[PATCH 06/17] gpio: mvebu: add suspend/resume support

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* [PATCH 06/17] gpio: mvebu: add suspend/resume support
       [not found] <1414151970-6626-1-git-send-email-thomas.petazzoni@free-electrons.com>
@ 2014-10-24 11:59 ` Thomas Petazzoni
  2014-10-24 16:30   ` David Cohen
                     ` (3 more replies)
  0 siblings, 4 replies; 12+ messages in thread
From: Thomas Petazzoni @ 2014-10-24 11:59 UTC (permalink / raw)
  To: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth, Gregory Clement
  Cc: linux-arm-kernel, Tawfik Bayouk, Nadav Haklai, Lior Amsalem,
	Ezequiel Garcia, devicetree, Thomas Petazzoni, Linus Walleij,
	Alexandre Courbot, linux-gpio

This commit adds the implementation of ->suspend() and ->resume()
platform_driver hooks in order to save and restore the state of the
GPIO configuration. In order to achieve that, additional fields are
added to the mvebu_gpio_chip structure.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: linux-gpio@vger.kernel.org
---
 drivers/gpio/gpio-mvebu.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index 418e386..dd5545c 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -83,6 +83,14 @@ struct mvebu_gpio_chip {
 	int		   irqbase;
 	struct irq_domain *domain;
 	int                soc_variant;
+
+	/* Used to preserve GPIO registers accross suspend/resume */
+	u32                out_reg;
+	u32                io_conf_reg;
+	u32                blink_en_reg;
+	u32                in_pol_reg;
+	u32                edge_mask_regs[4];
+	u32                level_mask_regs[4];
 };
 
 /*
@@ -554,6 +562,93 @@ static const struct of_device_id mvebu_gpio_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, mvebu_gpio_of_match);
 
+static int mvebu_gpio_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
+	int i;
+
+	mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
+	mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
+	mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
+	mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));
+
+	switch (mvchip->soc_variant) {
+	case MVEBU_GPIO_SOC_VARIANT_ORION:
+		mvchip->edge_mask_regs[0] =
+			readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
+		mvchip->level_mask_regs[0] =
+			readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
+		break;
+	case MVEBU_GPIO_SOC_VARIANT_MV78200:
+		for (i = 0; i < 2; i++) {
+			mvchip->edge_mask_regs[i] =
+				readl(mvchip->membase +
+				      GPIO_EDGE_MASK_MV78200_OFF(i));
+			mvchip->level_mask_regs[i] =
+				readl(mvchip->membase +
+				      GPIO_LEVEL_MASK_MV78200_OFF(i));
+		}
+		break;
+	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
+		for (i = 0; i < 4; i++) {
+			mvchip->edge_mask_regs[i] =
+				readl(mvchip->membase +
+				      GPIO_EDGE_MASK_ARMADAXP_OFF(i));
+			mvchip->level_mask_regs[i] =
+				readl(mvchip->membase +
+				      GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
+		}
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
+static int mvebu_gpio_resume(struct platform_device *pdev)
+{
+	struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
+	int i;
+
+	writel(mvchip->out_reg, mvebu_gpioreg_out(mvchip));
+	writel(mvchip->io_conf_reg, mvebu_gpioreg_io_conf(mvchip));
+	writel(mvchip->blink_en_reg, mvebu_gpioreg_blink(mvchip));
+	writel(mvchip->in_pol_reg, mvebu_gpioreg_in_pol(mvchip));
+
+	switch (mvchip->soc_variant) {
+	case MVEBU_GPIO_SOC_VARIANT_ORION:
+		writel(mvchip->edge_mask_regs[0],
+		       mvchip->membase + GPIO_EDGE_MASK_OFF);
+		writel(mvchip->level_mask_regs[0],
+		       mvchip->membase + GPIO_LEVEL_MASK_OFF);
+		break;
+	case MVEBU_GPIO_SOC_VARIANT_MV78200:
+		for (i = 0; i < 2; i++) {
+			writel(mvchip->edge_mask_regs[i],
+			       mvchip->membase + GPIO_EDGE_MASK_MV78200_OFF(i));
+			writel(mvchip->level_mask_regs[i],
+			       mvchip->membase +
+			       GPIO_LEVEL_MASK_MV78200_OFF(i));
+		}
+		break;
+	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
+		for (i = 0; i < 4; i++) {
+			writel(mvchip->edge_mask_regs[i],
+			       mvchip->membase +
+			       GPIO_EDGE_MASK_ARMADAXP_OFF(i));
+			writel(mvchip->level_mask_regs[i],
+			       mvchip->membase +
+			       GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
+		}
+		break;
+	default:
+		BUG();
+	}
+
+	return 0;
+}
+
 static int mvebu_gpio_probe(struct platform_device *pdev)
 {
 	struct mvebu_gpio_chip *mvchip;
@@ -577,6 +672,8 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
 	if (!mvchip)
 		return -ENOMEM;
 
+	platform_set_drvdata(pdev, mvchip);
+
 	if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
 		dev_err(&pdev->dev, "Missing ngpios OF property\n");
 		return -ENODEV;
@@ -735,5 +832,7 @@ static struct platform_driver mvebu_gpio_driver = {
 		.of_match_table = mvebu_gpio_of_match,
 	},
 	.probe		= mvebu_gpio_probe,
+	.suspend        = mvebu_gpio_suspend,
+	.resume         = mvebu_gpio_resume,
 };
 module_platform_driver(mvebu_gpio_driver);
-- 
2.0.0


^ permalink raw reply related	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: add suspend/resume support Thomas Petazzoni
@ 2014-10-24 16:30   ` David Cohen
  2014-10-24 20:45     ` Andrew Lunn
  2014-10-31  7:00   ` Linus Walleij
                     ` (2 subsequent siblings)
  3 siblings, 1 reply; 12+ messages in thread
From: David Cohen @ 2014-10-24 16:30 UTC (permalink / raw)
  To: Thomas Petazzoni
  Cc: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth, Gregory Clement,
	linux-arm-kernel, Tawfik Bayouk, Nadav Haklai, Lior Amsalem,
	Ezequiel Garcia, devicetree, Linus Walleij, Alexandre Courbot,
	linux-gpio

On Fri, Oct 24, 2014 at 01:59:19PM +0200, Thomas Petazzoni wrote:
> This commit adds the implementation of ->suspend() and ->resume()
> platform_driver hooks in order to save and restore the state of the
> GPIO configuration. In order to achieve that, additional fields are
> added to the mvebu_gpio_chip structure.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: linux-gpio@vger.kernel.org
> ---
>  drivers/gpio/gpio-mvebu.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 99 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
> index 418e386..dd5545c 100644
> --- a/drivers/gpio/gpio-mvebu.c
> +++ b/drivers/gpio/gpio-mvebu.c
> @@ -83,6 +83,14 @@ struct mvebu_gpio_chip {
>  	int		   irqbase;
>  	struct irq_domain *domain;
>  	int                soc_variant;
> +
> +	/* Used to preserve GPIO registers accross suspend/resume */
> +	u32                out_reg;
> +	u32                io_conf_reg;
> +	u32                blink_en_reg;
> +	u32                in_pol_reg;
> +	u32                edge_mask_regs[4];
> +	u32                level_mask_regs[4];
>  };
>  
>  /*
> @@ -554,6 +562,93 @@ static const struct of_device_id mvebu_gpio_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, mvebu_gpio_of_match);
>  
> +static int mvebu_gpio_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
> +	int i;
> +
> +	mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
> +	mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
> +	mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
> +	mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));
> +
> +	switch (mvchip->soc_variant) {
> +	case MVEBU_GPIO_SOC_VARIANT_ORION:
> +		mvchip->edge_mask_regs[0] =
> +			readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> +		mvchip->level_mask_regs[0] =
> +			readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> +		break;
> +	case MVEBU_GPIO_SOC_VARIANT_MV78200:
> +		for (i = 0; i < 2; i++) {
> +			mvchip->edge_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_EDGE_MASK_MV78200_OFF(i));
> +			mvchip->level_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_LEVEL_MASK_MV78200_OFF(i));
> +		}
> +		break;
> +	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
> +		for (i = 0; i < 4; i++) {
> +			mvchip->edge_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_EDGE_MASK_ARMADAXP_OFF(i));
> +			mvchip->level_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
> +		}
> +		break;
> +	default:
> +		BUG();

Isn't it too severe? Is the platform going too unstable if driver
reaches this case?
I'd consider a WARN() instead.

> +	}
> +
> +	return 0;
> +}
> +
> +static int mvebu_gpio_resume(struct platform_device *pdev)
> +{
> +	struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
> +	int i;
> +
> +	writel(mvchip->out_reg, mvebu_gpioreg_out(mvchip));
> +	writel(mvchip->io_conf_reg, mvebu_gpioreg_io_conf(mvchip));
> +	writel(mvchip->blink_en_reg, mvebu_gpioreg_blink(mvchip));
> +	writel(mvchip->in_pol_reg, mvebu_gpioreg_in_pol(mvchip));
> +
> +	switch (mvchip->soc_variant) {
> +	case MVEBU_GPIO_SOC_VARIANT_ORION:
> +		writel(mvchip->edge_mask_regs[0],
> +		       mvchip->membase + GPIO_EDGE_MASK_OFF);
> +		writel(mvchip->level_mask_regs[0],
> +		       mvchip->membase + GPIO_LEVEL_MASK_OFF);
> +		break;
> +	case MVEBU_GPIO_SOC_VARIANT_MV78200:
> +		for (i = 0; i < 2; i++) {
> +			writel(mvchip->edge_mask_regs[i],
> +			       mvchip->membase + GPIO_EDGE_MASK_MV78200_OFF(i));
> +			writel(mvchip->level_mask_regs[i],
> +			       mvchip->membase +
> +			       GPIO_LEVEL_MASK_MV78200_OFF(i));
> +		}
> +		break;
> +	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
> +		for (i = 0; i < 4; i++) {
> +			writel(mvchip->edge_mask_regs[i],
> +			       mvchip->membase +
> +			       GPIO_EDGE_MASK_ARMADAXP_OFF(i));
> +			writel(mvchip->level_mask_regs[i],
> +			       mvchip->membase +
> +			       GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
> +		}
> +		break;
> +	default:
> +		BUG();

Ditto.

Br, David Cohen

> +	}
> +
> +	return 0;
> +}
> +
>  static int mvebu_gpio_probe(struct platform_device *pdev)
>  {
>  	struct mvebu_gpio_chip *mvchip;
> @@ -577,6 +672,8 @@ static int mvebu_gpio_probe(struct platform_device *pdev)
>  	if (!mvchip)
>  		return -ENOMEM;
>  
> +	platform_set_drvdata(pdev, mvchip);
> +
>  	if (of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios)) {
>  		dev_err(&pdev->dev, "Missing ngpios OF property\n");
>  		return -ENODEV;
> @@ -735,5 +832,7 @@ static struct platform_driver mvebu_gpio_driver = {
>  		.of_match_table = mvebu_gpio_of_match,
>  	},
>  	.probe		= mvebu_gpio_probe,
> +	.suspend        = mvebu_gpio_suspend,
> +	.resume         = mvebu_gpio_resume,
>  };
>  module_platform_driver(mvebu_gpio_driver);
> -- 
> 2.0.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 16:30   ` David Cohen
@ 2014-10-24 20:45     ` Andrew Lunn
  2014-10-27  5:27       ` Alexandre Courbot
  0 siblings, 1 reply; 12+ messages in thread
From: Andrew Lunn @ 2014-10-24 20:45 UTC (permalink / raw)
  To: David Cohen
  Cc: Thomas Petazzoni, Jason Cooper, Andrew Lunn,
	Sebastian Hesselbarth, Gregory Clement, linux-arm-kernel,
	Tawfik Bayouk, Nadav Haklai, Lior Amsalem, Ezequiel Garcia,
	devicetree, Linus Walleij, Alexandre Courbot, linux-gpio

> > +	switch (mvchip->soc_variant) {
> > +	case MVEBU_GPIO_SOC_VARIANT_ORION:
> > +		mvchip->edge_mask_regs[0] =
> > +			readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> > +		mvchip->level_mask_regs[0] =
> > +			readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> > +		break;
> > +	case MVEBU_GPIO_SOC_VARIANT_MV78200:
> > +		for (i = 0; i < 2; i++) {
> > +			mvchip->edge_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_EDGE_MASK_MV78200_OFF(i));
> > +			mvchip->level_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_LEVEL_MASK_MV78200_OFF(i));
> > +		}
> > +		break;
> > +	case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
> > +		for (i = 0; i < 4; i++) {
> > +			mvchip->edge_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_EDGE_MASK_ARMADAXP_OFF(i));
> > +			mvchip->level_mask_regs[i] =
> > +				readl(mvchip->membase +
> > +				      GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
> > +		}
> > +		break;
> > +	default:
> > +		BUG();
> 
> Isn't it too severe? Is the platform going too unstable if driver
> reaches this case?
> I'd consider a WARN() instead.

This is a common pattern in this driver. So i guess Thomas just
cut/pasted the switch statement from _probe(), which also has the
BUG().

Given that _probe() should of thrown a BUG() in this situation, if it
happens here, it means mvchip->soc_variant has been corrupted, and so
bad things are happening. So a BUG() is maybe called for?

	 Andrew

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 20:45     ` Andrew Lunn
@ 2014-10-27  5:27       ` Alexandre Courbot
  2014-10-27 17:45         ` David Cohen
  0 siblings, 1 reply; 12+ messages in thread
From: Alexandre Courbot @ 2014-10-27  5:27 UTC (permalink / raw)
  To: Andrew Lunn
  Cc: David Cohen, Thomas Petazzoni, Jason Cooper,
	Sebastian Hesselbarth, Gregory Clement,
	linux-arm-kernel@lists.infradead.org, Tawfik Bayouk, Nadav Haklai,
	Lior Amsalem, Ezequiel Garcia, devicetree@vger.kernel.org,
	Linus Walleij, linux-gpio@vger.kernel.org

On Sat, Oct 25, 2014 at 5:45 AM, Andrew Lunn <andrew@lunn.ch> wrote:
>> > +   switch (mvchip->soc_variant) {
>> > +   case MVEBU_GPIO_SOC_VARIANT_ORION:
>> > +           mvchip->edge_mask_regs[0] =
>> > +                   readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
>> > +           mvchip->level_mask_regs[0] =
>> > +                   readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
>> > +           break;
>> > +   case MVEBU_GPIO_SOC_VARIANT_MV78200:
>> > +           for (i = 0; i < 2; i++) {
>> > +                   mvchip->edge_mask_regs[i] =
>> > +                           readl(mvchip->membase +
>> > +                                 GPIO_EDGE_MASK_MV78200_OFF(i));
>> > +                   mvchip->level_mask_regs[i] =
>> > +                           readl(mvchip->membase +
>> > +                                 GPIO_LEVEL_MASK_MV78200_OFF(i));
>> > +           }
>> > +           break;
>> > +   case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
>> > +           for (i = 0; i < 4; i++) {
>> > +                   mvchip->edge_mask_regs[i] =
>> > +                           readl(mvchip->membase +
>> > +                                 GPIO_EDGE_MASK_ARMADAXP_OFF(i));
>> > +                   mvchip->level_mask_regs[i] =
>> > +                           readl(mvchip->membase +
>> > +                                 GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
>> > +           }
>> > +           break;
>> > +   default:
>> > +           BUG();
>>
>> Isn't it too severe? Is the platform going too unstable if driver
>> reaches this case?
>> I'd consider a WARN() instead.
>
> This is a common pattern in this driver. So i guess Thomas just
> cut/pasted the switch statement from _probe(), which also has the
> BUG().
>
> Given that _probe() should of thrown a BUG() in this situation, if it
> happens here, it means mvchip->soc_variant has been corrupted, and so
> bad things are happening. So a BUG() is maybe called for?

I agree that BUG() is adequate here. probe() should recognize the
exact same set of chips - if we reach this point this means that
either the data has been corrupted or we added support for a new chip
in probe() and forgot suspend/resume. In both cases the driver should
express its discontent.

Acked-by: Alexandre Courbot <acourbot@nvidia.com>

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-27  5:27       ` Alexandre Courbot
@ 2014-10-27 17:45         ` David Cohen
  0 siblings, 0 replies; 12+ messages in thread
From: David Cohen @ 2014-10-27 17:45 UTC (permalink / raw)
  To: Alexandre Courbot
  Cc: Andrew Lunn, Thomas Petazzoni, Jason Cooper,
	Sebastian Hesselbarth, Gregory Clement,
	linux-arm-kernel@lists.infradead.org, Tawfik Bayouk, Nadav Haklai,
	Lior Amsalem, Ezequiel Garcia, devicetree@vger.kernel.org,
	Linus Walleij, linux-gpio@vger.kernel.org

On Mon, Oct 27, 2014 at 02:27:16PM +0900, Alexandre Courbot wrote:
> On Sat, Oct 25, 2014 at 5:45 AM, Andrew Lunn <andrew@lunn.ch> wrote:
> >> > +   switch (mvchip->soc_variant) {
> >> > +   case MVEBU_GPIO_SOC_VARIANT_ORION:
> >> > +           mvchip->edge_mask_regs[0] =
> >> > +                   readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> >> > +           mvchip->level_mask_regs[0] =
> >> > +                   readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> >> > +           break;
> >> > +   case MVEBU_GPIO_SOC_VARIANT_MV78200:
> >> > +           for (i = 0; i < 2; i++) {
> >> > +                   mvchip->edge_mask_regs[i] =
> >> > +                           readl(mvchip->membase +
> >> > +                                 GPIO_EDGE_MASK_MV78200_OFF(i));
> >> > +                   mvchip->level_mask_regs[i] =
> >> > +                           readl(mvchip->membase +
> >> > +                                 GPIO_LEVEL_MASK_MV78200_OFF(i));
> >> > +           }
> >> > +           break;
> >> > +   case MVEBU_GPIO_SOC_VARIANT_ARMADAXP:
> >> > +           for (i = 0; i < 4; i++) {
> >> > +                   mvchip->edge_mask_regs[i] =
> >> > +                           readl(mvchip->membase +
> >> > +                                 GPIO_EDGE_MASK_ARMADAXP_OFF(i));
> >> > +                   mvchip->level_mask_regs[i] =
> >> > +                           readl(mvchip->membase +
> >> > +                                 GPIO_LEVEL_MASK_ARMADAXP_OFF(i));
> >> > +           }
> >> > +           break;
> >> > +   default:
> >> > +           BUG();
> >>
> >> Isn't it too severe? Is the platform going too unstable if driver
> >> reaches this case?
> >> I'd consider a WARN() instead.
> >
> > This is a common pattern in this driver. So i guess Thomas just
> > cut/pasted the switch statement from _probe(), which also has the
> > BUG().
> >
> > Given that _probe() should of thrown a BUG() in this situation, if it
> > happens here, it means mvchip->soc_variant has been corrupted, and so
> > bad things are happening. So a BUG() is maybe called for?
> 
> I agree that BUG() is adequate here. probe() should recognize the
> exact same set of chips - if we reach this point this means that
> either the data has been corrupted or we added support for a new chip
> in probe() and forgot suspend/resume. In both cases the driver should
> express its discontent.

Just for the records, since I don't know this platform very well :)

IMHO unless this issue is the source of a serious instability or data
corruption, a WARN() would be a better way for the driver express its
discontent. It's way better to have a functional platform for further
debugging.

This driver can also be compiled as a module. I wonder if it's a good
behavior boot the platform and then crash the kernel when loading the
module driver.

But anyway, that would be just me.

Br, David Cohen

> 
> Acked-by: Alexandre Courbot <acourbot@nvidia.com>

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: add suspend/resume support Thomas Petazzoni
  2014-10-24 16:30   ` David Cohen
@ 2014-10-31  7:00   ` Linus Walleij
  2014-10-31  7:52     ` Gregory CLEMENT
  2014-11-03 13:29   ` Linus Walleij
  2014-11-03 17:53   ` Gregory CLEMENT
  3 siblings, 1 reply; 12+ messages in thread
From: Linus Walleij @ 2014-10-31  7:00 UTC (permalink / raw)
  To: Thomas Petazzoni
  Cc: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth, Gregory Clement,
	linux-arm-kernel@lists.infradead.org, Tawfik Bayouk, Nadav Haklai,
	Lior Amsalem, Ezequiel Garcia, devicetree@vger.kernel.org,
	Alexandre Courbot, linux-gpio@vger.kernel.org

On Fri, Oct 24, 2014 at 1:59 PM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:

> This commit adds the implementation of ->suspend() and ->resume()
> platform_driver hooks in order to save and restore the state of the
> GPIO configuration. In order to achieve that, additional fields are
> added to the mvebu_gpio_chip structure.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: linux-gpio@vger.kernel.org

(...)
> +       mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
> +       mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
> +       mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
> +       mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));

OK...

> +       switch (mvchip->soc_variant) {
> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
> +               mvchip->edge_mask_regs[0] =
> +                       readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> +               mvchip->level_mask_regs[0] =
> +                       readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> +               break;

You are assigning index [0] twice, why? There must be some
reason, and it should be stated in a comment. If the first read
is necessary for hardware reasons, don't assign it but
discard the result.

(void) readl(...);

(This pattern repeats for each save call below.)

> +       switch (mvchip->soc_variant) {
> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
> +               writel(mvchip->edge_mask_regs[0],
> +                      mvchip->membase + GPIO_EDGE_MASK_OFF);
> +               writel(mvchip->level_mask_regs[0],
> +                      mvchip->membase + GPIO_LEVEL_MASK_OFF);

And on the way up same thing. Now you write
each register twice. Why?

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-31  7:00   ` Linus Walleij
@ 2014-10-31  7:52     ` Gregory CLEMENT
  2014-10-31  8:14       ` Thomas Petazzoni
  2014-11-03 13:26       ` Linus Walleij
  0 siblings, 2 replies; 12+ messages in thread
From: Gregory CLEMENT @ 2014-10-31  7:52 UTC (permalink / raw)
  To: Linus Walleij
  Cc: Thomas Petazzoni, Jason Cooper, Andrew Lunn,
	Sebastian Hesselbarth, linux-arm-kernel@lists.infradead.org,
	Tawfik Bayouk, Nadav Haklai, Lior Amsalem, Ezequiel Garcia,
	devicetree@vger.kernel.org, Alexandre Courbot,
	linux-gpio@vger.kernel.org

Hi Linus,


> 
>> +       switch (mvchip->soc_variant) {
>> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
>> +               mvchip->edge_mask_regs[0] =
>> +                       readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
>> +               mvchip->level_mask_regs[0] =
>> +                       readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
>> +               break;
> 
> You are assigning index [0] twice, why? There must be some
> reason, and it should be stated in a comment. If the first read
> is necessary for hardware reasons, don't assign it but
> discard the result.

Maybe I missed something but for me these 2 registers are different:
one is the _EDGE_ mask and the other the _LEVEL_ mask.

Gregory

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-31  7:52     ` Gregory CLEMENT
@ 2014-10-31  8:14       ` Thomas Petazzoni
  2014-11-03 13:26       ` Linus Walleij
  1 sibling, 0 replies; 12+ messages in thread
From: Thomas Petazzoni @ 2014-10-31  8:14 UTC (permalink / raw)
  To: Gregory CLEMENT
  Cc: Linus Walleij, Jason Cooper, Andrew Lunn, Sebastian Hesselbarth,
	linux-arm-kernel@lists.infradead.org, Tawfik Bayouk, Nadav Haklai,
	Lior Amsalem, Ezequiel Garcia, devicetree@vger.kernel.org,
	Alexandre Courbot, linux-gpio@vger.kernel.org

Hello,

On Fri, 31 Oct 2014 08:52:15 +0100, Gregory CLEMENT wrote:

> >> +       switch (mvchip->soc_variant) {
> >> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
> >> +               mvchip->edge_mask_regs[0] =
> >> +                       readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> >> +               mvchip->level_mask_regs[0] =
> >> +                       readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> >> +               break;
> > 
> > You are assigning index [0] twice, why? There must be some
> > reason, and it should be stated in a comment. If the first read
> > is necessary for hardware reasons, don't assign it but
> > discard the result.
> 
> Maybe I missed something but for me these 2 registers are different:
> one is the _EDGE_ mask and the other the _LEVEL_ mask.

Good that you looked at it Greg because I must admit I did not
understand the comment from Linus :-)

I read things again and both the variable *and* the register offset are
different. I guess it's probably due to a -ENOTENOUGHCOFFEE :-)

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-31  7:52     ` Gregory CLEMENT
  2014-10-31  8:14       ` Thomas Petazzoni
@ 2014-11-03 13:26       ` Linus Walleij
  1 sibling, 0 replies; 12+ messages in thread
From: Linus Walleij @ 2014-11-03 13:26 UTC (permalink / raw)
  To: Gregory CLEMENT
  Cc: Thomas Petazzoni, Jason Cooper, Andrew Lunn,
	Sebastian Hesselbarth, linux-arm-kernel@lists.infradead.org,
	Tawfik Bayouk, Nadav Haklai, Lior Amsalem, Ezequiel Garcia,
	devicetree@vger.kernel.org, Alexandre Courbot,
	linux-gpio@vger.kernel.org

On Fri, Oct 31, 2014 at 8:52 AM, Gregory CLEMENT
<gregory.clement@free-electrons.com> wrote:
> Hi Linus,
>>> +       switch (mvchip->soc_variant) {
>>> +       case MVEBU_GPIO_SOC_VARIANT_ORION:
>>> +               mvchip->edge_mask_regs[0] =
>>> +                       readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
>>> +               mvchip->level_mask_regs[0] =
>>> +                       readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
>>> +               break;
>>
>> You are assigning index [0] twice, why? There must be some
>> reason, and it should be stated in a comment. If the first read
>> is necessary for hardware reasons, don't assign it but
>> discard the result.
>
> Maybe I missed something but for me these 2 registers are different:
> one is the _EDGE_ mask and the other the _LEVEL_ mask.

Yeah haha I must have had a bad perception day :D

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: add suspend/resume support Thomas Petazzoni
  2014-10-24 16:30   ` David Cohen
  2014-10-31  7:00   ` Linus Walleij
@ 2014-11-03 13:29   ` Linus Walleij
  2014-11-03 17:53   ` Gregory CLEMENT
  3 siblings, 0 replies; 12+ messages in thread
From: Linus Walleij @ 2014-11-03 13:29 UTC (permalink / raw)
  To: Thomas Petazzoni
  Cc: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth, Gregory Clement,
	linux-arm-kernel@lists.infradead.org, Tawfik Bayouk, Nadav Haklai,
	Lior Amsalem, Ezequiel Garcia, devicetree@vger.kernel.org,
	Alexandre Courbot, linux-gpio@vger.kernel.org

On Fri, Oct 24, 2014 at 1:59 PM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:

> This commit adds the implementation of ->suspend() and ->resume()
> platform_driver hooks in order to save and restore the state of the
> GPIO configuration. In order to achieve that, additional fields are
> added to the mvebu_gpio_chip structure.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: linux-gpio@vger.kernel.org

Patch applied with Alexandre's ACK.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: add suspend/resume support Thomas Petazzoni
                     ` (2 preceding siblings ...)
  2014-11-03 13:29   ` Linus Walleij
@ 2014-11-03 17:53   ` Gregory CLEMENT
  2014-11-03 21:21     ` Thomas Petazzoni
  3 siblings, 1 reply; 12+ messages in thread
From: Gregory CLEMENT @ 2014-11-03 17:53 UTC (permalink / raw)
  To: Thomas Petazzoni, Jason Cooper, Andrew Lunn,
	Sebastian Hesselbarth
  Cc: linux-arm-kernel, Tawfik Bayouk, Nadav Haklai, Lior Amsalem,
	Ezequiel Garcia, devicetree, Linus Walleij, Alexandre Courbot,
	linux-gpio

On 24/10/2014 13:59, Thomas Petazzoni wrote:
> This commit adds the implementation of ->suspend() and ->resume()
> platform_driver hooks in order to save and restore the state of the
> GPIO configuration. In order to achieve that, additional fields are
> added to the mvebu_gpio_chip structure.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Alexandre Courbot <gnurou@gmail.com>
> Cc: linux-gpio@vger.kernel.org
> ---
>  drivers/gpio/gpio-mvebu.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 99 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
> index 418e386..dd5545c 100644
> --- a/drivers/gpio/gpio-mvebu.c
> +++ b/drivers/gpio/gpio-mvebu.c
> @@ -83,6 +83,14 @@ struct mvebu_gpio_chip {
>  	int		   irqbase;
>  	struct irq_domain *domain;
>  	int                soc_variant;
> +
> +	/* Used to preserve GPIO registers accross suspend/resume */
                                           across

> +	u32                out_reg;
> +	u32                io_conf_reg;
> +	u32                blink_en_reg;
> +	u32                in_pol_reg;
> +	u32                edge_mask_regs[4];
> +	u32                level_mask_regs[4];
>  };
>  
>  /*
> @@ -554,6 +562,93 @@ static const struct of_device_id mvebu_gpio_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, mvebu_gpio_of_match);
>  
> +static int mvebu_gpio_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	struct mvebu_gpio_chip *mvchip = platform_get_drvdata(pdev);
> +	int i;
> +
> +	mvchip->out_reg = readl(mvebu_gpioreg_out(mvchip));
> +	mvchip->io_conf_reg = readl(mvebu_gpioreg_io_conf(mvchip));
> +	mvchip->blink_en_reg = readl(mvebu_gpioreg_blink(mvchip));
> +	mvchip->in_pol_reg = readl(mvebu_gpioreg_in_pol(mvchip));
> +
> +	switch (mvchip->soc_variant) {
> +	case MVEBU_GPIO_SOC_VARIANT_ORION:
> +		mvchip->edge_mask_regs[0] =
> +			readl(mvchip->membase + GPIO_EDGE_MASK_OFF);
> +		mvchip->level_mask_regs[0] =
> +			readl(mvchip->membase + GPIO_LEVEL_MASK_OFF);
> +		break;
> +	case MVEBU_GPIO_SOC_VARIANT_MV78200:
> +		for (i = 0; i < 2; i++) {
> +			mvchip->edge_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_EDGE_MASK_MV78200_OFF(i));
> +			mvchip->level_mask_regs[i] =
> +				readl(mvchip->membase +
> +				      GPIO_LEVEL_MASK_MV78200_OFF(i));
> +		}
> +		break;

I don't know if the suspend is supported on this platform but as we were
on the road to remove this platform I don't know it it worth testing it unless
some interested users show up.

I didn't tested it on a mv782xx platform but the patch looks correct:

Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>


Thanks,

Gregory



-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 06/17] gpio: mvebu: add suspend/resume support
  2014-11-03 17:53   ` Gregory CLEMENT
@ 2014-11-03 21:21     ` Thomas Petazzoni
  0 siblings, 0 replies; 12+ messages in thread
From: Thomas Petazzoni @ 2014-11-03 21:21 UTC (permalink / raw)
  To: Gregory CLEMENT
  Cc: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth,
	linux-arm-kernel, Tawfik Bayouk, Nadav Haklai, Lior Amsalem,
	Ezequiel Garcia, devicetree, Linus Walleij, Alexandre Courbot,
	linux-gpio

Dear Gregory CLEMENT,

On Mon, 03 Nov 2014 18:53:29 +0100, Gregory CLEMENT wrote:

> I don't know if the suspend is supported on this platform but as we were
> on the road to remove this platform I don't know it it worth testing it unless
> some interested users show up.

The same can be said of the entire mv78xx0 support in gpio-mvebu: it's
completely unused today. Since the migration to mv78xx0 has not been
started, this platform is still using the old style GPIO driver in
plat-orion/gpio.c. And therefore, all the mv78xx0 specific code in
gpio-mvebu.c is purely "tentative" and has never been actually tested
on HW.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2014-11-03 21:21 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
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2014-10-24 11:59 ` [PATCH 06/17] gpio: mvebu: add suspend/resume support Thomas Petazzoni
2014-10-24 16:30   ` David Cohen
2014-10-24 20:45     ` Andrew Lunn
2014-10-27  5:27       ` Alexandre Courbot
2014-10-27 17:45         ` David Cohen
2014-10-31  7:00   ` Linus Walleij
2014-10-31  7:52     ` Gregory CLEMENT
2014-10-31  8:14       ` Thomas Petazzoni
2014-11-03 13:26       ` Linus Walleij
2014-11-03 13:29   ` Linus Walleij
2014-11-03 17:53   ` Gregory CLEMENT
2014-11-03 21:21     ` Thomas Petazzoni

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