linux/drivers/hwmon/ltc4261.c
Thomas Gleixner 74ba9207e1 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:36:45 +02:00

246 lines
6.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller
*
* Copyright (C) 2010 Ericsson AB.
*
* Derived from:
*
* Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
* Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
*
* Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
/* chip registers */
#define LTC4261_STATUS 0x00 /* readonly */
#define LTC4261_FAULT 0x01
#define LTC4261_ALERT 0x02
#define LTC4261_CONTROL 0x03
#define LTC4261_SENSE_H 0x04
#define LTC4261_SENSE_L 0x05
#define LTC4261_ADIN2_H 0x06
#define LTC4261_ADIN2_L 0x07
#define LTC4261_ADIN_H 0x08
#define LTC4261_ADIN_L 0x09
/*
* Fault register bits
*/
#define FAULT_OV (1<<0)
#define FAULT_UV (1<<1)
#define FAULT_OC (1<<2)
struct ltc4261_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
/* Registers */
u8 regs[10];
};
static struct ltc4261_data *ltc4261_update_device(struct device *dev)
{
struct ltc4261_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
struct ltc4261_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) {
int i;
/* Read registers -- 0x00 to 0x09 */
for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
int val;
val = i2c_smbus_read_byte_data(client, i);
if (unlikely(val < 0)) {
dev_dbg(dev,
"Failed to read ADC value: error %d\n",
val);
ret = ERR_PTR(val);
data->valid = 0;
goto abort;
}
data->regs[i] = val;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
/* Return the voltage from the given register in mV or mA */
static int ltc4261_get_value(struct ltc4261_data *data, u8 reg)
{
u32 val;
val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6);
switch (reg) {
case LTC4261_ADIN_H:
case LTC4261_ADIN2_H:
/* 2.5mV resolution. Convert to mV. */
val = val * 25 / 10;
break;
case LTC4261_SENSE_H:
/*
* 62.5uV resolution. Convert to current as measured with
* an 1 mOhm sense resistor, in mA. If a different sense
* resistor is installed, calculate the actual current by
* dividing the reported current by the sense resistor value
* in mOhm.
*/
val = val * 625 / 10;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
val = 0;
break;
}
return val;
}
static ssize_t ltc4261_value_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc4261_data *data = ltc4261_update_device(dev);
int value;
if (IS_ERR(data))
return PTR_ERR(data);
value = ltc4261_get_value(data, attr->index);
return snprintf(buf, PAGE_SIZE, "%d\n", value);
}
static ssize_t ltc4261_bool_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc4261_data *data = ltc4261_update_device(dev);
u8 fault;
if (IS_ERR(data))
return PTR_ERR(data);
fault = data->regs[LTC4261_FAULT] & attr->index;
if (fault) /* Clear reported faults in chip register */
i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault);
return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0);
}
/*
* Input voltages.
*/
static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4261_value, LTC4261_ADIN_H);
static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4261_value, LTC4261_ADIN2_H);
/*
* Voltage alarms. The chip has only one set of voltage alarm status bits,
* triggered by input voltage alarms. In many designs, those alarms are
* associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin
* to the OV pin. ADIN2 is, however, not available on all chip variants.
* To ensure that the alarm condition is reported to the user, report it
* with both voltage sensors.
*/
static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4261_bool, FAULT_UV);
static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4261_bool, FAULT_OV);
static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc4261_bool, FAULT_UV);
static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc4261_bool, FAULT_OV);
/* Currents (via sense resistor) */
static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4261_value, LTC4261_SENSE_H);
/* Overcurrent alarm */
static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4261_bool, FAULT_OC);
static struct attribute *ltc4261_attrs[] = {
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
&sensor_dev_attr_in2_input.dev_attr.attr,
&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
&sensor_dev_attr_in2_max_alarm.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ltc4261);
static int ltc4261_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct device *dev = &client->dev;
struct ltc4261_data *data;
struct device *hwmon_dev;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) {
dev_err(dev, "Failed to read status register\n");
return -ENODEV;
}
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
/* Clear faults */
i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ltc4261_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4261_id[] = {
{"ltc4261", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, ltc4261_id);
/* This is the driver that will be inserted */
static struct i2c_driver ltc4261_driver = {
.driver = {
.name = "ltc4261",
},
.probe = ltc4261_probe,
.id_table = ltc4261_id,
};
module_i2c_driver(ltc4261_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("LTC4261 driver");
MODULE_LICENSE("GPL");