iio: imu: inv_mpu6050: update LPF bandwidth settings

/**

 *  inv_mpu6050_set_lpf() - set low pass filer based on fifo rate.

 *

 *                  Based on the Nyquist principle, the sampling rate must

 *                  exceed twice of the bandwidth of the signal, or there

 *                  would be alising. This function basically search for the

 *                  correct low pass parameters based on the fifo rate, e.g,

 *                  sampling frequency.

 *                  Based on the Nyquist principle, the bandwidth of the low

 *                  pass filter must not exceed the signal sampling rate divided

 *                  by 2, or there would be aliasing.

 *                  This function basically search for the correct low pass

 *                  parameters based on the fifo rate, e.g, sampling frequency.

 *

 *  lpf is set automatically when setting sampling rate to avoid any aliases.

 */

static int inv_mpu6050_set_lpf(struct inv_mpu6050_state *st, int rate)

{

	static const int hz[] = {188, 98, 42, 20, 10, 5};

	static const int hz[] = {400, 200, 90, 40, 20, 10};

	static const int d[] = {

		INV_MPU6050_FILTER_188HZ, INV_MPU6050_FILTER_98HZ,

		INV_MPU6050_FILTER_42HZ, INV_MPU6050_FILTER_20HZ,

		INV_MPU6050_FILTER_200HZ, INV_MPU6050_FILTER_100HZ,

		INV_MPU6050_FILTER_45HZ, INV_MPU6050_FILTER_20HZ,

		INV_MPU6050_FILTER_10HZ, INV_MPU6050_FILTER_5HZ

	};

	int i, h, result;

	int i, result;

	u8 data;

	h = (rate >> 1);

	i = 0;

	while ((h < hz[i]) && (i < ARRAY_SIZE(d) - 1))

		i++;

	data = INV_MPU6050_FILTER_5HZ;

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

		if (rate >= hz[i]) {

			data = d[i];

			break;

		}

	}

	result = inv_mpu6050_set_lpf_regs(st, data);

	if (result)

		return result;

};

enum inv_mpu6050_filter_e {

	INV_MPU6050_FILTER_256HZ_NOLPF2 = 0,

	INV_MPU6050_FILTER_188HZ,

	INV_MPU6050_FILTER_98HZ,

	INV_MPU6050_FILTER_42HZ,

	INV_MPU6050_FILTER_NOLPF2 = 0,

	INV_MPU6050_FILTER_200HZ,

	INV_MPU6050_FILTER_100HZ,

	INV_MPU6050_FILTER_45HZ,

	INV_MPU6050_FILTER_20HZ,

	INV_MPU6050_FILTER_10HZ,

	INV_MPU6050_FILTER_5HZ,

	INV_MPU6050_FILTER_2100HZ_NOLPF,

	INV_MPU6050_FILTER_NOLPF,

	NUM_MPU6050_FILTER

};