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path: root/drivers/usb/serial/ch341.c
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Diffstat (limited to 'drivers/usb/serial/ch341.c')
-rw-r--r--drivers/usb/serial/ch341.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 2798fca71261..6e1b87e67304 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -97,13 +97,16 @@ struct ch341_private {
u8 mcr;
u8 msr;
u8 lcr;
+
unsigned long quirks;
+ u8 version;
+
unsigned long break_end;
};
static void ch341_set_termios(struct tty_struct *tty,
struct usb_serial_port *port,
- struct ktermios *old_termios);
+ const struct ktermios *old_termios);
static int ch341_control_out(struct usb_device *dev, u8 request,
u16 value, u16 index)
@@ -250,8 +253,12 @@ static int ch341_set_baudrate_lcr(struct usb_device *dev,
/*
* CH341A buffers data until a full endpoint-size packet (32 bytes)
* has been received unless bit 7 is set.
+ *
+ * At least one device with version 0x27 appears to have this bit
+ * inverted.
*/
- val |= BIT(7);
+ if (priv->version > 0x27)
+ val |= BIT(7);
r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER,
@@ -265,6 +272,9 @@ static int ch341_set_baudrate_lcr(struct usb_device *dev,
* (stop bits, parity and word length). Version 0x30 and above use
* CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero.
*/
+ if (priv->version < 0x30)
+ return 0;
+
r = ch341_control_out(dev, CH341_REQ_WRITE_REG,
CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr);
if (r)
@@ -308,7 +318,9 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
if (r)
return r;
- dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
+
+ priv->version = buffer[0];
+ dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
if (r < 0)
@@ -470,7 +482,8 @@ err_kill_interrupt_urb:
* tty->termios contains the new setting to be used.
*/
static void ch341_set_termios(struct tty_struct *tty,
- struct usb_serial_port *port, struct ktermios *old_termios)
+ struct usb_serial_port *port,
+ const struct ktermios *old_termios)
{
struct ch341_private *priv = usb_get_serial_port_data(port);
unsigned baud_rate;