[V9,4/4] USB: serial: f81232: implement break control
diff mbox series

Message ID 1556587352-19500-4-git-send-email-hpeter+linux_kernel@gmail.com
State New
Headers show
Series
  • [V9,1/4] USB: serial: f81232: fix interrupt worker not stop
Related show

Commit Message

Ji-Ze Hong (Peter Hong) April 30, 2019, 1:22 a.m. UTC
Implement Fintek F81232 break on/off with LCR register.
It's the same with 16550A LCR register layout.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
v9:
	1: no change

v8:
	1: no change

v7:
	1: no change

v6:
	1: no change

v5:
	1: no change

v4:
	1: no change

v3:
	1: using shadow_lcr to save LCR in f81232_break_ctl()

 drivers/usb/serial/f81232.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

Comments

Johan Hovold May 3, 2019, 6:59 a.m. UTC | #1
On Tue, Apr 30, 2019 at 09:22:32AM +0800, Ji-Ze Hong (Peter Hong) wrote:
> Implement Fintek F81232 break on/off with LCR register.
> It's the same with 16550A LCR register layout.
> 
> Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
> ---

>  static void f81232_break_ctl(struct tty_struct *tty, int break_state)
>  {
> -	/* FIXME - Stubbed out for now */
> +	struct usb_serial_port *port = tty->driver_data;
> +	struct f81232_private *priv = usb_get_serial_port_data(port);
> +	int status;
>  
> -	/*
> -	 * break_state = -1 to turn on break, and 0 to turn off break
> -	 * see drivers/char/tty_io.c to see it used.
> -	 * last_set_data_urb_value NEVER has the break bit set in it.
> -	 */
> +	mutex_lock(&priv->lock);
> +
> +	if (break_state)
> +		priv->shadow_lcr |= UART_LCR_SBC;
> +	else
> +		priv->shadow_lcr &= ~UART_LCR_SBC;
> +
> +	status = f81232_set_register(port, LINE_CONTROL_REGISTER,
> +					priv->shadow_lcr);
> +	if (status)
> +		dev_err(&port->dev, "set break failed: %d\n", status);
> +
> +	mutex_unlock(&priv->lock);
>  }

> @@ -519,6 +530,7 @@ 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)
>  {
> +	struct f81232_private *priv = usb_get_serial_port_data(port);
>  	u8 new_lcr = 0;
>  	int status = 0;
>  	speed_t baudrate;
> @@ -572,11 +584,16 @@ static void f81232_set_termios(struct tty_struct *tty,
>  		break;
>  	}
>  
> +	mutex_lock(&priv->lock);
> +
> +	new_lcr |= (priv->shadow_lcr & UART_LCR_SBC);
>  	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);
>  	}
> +
> +	mutex_unlock(&priv->lock);

You forgot to update shadow_lcr here so the line settings would be
corrupted (e.g set to 5 bit words) whenever a break is signalled.

Did you not test this version of the patch?

I added the missing update, but please test the code that's in my
usb-next branch in a minute and confirm everything works as expected.

All four patches now applied.

Thanks,
Johan
Ji-Ze Hong (Peter Hong) May 6, 2019, 2:52 a.m. UTC | #2
Hi Johan,

Johan Hovold 於 2019/5/3 下午 02:59 寫道:
>> @@ -519,6 +530,7 @@ 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)
>>   {
>> +	struct f81232_private *priv = usb_get_serial_port_data(port);
>>   	u8 new_lcr = 0;
>>   	int status = 0;
>>   	speed_t baudrate;
>> @@ -572,11 +584,16 @@ static void f81232_set_termios(struct tty_struct *tty,
>>   		break;
>>   	}
>>   
>> +	mutex_lock(&priv->lock);
>> +
>> +	new_lcr |= (priv->shadow_lcr & UART_LCR_SBC);
>>   	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);
>>   	}
>> +
>> +	mutex_unlock(&priv->lock);
> 
> You forgot to update shadow_lcr here so the line settings would be
> corrupted (e.g set to 5 bit words) whenever a break is signalled.
> 
> Did you not test this version of the patch?
> 
> I added the missing update, but please test the code that's in my
> usb-next branch in a minute and confirm everything works as expected.
> 

Thanks for mention and patch the lost parts. I had only tested the
break signal and forgot to test full LCR. I'll add it to my test items
and it tested well on new usb-next branch after your fix.

BTW, Should I disable break control when port close ?

Thanks.
Johan Hovold May 7, 2019, 9:16 a.m. UTC | #3
On Mon, May 06, 2019 at 10:52:27AM +0800, Ji-Ze Hong (Peter Hong) wrote:

> > You forgot to update shadow_lcr here so the line settings would be
> > corrupted (e.g set to 5 bit words) whenever a break is signalled.
> > 
> > Did you not test this version of the patch?
> > 
> > I added the missing update, but please test the code that's in my
> > usb-next branch in a minute and confirm everything works as expected.
> > 
> 
> Thanks for mention and patch the lost parts. I had only tested the
> break signal and forgot to test full LCR. I'll add it to my test items
> and it tested well on new usb-next branch after your fix.

Thanks for confirming!

> BTW, Should I disable break control when port close ?

Yes, that would be good even if many tty drivers currently fail to do
so.

Johan

Patch
diff mbox series

diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
index 6a1e6a27ce16..562c9babd144 100644
--- a/drivers/usb/serial/f81232.c
+++ b/drivers/usb/serial/f81232.c
@@ -65,6 +65,7 @@  struct f81232_private {
 	struct mutex lock;
 	u8 modem_control;
 	u8 modem_status;
+	u8 shadow_lcr;
 	speed_t baud_base;
 	struct work_struct lsr_work;
 	struct work_struct interrupt_work;
@@ -377,13 +378,23 @@  static void f81232_process_read_urb(struct urb *urb)
 
 static void f81232_break_ctl(struct tty_struct *tty, int break_state)
 {
-	/* FIXME - Stubbed out for now */
+	struct usb_serial_port *port = tty->driver_data;
+	struct f81232_private *priv = usb_get_serial_port_data(port);
+	int status;
 
-	/*
-	 * break_state = -1 to turn on break, and 0 to turn off break
-	 * see drivers/char/tty_io.c to see it used.
-	 * last_set_data_urb_value NEVER has the break bit set in it.
-	 */
+	mutex_lock(&priv->lock);
+
+	if (break_state)
+		priv->shadow_lcr |= UART_LCR_SBC;
+	else
+		priv->shadow_lcr &= ~UART_LCR_SBC;
+
+	status = f81232_set_register(port, LINE_CONTROL_REGISTER,
+					priv->shadow_lcr);
+	if (status)
+		dev_err(&port->dev, "set break failed: %d\n", status);
+
+	mutex_unlock(&priv->lock);
 }
 
 static int f81232_find_clk(speed_t baudrate)
@@ -519,6 +530,7 @@  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)
 {
+	struct f81232_private *priv = usb_get_serial_port_data(port);
 	u8 new_lcr = 0;
 	int status = 0;
 	speed_t baudrate;
@@ -572,11 +584,16 @@  static void f81232_set_termios(struct tty_struct *tty,
 		break;
 	}
 
+	mutex_lock(&priv->lock);
+
+	new_lcr |= (priv->shadow_lcr & UART_LCR_SBC);
 	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);
 	}
+
+	mutex_unlock(&priv->lock);
 }
 
 static int f81232_tiocmget(struct tty_struct *tty)