linux-stable/drivers/hwmon/ltc4261.c
Stephen Kitt 6748703856 hwmon: use simple i2c probe function
Many hwmon drivers don't use the id information provided by the old
i2c probe function, and the remainder can easily be adapted to the new
form ("probe_new") by calling i2c_match_id explicitly.

This avoids scanning the identifier tables during probes.

Drivers which didn't use the id are converted as-is; drivers which did
are modified as follows:

* if the information in i2c_client is sufficient, that's used instead
  (client->name);
* anything else is handled by calling i2c_match_id() with the same
  level of error-handling (if any) as before.

A few drivers aren't included in this patch because they have a
different set of maintainers. They will be covered by other patches.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20200813160222.1503401-1-steve@sk2.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2020-09-23 09:42:39 -07:00

244 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)
{
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_new = 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");