linux/drivers/misc/ds1682.c
Uwe Kleine-König ed5c2f5fd1 i2c: Make remove callback return void
The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-16 12:46:26 +02:00

264 lines
6.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Dallas Semiconductor DS1682 Elapsed Time Recorder device driver
*
* Written by: Grant Likely <grant.likely@secretlab.ca>
*
* Copyright (C) 2007 Secret Lab Technologies Ltd.
*/
/*
* 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/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);
unsigned long long val, check;
__le32 val_le = 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_le);
if (rc < 0)
return -EIO;
val = le32_to_cpu(val_le);
if (sattr->index == DS1682_REG_ELAPSED) {
int retries = 5;
/* Detect and retry when a tick occurs mid-read */
do {
rc = i2c_smbus_read_i2c_block_data(client, sattr->index,
sattr->nr,
(u8 *)&val_le);
if (rc < 0 || retries <= 0)
return -EIO;
check = val;
val = le32_to_cpu(val_le);
retries--;
} while (val != check && val != (check + 1));
}
/* Format the output string and return # of bytes
* Special case: the 32 bit regs are time values with 1/4s
* resolution, scale them up to milliseconds
*/
return sprintf(buf, "%llu\n", (sattr->nr == 4) ? (val * 250) : 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);
u64 val;
__le32 val_le;
int rc;
dev_dbg(dev, "ds1682_store() called on %s\n", attr->attr.name);
/* Decode input */
rc = kstrtoull(buf, 0, &val);
if (rc < 0) {
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 file *filp, struct kobject *kobj,
struct bin_attribute *attr,
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);
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 file *filp, struct kobject *kobj,
struct bin_attribute *attr,
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);
/* 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 const struct bin_attribute ds1682_eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO | S_IWUSR,
},
.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,
const struct i2c_device_id *id)
{
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 void ds1682_remove(struct i2c_client *client)
{
sysfs_remove_bin_file(&client->dev.kobj, &ds1682_eeprom_attr);
sysfs_remove_group(&client->dev.kobj, &ds1682_group);
}
static const struct i2c_device_id ds1682_id[] = {
{ "ds1682", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1682_id);
static const struct of_device_id ds1682_of_match[] = {
{ .compatible = "dallas,ds1682", },
{}
};
MODULE_DEVICE_TABLE(of, ds1682_of_match);
static struct i2c_driver ds1682_driver = {
.driver = {
.name = "ds1682",
.of_match_table = ds1682_of_match,
},
.probe = ds1682_probe,
.remove = ds1682_remove,
.id_table = ds1682_id,
};
module_i2c_driver(ds1682_driver);
MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_DESCRIPTION("DS1682 Elapsed Time Indicator driver");
MODULE_LICENSE("GPL");