Commit 94ee5fcc authored by Zev Weiss's avatar Zev Weiss Committed by Guenter Roeck
Browse files

hwmon: (pmbus/lm25066) Support configurable sense resistor values 



The appropriate mantissa values for the lm25066 family's direct-format
current and power readings are a function of the sense resistor
employed between the SENSE and VIN pins of the chip.  Instead of
assuming that resistance is always the same 1mOhm as used in the
datasheet, allow it to be configured via a device-tree property
("shunt-resistor-micro-ohms").

Signed-off-by: default avatarZev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20210928092242.30036-8-zev@bewilderbeest.net


[groeck: Fixed checkpatch warnings]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent b7792f3e

Documentation/hwmon/lm25066.rst

+2 −0
Original line number Diff line number Diff line
@@ -79,6 +79,8 @@ This driver does not auto-detect devices. You will have to instantiate the 
devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for

details.



The shunt (sense) resistor value can be configured by a device tree property;

see Documentation/devicetree/bindings/hwmon/pmbus/ti,lm25066.yaml for details.



Platform data support

---------------------

drivers/hwmon/pmbus/lm25066.c

+11 −0
Original line number Diff line number Diff line
@@ -458,6 +458,7 @@ MODULE_DEVICE_TABLE(of, lm25066_of_match); 
static int lm25066_probe(struct i2c_client *client)

{

	int config;

	u32 shunt;

	struct lm25066_data *data;

	struct pmbus_driver_info *info;

	const struct __coeff *coeff;
@@ -534,6 +535,16 @@ static int lm25066_probe(struct i2c_client *client) 
		info->b[PSC_POWER] = coeff[PSC_POWER].b;

	}



	/*

	 * Values in the TI datasheets are normalized for a 1mOhm sense

	 * resistor; assume that unless DT specifies a value explicitly.

	 */

	if (of_property_read_u32(client->dev.of_node, "shunt-resistor-micro-ohms", &shunt))

		shunt = 1000;



	info->m[PSC_CURRENT_IN] = info->m[PSC_CURRENT_IN] * shunt / 1000;

	info->m[PSC_POWER] = info->m[PSC_POWER] * shunt / 1000;



	return pmbus_do_probe(client, info);

}