* [PATCH v3 0/2] Implement support for inverted serial TX/RX on i.MX
@ 2020-02-12 16:35 George Hilliard
2020-02-12 16:35 ` [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
2020-02-12 16:35 ` [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
0 siblings, 2 replies; 5+ messages in thread
From: George Hilliard @ 2020-02-12 16:35 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: George Hilliard, linux-serial, devicetree, NXP Linux Team, kernel
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.
Revision 3 sets *and* clears the bit as necessary during startup. It
also moves init before transmit is enabled.
George Hilliard (2):
dt-bindings: serial: document fsl,inverted-tx and -rx options
tty: imx serial: Implement support for reversing TX and RX polarity
.../bindings/serial/fsl-imx-uart.txt | 4 +++
drivers/tty/serial/imx.c | 29 +++++++++++++++----
2 files changed, 27 insertions(+), 6 deletions(-)
--
2.25.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options
2020-02-12 16:35 [PATCH v3 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
@ 2020-02-12 16:35 ` George Hilliard
2020-02-18 23:07 ` Rob Herring
2020-02-12 16:35 ` [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
1 sibling, 1 reply; 5+ messages in thread
From: George Hilliard @ 2020-02-12 16:35 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: George Hilliard, linux-serial, devicetree, NXP Linux Team, kernel
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>
---
v1..v2: Removed confidentiality spam
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
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
2020-02-12 16:35 [PATCH v3 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
2020-02-12 16:35 ` [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
@ 2020-02-12 16:35 ` George Hilliard
2020-02-12 20:47 ` Uwe Kleine-König
1 sibling, 1 reply; 5+ messages in thread
From: George Hilliard @ 2020-02-12 16:35 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: George Hilliard, linux-serial, devicetree, NXP Linux Team, kernel
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>
---
v1..v2: Remove confidentiality spam
v2..v3: Set *and* clear register, and do it before TX enable
drivers/tty/serial/imx.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 0c6c63166250..205627bcad66 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)
@@ -1390,8 +1392,22 @@ 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;
+ else
+ ucr4 &= ~UCR4_INVR;
imx_uart_writel(sport, ucr4, UCR4);
+ /*
+ * configure tx polarity before enabling tx
+ */
+ ucr3 = imx_uart_readl(sport, UCR3);
+ if (sport->inverted_tx)
+ ucr3 |= UCR3_INVT;
+ else
+ ucr3 &= ~UCR3_INVT;
+ imx_uart_writel(sport, ucr3, UCR3);
+
ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
ucr2 |= (UCR2_RXEN | UCR2_TXEN);
if (!sport->have_rtscts)
@@ -1405,10 +1421,6 @@ static int imx_uart_startup(struct uart_port *port)
imx_uart_writel(sport, ucr2, UCR2);
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)
@@ -2184,6 +2196,12 @@ 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
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
2020-02-12 16:35 ` [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
@ 2020-02-12 20:47 ` Uwe Kleine-König
0 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-12 20:47 UTC (permalink / raw)
To: George Hilliard
Cc: Greg Kroah-Hartman, linux-serial, devicetree, NXP Linux Team, kernel
On Wed, Feb 12, 2020 at 10:35:38AM -0600, George Hilliard wrote:
> 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>
> ---
> v1..v2: Remove confidentiality spam
> v2..v3: Set *and* clear register, and do it before TX enable
>
> drivers/tty/serial/imx.c | 28 +++++++++++++++++++++++-----
> 1 file changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 0c6c63166250..205627bcad66 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)
> @@ -1390,8 +1392,22 @@ 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;
> + else
> + ucr4 &= ~UCR4_INVR;
Maybe clear UCR4_INVR in the same way as UCR4_OREN is cleared just
above?
> imx_uart_writel(sport, ucr4, UCR4);
>
> + /*
> + * configure tx polarity before enabling tx
> + */
> + ucr3 = imx_uart_readl(sport, UCR3);
> + if (sport->inverted_tx)
> + ucr3 |= UCR3_INVT;
> + else
> + ucr3 &= ~UCR3_INVT;
> + imx_uart_writel(sport, ucr3, UCR3);
> +
> ucr2 = imx_uart_readl(sport, UCR2) & ~UCR2_ATEN;
> ucr2 |= (UCR2_RXEN | UCR2_TXEN);
> if (!sport->have_rtscts)
> @@ -1405,10 +1421,6 @@ static int imx_uart_startup(struct uart_port *port)
> imx_uart_writel(sport, ucr2, UCR2);
>
> if (!imx_uart_is_imx1(sport)) {
If this complete if block would be moved up, you only need to write this
register once.
> - u32 ucr3;
> -
> - ucr3 = imx_uart_readl(sport, UCR3);
> -
> ucr3 |= UCR3_DTRDEN | UCR3_RI | UCR3_DCD;
>
> if (sport->dte_mode)
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options
2020-02-12 16:35 ` [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
@ 2020-02-18 23:07 ` Rob Herring
0 siblings, 0 replies; 5+ messages in thread
From: Rob Herring @ 2020-02-18 23:07 UTC (permalink / raw)
To: George Hilliard
Cc: Greg Kroah-Hartman, George Hilliard, linux-serial, devicetree,
NXP Linux Team, kernel
On Wed, 12 Feb 2020 10:35:37 -0600, George Hilliard wrote:
> 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>
> ---
> v1..v2: Removed confidentiality spam
>
> Documentation/devicetree/bindings/serial/fsl-imx-uart.txt | 4 ++++
> 1 file changed, 4 insertions(+)
>
Reviewed-by: Rob Herring <robh@kernel.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-02-18 23:07 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-12 16:35 [PATCH v3 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
2020-02-12 16:35 ` [PATCH v3 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
2020-02-18 23:07 ` Rob Herring
2020-02-12 16:35 ` [PATCH v3 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
2020-02-12 20:47 ` Uwe Kleine-König
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).