linux/drivers/hwmon/ltc4215.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

267 lines
7.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Linear Technology LTC4215 I2C Hot Swap Controller
*
* Copyright (C) 2009 Ira W. Snyder <iws@ovro.caltech.edu>
*
* Datasheet:
* http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1163,P17572,D12697
*/
#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>
/* Here are names of the chip's registers (a.k.a. commands) */
enum ltc4215_cmd {
LTC4215_CONTROL = 0x00, /* rw */
LTC4215_ALERT = 0x01, /* rw */
LTC4215_STATUS = 0x02, /* ro */
LTC4215_FAULT = 0x03, /* rw */
LTC4215_SENSE = 0x04, /* rw */
LTC4215_SOURCE = 0x05, /* rw */
LTC4215_ADIN = 0x06, /* rw */
};
struct ltc4215_data {
struct i2c_client *client;
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
/* Registers */
u8 regs[7];
};
static struct ltc4215_data *ltc4215_update_device(struct device *dev)
{
struct ltc4215_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
s32 val;
int i;
mutex_lock(&data->update_lock);
/* The chip's A/D updates 10 times per second */
if (time_after(jiffies, data->last_updated + HZ / 10) || !data->valid) {
dev_dbg(&client->dev, "Starting ltc4215 update\n");
/* Read all registers */
for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
val = i2c_smbus_read_byte_data(client, i);
if (unlikely(val < 0))
data->regs[i] = 0;
else
data->regs[i] = val;
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
/* Return the voltage from the given register in millivolts */
static int ltc4215_get_voltage(struct device *dev, u8 reg)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
const u8 regval = data->regs[reg];
u32 voltage = 0;
switch (reg) {
case LTC4215_SENSE:
/* 151 uV per increment */
voltage = regval * 151 / 1000;
break;
case LTC4215_SOURCE:
/* 60.5 mV per increment */
voltage = regval * 605 / 10;
break;
case LTC4215_ADIN:
/*
* The ADIN input is divided by 12.5, and has 4.82 mV
* per increment, so we have the additional multiply
*/
voltage = regval * 482 * 125 / 1000;
break;
default:
/* If we get here, the developer messed up */
WARN_ON_ONCE(1);
break;
}
return voltage;
}
/* Return the current from the sense resistor in mA */
static unsigned int ltc4215_get_current(struct device *dev)
{
struct ltc4215_data *data = ltc4215_update_device(dev);
/*
* The strange looking conversions that follow are fixed-point
* math, since we cannot do floating point in the kernel.
*
* Step 1: convert sense register to microVolts
* Step 2: convert voltage to milliAmperes
*
* If you play around with the V=IR equation, you come up with
* the following: X uV / Y mOhm == Z mA
*
* With the resistors that are fractions of a milliOhm, we multiply
* the voltage and resistance by 10, to shift the decimal point.
* Now we can use the normal division operator again.
*/
/* Calculate voltage in microVolts (151 uV per increment) */
const unsigned int voltage = data->regs[LTC4215_SENSE] * 151;
/* Calculate current in milliAmperes (4 milliOhm sense resistor) */
const unsigned int curr = voltage / 4;
return curr;
}
static ssize_t ltc4215_voltage_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
const int voltage = ltc4215_get_voltage(dev, attr->index);
return snprintf(buf, PAGE_SIZE, "%d\n", voltage);
}
static ssize_t ltc4215_current_show(struct device *dev,
struct device_attribute *da, char *buf)
{
const unsigned int curr = ltc4215_get_current(dev);
return snprintf(buf, PAGE_SIZE, "%u\n", curr);
}
static ssize_t ltc4215_power_show(struct device *dev,
struct device_attribute *da, char *buf)
{
const unsigned int curr = ltc4215_get_current(dev);
const int output_voltage = ltc4215_get_voltage(dev, LTC4215_ADIN);
/* current in mA * voltage in mV == power in uW */
const unsigned int power = abs(output_voltage * curr);
return snprintf(buf, PAGE_SIZE, "%u\n", power);
}
static ssize_t ltc4215_alarm_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc4215_data *data = ltc4215_update_device(dev);
const u8 reg = data->regs[LTC4215_STATUS];
const u32 mask = attr->index;
return snprintf(buf, PAGE_SIZE, "%u\n", !!(reg & mask));
}
/*
* These macros are used below in constructing device attribute objects
* for use with sysfs_create_group() to make a sysfs device file
* for each register.
*/
/* Construct a sensor_device_attribute structure for each register */
/* Current */
static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4215_current, 0);
static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4215_alarm, 1 << 2);
/* Power (virtual) */
static SENSOR_DEVICE_ATTR_RO(power1_input, ltc4215_power, 0);
/* Input Voltage */
static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4215_voltage, LTC4215_ADIN);
static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4215_alarm, 1 << 0);
static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4215_alarm, 1 << 1);
/* Output Voltage */
static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4215_voltage, LTC4215_SOURCE);
static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc4215_alarm, 1 << 3);
/*
* Finally, construct an array of pointers to members of the above objects,
* as required for sysfs_create_group()
*/
static struct attribute *ltc4215_attrs[] = {
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
&sensor_dev_attr_in2_input.dev_attr.attr,
&sensor_dev_attr_in2_min_alarm.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ltc4215);
static int ltc4215_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct device *dev = &client->dev;
struct ltc4215_data *data;
struct device *hwmon_dev;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
/* Initialize the LTC4215 chip */
i2c_smbus_write_byte_data(client, LTC4215_FAULT, 0x00);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ltc4215_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4215_id[] = {
{ "ltc4215", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4215_id);
/* This is the driver that will be inserted */
static struct i2c_driver ltc4215_driver = {
.driver = {
.name = "ltc4215",
},
.probe_new = ltc4215_probe,
.id_table = ltc4215_id,
};
module_i2c_driver(ltc4215_driver);
MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("LTC4215 driver");
MODULE_LICENSE("GPL");