Commit e8e00c83 authored by Erik Rosen's avatar Erik Rosen Committed by Guenter Roeck
Browse files

hwmon: (pmbus) Add support for reading direct mode coefficients 



Add support for reading and decoding direct format coefficients to
the PMBus core driver. If the new flag PMBUS_USE_COEFFICIENTS_CMD
is set, the driver will use the COEFFICIENTS register together with
the information in the pmbus_sensor_attr structs to initialize
relevant coefficients for the direct mode format.

Signed-off-by: default avatarErik Rosen <erik.rosen@metormote.com>
[groeck: Initialize ret with -EINVAL in pmbus_init_coefficients()]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent dbc0860f

drivers/hwmon/pmbus/pmbus_core.c

+116 −0
Original line number Diff line number Diff line
@@ -2141,6 +2141,111 @@ static int pmbus_find_attributes(struct i2c_client *client, 
	return ret;

}



/*

 * The pmbus_class_attr_map structure maps one sensor class to

 * it's corresponding sensor attributes array.

 */

struct pmbus_class_attr_map {

	enum pmbus_sensor_classes class;

	int nattr;

	const struct pmbus_sensor_attr *attr;

};



static const struct pmbus_class_attr_map class_attr_map[] = {

	{

		.class = PSC_VOLTAGE_IN,

		.attr = voltage_attributes,

		.nattr = ARRAY_SIZE(voltage_attributes),

	}, {

		.class = PSC_VOLTAGE_OUT,

		.attr = voltage_attributes,

		.nattr = ARRAY_SIZE(voltage_attributes),

	}, {

		.class = PSC_CURRENT_IN,

		.attr = current_attributes,

		.nattr = ARRAY_SIZE(current_attributes),

	}, {

		.class = PSC_CURRENT_OUT,

		.attr = current_attributes,

		.nattr = ARRAY_SIZE(current_attributes),

	}, {

		.class = PSC_POWER,

		.attr = power_attributes,

		.nattr = ARRAY_SIZE(power_attributes),

	}, {

		.class = PSC_TEMPERATURE,

		.attr = temp_attributes,

		.nattr = ARRAY_SIZE(temp_attributes),

	}

};



/*

 * Read the coefficients for direct mode.

 */

static int pmbus_read_coefficients(struct i2c_client *client,

				   struct pmbus_driver_info *info,

				   const struct pmbus_sensor_attr *attr)

{

	int rv;

	union i2c_smbus_data data;

	enum pmbus_sensor_classes class = attr->class;

	s8 R;

	s16 m, b;



	data.block[0] = 2;

	data.block[1] = attr->reg;

	data.block[2] = 0x01;



	rv = i2c_smbus_xfer(client->adapter, client->addr, client->flags,

			    I2C_SMBUS_WRITE, PMBUS_COEFFICIENTS,

			    I2C_SMBUS_BLOCK_PROC_CALL, &data);



	if (rv < 0)

		return rv;



	if (data.block[0] != 5)

		return -EIO;



	m = data.block[1] | (data.block[2] << 8);

	b = data.block[3] | (data.block[4] << 8);

	R = data.block[5];

	info->m[class] = m;

	info->b[class] = b;

	info->R[class] = R;



	return rv;

}



static int pmbus_init_coefficients(struct i2c_client *client,

				   struct pmbus_driver_info *info)

{

	int i, n, ret = -EINVAL;

	const struct pmbus_class_attr_map *map;

	const struct pmbus_sensor_attr *attr;



	for (i = 0; i < ARRAY_SIZE(class_attr_map); i++) {

		map = &class_attr_map[i];

		if (info->format[map->class] != direct)

			continue;

		for (n = 0; n < map->nattr; n++) {

			attr = &map->attr[n];

			if (map->class != attr->class)

				continue;

			ret = pmbus_read_coefficients(client, info, attr);

			if (ret >= 0)

				break;

		}

		if (ret < 0) {

			dev_err(&client->dev,

				"No coefficients found for sensor class %d\n",

				map->class);

			return -EINVAL;

		}

	}



	return 0;

}



/*

 * Identify chip parameters.

 * This function is called for all chips.
@@ -2262,6 +2367,17 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data, 
			return ret;

		}

	}



	if (data->flags & PMBUS_USE_COEFFICIENTS_CMD) {

		if (!i2c_check_functionality(client->adapter,

					     I2C_FUNC_SMBUS_BLOCK_PROC_CALL))

			return -ENODEV;



		ret = pmbus_init_coefficients(client, info);

		if (ret < 0)

			return ret;

	}



	return 0;

}

include/linux/pmbus.h

+8 −0
Original line number Diff line number Diff line
@@ -65,6 +65,14 @@ 
 */

#define PMBUS_NO_WRITE_PROTECT			BIT(4)



/*

 * PMBUS_USE_COEFFICIENTS_CMD

 *

 * When this flag is set the PMBus core driver will use the COEFFICIENTS

 * register to initialize the coefficients for the direct mode format.

 */

#define PMBUS_USE_COEFFICIENTS_CMD		BIT(5)



struct pmbus_platform_data {

	u32 flags;		/* Device specific flags */