Re: [PATCH v3] USB: serial: pl2303: add support for PL256X multi-port devices

[Johan Hovold <johan@kernel.org>]

On Tue, Jul 21, 2026 at 07:24:40PM +0800, Charles Yeh wrote:
> Prolific PL256X devices are multi-port USB-to-UART controllers,
> including the PL2533, PL2543 and PL2565 variants.
> 
> These devices use vendor requests that differ from those used by the
> existing TYPE_HX and TYPE_HXN devices. They also require a separate UART
> reset request and use a port-specific register for configuring flow
> control.
> 
> Add a new TYPE_MP device type and select the appropriate vendor requests,
> reset operation and flow-control register for PL256X devices. Store the
> USB interface number so that requests can be directed to the corresponding
> UART port.
> 
> Detect the supported PL256X variants using bcdDevice before issuing any
> legacy vendor requests, as PL256X devices do not accept those requests.
> 
> PL256X devices support baud rates up to 24 Mbps and do not use divisor
> encoding.
> 
> Signed-off-by: Charles Yeh <charlesyeh522@gmail.com>
> ---
> v3:
> * update the patch subject to describe PL256X multi-port support
> * add device variant comments to the bcdDevice table
> * use lowercase hexadecimal constants
> * simplify pl256x_uart_reset() by removing unnecessary arguments
> * improve the UART reset error message
> * fix continuation-line indentation
> * preserve reverse Christmas tree declaration order
> * add a default error case for unsupported interface numbers
> * remove the redundant flow-control configuration from startup

Thanks for the update. Now applied.

Johan