Patchwork [1/2] tty: serial: imx: Allow UART to be a source for wakeup

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Submitter Fabio Estevam
Date Dec. 9, 2011, 12:42 p.m.
Message ID <1323434541-27689-1-git-send-email-festevam@gmail.com>
Download mbox | patch
Permalink /patch/130371/
State New
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Comments

Fabio Estevam - Dec. 9, 2011, 12:42 p.m.
Allow UART to be a source for wakeup from low power mode.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 .../bindings/tty/serial/fsl-imx-uart.txt           |    2 +
 arch/arm/plat-mxc/include/mach/imx-uart.h          |    1 +
 drivers/tty/serial/imx.c                           |   35 ++++++++++++++++++++
 3 files changed, 38 insertions(+), 0 deletions(-)
Shawn Guo - Dec. 11, 2011, 6:01 a.m.
On Fri, Dec 09, 2011 at 04:41:05PM -0200, Fabio Estevam wrote:
> Allow UART to be a source for wakeup from low power mode.
> 
> Tested on a MX27PDK by doing:
> 
> echo enabled > /sys/devices/platform/imx21-uart.0/power/wakeup
> 
> echo mem > /sys/power/state
> 
> and then pressing a key in the console will wakeup the sytem.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> Changes since v3:
> - Remove IMXUART_CANWAKE flag. Let userspace write in /sys/ file
> in order to enable UART wakeup source.
> Changes since v2:
> - Remove incorrect enable_irq_wake from serial_imx_resume
> Changes since v1:
> - Pass the can-wake property via DT correctly
>  drivers/tty/serial/imx.c |   24 ++++++++++++++++++++++++
>  1 files changed, 24 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 163fc90..283bf21 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -566,6 +566,9 @@ static irqreturn_t imx_int(int irq, void *dev_id)
>  	if (sts & USR1_RTSD)
>  		imx_rtsint(irq, dev_id);
>  
> +	if (sts & USR1_AWAKE)
> +		writel(USR1_AWAKE, sport->port.membase + USR1);
> +
>  	return IRQ_HANDLED;
>  }
>  
> @@ -1269,6 +1272,15 @@ static struct uart_driver imx_reg = {
>  static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
>  {
>  	struct imx_port *sport = platform_get_drvdata(dev);
> +	unsigned int val;
> +
> +	if (device_may_wakeup(&dev->dev)) {
> +		enable_irq_wake(sport->rxirq);
> +		/* enable wakeup from i.MX UART */
> +		val = readl(sport->port.membase + UCR3);
> +		val |= UCR3_AWAKEN;
> +		writel(val, sport->port.membase + UCR3);
> +	}
>  
>  	if (sport)
>  		uart_suspend_port(&imx_reg, &sport->port);
> @@ -1279,6 +1291,15 @@ static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
>  static int serial_imx_resume(struct platform_device *dev)
>  {
>  	struct imx_port *sport = platform_get_drvdata(dev);
> +	unsigned int val;
> +
> +	if (device_may_wakeup(&dev->dev)) {
> +		/* disable wakeup from i.MX UART */
> +		val = readl(sport->port.membase + UCR3);
> +		val &= ~UCR3_AWAKEN;
> +		writel(val, sport->port.membase + UCR3);
> +		disable_irq_wake(sport->rxirq);
> +	}
>  
>  	if (sport)
>  		uart_resume_port(&imx_reg, &sport->port);
> @@ -1408,6 +1429,9 @@ static int serial_imx_probe(struct platform_device *pdev)
>  		goto deinit;
>  	platform_set_drvdata(pdev, &sport->port);
>  
> +	device_init_wakeup(&pdev->dev, 1);
> +	device_set_wakeup_enable(&pdev->dev, 0);
> +
Rather than calling these two functions, simply calling 

	device_set_wakeup_capable(&pdev->dev, true);

can just do what we want to do here.

Other than that,

Acked-by: Shawn Guo <shawn.guo@linaro.org>

(Tested on i.MX6Q ARM2 board)
Fabio Estevam - Dec. 12, 2011, 6:17 p.m.
On Sun, Dec 11, 2011 at 4:01 AM, Shawn Guo <shawn.guo@freescale.com> wrote:

>> +     device_init_wakeup(&pdev->dev, 1);
>> +     device_set_wakeup_enable(&pdev->dev, 0);
>> +
> Rather than calling these two functions, simply calling
>
>        device_set_wakeup_capable(&pdev->dev, true);
>
> can just do what we want to do here.

Yes, this is correct.

After checking the code it seems to me that  neither of this calls are needed.

serial_core.c already calls:
		device_init_wakeup(tty_dev, 1);
		device_set_wakeup_enable(tty_dev, 0);

and we can see a wakeup entry at:

/sys/devices/platform/imx21-uart.0/tty/ttymxc0/power/wakeup

However, if I send "enabled" to this file the
"if (device_may_wakeup(&dev->dev)" statement is never true.

I am not sure what would be the correct argument for device_may_wakeup
to "see" the original wakeup entry.

Regards,

Fabio Estevam



>
> Other than that,
>
> Acked-by: Shawn Guo <shawn.guo@linaro.org>
>
> (Tested on i.MX6Q ARM2 board)
>
> --
> Regards,
> Shawn
>
Richard Zhao - Dec. 14, 2011, 12:44 a.m.
On Tue, Dec 13, 2011 at 01:23:48AM -0200, Fabio Estevam wrote:
> Allow UART to be a source for wakeup from low power mode.
> 
> Tested on a MX27PDK by doing:
> 
> echo enabled > /sys/devices/platform/imx21-uart.0/tty/ttymxc0/power/wakeup
> 
> echo mem > /sys/power/state
> 
> and then pressing a key in the console will wakeup the sytem.
> 
> Suggested-by: Shawn Guo <shawn.guo@freescale.com>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
For imx6q sabrelite,
Tested-by: Richard Zhao <richard.zhao@freescale.com>
> ---
> Changes since v4:
> - Let serial core handle device_init_wakeup/device_set_wakeup_enable.
> Changes since v3:
> - Remove IMXUART_CANWAKE flag. Let userspace write in /sys/ file
> in order to enable UART wakeup source.
> Changes since v2:
> - Remove incorrect enable_irq_wake from serial_imx_resume
> Changes since v1:
> - Pass the can-wake property via DT correctly
>  drivers/tty/serial/imx.c |   15 +++++++++++++++
>  1 files changed, 15 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 163fc90..0022bbd 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -566,6 +566,9 @@ static irqreturn_t imx_int(int irq, void *dev_id)
>  	if (sts & USR1_RTSD)
>  		imx_rtsint(irq, dev_id);
>  
> +	if (sts & USR1_AWAKE)
> +		writel(USR1_AWAKE, sport->port.membase + USR1);
> +
>  	return IRQ_HANDLED;
>  }
>  
> @@ -1269,6 +1272,12 @@ static struct uart_driver imx_reg = {
>  static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
>  {
>  	struct imx_port *sport = platform_get_drvdata(dev);
> +	unsigned int val;
> +
> +	/* enable wakeup from i.MX UART */
> +	val = readl(sport->port.membase + UCR3);
> +	val |= UCR3_AWAKEN;
> +	writel(val, sport->port.membase + UCR3);
>  
>  	if (sport)
>  		uart_suspend_port(&imx_reg, &sport->port);
> @@ -1279,7 +1288,13 @@ static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
>  static int serial_imx_resume(struct platform_device *dev)
>  {
>  	struct imx_port *sport = platform_get_drvdata(dev);
> +	unsigned int val;
>  
> +	/* disable wakeup from i.MX UART */
> +	val = readl(sport->port.membase + UCR3);
> +	val &= ~UCR3_AWAKEN;
> +	writel(val, sport->port.membase + UCR3);
> +
>  	if (sport)
>  		uart_resume_port(&imx_reg, &sport->port);
>  
> -- 
> 1.7.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
Shawn Guo - Dec. 26, 2011, 1:53 a.m.
On Tue, Dec 13, 2011 at 01:23:48AM -0200, Fabio Estevam wrote:
> Allow UART to be a source for wakeup from low power mode.
> 
> Tested on a MX27PDK by doing:
> 
> echo enabled > /sys/devices/platform/imx21-uart.0/tty/ttymxc0/power/wakeup
> 
> echo mem > /sys/power/state
> 
> and then pressing a key in the console will wakeup the sytem.
> 
> Suggested-by: Shawn Guo <shawn.guo@freescale.com>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---

I queued this for 3.3, and will send a pull-request to Greg.

Patch

diff --git a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
index a9c0406..676cc39 100644
--- a/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
+++ b/Documentation/devicetree/bindings/tty/serial/fsl-imx-uart.txt
@@ -8,6 +8,8 @@  Required properties:
 Optional properties:
 - fsl,uart-has-rtscts : Indicate the uart has rts and cts
 - fsl,irda-mode : Indicate the uart supports irda mode
+- fsl,uart-can-wake : Indicate that uart can be a source for wakeup from
+low-power mode
 
 Example:
 
diff --git a/arch/arm/plat-mxc/include/mach/imx-uart.h b/arch/arm/plat-mxc/include/mach/imx-uart.h
index 4adec9b..0ba6c6b 100644
--- a/arch/arm/plat-mxc/include/mach/imx-uart.h
+++ b/arch/arm/plat-mxc/include/mach/imx-uart.h
@@ -21,6 +21,7 @@ 
 
 #define IMXUART_HAVE_RTSCTS (1<<0)
 #define IMXUART_IRDA        (1<<1)
+#define IMXUART_CANWAKE     (1<<2)
 
 struct imxuart_platform_data {
 	int (*init)(struct platform_device *pdev);
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 163fc90..f9bee68 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -200,6 +200,7 @@  struct imx_port {
 	int			txirq,rxirq,rtsirq;
 	unsigned int		have_rtscts:1;
 	unsigned int		use_irda:1;
+	unsigned int		can_wake:1;
 	unsigned int		irda_inv_rx:1;
 	unsigned int		irda_inv_tx:1;
 	unsigned short		trcv_delay; /* transceiver delay */
@@ -566,6 +567,9 @@  static irqreturn_t imx_int(int irq, void *dev_id)
 	if (sts & USR1_RTSD)
 		imx_rtsint(irq, dev_id);
 
+	if (sts & USR1_AWAKE)
+		writel(USR1_AWAKE, sport->port.membase + USR1);
+
 	return IRQ_HANDLED;
 }
 
@@ -660,6 +664,7 @@  static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
 static int imx_startup(struct uart_port *port)
 {
 	struct imx_port *sport = (struct imx_port *)port;
+	struct tty_struct *tty;
 	int retval;
 	unsigned long flags, temp;
 
@@ -791,6 +796,8 @@  static int imx_startup(struct uart_port *port)
 		if (pdata->irda_enable)
 			pdata->irda_enable(1);
 	}
+	tty = sport->port.state->port.tty;
+	device_set_wakeup_enable(tty->dev, 1);
 
 	return 0;
 
@@ -1269,6 +1276,15 @@  static struct uart_driver imx_reg = {
 static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
 {
 	struct imx_port *sport = platform_get_drvdata(dev);
+	unsigned int val;
+
+	if (device_may_wakeup(&dev->dev)) {
+		enable_irq_wake(sport->rxirq);
+		/* enable wakeup from i.MX UART */
+		val = readl(sport->port.membase + UCR3);
+		val |= UCR3_AWAKEN;
+		writel(val, sport->port.membase + UCR3);
+	}
 
 	if (sport)
 		uart_suspend_port(&imx_reg, &sport->port);
@@ -1279,6 +1295,17 @@  static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
 static int serial_imx_resume(struct platform_device *dev)
 {
 	struct imx_port *sport = platform_get_drvdata(dev);
+	unsigned int val;
+
+	if (device_may_wakeup(&dev->dev)) {
+		enable_irq_wake(sport->rxirq);
+		/* enable wakeup from i.MX UART */
+		val = readl(sport->port.membase + UCR3);
+		val &= ~UCR3_AWAKEN;
+		writel(val, sport->port.membase + UCR3);
+
+		disable_irq_wake(sport->rxirq);
+	}
 
 	if (sport)
 		uart_resume_port(&imx_reg, &sport->port);
@@ -1311,6 +1338,9 @@  static int serial_imx_probe_dt(struct imx_port *sport,
 	if (of_get_property(np, "fsl,irda-mode", NULL))
 		sport->use_irda = 1;
 
+	if (of_get_property(np, "fsl,uart-can-wake", NULL))
+		sport->can_wake = 1;
+
 	sport->devdata = of_id->data;
 
 	return 0;
@@ -1408,6 +1438,11 @@  static int serial_imx_probe(struct platform_device *pdev)
 		goto deinit;
 	platform_set_drvdata(pdev, &sport->port);
 
+	if (pdata && (pdata->flags & IMXUART_CANWAKE))
+		device_init_wakeup(&pdev->dev, 1);
+	else
+		device_init_wakeup(&pdev->dev, 0);
+
 	return 0;
 deinit:
 	if (pdata && pdata->exit)