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[PATCH v2 00/10] serial: st-asc: Allow handling of RTS line

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  [PATCH v2 00/10] serial: st-asc: Allow handling of RTS line Lee Jones <lee.jones@linaro.org> - 2017-02-01 15:40 +0100
    [PATCH v2 04/10] serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles Lee Jones <lee.jones@linaro.org> - 2017-02-01 15:40 +0100
    [PATCH v2 08/10] ARM: dts: STiH407-pinctrl: Add Pinctrl group for HW flow-control Lee Jones <lee.jones@linaro.org> - 2017-02-01 15:40 +0100
    [PATCH v2 03/10] serial: st-asc: Read in all Pinctrl states Lee Jones <lee.jones@linaro.org> - 2017-02-01 15:40 +0100
      Re: [STLinux Kernel] [PATCH v2 03/10] serial: st-asc: Read in all  Pinctrl states Peter Griffin <peter.griffin@linaro.org> - 2017-02-01 16:00 +0100
    Re: [PATCH v2 00/10] serial: st-asc: Allow handling of RTS line Greg KH <gregkh@linuxfoundation.org> - 2017-02-03 10:20 +0100
      Re: [PATCH v2 00/10] serial: st-asc: Allow handling of RTS line Lee Jones <lee.jones@linaro.org> - 2017-02-03 11:20 +0100

#1571597 — [PATCH v2 00/10] serial: st-asc: Allow handling of RTS line

When hardware flow-control is disabled, manual toggling of the UART's
reset line (RTS) using userland applications (e.g. stty) is not
possible, since the ASC IP does not provide this functionality in the
same was as some other IPs do.  Thus, we have to do this manually.

This set ensures the correct Pinctrl groups are configured and
obtained for both manual toggling of the RTS line and for the IP to
take over the lines when HW flow-control is requested by the user.

Lee Jones (10):
  serial: st-asc: Ignore the parity error bit if 8-bit mode is enabled
  serial: st-asc: Provide RTS functionality
  serial: st-asc: Read in all Pinctrl states
  serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles
  serial: st-asc: Use generic DT binding for announcing RTS/CTS lines
  dt-bindings: serial: Update 'uart-has-rtscts' description
  ARM: dts: STiH410-b2260: Identify the UART RTS line
  ARM: dts: STiH407-pinctrl: Add Pinctrl group for HW flow-control
  ARM: dts: STiH407-family: Use new Pinctrl groups
  ARM: dts: STiH410-b2260: Enable HW flow-control

 .../devicetree/bindings/serial/serial.txt          |   3 +-
 arch/arm/boot/dts/stih407-family.dtsi              |   3 +-
 arch/arm/boot/dts/stih407-pinctrl.dtsi             |  12 ++-
 arch/arm/boot/dts/stih410-b2260.dts                |   5 +
 drivers/tty/serial/st-asc.c                        | 101 +++++++++++++++++++--
 5 files changed, 110 insertions(+), 14 deletions(-)

-- 
2.9.3

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#1571602 — [PATCH v2 04/10] serial: st-asc: (De)Register GPIOD and swap Pinctrl profiles

When hardware flow-control is disabled, manual toggling of the UART's
reset line (RTS) using userland applications (e.g. stty) is not
possible, since the ASC IP does not provide this functionality in the
same was as some other IPs do.  Thus, we have to do this manually.

This patch ensures that when HW flow-control is disabled the RTS/CTS
lines are free to be registered via the GPIO API.  It also ensures
any registered GPIO lines are unregistered when HW flow-control is
requested, allowing the IP to control them automatically.

Acked-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/tty/serial/st-asc.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 1058020..e521078 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -513,6 +513,8 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 			    struct ktermios *old)
 {
 	struct asc_port *ascport = to_asc_port(port);
+	struct device_node *np = port->dev->of_node;
+	struct gpio_desc *gpiod;
 	unsigned int baud;
 	u32 ctrl_val;
 	tcflag_t cflag;
@@ -556,9 +558,32 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 		ctrl_val |= ASC_CTL_PARITYODD;
 
 	/* hardware flow control */
-	if ((cflag & CRTSCTS))
+	if ((cflag & CRTSCTS)) {
 		ctrl_val |= ASC_CTL_CTSENABLE;
 
+		/* If flow-control selected, stop handling RTS manually */
+		if (ascport->rts) {
+			devm_gpiod_put(port->dev, ascport->rts);
+			ascport->rts = NULL;
+
+			pinctrl_select_state(ascport->pinctrl,
+					     ascport->states[DEFAULT]);
+		}
+	} else {
+		/* If flow-control disabled, it's safe to handle RTS manually */
+		if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) {
+			pinctrl_select_state(ascport->pinctrl,
+					     ascport->states[NO_HW_FLOWCTRL]);
+
+			gpiod =	devm_get_gpiod_from_child(port->dev, "rts",
+							  &np->fwnode);
+			if (!IS_ERR(gpiod)) {
+				gpiod_direction_output(gpiod, 0);
+				ascport->rts = gpiod;
+			}
+		}
+	}
+
 	if ((baud < 19200) && !ascport->force_m1) {
 		asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud)));
 	} else {
-- 
2.9.3

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#1571604 — [PATCH v2 08/10] ARM: dts: STiH407-pinctrl: Add Pinctrl group for HW flow-control

Each serial port which supports HW flow-control should have 2 Pinctrl
groups.  One for when HW flow-control is in progress, where the IP
will take over controlling the lines and another group which enables
the lines to be toggled using GPIO mechanisms.

Acked-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 arch/arm/boot/dts/stih407-pinctrl.dtsi | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boot/dts/stih407-pinctrl.dtsi b/arch/arm/boot/dts/stih407-pinctrl.dtsi
index daab16b..bd1a82e 100644
--- a/arch/arm/boot/dts/stih407-pinctrl.dtsi
+++ b/arch/arm/boot/dts/stih407-pinctrl.dtsi
@@ -465,8 +465,16 @@
 			serial0 {
 				pinctrl_serial0: serial0-0 {
 					st,pins {
-						tx = <&pio17 0 ALT1 OUT>;
-						rx = <&pio17 1 ALT1 IN>;
+						tx =  <&pio17 0 ALT1 OUT>;
+						rx =  <&pio17 1 ALT1 IN>;
+					};
+				};
+				pinctrl_serial0_hw_flowctrl: serial0-0_hw_flowctrl {
+					st,pins {
+						tx =  <&pio17 0 ALT1 OUT>;
+						rx =  <&pio17 1 ALT1 IN>;
+						cts = <&pio17 2 ALT1 IN>;
+						rts = <&pio17 3 ALT1 OUT>;
 					};
 				};
 			};
-- 
2.9.3

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#1571605 — [PATCH v2 03/10] serial: st-asc: Read in all Pinctrl states

There are now 2 possible separate/different Pinctrl states which can
be provided from platform data.  One which encompasses the lines
required for HW flow-control (CTS/RTS) and another which does not
specify these lines, such that they can be used via GPIO mechanisms
for manually toggling (i.e. from a request by `stty`).

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/tty/serial/st-asc.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index 397df50..1058020 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -18,6 +18,7 @@
 #include <linux/serial.h>
 #include <linux/console.h>
 #include <linux/sysrq.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -37,10 +38,16 @@
 #define ASC_FIFO_SIZE 16
 #define ASC_MAX_PORTS 8
 
+/* Pinctrl states */
+#define DEFAULT		0
+#define NO_HW_FLOWCTRL	1
+
 struct asc_port {
 	struct uart_port port;
 	struct gpio_desc *rts;
 	struct clk *clk;
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *states[2];
 	unsigned int hw_flow_control:1;
 	unsigned int force_m1:1;
 };
@@ -694,6 +701,7 @@ static int asc_init_port(struct asc_port *ascport,
 {
 	struct uart_port *port = &ascport->port;
 	struct resource *res;
+	int ret;
 
 	port->iotype	= UPIO_MEM;
 	port->flags	= UPF_BOOT_AUTOCONF;
@@ -720,6 +728,27 @@ static int asc_init_port(struct asc_port *ascport,
 	WARN_ON(ascport->port.uartclk == 0);
 	clk_disable_unprepare(ascport->clk);
 
+	ascport->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(ascport->pinctrl)) {
+		ret = PTR_ERR(ascport->pinctrl);
+		dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret);
+	}
+
+	ascport->states[DEFAULT] =
+		pinctrl_lookup_state(ascport->pinctrl, "default");
+	if (IS_ERR(ascport->states[DEFAULT])) {
+		ret = PTR_ERR(ascport->states[DEFAULT]);
+		dev_err(&pdev->dev,
+			"Failed to look up Pinctrl state 'default': %d\n", ret);
+		return ret;
+	}
+
+	/* "no-hw-flowctrl" state is optional */
+	ascport->states[NO_HW_FLOWCTRL] =
+		pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl");
+	if (IS_ERR(ascport->states[NO_HW_FLOWCTRL]))
+		ascport->states[NO_HW_FLOWCTRL] = NULL;
+
 	return 0;
 }
 
-- 
2.9.3

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#1571624 — Re: [STLinux Kernel] [PATCH v2 03/10] serial: st-asc: Read in all Pinctrl states

On Wed, 01 Feb 2017, Lee Jones wrote:

> There are now 2 possible separate/different Pinctrl states which can
> be provided from platform data.  One which encompasses the lines
> required for HW flow-control (CTS/RTS) and another which does not
> specify these lines, such that they can be used via GPIO mechanisms
> for manually toggling (i.e. from a request by `stty`).
> 
> Signed-off-by: Lee Jones <lee.jones@linaro.org>

Acked-by: Peter Griffin <peter.griffin@linaro.org>

> ---
>  drivers/tty/serial/st-asc.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
> index 397df50..1058020 100644
> --- a/drivers/tty/serial/st-asc.c
> +++ b/drivers/tty/serial/st-asc.c
> @@ -18,6 +18,7 @@
>  #include <linux/serial.h>
>  #include <linux/console.h>
>  #include <linux/sysrq.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/platform_device.h>
>  #include <linux/io.h>
>  #include <linux/irq.h>
> @@ -37,10 +38,16 @@
>  #define ASC_FIFO_SIZE 16
>  #define ASC_MAX_PORTS 8
>  
> +/* Pinctrl states */
> +#define DEFAULT		0
> +#define NO_HW_FLOWCTRL	1
> +
>  struct asc_port {
>  	struct uart_port port;
>  	struct gpio_desc *rts;
>  	struct clk *clk;
> +	struct pinctrl *pinctrl;
> +	struct pinctrl_state *states[2];
>  	unsigned int hw_flow_control:1;
>  	unsigned int force_m1:1;
>  };
> @@ -694,6 +701,7 @@ static int asc_init_port(struct asc_port *ascport,
>  {
>  	struct uart_port *port = &ascport->port;
>  	struct resource *res;
> +	int ret;
>  
>  	port->iotype	= UPIO_MEM;
>  	port->flags	= UPF_BOOT_AUTOCONF;
> @@ -720,6 +728,27 @@ static int asc_init_port(struct asc_port *ascport,
>  	WARN_ON(ascport->port.uartclk == 0);
>  	clk_disable_unprepare(ascport->clk);
>  
> +	ascport->pinctrl = devm_pinctrl_get(&pdev->dev);
> +	if (IS_ERR(ascport->pinctrl)) {
> +		ret = PTR_ERR(ascport->pinctrl);
> +		dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret);
> +	}
> +
> +	ascport->states[DEFAULT] =
> +		pinctrl_lookup_state(ascport->pinctrl, "default");
> +	if (IS_ERR(ascport->states[DEFAULT])) {
> +		ret = PTR_ERR(ascport->states[DEFAULT]);
> +		dev_err(&pdev->dev,
> +			"Failed to look up Pinctrl state 'default': %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* "no-hw-flowctrl" state is optional */
> +	ascport->states[NO_HW_FLOWCTRL] =
> +		pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl");
> +	if (IS_ERR(ascport->states[NO_HW_FLOWCTRL]))
> +		ascport->states[NO_HW_FLOWCTRL] = NULL;
> +
>  	return 0;
>  }
>  

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#1572962

On Wed, Feb 01, 2017 at 02:31:35PM +0000, Lee Jones wrote:
> When hardware flow-control is disabled, manual toggling of the UART's
> reset line (RTS) using userland applications (e.g. stty) is not
> possible, since the ASC IP does not provide this functionality in the
> same was as some other IPs do.  Thus, we have to do this manually.
> 
> This set ensures the correct Pinctrl groups are configured and
> obtained for both manual toggling of the RTS line and for the IP to
> take over the lines when HW flow-control is requested by the user.

I see 2 series that are listed as "v2", which one to take?

I know, I'll drop both and wait for an updated set with all of the acks
added to them...

Please fix up and resend.

thanks,

greg k-h

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#1573002

On Fri, 03 Feb 2017, Greg KH wrote:

> On Wed, Feb 01, 2017 at 02:31:35PM +0000, Lee Jones wrote:
> > When hardware flow-control is disabled, manual toggling of the UART's
> > reset line (RTS) using userland applications (e.g. stty) is not
> > possible, since the ASC IP does not provide this functionality in the
> > same was as some other IPs do.  Thus, we have to do this manually.
> > 
> > This set ensures the correct Pinctrl groups are configured and
> > obtained for both manual toggling of the RTS line and for the IP to
> > take over the lines when HW flow-control is requested by the user.
> 
> I see 2 series that are listed as "v2", which one to take?

The one which was sent most recently. ;)

> I know, I'll drop both and wait for an updated set with all of the acks
> added to them...

Easy way out. ;)

> Please fix up and resend.

Okay, give me 5.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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