| Message ID | 20180718122501.14926-5-johan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jul 18, 2018 at 3:25 PM, Johan Hovold <johan@kernel.org> wrote: > The CP2102N equations for determining the actual baud rate can be used > also for other device types, so let's factor it out. > > Note that this removes the now unused cp210x_is_cp2102n() helper. > +static speed_t cp210x_get_actual_rate(struct usb_serial *serial, speed_t baud) > +{ > + struct cp210x_serial_private *priv = usb_get_serial_data(serial); > + unsigned int prescale = 1; > + unsigned int div; > + > + baud = clamp(baud, 300u, priv->max_speed); > + > + if (baud <= 365) > + prescale = 4; > + > + div = DIV_ROUND_CLOSEST(48000000, 2 * prescale * baud); > + baud = 48000000 / (2 * prescale * div); > + > + return baud; > +} > - if (cp210x_is_cp2102n(serial)) { > - int clk_div; > - int prescaler; > - > - baud = clamp(baud, 300u, priv->max_speed); > - prescaler = (baud <= 365) ? 4 : 1; > - clk_div = DIV_ROUND_CLOSEST(48000000, 2 * prescaler * baud); > - baud = 48000000 / (2 * prescaler * clk_div); > - } Looks like ping-pong type of changes. I think the factoring of this particular piece of code can be done in patch 3 in somewhat similar way.
On Wed, Jul 18, 2018 at 03:34:34PM +0300, Andy Shevchenko wrote: > On Wed, Jul 18, 2018 at 3:25 PM, Johan Hovold <johan@kernel.org> wrote: > > The CP2102N equations for determining the actual baud rate can be used > > also for other device types, so let's factor it out. > > > > Note that this removes the now unused cp210x_is_cp2102n() helper. > > > > +static speed_t cp210x_get_actual_rate(struct usb_serial *serial, speed_t baud) > > +{ > > + struct cp210x_serial_private *priv = usb_get_serial_data(serial); > > + unsigned int prescale = 1; > > + unsigned int div; > > + > > + baud = clamp(baud, 300u, priv->max_speed); > > + > > + if (baud <= 365) > > + prescale = 4; > > + > > + div = DIV_ROUND_CLOSEST(48000000, 2 * prescale * baud); > > + baud = 48000000 / (2 * prescale * div); > > + > > + return baud; > > +} > > > - if (cp210x_is_cp2102n(serial)) { > > - int clk_div; > > - int prescaler; > > - > > - baud = clamp(baud, 300u, priv->max_speed); > > - prescaler = (baud <= 365) ? 4 : 1; > > - clk_div = DIV_ROUND_CLOSEST(48000000, 2 * prescaler * baud); > > - baud = 48000000 / (2 * prescaler * clk_div); > > - } > > Looks like ping-pong type of changes. > I think the factoring of this particular piece of code can be done in > patch 3 in somewhat similar way. Indeed, and it was done like this on purpose this time to save time (and I did not want to rewrite Karoly's patch beyond recognition). Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Jul 18, 2018 at 3:37 PM, Johan Hovold <johan@kernel.org> wrote: > On Wed, Jul 18, 2018 at 03:34:34PM +0300, Andy Shevchenko wrote: >> On Wed, Jul 18, 2018 at 3:25 PM, Johan Hovold <johan@kernel.org> wrote: >> Looks like ping-pong type of changes. >> I think the factoring of this particular piece of code can be done in >> patch 3 in somewhat similar way. > > Indeed, and it was done like this on purpose this time to save time (and > I did not want to rewrite Karoly's patch beyond recognition). Ah, it explains.
On Wed, Jul 18, 2018 at 02:25:00PM +0200, Johan Hovold wrote: > The CP2102N equations for determining the actual baud rate can be used > also for other device types, so let's factor it out. > > Note that this removes the now unused cp210x_is_cp2102n() helper. > > Signed-off-by: Johan Hovold <johan@kernel.org> > --- > drivers/usb/serial/cp210x.c | 50 ++++++++++++++++++++----------------- > 1 file changed, 27 insertions(+), 23 deletions(-) Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 3778685c7b99..957406aac9bd 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -230,6 +230,7 @@ struct cp210x_serial_private { #endif u8 partnum; speed_t max_speed; + bool use_actual_rate; }; struct cp210x_port_private { @@ -457,15 +458,6 @@ struct cp210x_gpio_write { u8 state; } __packed; -static bool cp210x_is_cp2102n(struct usb_serial *serial) -{ - struct cp210x_serial_private *priv = usb_get_serial_data(serial); - - return (priv->partnum == CP210X_PARTNUM_CP2102N_QFN28) || - (priv->partnum == CP210X_PARTNUM_CP2102N_QFN24) || - (priv->partnum == CP210X_PARTNUM_CP2102N_QFN20); -} - /* * Helper to get interface number when we only have struct usb_serial. */ @@ -1036,6 +1028,23 @@ static speed_t cp210x_get_an205_rate(speed_t baud) return cp210x_an205_table1[i].rate; } +static speed_t cp210x_get_actual_rate(struct usb_serial *serial, speed_t baud) +{ + struct cp210x_serial_private *priv = usb_get_serial_data(serial); + unsigned int prescale = 1; + unsigned int div; + + baud = clamp(baud, 300u, priv->max_speed); + + if (baud <= 365) + prescale = 4; + + div = DIV_ROUND_CLOSEST(48000000, 2 * prescale * baud); + baud = 48000000 / (2 * prescale * div); + + return baud; +} + /* * CP2101 supports the following baud rates: * @@ -1072,25 +1081,17 @@ static void cp210x_change_speed(struct tty_struct *tty, baud = tty->termios.c_ospeed; /* - * This maps the requested rate to the actual rate on cp2102n, a valid - * rate on cp2102 or cp2103, or to an arbitrary rate in - * [1M, max_speed]. + * This maps the requested rate to the actual rate, a valid rate on + * cp2102 or cp2103, or to an arbitrary rate in [1M, max_speed]. * * NOTE: B0 is not implemented. */ - if (cp210x_is_cp2102n(serial)) { - int clk_div; - int prescaler; - - baud = clamp(baud, 300u, priv->max_speed); - prescaler = (baud <= 365) ? 4 : 1; - clk_div = DIV_ROUND_CLOSEST(48000000, 2 * prescaler * baud); - baud = 48000000 / (2 * prescaler * clk_div); - } else if (baud < 1000000) { + if (priv->use_actual_rate) + baud = cp210x_get_actual_rate(serial, baud); + else if (baud < 1000000) baud = cp210x_get_an205_rate(baud); - } else if (baud > priv->max_speed) { + else if (baud > priv->max_speed) baud = priv->max_speed; - } dev_dbg(&port->dev, "%s - setting baud rate to %u\n", __func__, baud); if (cp210x_write_u32_reg(port, CP210X_SET_BAUDRATE, baud)) { @@ -1524,6 +1525,7 @@ static int cp210x_port_remove(struct usb_serial_port *port) static void cp210x_init_max_speed(struct usb_serial *serial) { struct cp210x_serial_private *priv = usb_get_serial_data(serial); + bool use_actual_rate = false; speed_t max; switch (priv->partnum) { @@ -1547,6 +1549,7 @@ static void cp210x_init_max_speed(struct usb_serial *serial) case CP210X_PARTNUM_CP2102N_QFN28: case CP210X_PARTNUM_CP2102N_QFN24: case CP210X_PARTNUM_CP2102N_QFN20: + use_actual_rate = true; max = 3000000; break; default: @@ -1555,6 +1558,7 @@ static void cp210x_init_max_speed(struct usb_serial *serial) } priv->max_speed = max; + priv->use_actual_rate = use_actual_rate; } static int cp210x_attach(struct usb_serial *serial)
The CP2102N equations for determining the actual baud rate can be used also for other device types, so let's factor it out. Note that this removes the now unused cp210x_is_cp2102n() helper. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/cp210x.c | 50 ++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 23 deletions(-)