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linux/drivers/hwmon/pmbus/max16064.c
Guenter Roeck 866cf12a0e hwmon: (pmbus) Don't return errors from driver remove functions
Driver remove functions have an error return value, but rarely return an error
in practice. If a driver does return an error from its remove function, the
driver won't be unloaded and is expected to stay alive.

pmbus_do_remove() is defined as returning an int, but always returns 0 (no
error). Calling code passes that return value on to high level driver
remove functions, but does not evaluate it and removes driver data even if
pmbus_do_remove() returned an error (which it in practice never does). Even if
this code could never cause a real problem, it is nevertheless conceptually
wrong.

To reduce confusion and simplify the code, change pmbus_do_remove() to be a void
function, and have PMBus client drivers always return zero in their driver
remove functions.

Reported-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
2011-10-24 11:09:33 -07:00

144 lines
3.6 KiB
C

/*
* Hardware monitoring driver for Maxim MAX16064
*
* Copyright (c) 2011 Ericsson AB.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include "pmbus.h"
#define MAX16064_MFR_VOUT_PEAK 0xd4
#define MAX16064_MFR_TEMPERATURE_PEAK 0xd6
static int max16064_read_word_data(struct i2c_client *client, int page, int reg)
{
int ret;
switch (reg) {
case PMBUS_VIRT_READ_VOUT_MAX:
ret = pmbus_read_word_data(client, page,
MAX16064_MFR_VOUT_PEAK);
break;
case PMBUS_VIRT_READ_TEMP_MAX:
ret = pmbus_read_word_data(client, page,
MAX16064_MFR_TEMPERATURE_PEAK);
break;
case PMBUS_VIRT_RESET_VOUT_HISTORY:
case PMBUS_VIRT_RESET_TEMP_HISTORY:
ret = 0;
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static int max16064_write_word_data(struct i2c_client *client, int page,
int reg, u16 word)
{
int ret;
switch (reg) {
case PMBUS_VIRT_RESET_VOUT_HISTORY:
ret = pmbus_write_word_data(client, page,
MAX16064_MFR_VOUT_PEAK, 0);
break;
case PMBUS_VIRT_RESET_TEMP_HISTORY:
ret = pmbus_write_word_data(client, page,
MAX16064_MFR_TEMPERATURE_PEAK,
0xffff);
break;
default:
ret = -ENODATA;
break;
}
return ret;
}
static struct pmbus_driver_info max16064_info = {
.pages = 4,
.format[PSC_VOLTAGE_IN] = direct,
.format[PSC_VOLTAGE_OUT] = direct,
.format[PSC_TEMPERATURE] = direct,
.m[PSC_VOLTAGE_IN] = 19995,
.b[PSC_VOLTAGE_IN] = 0,
.R[PSC_VOLTAGE_IN] = -1,
.m[PSC_VOLTAGE_OUT] = 19995,
.b[PSC_VOLTAGE_OUT] = 0,
.R[PSC_VOLTAGE_OUT] = -1,
.m[PSC_TEMPERATURE] = -7612,
.b[PSC_TEMPERATURE] = 335,
.R[PSC_TEMPERATURE] = -3,
.func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_TEMP
| PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_TEMP,
.func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT,
.func[2] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT,
.func[3] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT,
.read_word_data = max16064_read_word_data,
.write_word_data = max16064_write_word_data,
};
static int max16064_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
return pmbus_do_probe(client, id, &max16064_info);
}
static int max16064_remove(struct i2c_client *client)
{
pmbus_do_remove(client);
return 0;
}
static const struct i2c_device_id max16064_id[] = {
{"max16064", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, max16064_id);
/* This is the driver that will be inserted */
static struct i2c_driver max16064_driver = {
.driver = {
.name = "max16064",
},
.probe = max16064_probe,
.remove = max16064_remove,
.id_table = max16064_id,
};
static int __init max16064_init(void)
{
return i2c_add_driver(&max16064_driver);
}
static void __exit max16064_exit(void)
{
i2c_del_driver(&max16064_driver);
}
MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for Maxim MAX16064");
MODULE_LICENSE("GPL");
module_init(max16064_init);
module_exit(max16064_exit);