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Commit 30fe976f authored by Daniel Golle's avatar Daniel Golle Committed by Guenter Roeck
Browse files

hwmon: (ltc4151) Make shunt-resistor configurable 



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: default avatarDaniel Golle <daniel@makrotopia.org>
[groeck: Fixed 'line over 80 columns' checkpatch warning]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 4f120397

drivers/hwmon/ltc4151.c

+20 −2
Original line number Diff line number Diff line
@@ -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,