USB: f81232: implement set_termios()

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.

We are checking baudrate in set_termios() too, If baudrate larger then 115200,
it will be changed to 115200 and use tty_encode_baud_rate() to encode into tty

Signed-off-by: Peter Hung <hpeter+linux_kernel@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 108 insertions, 4 deletions

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 960282304b50..c00ced1ed281 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 +69,11 @@ struct f81232_private {
         struct usb_serial_port *port;
 };
 
+static int calc_baud_divisor(speed_t baudrate)
+{
+        return DIV_ROUND_CLOSEST(F81232_MAX_BAUDRATE, baudrate);
+}
+
 static int f81232_get_register(struct usb_serial_port *port, u16 reg, u8 *val)
 {
         int status;
@@ -350,6 +360,53 @@ static void f81232_break_ctl(struct tty_struct *tty, int break_state)
          */
 }
 
+static void f81232_set_baudrate(struct usb_serial_port *port, speed_t baudrate)
+{
+        u8 lcr;
+        int divisor, status = 0;
+
+        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);
+                return;
+        }
+
+        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);
+                return;
+        }
+
+        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);
+                goto reapply_lcr;
+        }
+
+        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);
+        }
+
+reapply_lcr:
+        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)
 {
         u8 val;
@@ -395,15 +452,62 @@ static int f81232_port_disable(struct usb_serial_port *port)
 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;
+        speed_t baudrate;
 
         /* 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);
+
+        baudrate = tty_get_baud_rate(tty);
+        if (baudrate > 0) {
+                if (baudrate > F81232_MAX_BAUDRATE) {
+                        baudrate = F81232_MAX_BAUDRATE;
+                        tty_encode_baud_rate(tty, baudrate, baudrate);
+                }
+                f81232_set_baudrate(port, baudrate);
+        }
+
+        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)