[PATCH v3 0/2] support 8250-mtk uart in-band wake up

[PATCH v3 0/2] support 8250-mtk uart in-band wake up

[Claire Chang]

changes in v3:
	1. remove an extra line in patch 2/2

changes in v2:
	1. add commit message
	2. drop return err in the resume path
	3. ignore disable_irq_wake()'s return value

Claire Chang (2):
  dt-bindings: serial: add documentation for Rx in-band wakeup support
  uart: mediatek: support Rx in-band wakeup

 .../devicetree/bindings/serial/mtk-uart.txt   | 13 ++++++++--
 drivers/tty/serial/8250/8250_mtk.c            | 24 +++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

-- 
2.22.0.rc1.257.g3120a18244-goog

[PATCH v3 1/2] dt-bindings: serial: add documentation for Rx in-band wakeup support

[Claire Chang]

To support Rx in-band wakeup, one must create an interrupt specifier with
edge sensitivity on Rx pin and an addtional pinctrl to reconfigure Rx pin
to normal GPIO in sleep state. Driver will switch to sleep mode pinctrl and
enable irq wake before suspend and restore to default settings when
resuming.

Signed-off-by: Claire Chang <tientzu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 .../devicetree/bindings/serial/mtk-uart.txt         | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
index c6b5262eb352..11966de2a4b3 100644
--- a/Documentation/devicetree/bindings/serial/mtk-uart.txt
+++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
@@ -23,7 +23,12 @@ Required properties:
 
 - reg: The base address of the UART register bank.
 
-- interrupts: A single interrupt specifier.
+- interrupts or interrupts-extended:
+  index 0: an interrupt specifier for the UART controller itself
+  index 1: optional, an interrupt specifier with edge sensitivity on Rx pin to
+           support Rx in-band wake up. If one would like to use this feature,
+           one must create an addtional pinctrl to reconfigure Rx pin to normal
+           GPIO before suspend.
 
 - clocks : Must contain an entry for each entry in clock-names.
   See ../clocks/clock-bindings.txt for details.
@@ -39,7 +44,11 @@ Example:
 	uart0: serial@11006000 {
 		compatible = "mediatek,mt6589-uart", "mediatek,mt6577-uart";
 		reg = <0x11006000 0x400>;
-		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
+		interrupts-extended = <&sysirq GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>,
+				      <&gpio 121 IRQ_TYPE_EDGE_FALLING>;
 		clocks = <&uart_clk>, <&bus_clk>;
 		clock-names = "baud", "bus";
+		pinctrl-names = "default", "sleep";
+		pinctrl-0 = <&uart_pin>;
+		pinctrl-1 = <&uart_pin_sleep>;
 	};
-- 
2.22.0.rc1.257.g3120a18244-goog

Re: [PATCH v3 1/2] dt-bindings: serial: add documentation for Rx in-band wakeup support

[Claire Chang]

(cc-ed device tree maintainers and mailing list)

The second patch in this series[1] is already in tty-next[2].

Sorry for not cc-ing device tree maintainers/mailing list at the beginning.
I can resend this patch if needed.

Thanks.

[1] https://patchwork.kernel.org/patch/10962299/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/log/?h=tty-testing

Re: [PATCH v3 1/2] dt-bindings: serial: add documentation for Rx in-band wakeup support

[Greg KH]

On Tue, Jun 11, 2019 at 05:53:54PM +0800, Claire Chang wrote:
> (cc-ed device tree maintainers and mailing list)
> 
> The second patch in this series[1] is already in tty-next[2].
> 
> Sorry for not cc-ing device tree maintainers/mailing list at the beginning.
> I can resend this patch if needed.

Please do, as it is not here for them to review :(

greg k-h

Re: [PATCH v3 1/2] dt-bindings: serial: add documentation for Rx in-band wakeup support

[Claire Chang]

resent here: https://patchwork.ozlabs.org/patch/1113768/
sorry for the inconvenience

[PATCH v3 2/2] uart: mediatek: support Rx in-band wakeup

[Claire Chang]

In order to support Rx in-band wakeup, we need to enable irq wake on an
edge sensitive interrupt of Rx pin before suspend and disable it when
resuming.

This interrupt is used only as wake source to resume the system when
suspended. Note that the sent character will be lost as the controller is
actually suspended.

We use this to support wakeup on bluetooth. Bluetooth will repeatedly send
0xFD to wakeup host. Once host detects Rx falling, an interrupt is
triggered, and the system leaves sleep state. Then, the bluetooth driver
will send 0xFC to bluetooth and bluetooth can start to send normal HCI
packets.

Signed-off-by: Claire Chang <tientzu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---
 drivers/tty/serial/8250/8250_mtk.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 417c7c810df9..5b94b853387d 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/serial_8250.h>
@@ -70,6 +71,7 @@ struct mtk8250_data {
 #ifdef CONFIG_SERIAL_8250_DMA
 	enum dma_rx_status	rx_status;
 #endif
+	int			rx_wakeup_irq;
 };
 
 /* flow control mode */
@@ -551,6 +553,8 @@ static int mtk8250_probe(struct platform_device *pdev)
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
+	data->rx_wakeup_irq = platform_get_irq(pdev, 1);
+
 	return 0;
 }
 
@@ -572,15 +576,35 @@ static int mtk8250_remove(struct platform_device *pdev)
 static int __maybe_unused mtk8250_suspend(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
+	int irq = data->rx_wakeup_irq;
+	int err;
 
 	serial8250_suspend_port(data->line);
 
+	pinctrl_pm_select_sleep_state(dev);
+	if (irq >= 0) {
+		err = enable_irq_wake(irq);
+		if (err) {
+			dev_err(dev,
+				"failed to enable irq wake on IRQ %d: %d\n",
+				irq, err);
+			pinctrl_pm_select_default_state(dev);
+			serial8250_resume_port(data->line);
+			return err;
+		}
+	}
+
 	return 0;
 }
 
 static int __maybe_unused mtk8250_resume(struct device *dev)
 {
 	struct mtk8250_data *data = dev_get_drvdata(dev);
+	int irq = data->rx_wakeup_irq;
+
+	if (irq >= 0)
+		disable_irq_wake(irq);
+	pinctrl_pm_select_default_state(dev);
 
 	serial8250_resume_port(data->line);
 
-- 
2.22.0.rc1.257.g3120a18244-goog

Re: [PATCH v3 2/2] uart: mediatek: support Rx in-band wakeup

[Nicolas Boichat]

On Mon, May 27, 2019 at 4:32 PM Claire Chang <tientzu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
>
> In order to support Rx in-band wakeup, we need to enable irq wake on an
> edge sensitive interrupt of Rx pin before suspend and disable it when
> resuming.
>
> This interrupt is used only as wake source to resume the system when
> suspended. Note that the sent character will be lost as the controller is
> actually suspended.
>
> We use this to support wakeup on bluetooth. Bluetooth will repeatedly send
> 0xFD to wakeup host. Once host detects Rx falling, an interrupt is
> triggered, and the system leaves sleep state. Then, the bluetooth driver
> will send 0xFC to bluetooth and bluetooth can start to send normal HCI
> packets.
>
> Signed-off-by: Claire Chang <tientzu-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Reviewed-by: Nicolas Boichat <drinkcat-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

> ---
>  drivers/tty/serial/8250/8250_mtk.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
> index 417c7c810df9..5b94b853387d 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -10,6 +10,7 @@
>  #include <linux/module.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
> +#include <linux/pinctrl/consumer.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/serial_8250.h>
> @@ -70,6 +71,7 @@ struct mtk8250_data {
>  #ifdef CONFIG_SERIAL_8250_DMA
>         enum dma_rx_status      rx_status;
>  #endif
> +       int                     rx_wakeup_irq;
>  };
>
>  /* flow control mode */
> @@ -551,6 +553,8 @@ static int mtk8250_probe(struct platform_device *pdev)
>         pm_runtime_set_active(&pdev->dev);
>         pm_runtime_enable(&pdev->dev);
>
> +       data->rx_wakeup_irq = platform_get_irq(pdev, 1);
> +
>         return 0;
>  }
>
> @@ -572,15 +576,35 @@ static int mtk8250_remove(struct platform_device *pdev)
>  static int __maybe_unused mtk8250_suspend(struct device *dev)
>  {
>         struct mtk8250_data *data = dev_get_drvdata(dev);
> +       int irq = data->rx_wakeup_irq;
> +       int err;
>
>         serial8250_suspend_port(data->line);
>
> +       pinctrl_pm_select_sleep_state(dev);
> +       if (irq >= 0) {
> +               err = enable_irq_wake(irq);
> +               if (err) {
> +                       dev_err(dev,
> +                               "failed to enable irq wake on IRQ %d: %d\n",
> +                               irq, err);
> +                       pinctrl_pm_select_default_state(dev);
> +                       serial8250_resume_port(data->line);
> +                       return err;
> +               }
> +       }
> +
>         return 0;
>  }
>
>  static int __maybe_unused mtk8250_resume(struct device *dev)
>  {
>         struct mtk8250_data *data = dev_get_drvdata(dev);
> +       int irq = data->rx_wakeup_irq;
> +
> +       if (irq >= 0)
> +               disable_irq_wake(irq);
> +       pinctrl_pm_select_default_state(dev);
>
>         serial8250_resume_port(data->line);
>
> --
> 2.22.0.rc1.257.g3120a18244-goog
>