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linux-stable/drivers/hwmon/ltc2945.c
John Pruitt b11f3d47c0 hwmon: (ltc2945) Allow setting shunt resistor 
Add the ability to specify the value of the shunt resistor in the
device tree instead of assuming it is 1 milliOhm. The value in the
device tree has the name shunt-resistor-micro-ohms and the
default value is 1000 micro-ohms in order to preserve the
current behavior.

Signed-off-by: Jonathan Cormier <jcormier@criticallink.com>
Signed-off-by: John Pruitt <jpruitt@criticallink.com>
[groeck: Fixed multi-line alignment, squashed last patch of series]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-02-03 07:30:10 -08:00

530 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Linear Technology LTC2945 I2C Power Monitor
*
* Copyright (c) 2014 Guenter Roeck
*/
#include <linux/kernel.h>
#include <linux/module.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>
#include <linux/regmap.h>
/* chip registers */
#define LTC2945_CONTROL 0x00
#define LTC2945_ALERT 0x01
#define LTC2945_STATUS 0x02
#define LTC2945_FAULT 0x03
#define LTC2945_POWER_H 0x05
#define LTC2945_MAX_POWER_H 0x08
#define LTC2945_MIN_POWER_H 0x0b
#define LTC2945_MAX_POWER_THRES_H 0x0e
#define LTC2945_MIN_POWER_THRES_H 0x11
#define LTC2945_SENSE_H 0x14
#define LTC2945_MAX_SENSE_H 0x16
#define LTC2945_MIN_SENSE_H 0x18
#define LTC2945_MAX_SENSE_THRES_H 0x1a
#define LTC2945_MIN_SENSE_THRES_H 0x1c
#define LTC2945_VIN_H 0x1e
#define LTC2945_MAX_VIN_H 0x20
#define LTC2945_MIN_VIN_H 0x22
#define LTC2945_MAX_VIN_THRES_H 0x24
#define LTC2945_MIN_VIN_THRES_H 0x26
#define LTC2945_ADIN_H 0x28
#define LTC2945_MAX_ADIN_H 0x2a
#define LTC2945_MIN_ADIN_H 0x2c
#define LTC2945_MAX_ADIN_THRES_H 0x2e
#define LTC2945_MIN_ADIN_THRES_H 0x30
#define LTC2945_MIN_ADIN_THRES_L 0x31
/* Fault register bits */
#define FAULT_ADIN_UV (1 << 0)
#define FAULT_ADIN_OV (1 << 1)
#define FAULT_VIN_UV (1 << 2)
#define FAULT_VIN_OV (1 << 3)
#define FAULT_SENSE_UV (1 << 4)
#define FAULT_SENSE_OV (1 << 5)
#define FAULT_POWER_UV (1 << 6)
#define FAULT_POWER_OV (1 << 7)
/* Control register bits */
#define CONTROL_MULT_SELECT (1 << 0)
#define CONTROL_TEST_MODE (1 << 4)
static const struct of_device_id __maybe_unused ltc2945_of_match[] = {
{ .compatible = "adi,ltc2945" },
{ }
};
MODULE_DEVICE_TABLE(of, ltc2945_of_match);
/**
* struct ltc2945_data - LTC2945 device data
* @regmap: regmap device
* @shunt_resistor: shunt resistor value in micro ohms (1000 by default)
*/
struct ltc2945_data {
struct regmap *regmap;
u32 shunt_resistor;
};
static inline bool is_power_reg(u8 reg)
{
return reg < LTC2945_SENSE_H;
}
/* Return the value from the given register in uW, mV, or mA */
static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
{
struct ltc2945_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u32 shunt_resistor = data->shunt_resistor;
unsigned int control;
u8 buf[3];
long long val;
int ret;
ret = regmap_bulk_read(regmap, reg, buf,
is_power_reg(reg) ? 3 : 2);
if (ret < 0)
return ret;
if (is_power_reg(reg)) {
/* 24-bit power */
val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
} else {
/* 12-bit current, voltage */
val = (buf[0] << 4) + (buf[1] >> 4);
}
switch (reg) {
case LTC2945_POWER_H:
case LTC2945_MAX_POWER_H:
case LTC2945_MIN_POWER_H:
case LTC2945_MAX_POWER_THRES_H:
case LTC2945_MIN_POWER_THRES_H:
/*
* Convert to uW
* Control register bit 0 selects if voltage at SENSE+/VDD
* or voltage at ADIN is used to measure power.
*/
ret = regmap_read(regmap, LTC2945_CONTROL, &control);
if (ret < 0)
return ret;
if (control & CONTROL_MULT_SELECT) {
/* 25 mV * 25 uV = 0.625 uV resolution. */
val *= 625LL;
} else {
/* 0.5 mV * 25 uV = 0.0125 uV resolution. */
val = (val * 25LL) >> 1;
}
val *= 1000;
/* Overflow check: Assuming max 24-bit power, val is at most 53 bits right now. */
val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
/*
* Overflow check: After division, depending on shunt resistor,
* val can still be > 32 bits so returning long long makes sense
*/
break;
case LTC2945_VIN_H:
case LTC2945_MAX_VIN_H:
case LTC2945_MIN_VIN_H:
case LTC2945_MAX_VIN_THRES_H:
case LTC2945_MIN_VIN_THRES_H:
/* 25 mV resolution. Convert to mV. */
val *= 25;
break;
case LTC2945_ADIN_H:
case LTC2945_MAX_ADIN_H:
case LTC2945_MIN_ADIN_THRES_H:
case LTC2945_MAX_ADIN_THRES_H:
case LTC2945_MIN_ADIN_H:
/* 0.5mV resolution. Convert to mV. */
val = val >> 1;
break;
case LTC2945_SENSE_H:
case LTC2945_MAX_SENSE_H:
case LTC2945_MIN_SENSE_H:
case LTC2945_MAX_SENSE_THRES_H:
case LTC2945_MIN_SENSE_THRES_H:
/* 25 uV resolution. Convert to mA. */
val *= 25 * 1000;
/* Overflow check: Assuming max 12-bit sense, val is at most 27 bits right now */
val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
/* Overflow check: After division, <= 27 bits */
break;
default:
return -EINVAL;
}
return val;
}
static long long ltc2945_val_to_reg(struct device *dev, u8 reg,
unsigned long long val)
{
struct ltc2945_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u32 shunt_resistor = data->shunt_resistor;
unsigned int control;
int ret;
/* Ensure we don't overflow */
val = clamp_val(val, 0, U32_MAX);
switch (reg) {
case LTC2945_POWER_H:
case LTC2945_MAX_POWER_H:
case LTC2945_MIN_POWER_H:
case LTC2945_MAX_POWER_THRES_H:
case LTC2945_MIN_POWER_THRES_H:
/*
* Control register bit 0 selects if voltage at SENSE+/VDD
* or voltage at ADIN is used to measure power, which in turn
* determines register calculations.
*/
ret = regmap_read(regmap, LTC2945_CONTROL, &control);
if (ret < 0)
return ret;
if (control & CONTROL_MULT_SELECT) {
/* 25 mV * 25 uV = 0.625 uV resolution. */
val *= shunt_resistor;
/* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
val = DIV_ROUND_CLOSEST_ULL(val, 625 * 1000);
/* Overflow check: val is now <= 44 bits */
} else {
/* 0.5 mV * 25 uV = 0.0125 uV resolution. */
val *= shunt_resistor;
/* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000) * 2;
/* Overflow check: val is now <= 51 bits */
}
break;
case LTC2945_VIN_H:
case LTC2945_MAX_VIN_H:
case LTC2945_MIN_VIN_H:
case LTC2945_MAX_VIN_THRES_H:
case LTC2945_MIN_VIN_THRES_H:
/* 25 mV resolution. */
val = DIV_ROUND_CLOSEST_ULL(val, 25);
break;
case LTC2945_ADIN_H:
case LTC2945_MAX_ADIN_H:
case LTC2945_MIN_ADIN_THRES_H:
case LTC2945_MAX_ADIN_THRES_H:
case LTC2945_MIN_ADIN_H:
/* 0.5mV resolution. */
val *= 2;
break;
case LTC2945_SENSE_H:
case LTC2945_MAX_SENSE_H:
case LTC2945_MIN_SENSE_H:
case LTC2945_MAX_SENSE_THRES_H:
case LTC2945_MIN_SENSE_THRES_H:
/* 25 uV resolution. Convert to mA. */
val *= shunt_resistor;
/* Overflow check: Assuming 32-bit val and 32-bit shunt resistor, val is 64bits */
val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000);
/* Overflow check: val is now <= 50 bits */
break;
default:
return -EINVAL;
}
return val;
}
static ssize_t ltc2945_value_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
long long value;
value = ltc2945_reg_to_val(dev, attr->index);
if (value < 0)
return value;
return sysfs_emit(buf, "%lld\n", value);
}
static ssize_t ltc2945_value_store(struct device *dev,
struct device_attribute *da,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc2945_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u8 reg = attr->index;
unsigned int val;
u8 regbuf[3];
int num_regs;
long long regval;
int ret;
ret = kstrtouint(buf, 10, &val);
if (ret)
return ret;
/* convert to register value, then clamp and write result */
regval = ltc2945_val_to_reg(dev, reg, val);
if (regval < 0)
return regval;
if (is_power_reg(reg)) {
regval = clamp_val(regval, 0, 0xffffff);
regbuf[0] = regval >> 16;
regbuf[1] = (regval >> 8) & 0xff;
regbuf[2] = regval;
num_regs = 3;
} else {
regval = clamp_val(regval, 0, 0xfff) << 4;
regbuf[0] = regval >> 8;
regbuf[1] = regval & 0xff;
num_regs = 2;
}
ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
return ret < 0 ? ret : count;
}
static ssize_t ltc2945_history_store(struct device *dev,
struct device_attribute *da,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc2945_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
u8 reg = attr->index;
int num_regs = is_power_reg(reg) ? 3 : 2;
u8 buf_min[3] = { 0xff, 0xff, 0xff };
u8 buf_max[3] = { 0, 0, 0 };
unsigned long val;
int ret;
ret = kstrtoul(buf, 10, &val);
if (ret)
return ret;
if (val != 1)
return -EINVAL;
ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
CONTROL_TEST_MODE);
/* Reset minimum */
ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
if (ret)
return ret;
switch (reg) {
case LTC2945_MIN_POWER_H:
reg = LTC2945_MAX_POWER_H;
break;
case LTC2945_MIN_SENSE_H:
reg = LTC2945_MAX_SENSE_H;
break;
case LTC2945_MIN_VIN_H:
reg = LTC2945_MAX_VIN_H;
break;
case LTC2945_MIN_ADIN_H:
reg = LTC2945_MAX_ADIN_H;
break;
default:
WARN_ONCE(1, "Bad register: 0x%x\n", reg);
return -EINVAL;
}
/* Reset maximum */
ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
/* Try resetting test mode even if there was an error */
regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
return ret ? : count;
}
static ssize_t ltc2945_bool_show(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ltc2945_data *data = dev_get_drvdata(dev);
struct regmap *regmap = data->regmap;
unsigned int fault;
int ret;
ret = regmap_read(regmap, LTC2945_FAULT, &fault);
if (ret < 0)
return ret;
fault &= attr->index;
if (fault) /* Clear reported faults in chip register */
regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
return sysfs_emit(buf, "%d\n", !!fault);
}
/* Input voltages */
static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
LTC2945_MIN_VIN_H);
static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
LTC2945_MIN_ADIN_H);
/* Voltage alarms */
static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);
/* Currents (via sense resistor) */
static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
LTC2945_MIN_SENSE_THRES_H);
static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
LTC2945_MAX_SENSE_THRES_H);
static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
LTC2945_MAX_SENSE_H);
static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
LTC2945_MIN_SENSE_H);
/* Current alarms */
static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);
/* Power */
static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
LTC2945_MIN_POWER_THRES_H);
static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
LTC2945_MAX_POWER_THRES_H);
static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
LTC2945_MIN_POWER_H);
static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
LTC2945_MAX_POWER_H);
static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
LTC2945_MIN_POWER_H);
/* Power alarms */
static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);
static struct attribute *ltc2945_attrs[] = {
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in1_min.dev_attr.attr,
&sensor_dev_attr_in1_max.dev_attr.attr,
&sensor_dev_attr_in1_lowest.dev_attr.attr,
&sensor_dev_attr_in1_highest.dev_attr.attr,
&sensor_dev_attr_in1_reset_history.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.dev_attr.attr,
&sensor_dev_attr_in2_max.dev_attr.attr,
&sensor_dev_attr_in2_lowest.dev_attr.attr,
&sensor_dev_attr_in2_highest.dev_attr.attr,
&sensor_dev_attr_in2_reset_history.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_min.dev_attr.attr,
&sensor_dev_attr_curr1_max.dev_attr.attr,
&sensor_dev_attr_curr1_lowest.dev_attr.attr,
&sensor_dev_attr_curr1_highest.dev_attr.attr,
&sensor_dev_attr_curr1_reset_history.dev_attr.attr,
&sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
&sensor_dev_attr_power1_min.dev_attr.attr,
&sensor_dev_attr_power1_max.dev_attr.attr,
&sensor_dev_attr_power1_input_lowest.dev_attr.attr,
&sensor_dev_attr_power1_input_highest.dev_attr.attr,
&sensor_dev_attr_power1_reset_history.dev_attr.attr,
&sensor_dev_attr_power1_min_alarm.dev_attr.attr,
&sensor_dev_attr_power1_max_alarm.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ltc2945);
static const struct regmap_config ltc2945_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = LTC2945_MIN_ADIN_THRES_L,
};
static int ltc2945_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct regmap *regmap;
struct ltc2945_data *data;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
dev_set_drvdata(dev, data);
regmap = devm_regmap_init_i2c(client, &ltc2945_regmap_config);
if (IS_ERR(regmap)) {
dev_err(dev, "failed to allocate register map\n");
return PTR_ERR(regmap);
}
data->regmap = regmap;
if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
&data->shunt_resistor))
data->shunt_resistor = 1000;
if (data->shunt_resistor == 0)
return -EINVAL;
/* Clear faults */
regmap_write(regmap, LTC2945_FAULT, 0x00);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ltc2945_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc2945_id[] = {
{"ltc2945", 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc2945_id);
static struct i2c_driver ltc2945_driver = {
.driver = {
.name = "ltc2945",
.of_match_table = of_match_ptr(ltc2945_of_match),
},
.probe_new = ltc2945_probe,
.id_table = ltc2945_id,
};
module_i2c_driver(ltc2945_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("LTC2945 driver");
MODULE_LICENSE("GPL");
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