I was planning to define all these bits in a separate future patch.
Would you rather prefer the magic numbers defined before fixing the bugs?
I guess I can do that. Is something like this acceptable?
/* CP210X_GET_FLOW/CP210X_SET_FLOW read/write these 0x10 bytes */
struct cp210x_flow_ctl {
u8 SERIAL_DTR_MASK : 2; /* byte 0 */
u8 : 1;
u8 SERIAL_CTS_HANDSHAKE : 1;
u8 SERIAL_DSR_HANDSHAKE : 1;
u8 SERIAL_DCD_HANDSHAKE : 1;
u8 SERIAL_DSR_SENSITIVITY : 1;
u8 : 1;
u8; /* byte 1 */
u8; /* byte 2 */
u8; /* byte 3 */
u8 SERIAL_AUTO_TRANSMIT : 1; /* byte 4 */
u8 SERIAL_AUTO_RECEIVE : 1;
u8 SERIAL_ERROR_CHAR : 1;
u8 SERIAL_NULL_STRIPPING : 1;
u8 SERIAL_BREAK_CHAR : 1;
u8 : 1;
u8 SERIAL_RTS_MASK : 2;
u8; /* byte 5 */
u8; /* byte 6 */
u8 : 7; /* byte 7 */
u8 SERIAL_XOFF_CONTINUE : 1;
__le32 ulXonLimit;
__le32 ulXoffLimit;
} __packed;
> -----Original Message-----
> From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Johan Hovold
> Sent: Monday, April 25, 2016 05:17
> To: Konstantin Shkolnyy
> Cc: johan@xxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: [EXT] Re: [PATCH RESEND 3/5] USB: serial: cp210x: Added comments
> to CRTSCT flag code.
>
> On Sun, Apr 24, 2016 at 12:09:21PM -0500, Konstantin Shkolnyy wrote:
> > Documented "magic numbers" used in the CRTSCT flag code in terms of
> > register bit names from the chip specification.
>
> Documenting these is long overdue. I even started adding defines just to
> be able to review the first patch in the series.
>
> > Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@xxxxxxxxx>
> > ---
> > drivers/usb/serial/cp210x.c | 38
> ++++++++++++++++++++++++++++++++++----
> > 1 file changed, 34 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> > index ede5c52..b2321a7 100644
> > --- a/drivers/usb/serial/cp210x.c
> > +++ b/drivers/usb/serial/cp210x.c
> > @@ -790,7 +790,7 @@ static void cp210x_get_termios_port(struct
> usb_serial_port *port,
> >
> > cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
> > sizeof(modem_ctl));
> > - if (modem_ctl[0] & 0x08) {
> > + if (modem_ctl[0] & 0x08) { /* if SERIAL_CTS_HANDSHAKE */
>
> But instead of adding comments like this one and below, please add
> proper defines for the various flags and masks. That will make the code
> mostly self-explanatory.
>
> > dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
> > cflag |= CRTSCTS;
> > } else {
> > @@ -952,17 +952,47 @@ static void cp210x_set_termios(struct tty_struct
> *tty,
> > __func__, modem_ctl[0], modem_ctl[4],
> modem_ctl[7]);
> >
> > if (cflag & CRTSCTS) {
> > - modem_ctl[0] &= ~0x7B;
> > + modem_ctl[0] &= ~0x7B; /* keep reserved D2 and D7
> */
> > + /*
> > + * D1-D0 SERIAL_DTR_MASK =01b: DTR is held
> active
> > + * D3 SERIAL_CTS_HANDSHAKE =1: CTS is a
> handshake line
> > + * D4 SERIAL_DSR_HANDSHAKE =0
> > + * D5 SERIAL_DCD_HANDSHAKE =0
> > + * D6 SERIAL_DSR_SENSITIVITY =0
> > + */
>
> > - modem_ctl[7] = 0;
> > + modem_ctl[7] = 0; /* SERIAL_XOFF_CONTINUE = 0 */
>
> And this would be better as a bit operation as well (as already
> mentioned).
>
> Thanks,
> Johan
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