Re: [PATCH 2/2] sc16is7xx: add reading CTS

Re: [PATCH 2/2] sc16is7xx: add reading CTS

[Maarten Brock]

Hello Pascal,

If you look at the history of this driver, you'll see that something similar was
present in the past, but was removed because it introduced problems. The problem
is that you can't just call sc16is7xx_port_read() unsynchronized to the worker
thread. And this is related to the device using indirect access through an I2C
or SPI driver with separate interrupts from the UART. There is also more info on
the linux-serial mailing list.

Kind regards,
Maarten Brock

----- Original Message -----
From: Pascal JEAN [mailto:epsilonrt@gmail.com]
To: Greg KH [mailto:gregkh@linuxfoundation.org]
Cc: jslaby@suse.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Sent: Thu, 28 Jul 2016 09:07:36 +0200
Subject: [PATCH 2/2] sc16is7xx: add reading CTS


> Hi Greg,
> 
> Here are changelog for this patch.
> Best Regards
> 
> Changelog:
> 
> sc16is7xx: add reading CTS
> 
> 	This patch adds the possibility to read the actual
> 	status of the CTS input when RTS/CTS handshaking is
> 	not activated (for general purposes).
> 
> 
> Signed-off-by: Pascal JEAN <epsilonrt@gmail.com>
> ---
>  drivers/tty/serial/sc16is7xx.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
> index 3e65079..8833a18 100644
> --- a/drivers/tty/serial/sc16is7xx.c
> +++ b/drivers/tty/serial/sc16is7xx.c
> @@ -818,10 +818,19 @@ static unsigned int sc16is7xx_tx_empty(struct
> uart_port *port)
> 
>  static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
>  {
> -	/* DCD and DSR are not wired and CTS/RTS is handled automatically
> -	 * so just indicate all inputs asserted
> -	 */
> -	return TIOCM_DSR | TIOCM_CAR | TIOCM_RI | TIOCM_CTS;
> +	/* DCD, DSR and RI are not wired so just indicate asserted */
> +	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_RI;
> +
> +	if (port->status & UPSTAT_CTS_ENABLE)
> +		/* CTS handled automatically, indicates that it is always
> +		 * asserted, this is required for proper management of
> +		 * the upper layer
> +		 */
> +		mctrl |= TIOCM_CTS;
> +	else {
> +		/* CTS is not managed automatically, returns its actual state
> +		 * the upper layer
> +		 */
> +		u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
> +
> +		mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
> +	}
> +	return mctrl;
>  }
> 
>  static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
> -- 
> 2.7.4
> 
> --
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Re: [PATCH 2/2] sc16is7xx: add reading CTS

[Greg KH]

On Thu, Jul 28, 2016 at 09:07:36AM +0200, Pascal JEAN wrote:
> Hi Greg,
> 
> Here are changelog for this patch.
> Best Regards
> 
> Changelog:

<snip>

Um, I can't take this, sorry.  Please re-read
Documentation/SubmittingPatches for how to properly format and send
things, I should not have to hand-edit any files in order to accept a
patch.

Please also version number your patches, with the needed information.
This would have been "v2", I'll expect to see "v3" after this.

Same goes for the other patch in this series.

thanks,

greg k-h

[PATCH 2/2] sc16is7xx: add reading CTS

[Pascal JEAN]

Hi Greg,

Here are changelog for this patch.
Best Regards

Changelog:

sc16is7xx: add reading CTS

	This patch adds the possibility to read the actual
	status of the CTS input when RTS/CTS handshaking is
	not activated (for general purposes).


Signed-off-by: Pascal JEAN <epsilonrt@gmail.com>
---
 drivers/tty/serial/sc16is7xx.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3e65079..8833a18 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -818,10 +818,19 @@ static unsigned int sc16is7xx_tx_empty(struct
uart_port *port)

 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
 {
-	/* DCD and DSR are not wired and CTS/RTS is handled automatically
-	 * so just indicate all inputs asserted
-	 */
-	return TIOCM_DSR | TIOCM_CAR | TIOCM_RI | TIOCM_CTS;
+	/* DCD, DSR and RI are not wired so just indicate asserted */
+	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_RI;
+
+	if (port->status & UPSTAT_CTS_ENABLE)
+		/* CTS handled automatically, indicates that it is always
+		 * asserted, this is required for proper management of
+		 * the upper layer
+		 */
+		mctrl |= TIOCM_CTS;
+	else {
+		/* CTS is not managed automatically, returns its actual state
+		 * the upper layer
+		 */
+		u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
+
+		mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
+	}
+	return mctrl;
 }

 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
-- 
2.7.4

[PATCH 2/2] sc16is7xx: add reading CTS

[Pascal JEAN]

Signed-off-by: Pascal JEAN <epsilonrt@gmail.com>
---
 drivers/tty/serial/sc16is7xx.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3e65079..8833a18 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -818,10 +818,19 @@ static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
 
 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
 {
-	/* DCD and DSR are not wired and CTS/RTS is handled automatically
-	 * so just indicate all inputs asserted
-	 */
-	return TIOCM_DSR | TIOCM_CAR | TIOCM_RI | TIOCM_CTS;
+	/* DCD, DSR and RI are not wired so just indicate asserted */
+	unsigned int mctrl = TIOCM_CAR | TIOCM_DSR | TIOCM_RI;
+
+	if (port->status & UPSTAT_CTS_ENABLE)
+		/* CTS handled automatically, indicates that it is always
+		 * asserted, this is required for proper management of
+		 * the upper layer
+		 */
+		mctrl |= TIOCM_CTS;
+	else {
+		/* CTS is not managed automatically, returns its actual state
+		 * the upper layer
+		 */
+		u8 msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
+
+		mctrl |= (msr & SC16IS7XX_MSR_CTS_BIT) ? TIOCM_CTS : 0;
+	}
+	return mctrl;
 }
 
 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
-- 
2.7.4