[PATCHv2 0/2] serial: uartps: Make flowcontrol configurable

[PATCHv2 0/2] serial: uartps: Make flowcontrol configurable

[shubhrajyoti.datta]

From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

Add support for nortscts.
To add support for same.
 

Shubhrajyoti Datta (2):
  dt-bindings: xilinx-uartps: Add support for noctsrts
  serial: uartps: Add support for nortscts

 Documentation/devicetree/bindings/serial/cdns,uart.txt |  4 ++++
 drivers/tty/serial/xilinx_uartps.c                     | 12 ++++++++++++
 2 files changed, 16 insertions(+)

-- 
2.1.1

[PATCHv2 1/2] dt-bindings: xilinx-uartps: Add support for noctsrts

[shubhrajyoti.datta]

From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

Vivado has a configurationo for selecting the flow control.
Add a dt binding to check for the same.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
---
 Documentation/devicetree/bindings/serial/cdns,uart.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/cdns,uart.txt b/Documentation/devicetree/bindings/serial/cdns,uart.txt
index 227bb77..5161a05 100644
--- a/Documentation/devicetree/bindings/serial/cdns,uart.txt
+++ b/Documentation/devicetree/bindings/serial/cdns,uart.txt
@@ -12,6 +12,10 @@ Required properties:
   See ../clocks/clock-bindings.txt for details.
 
 
+Optional properties:
+- xlnx,nortscts: The presence of this property indicates that the
+    UART does not support modem lines for RTS/CTS hardware flow control.
+
 Example:
 	uart@e0000000 {
 		compatible = "cdns,uart-r1p8";
-- 
2.1.1

Re: [PATCHv2 1/2] dt-bindings: xilinx-uartps: Add support for noctsrts

[Rob Herring]

On Tue, Apr 02, 2019 at 10:36:17AM +0530, shubhrajyoti.datta@gmail.com wrote:
> From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> 
> Vivado has a configurationo for selecting the flow control.

Vivado is ?

> Add a dt binding to check for the same.
> 
> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> ---
>  Documentation/devicetree/bindings/serial/cdns,uart.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/serial/cdns,uart.txt b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> index 227bb77..5161a05 100644
> --- a/Documentation/devicetree/bindings/serial/cdns,uart.txt
> +++ b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> @@ -12,6 +12,10 @@ Required properties:
>    See ../clocks/clock-bindings.txt for details.
>  
>  
> +Optional properties:
> +- xlnx,nortscts: The presence of this property indicates that the
> +    UART does not support modem lines for RTS/CTS hardware flow control.

We already have 'uart-has-rtscts'. Please use that. Maybe you need a new 
compatible as I'd guess current users assume RTS/CTS is present.

> +
>  Example:
>  	uart@e0000000 {
>  		compatible = "cdns,uart-r1p8";
> -- 
> 2.1.1
> 

Re: [PATCHv2 1/2] dt-bindings: xilinx-uartps: Add support for noctsrts

[Shubhrajyoti Datta]

Hi Rob,
Thanks for  the review.

On Sat, Apr 6, 2019 at 11:36 AM Rob Herring <robh@kernel.org> wrote:
>
> On Tue, Apr 02, 2019 at 10:36:17AM +0530, shubhrajyoti.datta@gmail.com wrote:
> > From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> >
> > Vivado has a configurationo for selecting the flow control.
>
> Vivado is ?
>
> > Add a dt binding to check for the same.
> >
> > Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> > ---
> >  Documentation/devicetree/bindings/serial/cdns,uart.txt | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/serial/cdns,uart.txt b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > index 227bb77..5161a05 100644
> > --- a/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > +++ b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > @@ -12,6 +12,10 @@ Required properties:
> >    See ../clocks/clock-bindings.txt for details.
> >
> >
> > +Optional properties:
> > +- xlnx,nortscts: The presence of this property indicates that the
> > +    UART does not support modem lines for RTS/CTS hardware flow control.
>
> We already have 'uart-has-rtscts'. Please use that. Maybe you need a new
> compatible as I'd guess current users assume RTS/CTS is present.

the setting in vivado (tool helps configure the board) which says no
flowcontrol.
this just keeps the lines in a unknown state.

this issue  with 'uart-has-rtscts'  is  backward compatibility
current code assumes rts / cts is
present. If not preset then it  will return false. So I  thought of
having a property with the inverse.
>
> > +
> >  Example:
> >       uart@e0000000 {
> >               compatible = "cdns,uart-r1p8";
> > --
> > 2.1.1
> >
>

Re: [PATCHv2 1/2] dt-bindings: xilinx-uartps: Add support for noctsrts

[Rob Herring]

On Sun, Apr 7, 2019 at 10:26 PM Shubhrajyoti Datta
<shubhrajyoti.datta@gmail.com> wrote:
>
> Hi Rob,
> Thanks for  the review.
>
> On Sat, Apr 6, 2019 at 11:36 AM Rob Herring <robh@kernel.org> wrote:
> >
> > On Tue, Apr 02, 2019 at 10:36:17AM +0530, shubhrajyoti.datta@gmail.com wrote:
> > > From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> > >
> > > Vivado has a configurationo for selecting the flow control.
> >
> > Vivado is ?
> >
> > > Add a dt binding to check for the same.
> > >
> > > Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> > > ---
> > >  Documentation/devicetree/bindings/serial/cdns,uart.txt | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/serial/cdns,uart.txt b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > > index 227bb77..5161a05 100644
> > > --- a/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > > +++ b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > > @@ -12,6 +12,10 @@ Required properties:
> > >    See ../clocks/clock-bindings.txt for details.
> > >
> > >
> > > +Optional properties:
> > > +- xlnx,nortscts: The presence of this property indicates that the
> > > +    UART does not support modem lines for RTS/CTS hardware flow control.
> >
> > We already have 'uart-has-rtscts'. Please use that. Maybe you need a new
> > compatible as I'd guess current users assume RTS/CTS is present.
>
> the setting in vivado (tool helps configure the board) which says no
> flowcontrol.
> this just keeps the lines in a unknown state.
>
> this issue  with 'uart-has-rtscts'  is  backward compatibility
> current code assumes rts / cts is
> present. If not preset then it  will return false. So I  thought of
> having a property with the inverse.

Searching more, we also have 'cts-override' (in snps-dw-apb-uart.txt).
How about using that? You don't really need to care about RTS as
setting it will just have no effect.

Rob

Re: [PATCHv2 1/2] dt-bindings: xilinx-uartps: Add support for noctsrts

[Shubhrajyoti Datta]

Hi Rob,
Thanks for the review.

On Sat, Apr 6, 2019 at 11:36 AM Rob Herring <robh@kernel.org> wrote:
>
> On Tue, Apr 02, 2019 at 10:36:17AM +0530, shubhrajyoti.datta@gmail.com wrote:
> > From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> >
> > Vivado has a configurationo for selecting the flow control.
>
> Vivado is ?
>
> > Add a dt binding to check for the same.
> >
> > Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
> > ---
> >  Documentation/devicetree/bindings/serial/cdns,uart.txt | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/serial/cdns,uart.txt b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > index 227bb77..5161a05 100644
> > --- a/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > +++ b/Documentation/devicetree/bindings/serial/cdns,uart.txt
> > @@ -12,6 +12,10 @@ Required properties:
> >    See ../clocks/clock-bindings.txt for details.
> >
> >
> > +Optional properties:
> > +- xlnx,nortscts: The presence of this property indicates that the
> > +    UART does not support modem lines for RTS/CTS hardware flow control.
>
> We already have 'uart-has-rtscts'. Please use that. Maybe you need a new
> compatible as I'd guess current users assume RTS/CTS is present.
>
Current behavior is it is with 'uart-has-rtscts . However to keep
backward compatibility.
I added nortscts .

Let me know if we can tackle that or can we change the default behavior?
> > +
> >  Example:
> >       uart@e0000000 {
> >               compatible = "cdns,uart-r1p8";
> > --
> > 2.1.1
> >
>

[PATCHv2 2/2] serial: uartps: Add support for nortscts

[shubhrajyoti.datta]

From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

Having modem control is configurable. Add support for the same by
adding a nortscts property.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
---
 drivers/tty/serial/xilinx_uartps.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 9a7f943..1035339 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -193,6 +193,7 @@ struct cdns_uart {
 	int			id;
 	struct notifier_block	clk_rate_change_nb;
 	u32			quirks;
+	bool nortscts;
 };
 struct cdns_platform_data {
 	u32 quirks;
@@ -1004,6 +1005,11 @@ static void cdns_uart_config_port(struct uart_port *port, int flags)
  */
 static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
 {
+	struct cdns_uart *cdns_uart_data = port->private_data;
+
+	if (cdns_uart_data->nortscts)
+		return 0;
+
 	return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 }
 
@@ -1011,6 +1017,10 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	u32 val;
 	u32 mode_reg;
+	struct cdns_uart *cdns_uart_data = port->private_data;
+
+	if (cdns_uart_data->nortscts)
+		return;
 
 	val = readl(port->membase + CDNS_UART_MODEMCR);
 	mode_reg = readl(port->membase + CDNS_UART_MR);
@@ -1669,6 +1679,8 @@ static int cdns_uart_probe(struct platform_device *pdev)
 		console_port = NULL;
 #endif
 
+	cdns_uart_data->nortscts = of_property_read_bool(pdev->dev.of_node,
+							 "xlnx,uart-nortscts");
 	return 0;
 
 err_out_pm_disable:
-- 
2.1.1