iio: admv1013: add mixer_vgate corner cases

Include the corner cases in the computation of the MIXER_VGATE register
value.

According to the datasheet: The MIXER_VGATE values follows the VCM such
as, that for a 0V to 1.8V VCM, MIXER_VGATE = 23.89 VCM + 81, and for a >
1.8V to 2.6V VCM, MIXER_VGATE = 23.75 VCM + 1.25.

Fixes: da35a7b ("iio: frequency: admv1013: add support for ADMV1013")
Signed-off-by: Antoniu Miclaus <[email protected]>
Reviewed-by: Nuno Sa <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>

Author: amiclaus

drivers/iio/frequency/admv1013.c

@@ -351,9 +351,9 @@ static int admv1013_update_mixer_vgate(struct admv1013_state *st)
 	if (vcm < 0)
 		return vcm;
 
-	if (vcm < 1800000)
+	if (vcm <= 1800000)
 		mixer_vgate = (2389 * vcm / 1000000 + 8100) / 100;
-	else if (vcm > 1800000 && vcm < 2600000)
+	else if (vcm > 1800000 && vcm <= 2600000)
 		mixer_vgate = (2375 * vcm / 1000000 + 125) / 100;
 	else
 		return -EINVAL;