Having concentration as a unit is vague, as it can be expressed in
many ways. In the context of sigrok, concentration means a normalized
number from 0 to 1.
Document its meaning.
Signed-off-by: Alexandru Gagniuc <redacted>
SR_UNIT_UNITLESS,
/** Sound pressure level relative so 20 micropascals. */
SR_UNIT_DECIBEL_SPL,
+ /**
+ * Normalized (0 to 1) concentration of a substance or compound with 0
+ * representing a concentration of 0%, and 1 being 100%. This is
+ * represented as the fraction of number of particles of the substance.
+ */
SR_UNIT_CONCENTRATION,
};