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hwmon: (ltc4151) Make shunt-resistor configurable

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Allow to specify the resistance of the attached shunt via DT by
adding the shunt-resistor property. Fall-back to the previous
default (1 mOhm) if unset.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
[groeck: Fixed 'line over 80 columns' checkpatch warning]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Daniel Golle 2016-08-01 12:07:18 +02:00 committed by Guenter Roeck
parent 4f120397fc
commit 30fe976fe7
1 changed files with 20 additions and 2 deletions
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22
drivers/hwmon/ltc4151.c
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@ -30,6 +30,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
@ -52,6 +53,7 @@ struct ltc4151_data {
struct mutex update_lock;
bool valid;
unsigned long last_updated; /* in jiffies */
unsigned int shunt; /* in micro ohms */
/* Registers */
u8 regs[6];
@ -111,9 +113,9 @@ static int ltc4151_get_value(struct ltc4151_data *data, u8 reg)
case LTC4151_SENSE_H:
/*
* 20uV resolution. Convert to current as measured with
* an 1 mOhm sense resistor, in mA.
* a given sense resistor, in mA.
*/
val = val * 20;
val = val * 20 * 1000 / data->shunt;
break;
case LTC4151_VIN_H:
/* 25 mV per increment */
@ -176,6 +178,7 @@ static int ltc4151_probe(struct i2c_client *client,
struct device *dev = &client->dev;
struct ltc4151_data *data;
struct device *hwmon_dev;
u32 shunt;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
@ -184,6 +187,15 @@ static int ltc4151_probe(struct i2c_client *client,
if (!data)
return -ENOMEM;
if (of_property_read_u32(client->dev.of_node,
"shunt-resistor-micro-ohms", &shunt))
shunt = 1000; /* 1 mOhm if not set via DT */
if (shunt == 0)
return -EINVAL;
data->shunt = shunt;
data->client = client;
mutex_init(&data->update_lock);
@ -199,10 +211,16 @@ static const struct i2c_device_id ltc4151_id[] = {
};
MODULE_DEVICE_TABLE(i2c, ltc4151_id);
static const struct of_device_id ltc4151_match[] = {
{ .compatible = "lltc,ltc4151" },
{},
};
/* This is the driver that will be inserted */
static struct i2c_driver ltc4151_driver = {
.driver = {
.name = "ltc4151",
.of_match_table = of_match_ptr(ltc4151_match),
},
.probe = ltc4151_probe,
.id_table = ltc4151_id,