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Date: Tue, 17 Feb 2015 16:40:33 +0700
From: Johan Hovold <johan@...nel.org>
To: Peter Hung <hpeter@...il.com>
Cc: johan@...nel.org, gregkh@...uxfoundation.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
tom_tsai@...tek.com.tw, peter_hong@...tek.com.tw,
Peter Hung <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH V6 05/10] USB: f81232: implement MCR/MSR function
On Mon, Feb 16, 2015 at 03:57:57PM +0800, Peter Hung wrote:
> This patch implement relative MCR/MSR function, such like
> tiocmget()/tiocmset()/dtr_rts().
>
> The f81232_set_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@...il.com>
> ---
> drivers/usb/serial/f81232.c | 98 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 77 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 06d1eb0..e1cdf42 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -44,6 +44,7 @@ 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)
>
> #define CONTROL_DTR 0x01
> @@ -156,6 +157,50 @@ static void f81232_read_msr(struct usb_serial_port *port)
> wake_up_interruptible(&port->port.delta_msr_wait);
> }
>
> +static int f81232_set_mctrl(struct usb_serial_port *port,
> + unsigned int set, unsigned int clear)
> +{
> + u8 urb_value;
> + int status;
> + unsigned long flags;
> + struct f81232_private *priv = usb_get_serial_port_data(port);
> +
> + if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0)
> + return 0; /* no change */
> +
> + /* 'set' takes precedence over 'clear' */
> + clear &= ~set;
> +
> + /* force enable interrupt with OUT2 */
> + urb_value = UART_MCR_OUT2 | priv->line_control;
You should rename this one priv->modem_control.
And what about locking above?
> +
> + if (clear & TIOCM_DTR)
> + urb_value &= ~UART_MCR_DTR;
> +
> + if (clear & TIOCM_RTS)
> + urb_value &= ~UART_MCR_RTS;
> +
> + if (set & TIOCM_DTR)
> + urb_value |= UART_MCR_DTR;
> +
> + if (set & TIOCM_RTS)
> + urb_value |= UART_MCR_RTS;
> +
> + dev_dbg(&port->dev, "%s new:%02x old:%02x\n", __func__,
> + urb_value, priv->line_control);
> +
> + status = f81232_set_register(port, MODEM_CONTROL_REGISTER, urb_value);
> + if (status < 0) {
> + dev_err(&port->dev, "%s set MCR status < 0\n", __func__);
Return here on errors and skip the else branch.
> + } else {
> + spin_lock_irqsave(&priv->lock, flags);
> + priv->line_control = urb_value;
> + spin_unlock_irqrestore(&priv->lock, flags);
It looks like you could replace the private spin lock with a mutex and
protect all accesses to MCR and MSR using it.
> + }
> +
> + return status;
Return 0;
> +}
> +
> static void f81232_update_modem_status(struct usb_serial_port *port,
> unsigned char *data,
> unsigned int actual_length)
> @@ -267,12 +312,6 @@ static void f81232_process_read_urb(struct urb *urb)
> tty_flip_buffer_push(&port->port);
> }
>
> -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 */
> @@ -388,15 +427,41 @@ 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;
> +
> + /* force get current MSR changed state */
> + f81232_read_msr(port);
> +
> + spin_lock_irqsave(&port_priv->lock, flags);
> + mcr = port_priv->line_control;
> + msr = port_priv->modem_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 */
> - return 0;
> + int status;
> + struct usb_serial_port *port = tty->driver_data;
> +
> + status = f81232_set_mctrl(port, set, clear);
> + if (status < 0)
> + return usb_translate_errors(status);
> + else
> + return 0;
Remove the else branch and just return 0 at the end.
Johan
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