Hi Alan, Thank you for your kind comments for this patch. I will refine the patch according to your comments and re-submit it then. Regards, Donald -----Original Message----- From: Alan Cox [mailto:alan@xxxxxxxxxxxxxxxxxxx] Sent: Thursday, March 29, 2012 11:04 PM To: Donald Cc: 'Greg KH'; 'open list:USB SUBSYSTEM'; 'open list' Subject: Re: Patch "USB: serial: mos7840: Supported MCS7810 device" > +static void mos7810_control_callback(struct urb *urb) { > + if (!urb) > + return; How can this ever occur. If its not theoretically possible then this check is just going to hide bugs in future. > +static void mos7810_led_off(unsigned long arg) { > + struct moschip_port *mcs = (struct moschip_port *) arg; > + > + if (!mcs) > + return; Ditto > + /* Turn on MCS7810 LED */ > + if (serial->num_ports == 1 && mos7840_port->mos7810_led_flag == 0) { > + mos7840_port->mos7810_led_flag = 1; > + mos7810_set_reg(mos7840_port, 0x0301, > MODEM_CONTROL_REGISTER); > + mod_timer(&mos7840_port->mos7810_led_timer1, jiffies + 500); > + } The assumption that serial->num_ports = 1 means "has LED" is going to cause problems later if another deivce appears with 1 port and no LED. I think it would be much clearer to have something like if (mos7840_port->has_led) for these tests of the driver > +static int mos7810_check(struct usb_serial *serial) { > + int i, pass_count = 0; > + __u16 Data = 0, MCR_Data = 0; > + __u16 test_pattern = 0x55AA, write_pattern; generally linux style is all lower case for egister names. Not a big deal > + /* If this a MCS7810 device, both test patterns must match > */ > + if (((test_pattern >> i) & 0x0001) != ((~(Data >> 1)) & > 0x0001)) if (((test_pattern >> i) ^ (~Data >> 1)) & 0x0001) ? again trivia... > + mos7840_port->mos7810_led_timer1.expires = > + jiffies + 500; This 500 value depends upon the HZ value of the kernel which won't always be 1000 on all platforms. You probably want jiffies + msecs_to_jiffies(500); (or indeed HZ/2) > + /* Turn off MCS7810 LED */ > + usb_control_msg(serial->dev, > + usb_sndctrlpipe(serial->dev, 0), > + MCS_WRREQ, MCS_WR_RTYPE, 0x0300, > + MODEM_CONTROL_REGISTER, NULL, 0, > + MOS_WDR_TIMEOUT); > + Might be clearer if these occurences were a separate small function - gcc will inline them if it makes sense, and it will be clearer. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
