Changing the LCR register after initialization does not seem to be
reliable on all chips (particularly not on CH341A). Restructure
initialization and configuration to always reinit the chip on
configuration changes instead and pass the LCR register value directly
to the initialization command.
With this change, configuring parity, different frame lengths and
different stop bit settings work as expected on both CH340G and CH341A.
This has been extensively tested with a logic analyzer.
Tested-by: Ryan Barber <rfb@xxxxxxxxxxxxx>
Signed-off-by: Grigori Goronzy <greg@xxxxxxxxxxxx>
---
drivers/usb/serial/ch341.c | 76 +++++++++++++++++++++++++++++++---------------
1 file changed, 51 insertions(+), 25 deletions(-)
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 6781911..8386e95 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -62,6 +62,8 @@
* the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
*/
+#define CH341_SERIAL_INIT 0xA1
+#define CH341_VERSION 0x5F
#define CH341_MODEM_CTRL 0xA4
#define CH341_REQ_WRITE_REG 0x9A
#define CH341_REQ_READ_REG 0x95
@@ -130,8 +132,8 @@ static int ch341_control_in(struct usb_device *dev,
return r;
}
-static int ch341_set_baudrate(struct usb_device *dev,
- struct ch341_private *priv)
+static int ch341_init_set_baudrate(struct usb_device *dev,
+ struct ch341_private *priv, unsigned ctrl)
{
short a, b;
int r;
@@ -155,9 +157,7 @@ static int ch341_set_baudrate(struct usb_device *dev,
a = (factor & 0xff00) | divisor;
b = factor & 0xff;
- r = ch341_control_out(dev, 0x9a, 0x1312, a);
- if (!r)
- r = ch341_control_out(dev, 0x9a, 0x0f2c, b);
+ r = ch341_control_out(dev, CH341_SERIAL_INIT, 0x9c | (ctrl << 8) , a | 0x80);
return r;
}
@@ -178,7 +178,7 @@ static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
if (!buffer)
return -ENOMEM;
- r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
+ r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
if (r < 0)
goto out;
@@ -208,24 +208,20 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
return -ENOMEM;
/* expect two bytes 0x27 0x00 */
- r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size);
+ r = ch341_control_in(dev, CH341_VERSION, 0, 0, buffer, size);
if (r < 0)
goto out;
- r = ch341_control_out(dev, 0xa1, 0, 0);
- if (r < 0)
- goto out;
-
- r = ch341_set_baudrate(dev, priv);
+ r = ch341_control_out(dev, CH341_SERIAL_INIT, 0, 0);
if (r < 0)
goto out;
/* expect two bytes 0x56 0x00 */
- r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size);
+ r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x2518, 0, buffer, size);
if (r < 0)
goto out;
- r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050);
+ r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, 0x00c3);
if (r < 0)
goto out;
@@ -234,11 +230,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
if (r < 0)
goto out;
- r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a);
- if (r < 0)
- goto out;
-
- r = ch341_set_baudrate(dev, priv);
+ r = ch341_init_set_baudrate(dev, priv, 0);
if (r < 0)
goto out;
@@ -353,16 +345,55 @@ static void ch341_set_termios(struct tty_struct *tty,
struct ch341_private *priv = usb_get_serial_port_data(port);
unsigned baud_rate;
unsigned long flags;
+ unsigned char ctrl;
+ unsigned int cflag = tty->termios.c_cflag;
+ int r;
+
+ /* redundant changes may cause the chip to lose bytes */
+ if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
+ return;
baud_rate = tty_get_baud_rate(tty);
priv->baud_rate = baud_rate;
+ ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
+
+ switch (cflag & CSIZE) {
+ case CS5:
+ ctrl |= CH341_LCR_CS5;
+ break;
+ case CS6:
+ ctrl |= CH341_LCR_CS6;
+ break;
+ case CS7:
+ ctrl |= CH341_LCR_CS7;
+ break;
+ case CS8:
+ default:
+ ctrl |= CH341_LCR_CS8;
+ break;
+ }
+
+ if (cflag & PARENB) {
+ ctrl |= CH341_LCR_ENABLE_PAR;
+ if ((cflag & PARODD) == 0)
+ ctrl |= CH341_LCR_PAR_EVEN;
+ }
+
+ if (cflag & CMSPAR)
+ ctrl |= CH341_LCR_MARK_SPACE;
+
+ if (cflag & CSTOPB)
+ ctrl |= CH341_LCR_STOP_BITS_2;
+
if (baud_rate) {
spin_lock_irqsave(&priv->lock, flags);
priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
spin_unlock_irqrestore(&priv->lock, flags);
- ch341_set_baudrate(port->serial->dev, priv);
+ r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl);
+ if (r < 0)
+ priv->baud_rate = tty_termios_baud_rate(old_termios);
} else {
spin_lock_irqsave(&priv->lock, flags);
priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
@@ -371,11 +402,6 @@ static void ch341_set_termios(struct tty_struct *tty,
ch341_set_handshake(port->serial->dev, priv->line_control);
- /* Unimplemented:
- * (cflag & CSIZE) : data bits [5, 8]
- * (cflag & PARENB) : parity {NONE, EVEN, ODD}
- * (cflag & CSTOPB) : stop bits [1, 2]
- */
}
static void ch341_break_ctl(struct tty_struct *tty, int break_state)
--
1.9.1
--
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