Re: [PATCH v4 6/7] usb: serial: implement MCR/MSR function for F81232

[Johan Hovold]

On Fri, Jan 30, 2015 at 02:13:40PM +0800, Peter Hung wrote:
> This patch implement relative MCR/MSR function, such like
> tiocmget()/tiocmset()/dtr_rts().
> 
> The update_mctrl() replace set_control_lines() to do MCR control
> so we clean-up the set_control_lines() function.
> 
> Signed-off-by: Peter Hung <hpeter+linux_kernel@xxxxxxxxx>
> ---
>  drivers/usb/serial/f81232.c | 105 ++++++++++++++++++++++++++++++++++----------
>  1 file changed, 83 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 248f40d..0ed7e36 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -38,11 +38,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #define UART_STATE_TRANSIENT_MASK	0x74
>  #define UART_DCD			0x01
>  #define UART_DSR			0x02
> -#define UART_BREAK_ERROR		0x04
>  #define UART_RING			0x08
> -#define UART_FRAME_ERROR		0x10
> -#define UART_PARITY_ERROR		0x20
> -#define UART_OVERRUN_ERROR		0x40
>  #define UART_CTS			0x80
>  
>  #define REGISTER_REQUEST 0xA0
> @@ -55,6 +51,7 @@ MODULE_DEVICE_TABLE(usb, id_table);
>  #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)
>  struct f81232_private {
>  	spinlock_t lock;
> @@ -165,6 +162,62 @@ static void f81232_read_msr(struct f81232_private *priv)
>  
>  	dev_dbg(&dev->dev, "%s: %x\n", __func__, priv->line_status);
>  }
> +
> +static inline int update_mctrl(struct f81232_private *port_priv,
> +					   unsigned int set, unsigned int clear)

Rename this on f81232_set_mctrl or similar, and pass the usb-serial port
instead of port-data.

Drop the inline (from all you functions).

> +{
> +	struct usb_device *dev = port_priv->port->serial->dev;
> +	u8 urb_value;
> +	int status;
> +	unsigned long flags;
> +
> +	if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
> +		dev_dbg(&dev->dev, "%s fail - DTR|RTS %d\n",
> +			__func__, __LINE__);

Just skip the dev_dbg.

> +		return 0;	/* no change */
> +	}
> +
> +	clear &= ~set;	/* 'set' takes precedence over 'clear' */
> +	urb_value = 8 | port_priv->line_control;

Use the UART_MCR_OUT2 define if needed (and comment on why).

> +
> +	if (clear & TIOCM_DTR) {
> +		urb_value &= ~UART_MCR_DTR;
> +		dev_dbg(&dev->dev, "clear DTR\n");
> +	}
> +
> +	if (clear & TIOCM_RTS) {
> +		urb_value &= ~UART_MCR_RTS;
> +		dev_dbg(&dev->dev, "clear RTS\n");
> +	}
> +
> +	if (set & TIOCM_DTR) {
> +		urb_value |= UART_MCR_DTR;
> +		dev_dbg(&dev->dev, "set DTR\n");
> +	}
> +
> +	if (set & TIOCM_RTS) {
> +		urb_value |= UART_MCR_RTS;
> +		dev_dbg(&dev->dev, "set RTS\n");
> +	}

You don't need all those dev_dbg, the one below should suffice.

> +
> +	dev_dbg(&dev->dev, "%s n:%x o:%x\n", __func__, urb_value,
> +			port_priv->line_control);

Use %02x, and it doesn't hurt spelling out "new" and "old".

> +
> +	status = f81232_set_register(dev, MODEM_CONTROL_REGISTER, urb_value);
> +
> +	if (status < 0) {
> +		dev_dbg(&dev->dev, "%s read MSR status < 0\n", __func__);

dev_err, and the error message is incorrect (you're updating MCR).

> +	} else {
> +		spin_lock_irqsave(&port_priv->lock, flags);
> +		port_priv->line_control = urb_value;
> +		spin_unlock_irqrestore(&port_priv->lock, flags);
> +	}
> +
> +	f81232_read_msr(port_priv);

Won't you get an interrupt if MSR changes?

> +
> +	return status;
> +}
> +
>  static void f81232_update_line_status(struct usb_serial_port *port,
>  				      unsigned char *data,
>  				      unsigned int actual_length)
> @@ -261,12 +314,6 @@ static void f81232_process_read_urb(struct urb *urb)
>  
>  }
>  
> -static int set_control_lines(struct usb_device *dev, u8 value)
> -{
> -	/* FIXME - Stubbed out for now */
> -	return 0;
> -}
> -
>  static void f81232_break_ctl(struct tty_struct *tty, int break_state)
>  {
>  	/* FIXME - Stubbed out for now */
> @@ -383,14 +430,35 @@ static void f81232_set_termios(struct tty_struct *tty,
>  
>  static int f81232_tiocmget(struct tty_struct *tty)
>  {
> -	/* FIXME - Stubbed out for now */
> -	return 0;
> +	int r;
> +	struct usb_serial_port *port = tty->driver_data;
> +	struct f81232_private *port_priv = usb_get_serial_port_data(port);
> +	unsigned long flags;
> +	u8 mcr, msr;
> +
> +	spin_lock_irqsave(&port_priv->lock, flags);
> +	mcr = port_priv->line_control;
> +	msr = port_priv->line_status;
> +	spin_unlock_irqrestore(&port_priv->lock, flags);
> +
> +	r = (mcr & UART_MCR_DTR ? TIOCM_DTR : 0) |
> +		(mcr & UART_MCR_RTS ? TIOCM_RTS : 0) |
> +		(msr & UART_MSR_CTS ? TIOCM_CTS : 0) |
> +		(msr & UART_MSR_DCD ? TIOCM_CAR : 0) |
> +		(msr & UART_MSR_RI ? TIOCM_RI : 0) |
> +		(msr & UART_MSR_DSR ? TIOCM_DSR : 0);
> +
> +	return r;
>  }
>  
>  static int f81232_tiocmset(struct tty_struct *tty,
>  			unsigned int set, unsigned int clear)
>  {
> -	/* FIXME - Stubbed out for now */
> +	struct usb_serial_port *port = tty->driver_data;
> +	struct f81232_private *port_priv =
> +		usb_get_serial_port_data(port);
> +
> +	update_mctrl(port_priv, set, clear);

You should return any errors here (after passing it to
usb_translate_error()).

>  	return 0;
>  }
>  
> @@ -427,18 +495,11 @@ static void f81232_close(struct usb_serial_port *port)
>  static void f81232_dtr_rts(struct usb_serial_port *port, int on)
>  {
>  	struct f81232_private *priv = usb_get_serial_port_data(port);
> -	unsigned long flags;
> -	u8 control;
>  
> -	spin_lock_irqsave(&priv->lock, flags);
> -	/* Change DTR and RTS */
>  	if (on)
> -		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
> +		update_mctrl(priv, TIOCM_DTR | TIOCM_RTS, 0);
>  	else
> -		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
> -	control = priv->line_control;
> -	spin_unlock_irqrestore(&priv->lock, flags);
> -	set_control_lines(port->serial->dev, control);
> +		update_mctrl(priv, 0, TIOCM_DTR | TIOCM_RTS);
>  }
>  
>  static int f81232_carrier_raised(struct usb_serial_port *port)

Johan
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