The original driver had do not any h/w change in driver.
This patch implements with configure H/W for
baud/parity/word length/stop bits functional in f81232_set_termios().

This patch also implement DTR/RTS control when baudrate B0.
We drop DTR/RTS when B0, otherwise enable it.

Signed-off-by: Peter Hung <hpeter+linux_ker...@gmail.com>
---
 drivers/usb/serial/f81232.c | 106 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 102 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index f5c9060..0c96b9a 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -31,14 +31,19 @@ static const struct usb_device_id id_table[] = {
 };
 MODULE_DEVICE_TABLE(usb, id_table);
 
+/* Maximum baudrate for F81232 */
+#define F81232_MAX_BAUDRATE    115200
+
 /* USB Control EP parameter */
 #define F81232_REGISTER_REQUEST        0xA0
 #define F81232_GET_REGISTER    0xc0
 #define F81232_SET_REGISTER    0x40
 
 #define SERIAL_BASE_ADDRESS    0x0120
+#define RECEIVE_BUFFER_REGISTER        (0x00 + SERIAL_BASE_ADDRESS)
 #define INTERRUPT_ENABLE_REGISTER      (0x01 + SERIAL_BASE_ADDRESS)
 #define FIFO_CONTROL_REGISTER  (0x02 + SERIAL_BASE_ADDRESS)
+#define LINE_CONTROL_REGISTER  (0x03 + SERIAL_BASE_ADDRESS)
 #define MODEM_CONTROL_REGISTER (0x04 + SERIAL_BASE_ADDRESS)
 #define MODEM_STATUS_REGISTER  (0x06 + SERIAL_BASE_ADDRESS)
 
@@ -64,6 +69,14 @@ struct f81232_private {
        struct usb_serial_port *port;
 };
 
+static int calc_baud_divisor(u32 baudrate)
+{
+       if (!baudrate)
+               return 0;
+       else
+               return DIV_ROUND_CLOSEST(F81232_MAX_BAUDRATE, baudrate);
+}
+
 static int f81232_get_register(struct usb_serial_port *port, u16 reg, u8 *data)
 {
        int status;
@@ -369,6 +382,52 @@ static void f81232_break_ctl(struct tty_struct *tty, int 
break_state)
         */
 }
 
+static void f81232_set_baudrate(struct usb_serial_port *port, int baudrate)
+{
+       u8 divisor, lcr;
+       int status = 0;
+
+       if (!baudrate)
+               return;
+
+       divisor = calc_baud_divisor(baudrate);
+
+       status = f81232_get_register(port, LINE_CONTROL_REGISTER,
+                        &lcr); /* get LCR */
+       if (status) {
+               dev_err(&port->dev, "%s failed to get LCR: %d\n",
+                       __func__, status);
+       }
+
+       status = f81232_set_register(port, LINE_CONTROL_REGISTER,
+                        lcr | UART_LCR_DLAB); /* Enable DLAB */
+       if (status) {
+               dev_err(&port->dev, "%s failed to set DLAB: %d\n",
+                       __func__, status);
+       }
+
+       status = f81232_set_register(port, RECEIVE_BUFFER_REGISTER,
+                        divisor & 0x00ff); /* low */
+       if (status) {
+               dev_err(&port->dev, "%s failed to set baudrate MSB: %d\n",
+                       __func__, status);
+       }
+
+       status = f81232_set_register(port, INTERRUPT_ENABLE_REGISTER,
+                        (divisor & 0xff00) >> 8); /* high */
+       if (status) {
+               dev_err(&port->dev, "%s failed to set baudrate LSB: %d\n",
+                       __func__, status);
+       }
+
+       status = f81232_set_register(port, LINE_CONTROL_REGISTER,
+                       lcr & ~UART_LCR_DLAB);
+       if (status) {
+               dev_err(&port->dev, "%s failed to set DLAB: %d\n",
+                       __func__, status);
+       }
+}
+
 static int f81232_port_enable(struct usb_serial_port *port, int enable)
 {
        u8 data = 0;
@@ -399,15 +458,54 @@ static int f81232_port_enable(struct usb_serial_port 
*port, int enable)
 static void f81232_set_termios(struct tty_struct *tty,
                struct usb_serial_port *port, struct ktermios *old_termios)
 {
-       /* FIXME - Stubbed out for now */
+       u8 new_lcr = 0;
+       int status = 0;
+
 
        /* Don't change anything if nothing has changed */
        if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
                return;
 
-       /* Do the real work here... */
-       if (old_termios)
-               tty_termios_copy_hw(&tty->termios, old_termios);
+       if (C_BAUD(tty) == B0)
+               f81232_set_mctrl(port, 0, TIOCM_DTR | TIOCM_RTS);
+       else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
+               f81232_set_mctrl(port, TIOCM_DTR | TIOCM_RTS, 0);
+
+       f81232_set_baudrate(port, tty_get_baud_rate(tty));
+
+       if (C_PARENB(tty)) {
+               new_lcr |= UART_LCR_PARITY;
+
+               if (!C_PARODD(tty))
+                       new_lcr |= UART_LCR_EPAR;
+
+               if (C_CMSPAR(tty))
+                       new_lcr |= UART_LCR_SPAR;
+       }
+
+       if (C_CSTOPB(tty))
+               new_lcr |= UART_LCR_STOP;
+
+       switch (C_CSIZE(tty)) {
+       case CS5:
+               new_lcr |= UART_LCR_WLEN5;
+               break;
+       case CS6:
+               new_lcr |= UART_LCR_WLEN6;
+               break;
+       case CS7:
+               new_lcr |= UART_LCR_WLEN7;
+               break;
+       default:
+       case CS8:
+               new_lcr |= UART_LCR_WLEN8;
+               break;
+       }
+
+       status = f81232_set_register(port, LINE_CONTROL_REGISTER, new_lcr);
+       if (status)
+               dev_err(&port->dev, "%s failed to set LCR: %d\n", __func__, 
status);
+
 }
 
 static int f81232_tiocmget(struct tty_struct *tty)
-- 
1.9.1

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