On Wed, Apr 29, 2020 at 01:26:50AM +0530, mani@xxxxxxxxxx wrote: > From: Manivannan Sadhasivam <mani@xxxxxxxxxx> > > Add support for MaxLinear/Exar USB to Serial converters. This driver > only supports XR21V141X series but provision has been made to support > other series in future. > > This driver is inspired from the initial one submitted by Patong Yang: > > https://patchwork.kernel.org/patch/10543261/ > > While the initial driver was a custom tty USB driver exposing whole > new serial interface ttyXRUSBn, this version is completely based on USB > serial core thus exposing the interfaces as ttyUSBn. This will avoid > the overhead of exposing a new USB serial interface which the userspace > tools are unaware of. Nice work! Some comments below: > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * MaxLinear/Exar USB to Serial driver > + * > + * Based on initial driver written by Patong Yang <patong.mxl@xxxxxxxxx> > + * > + * Copyright (c) 2020 Manivannan Sadhasivam <mani@xxxxxxxxxx> > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/tty.h> > +#include <linux/usb.h> > +#include <linux/usb/serial.h> > + > +#include "xr_serial.h" No need for a .h file for a single .c file. > +static int xr_get_reg(struct usb_serial_port *port, u8 block, u16 reg, > + u16 *val) > +{ > + struct usb_serial *serial = port->serial; > + struct xr_port_private *port_priv = usb_get_serial_port_data(port); > + void *dmabuf; > + int ret = -EINVAL; > + > + dmabuf = kmalloc(sizeof(reg), GFP_KERNEL); So that is 2 bytes? > + if (!dmabuf) > + return -ENOMEM; > + > + if (port_priv->idProduct == XR21V141X_ID) { > + /* XR21V141X uses custom command for reading UART registers */ > + ret = usb_control_msg(serial->dev, > + usb_rcvctrlpipe(serial->dev, 0), > + XR_GET_XR21V141X, > + USB_DIR_IN | USB_TYPE_VENDOR, 0, > + reg | (block << 8), dmabuf, > + port_priv->reg_width, > + USB_CTRL_SET_TIMEOUT); > + } > + > + if (ret == port_priv->reg_width) { > + memcpy(val, dmabuf, port_priv->reg_width); But here you copy ->reg_width bytes in? How do you know val can hold that much? It's only set to be 1, so you copy 1 byte to a 16bit value? What part of the 16bits did you just copy those 8 bits to (hint, think cpu endian issues...) That feels really really odd and a bit broken. > --- /dev/null > +++ b/drivers/usb/serial/xr_serial.h > @@ -0,0 +1,103 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ Are you sure about the "+"? I have to ask :) > + > +#ifndef __LINUX_USB_SERIAL_XR_SERIAL_H > +#define __LINUX_USB_SERIAL_XR_SERIAL_H As you will drop this file, just a general statement, no need for __LINUX as this is all Linux :) thanks, greg k-h
