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@xxxxxxxxxx>
---
drivers/usb/serial/cp210x.c | 50 ++++++++++++++++++++-----------------
1 file changed, 27 insertions(+), 23 deletions(-)
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)
--
2.18.0
--
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