSORS_DS1374
This driver is deprecated and will be dropped soon. Use
rtc-ds1374 instead.
config DS1682
tristate "Dallas DS1682 Total Elapsed Time Recorder with Alarm"
depends on EXPERIMENTAL
help
If you say yes here you get support for Dallas Semiconductor
DS1682 Total Elapsed Time Recorder.
This driver can also be built as a module. If so, the module
will be called ds1682.
config SENSORS_EEPROM
tristate "EEPROM reader"
depends on EXPERIMENTAL
......
......@@ -4,6 +4,7 @@
obj-$(CONFIG_SENSORS_DS1337) += ds1337.o
obj-$(CONFIG_SENSORS_DS1374) += ds1374.o
obj-$(CONFIG_DS1682) += ds1682.o
obj-$(CONFIG_SENSORS_EEPROM) += eeprom.o
obj-$(CONFIG_SENSORS_MAX6875) += max6875.o
obj-$(CONFIG_SENSORS_M41T00) += m41t00.o
......
/*
* Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
*
* Written by: Grant Likely <grant.likely@secretlab.ca>
*
* Copyright (C) 2007 Secret Lab Technologies Ltd.
*
* 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.
*/
/*
* The DS1682 elapsed timer recorder is a simple device that implements
* one elapsed time counter, one event counter, an alarm signal and 10
* bytes of general purpose EEPROM.
*
* This driver provides access to the DS1682 counters and user data via
* the sysfs. The following attributes are added to the device node:
* elapsed_time (u32): Total elapsed event time in ms resolution
* alarm_time (u32): When elapsed time exceeds the value in alarm_time,
* then the alarm pin is asserted.
* event_count (u16): number of times the event pin has gone low.
* eeprom (u8[10]): general purpose EEPROM
*
* Counter registers and user data are both read/write unless the device
* has been write protected. This driver does not support turning off write
* protection. Once write protection is turned on, it is impossible to
* turn it off again, so I have left the feature out of this driver to avoid
* accidental enabling, but it is trivial to add write protect support.
*
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/sysfs.h>
#include <linux/ctype.h>
#include <linux/hwmon-sysfs.h>
/* Device registers */
#define DS1682_REG_CONFIG 0x00
#define DS1682_REG_ALARM 0x01
#define DS1682_REG_ELAPSED 0x05
#define DS1682_REG_EVT_CNTR 0x09
#define DS1682_REG_EEPROM 0x0b
#define DS1682_REG_RESET 0x1d
#define DS1682_REG_WRITE_DISABLE 0x1e
#define DS1682_REG_WRITE_MEM_DISABLE 0x1f
#define DS1682_EEPROM_SIZE 10
/*
* Generic counter attributes
*/
static ssize_t ds1682_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
struct i2c_client *client = to_i2c_client(dev);
__le32 val = 0;
int rc;
dev_dbg(dev, "ds1682_show() called on %s\n", attr->attr.name);
/* Read the register */
rc = i2c_smbus_read_i2c_block_data(client, sattr->index, sattr->nr,
(u8 *) & val);
if (rc < 0)
return -EIO;
/* Special case: the 32 bit regs are time values with 1/4s
* resolution, scale them up to milliseconds */
if (sattr->nr == 4)
return sprintf(buf, "%llu\n", ((u64) le32_to_cpu(val)) * 250);
/* Format the output string and return # of bytes */
return sprintf(buf, "%li\n", (long)le32_to_cpu(val));
}
static ssize_t ds1682_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
struct i2c_client *client = to_i2c_client(dev);
char *endp;
u64 val;
__le32 val_le;
int rc;
dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
/* Decode input */
val = simple_strtoull(buf, &endp, 0);
if (buf == endp) {
dev_dbg(dev, "input string not a number\n");
return -EINVAL;
}
/* Special case: the 32 bit regs are time values with 1/4s
* resolution, scale input down to quarter-seconds */
if (sattr->nr == 4)
do_div(val, 250);
/* write out the value */
val_le = cpu_to_le32(val);
rc = i2c_smbus_write_i2c_block_data(client, sattr->index, sattr->nr,
(u8 *) & val_le);
if (rc < 0) {
dev_err(dev, "register write failed; reg=0x%x, size=%i\n",
sattr->index, sattr->nr);
return -EIO;
}
return count;
}
/*
* Simple register attributes
*/
static SENSOR_DEVICE_ATTR_2(elapsed_time, S_IRUGO | S_IWUSR, ds1682_show,
ds1682_store, 4, DS1682_REG_ELAPSED);
static SENSOR_DEVICE_ATTR_2(alarm_time, S_IRUGO | S_IWUSR, ds1682_show,
ds1682_store, 4, DS1682_REG_ALARM);
static SENSOR_DEVICE_ATTR_2(event_count, S_IRUGO | S_IWUSR, ds1682_show,
ds1682_store, 2, DS1682_REG_EVT_CNTR);
static const struct attribute_group ds1682_group = {
.attrs = (struct attribute *[]) {
&sensor_dev_attr_elapsed_time.dev_attr.attr,
&sensor_dev_attr_alarm_time.dev_attr.attr,
&sensor_dev_attr_event_count.dev_attr.attr,
NULL,
},
};
/*
* User data attribute
*/
static ssize_t ds1682_eeprom_read(struct kobject *kobj, char *buf, loff_t off,
size_t count)
{
struct i2c_client *client = kobj_to_i2c_client(kobj);
int rc;
dev_dbg(&client->dev, "ds1682_eeprom_read(p=%p, off=%lli, c=%zi)\n",
buf, off, count);
if (off >= DS1682_EEPROM_SIZE)
return 0;
if (off + count > DS1682_EEPROM_SIZE)
count = DS1682_EEPROM_SIZE - off;
rc = i2c_smbus_read_i2c_block_data(client, DS1682_REG_EEPROM + off,
count, buf);
if (rc < 0)
return -EIO;
return count;
}
static ssize_t ds1682_eeprom_write(struct kobject *kobj, char *buf, loff_t off,
size_t count)
{
struct i2c_client *client = kobj_to_i2c_client(kobj);
dev_dbg(&client->dev, "ds1682_eeprom_write(p=%p, off=%lli, c=%zi)\n",
buf, off, count);
if (off >= DS1682_EEPROM_SIZE)
return -ENOSPC;
if (off + count > DS1682_EEPROM_SIZE)
count = DS1682_EEPROM_SIZE - off;
/* Write out to the device */
if (i2c_smbus_write_i2c_block_data(client, DS1682_REG_EEPROM + off,
count, buf) < 0)
return -EIO;
return count;
}
static struct bin_attribute ds1682_eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO | S_IWUSR,
.owner = THIS_MODULE,
},
.size = DS1682_EEPROM_SIZE,
.read = ds1682_eeprom_read,
.write = ds1682_eeprom_write,
};
/*
* Called when a ds1682 device is matched with this driver
*/
static int ds1682_probe(struct i2c_client *client)
{
int rc;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_I2C_BLOCK)) {
dev_err(&client->dev, "i2c bus does not support the ds1682\n");
rc = -ENODEV;
goto exit;
}
rc = sysfs_create_group(&client->dev.kobj, &ds1682_group);
if (rc)
goto exit;
rc = sysfs_create_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
if (rc)
goto exit_bin_attr;
return 0;
exit_bin_attr:
sysfs_remove_group(&client->dev.kobj, &ds1682_group);
exit:
return rc;
}
static int ds1682_remove(struct i2c_client *client)
{
sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
sysfs_remove_group(&client->dev.kobj, &ds1682_group);
return 0;
}
static struct i2c_driver ds1682_driver = {
.driver = {
.name = "ds1682",
},
.probe = ds1682_probe,
.remove = ds1682_remove,
};
static int __init ds1682_init(void)
{
return i2c_add_driver(&ds1682_driver);
}
static void __exit ds1682_exit(void)
{
i2c_del_driver(&ds1682_driver);
}
MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
MODULE_LICENSE("GPL");
module_init(ds1682_init);
module_exit(ds1682_exit);
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