common/util/util_pmbus.c

#include <stdint.h>
#include "sensor.h"
#include "hal_i2c.h"

const float slinear11_exponents[32] = { 1.0,
					2.0,
					4.0,
					8.0,
					16.0,
					32.0,
					64.0,
					128.0,
					256.0,
					512.0,
					1024.0,
					2048.0,
					4096.0,
					8192.0,
					16384.0,
					32768.0,
					0.0000152587890625,
					0.000030517578125,
					0.00006103515625,
					0.0001220703125,
					0.000244140625,
					0.00048828125,
					0.0009765625,
					0.001953125,
					0.00390625,
					0.0078125,
					0.015625,
					0.03125,
					0.0625,
					0.125,
					0.25,
					0.5 };

float slinear11_to_float(uint16_t read_value)
{
	uint8_t exponent;
	int16_t mantissa;
	float lsb;
	float ret;

	exponent = read_value >> 11;
	mantissa = read_value & 0x07FF;
	/* Sign extend Mantissa to 16 bits */
	if (mantissa > 0x03FF)
		mantissa |= 0xF800;

	lsb = slinear11_exponents[exponent];
	ret = mantissa * lsb;
	return ret;
}

bool get_exponent_from_vout_mode(uint8_t sensor_num, float *exponent)
{
	uint8_t retry = 5;
	I2C_MSG msg;

	msg.bus = sensor_config[SensorNum_SensorCfg_map[sensor_num]].port;
	msg.slave_addr = sensor_config[SensorNum_SensorCfg_map[sensor_num]].slave_addr;
	msg.tx_len = 1;
	msg.rx_len = 1;
	msg.data[0] = PMBUS_VOUT_MODE;

	if (i2c_master_read(&msg, retry))
		return false;

	*exponent = slinear11_exponents[msg.data[0] & 0x1f];
	return true;
}