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* [PATCH 0/2] Implement support for inverted serial TX/RX on i.MX
@ 2020-02-10 17:49 George Hilliard
  2020-02-10 17:49 ` [PATCH 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
  2020-02-10 17:49 ` [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
  0 siblings, 2 replies; 6+ messages in thread
From: George Hilliard @ 2020-02-10 17:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman, linux-serial, devicetree

This peripheral has dedicated control bits that flip input/output
signals before handing them off to the OS.  This is useful on my
hardware because the UART is connected to an RS-422 transceiver with the
+/- pins hooked up backward.  Instead of a hack flipping all the bits
before sending them, the hardware can do it for free.



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^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options
  2020-02-10 17:49 [PATCH 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
@ 2020-02-10 17:49 ` George Hilliard
  2020-02-10 17:49 ` [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
  1 sibling, 0 replies; 6+ messages in thread
From: George Hilliard @ 2020-02-10 17:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman, linux-serial, devicetree; +Cc: George Hilliard

Add a description for the new fsl,inverted-tx and fsl,inverted-rx
options for the i.MX UART peripheral.

Signed-off-by: George Hilliard <ghilliard@kopismobile.com>
---
 Documentation/devicetree/bindings/serial/fsl-imx-uart.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
index 35957cbf1571..c8d677f9491f 100644
--- a/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
+++ b/Documentation/devicetree/bindings/serial/fsl-imx-uart.txt
@@ -8,6 +8,10 @@ Required properties:
 Optional properties:
 - fsl,dte-mode : Indicate the uart works in DTE mode. The uart works
                   in DCE mode by default.
+- fsl,inverted-tx , fsl,inverted-rx : Indicate that the hardware attached
+  to the peripheral inverts the signal transmitted or received,
+  respectively, and that the peripheral should invert its output/input
+  using the INVT/INVR registers.
 - rs485-rts-delay, rs485-rts-active-low, rs485-rx-during-tx,
   linux,rs485-enabled-at-boot-time: see rs485.txt. Note that for RS485
   you must enable either the "uart-has-rtscts" or the "rts-gpios"
-- 
2.25.0


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you are not the intended recipient, please contact the sender and delete 
all copies without reading, printing, or saving.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
  2020-02-10 17:49 [PATCH 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
  2020-02-10 17:49 ` [PATCH 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
@ 2020-02-10 17:49 ` George Hilliard
  2020-02-10 18:11   ` Uwe Kleine-König
  1 sibling, 1 reply; 6+ messages in thread
From: George Hilliard @ 2020-02-10 17:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman, linux-serial, devicetree; +Cc: George Hilliard

The peripheral has support for inverting its input and/or output
signals.  This is useful if the hardware flips polarity of the
peripheral's signal, such as swapped +/- pins on an RS-422 transceiver,
or an inverting level shifter.  Add support for these control registers
via the device tree binding.

Signed-off-by: George Hilliard <ghilliard@kopismobile.com>
---
 drivers/tty/serial/imx.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 0c6c63166250..467e78794997 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -195,6 +195,8 @@ struct imx_port {
 	unsigned int		have_rtscts:1;
 	unsigned int		have_rtsgpio:1;
 	unsigned int		dte_mode:1;
+	unsigned int		inverted_tx:1;
+	unsigned int		inverted_rx:1;
 	struct clk		*clk_ipg;
 	struct clk		*clk_per;
 	const struct imx_uart_data *devdata;
@@ -1335,7 +1337,7 @@ static int imx_uart_startup(struct uart_port *port)
 	int retval, i;
 	unsigned long flags;
 	int dma_is_inited = 0;
-	u32 ucr1, ucr2, ucr4;
+	u32 ucr1, ucr2, ucr3, ucr4;
 
 	retval = clk_prepare_enable(sport->clk_per);
 	if (retval)
@@ -1390,6 +1392,8 @@ static int imx_uart_startup(struct uart_port *port)
 	ucr4 = imx_uart_readl(sport, UCR4) & ~UCR4_OREN;
 	if (!sport->dma_is_enabled)
 		ucr4 |= UCR4_OREN;
+	if (sport->inverted_rx)
+		ucr4 |= UCR4_INVR;
 	imx_uart_writel(sport, ucr4, UCR4);
 
 	ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
@@ -1404,19 +1408,17 @@ static int imx_uart_startup(struct uart_port *port)
 		ucr2 &= ~UCR2_RTSEN;
 	imx_uart_writel(sport, ucr2, UCR2);
 
+	ucr3 = imx_uart_readl(sport, UCR3);
+	if (sport->inverted_tx)
+		ucr3 |= UCR3_INVT;
 	if (!imx_uart_is_imx1(sport)) {
-		u32 ucr3;
-
-		ucr3 = imx_uart_readl(sport, UCR3);
-
 		ucr3 |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
 
 		if (sport->dte_mode)
 			/* disable broken interrupts */
 			ucr3 &= ~(UCR3_RI | UCR3_DCD);
-
-		imx_uart_writel(sport, ucr3, UCR3);
 	}
+	imx_uart_writel(sport, ucr3, UCR3);
 
 	/*
 	 * Enable modem status interrupts
@@ -2184,6 +2186,12 @@ static int imx_uart_probe_dt(struct imx_port *sport,
 	if (of_get_property(np, "rts-gpios", NULL))
 		sport->have_rtsgpio = 1;
 
+	if (of_get_property(np, "fsl,inverted-tx", NULL))
+		sport->inverted_tx = 1;
+
+	if (of_get_property(np, "fsl,inverted-rx", NULL))
+		sport->inverted_rx = 1;
+
 	return 0;
 }
 #else
-- 
2.25.0


-- 
CONFIDENTIALITY NOTICE: This email and any attachments are for the sole use 
of the intended recipient and may contain material that is proprietary, 
confidential, privileged or otherwise legally protected or restricted under 
applicable government laws. Any review, disclosure, distributing or other 
use without expressed permission of the sender is strictly prohibited. If 
you are not the intended recipient, please contact the sender and delete 
all copies without reading, printing, or saving.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
  2020-02-10 17:49 ` [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
@ 2020-02-10 18:11   ` Uwe Kleine-König
  2020-02-10 18:38     ` George Hilliard
  0 siblings, 1 reply; 6+ messages in thread
From: Uwe Kleine-König @ 2020-02-10 18:11 UTC (permalink / raw)
  To: George Hilliard
  Cc: Greg Kroah-Hartman, linux-serial, devicetree, kernel, NXP Linux Team

Hello George,

expanding Cc: a bit

On Mon, Feb 10, 2020 at 11:49:42AM -0600, George Hilliard wrote:
> CONFIDENTIALITY NOTICE: This email and any attachments are for the sole use 
> of the intended recipient and may contain material that is proprietary, 
> confidential, privileged or otherwise legally protected or restricted under 
> applicable government laws. Any review, disclosure, distributing or other 
> use without expressed permission of the sender is strictly prohibited. If 
> you are not the intended recipient, please contact the sender and delete 
> all copies without reading, printing, or saving.

Hmm, sad, I would have had some review feedback that should be addressed
before application of the patch. As I only noticed the footer after
looking at the patch, it was already too late to stop me reviewing it.
As I don't have an expressed permission I will at least not share it
(and I expect that Greg will also refuse to apply a patch with such a
footer).

:-|
Uwe

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

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
  2020-02-10 18:11   ` Uwe Kleine-König
@ 2020-02-10 18:38     ` George Hilliard
  2020-02-10 21:16       ` Uwe Kleine-König
  0 siblings, 1 reply; 6+ messages in thread
From: George Hilliard @ 2020-02-10 18:38 UTC (permalink / raw)
  To: Uwe Kleine-König
  Cc: Greg Kroah-Hartman, linux-serial, devicetree, kernel, NXP Linux Team

On Mon, Feb 10, 2020 at 12:11 PM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
> On Mon, Feb 10, 2020 at 11:49:42AM -0600, George Hilliard wrote:
> > (confidentiality spam)
>
> Hmm, sad, I would have had some review feedback that should be addressed
> before application of the patch. As I only noticed the footer after
> looking at the patch, it was already too late to stop me reviewing it.
> As I don't have an expressed permission I will at least not share it
> (and I expect that Greg will also refuse to apply a patch with such a
> footer).
>
This is fixed now. Apologies - added without my knowledge. Should I
simply resend a v2 without the notice?  Happy to CC everyone else you
included.

George

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
  2020-02-10 18:38     ` George Hilliard
@ 2020-02-10 21:16       ` Uwe Kleine-König
  0 siblings, 0 replies; 6+ messages in thread
From: Uwe Kleine-König @ 2020-02-10 21:16 UTC (permalink / raw)
  To: George Hilliard
  Cc: Greg Kroah-Hartman, linux-serial, devicetree, kernel, NXP Linux Team

Hi George,

On Mon, Feb 10, 2020 at 12:38:59PM -0600, George Hilliard wrote:
> On Mon, Feb 10, 2020 at 12:11 PM Uwe Kleine-König
> <u.kleine-koenig@pengutronix.de> wrote:
> > On Mon, Feb 10, 2020 at 11:49:42AM -0600, George Hilliard wrote:
> > > (confidentiality spam)
> >
> > Hmm, sad, I would have had some review feedback that should be addressed
> > before application of the patch. As I only noticed the footer after
> > looking at the patch, it was already too late to stop me reviewing it.
> > As I don't have an expressed permission I will at least not share it
> > (and I expect that Greg will also refuse to apply a patch with such a
> > footer).
>
> This is fixed now. Apologies - added without my knowledge. Should I
> simply resend a v2 without the notice?  Happy to CC everyone else you
> included.

You did it right. (i.e. yes, resend without the notice is the right
thing.)

Best regards
Uwe

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

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-10 17:49 [PATCH 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
2020-02-10 17:49 ` [PATCH 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
2020-02-10 17:49 ` [PATCH 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
2020-02-10 18:11   ` Uwe Kleine-König
2020-02-10 18:38     ` George Hilliard
2020-02-10 21:16       ` Uwe Kleine-König

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