The specification has evolved through several "Gears" (HS-GEARs) to double bandwidth periodically. MIPI M-PHY | MIPI
As smartphone architectures have moved from a single large SoC (System on Chip) to multiple discrete packages (e.g., separate Modem, AI Processor, and AP), the communication between these chips requires high bandwidth with low latency. M-PHY facilitates this via the LLI (Low Latency Interface) protocol. mipi m-phy specification pdf
The M-PHY specification is defined as a serial link optimized for short-distance inter-chip communication (typically mipi m-phy specification pdf