[PATCH 0/2] serial: introduce DSR handling property

[PATCH 0/2] serial: introduce DSR handling property

[Christoph Fritz]

This patchset introduces device-tree property "disable-dsr" including
documentation and usage.

Christoph Fritz (2):
  doc: DT: add generic serial property to disable DSR
  serial: imx: make DSR irq handling conditional

 Documentation/devicetree/bindings/serial/serial.txt | 2 ++
 drivers/tty/serial/imx.c                            | 9 +++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

-- 
2.1.4

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[PATCH 1/2] doc: DT: add generic serial property to disable DSR

[Christoph Fritz]

Introduce a generic serial property to disable DSR events which
can be necessary for buggy hardware.

Signed-off-by: Christoph Fritz <chf.fritz-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
---
 Documentation/devicetree/bindings/serial/serial.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/serial.txt b/Documentation/devicetree/bindings/serial/serial.txt
index fd970f7..26e274e 100644
--- a/Documentation/devicetree/bindings/serial/serial.txt
+++ b/Documentation/devicetree/bindings/serial/serial.txt
@@ -25,6 +25,8 @@ Optional properties:
     Note that this property is mutually-exclusive with "cts-gpios" and
     "rts-gpios" above.
 
+  - disable-dsr: The presence of this property disables DSR events reporting.
+
 
 Examples:
 
-- 
2.1.4

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[PATCH 2/2] serial: imx: make DSR irq handling conditional

[Christoph Fritz]

This patch makes use of device-tree property disable-dsr. Disabling
DSR can be necessary on i.MX6SX to quirk buggy hardware, for more
info see commit 276b891e3879 ("ARM: dts: imx6sx: document SION
necessity of ENET1_REF_CLK1").

Signed-off-by: Christoph Fritz <chf.fritz-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
---
 drivers/tty/serial/imx.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 0df2b1c..bd85a69a4 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -207,6 +207,7 @@ struct imx_port {
 	unsigned int		dte_mode:1;
 	unsigned int		irda_inv_rx:1;
 	unsigned int		irda_inv_tx:1;
+	unsigned int		dsr:1;
 	unsigned short		trcv_delay; /* transceiver delay */
 	struct clk		*clk_ipg;
 	struct clk		*clk_per;
@@ -1219,7 +1220,8 @@ static int imx_startup(struct uart_port *port)
 	/*
 	 * Finally, clear and enable interrupts
 	 */
-	writel(USR1_RTSD | USR1_DTRD, sport->port.membase + USR1);
+	temp = USR1_RTSD | (sport->dsr ? USR1_DTRD : 0);
+	writel(temp, sport->port.membase + USR1);
 	writel(USR2_ORE, sport->port.membase + USR2);
 
 	if (sport->dma_is_inited && !sport->dma_is_enabled)
@@ -1259,7 +1261,7 @@ static int imx_startup(struct uart_port *port)
 		 * now, too.
 		 */
 		temp |= IMX21_UCR3_RXDMUXSEL | UCR3_ADNIMP |
-			UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
+			(sport->dsr ? UCR3_DTRDEN : 0) | UCR3_RI | UCR3_DCD;
 
 		if (sport->dte_mode)
 			temp &= ~(UCR3_RI | UCR3_DCD);
@@ -1987,6 +1989,9 @@ static int serial_imx_probe_dt(struct imx_port *sport,
 	if (of_get_property(np, "fsl,dte-mode", NULL))
 		sport->dte_mode = 1;
 
+	if (!of_property_read_bool(np, "disable-dsr"))
+		sport->dsr = 1;
+
 	return 0;
 }
 #else
-- 
2.1.4

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Re: [PATCH 0/2] serial: introduce DSR handling property

[Uwe Kleine-König]

On Tue, Nov 22, 2016 at 06:14:09PM +0100, Christoph Fritz wrote:
> This patchset introduces device-tree property "disable-dsr" including
> documentation and usage.
> 
> Christoph Fritz (2):
>   doc: DT: add generic serial property to disable DSR

I'd add the documentation for all handshaking lines, not only dsr. And
I'd call it disable-hw-dsr, otherwise

	{
		disable-dsr;
		dsr-gpios = <&gpio1 2 GPIO_ACTIVE_LOW>;
	}

looks strange. (Not 100% sure this would make sense, but I think it
does.)

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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