diff mbox

[RESEND,v2] thermal: tango: add resume support

Message ID 57726196.5060909@free.fr (mailing list archive)
State Superseded, archived
Delegated to: Zhang Rui
Headers show

Commit Message

Mason June 28, 2016, 11:37 a.m. UTC
From: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>

When this platform is suspended, firmware powers the entire SoC down,
except a few hardware blocks waiting for wakeup events. And there is
no context to save for this particular block.

Therefore, there is nothing useful for the driver to do on suspend;
so we define a NULL suspend hook. On resume, the driver initializes
the block exactly as is done in the probe callback.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
---
Add Kevin's Reviewed-by tag.
Eduardo/Zhang, can you pick this patch up for 4.8?
---
 drivers/thermal/tango_thermal.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

Comments

Thierry Reding July 18, 2016, 9:33 a.m. UTC | #1
On Tue, Jun 28, 2016 at 01:37:58PM +0200, Mason wrote:
> From: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
> 
> When this platform is suspended, firmware powers the entire SoC down,
> except a few hardware blocks waiting for wakeup events. And there is
> no context to save for this particular block.
> 
> Therefore, there is nothing useful for the driver to do on suspend;
> so we define a NULL suspend hook. On resume, the driver initializes
> the block exactly as is done in the probe callback.
> 
> Reviewed-by: Kevin Hilman <khilman@baylibre.com>
> Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
> ---
> Add Kevin's Reviewed-by tag.
> Eduardo/Zhang, can you pick this patch up for 4.8?
> ---
>  drivers/thermal/tango_thermal.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/tango_thermal.c b/drivers/thermal/tango_thermal.c
> index 70e0d9f406e9..d571ce2f546d 100644
> --- a/drivers/thermal/tango_thermal.c
> +++ b/drivers/thermal/tango_thermal.c
> @@ -64,6 +64,12 @@ static const struct thermal_zone_of_device_ops ops = {
>  	.get_temp	= tango_get_temp,
>  };
>  
> +static void tango_thermal_init(struct tango_thermal_priv *priv)
> +{
> +	writel(0, priv->base + TEMPSI_CFG);
> +	writel(CMD_ON, priv->base + TEMPSI_CMD);
> +}
> +
>  static int tango_thermal_probe(struct platform_device *pdev)
>  {
>  	struct resource *res;
> @@ -79,14 +85,30 @@ static int tango_thermal_probe(struct platform_device *pdev)
>  	if (IS_ERR(priv->base))
>  		return PTR_ERR(priv->base);
>  
> +	platform_set_drvdata(pdev, priv);
>  	priv->thresh_idx = IDX_MIN;
> -	writel(0, priv->base + TEMPSI_CFG);
> -	writel(CMD_ON, priv->base + TEMPSI_CMD);
> +	tango_thermal_init(priv);
>  
>  	tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &ops);
>  	return PTR_ERR_OR_ZERO(tzdev);
>  }
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int tango_thermal_resume(struct device *dev)
> +{
> +	struct tango_thermal_priv *priv = dev_get_drvdata(dev);
> +	tango_thermal_init(priv);

checkpatch will warn about this. You're supposed to separate the local
variable declarations and code by a single blank line.

> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
> +
> +#define DEV_PM_OPS	&tango_thermal_pm
> +#else
> +#define DEV_PM_OPS	NULL
> +#endif

In my experience it's often not useful to #ifdef the struct pm_ops.
These days you almost certainly want PM enabled, and the conditional
doesn't save you all that much in the first place, because it's not
unlikely for this to fit into some of the space that would be padded
out anyway.

As a side-note, I've noticed that this driver has the following
dependencies:

	depends on ARCH_TANGO || COMPILE_TEST

which, last I checked, is probably going to fail on some architectures
because you need at least another one on HAS_IOMEM (for readl() and
writel()). That's a pre-existing problem, of course, so should be fixed
in a separate patch.

Thierry
Arnd Bergmann July 18, 2016, 10:09 a.m. UTC | #2
On Monday, July 18, 2016 11:33:28 AM CEST Thierry Reding wrote:

> > +
> > +     return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
> > +
> > +#define DEV_PM_OPS   &tango_thermal_pm
> > +#else
> > +#define DEV_PM_OPS   NULL
> > +#endif
> 
> In my experience it's often not useful to #ifdef the struct pm_ops.
> These days you almost certainly want PM enabled, and the conditional
> doesn't save you all that much in the first place, because it's not
> unlikely for this to fit into some of the space that would be padded
> out anyway.

This will also generate a warning when CONFIG_PM_SLEEP is not set.
Better write this as

#define DEV_PM_OPS (IS_ENABLED(CONFIG_PM_SLEEP) ? &tango_thermal_pm : NULL)

so the compiler can drop the variable definition when it's not
needed.

> As a side-note, I've noticed that this driver has the following
> dependencies:
> 
>         depends on ARCH_TANGO || COMPILE_TEST
> 
> which, last I checked, is probably going to fail on some architectures
> because you need at least another one on HAS_IOMEM (for readl() and
> writel()). That's a pre-existing problem, of course, so should be fixed
> in a separate patch.

No need, we just merged a patch to no longer allow COMPILE_TEST on
arch/um/, so we can safely rely on MMIO to be available for COMPILE_TEST.

	Arnd
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Thierry Reding July 18, 2016, 10:13 a.m. UTC | #3
On Mon, Jul 18, 2016 at 12:09:39PM +0200, Arnd Bergmann wrote:
> On Monday, July 18, 2016 11:33:28 AM CEST Thierry Reding wrote:
> 
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
> > > +
> > > +#define DEV_PM_OPS   &tango_thermal_pm
> > > +#else
> > > +#define DEV_PM_OPS   NULL
> > > +#endif
> > 
> > In my experience it's often not useful to #ifdef the struct pm_ops.
> > These days you almost certainly want PM enabled, and the conditional
> > doesn't save you all that much in the first place, because it's not
> > unlikely for this to fit into some of the space that would be padded
> > out anyway.
> 
> This will also generate a warning when CONFIG_PM_SLEEP is not set.
> Better write this as
> 
> #define DEV_PM_OPS (IS_ENABLED(CONFIG_PM_SLEEP) ? &tango_thermal_pm : NULL)
> 
> so the compiler can drop the variable definition when it's not
> needed.

My suggestion was to define tango_thermal_pm unconditionally to avoid
any of these tricks. For any real use-case in which the 92 bytes for the
struct dev_pm_ops would matter you most likely want PM_SLEEP anyway, so
I don't really see why we would even want to make it optional.

> > As a side-note, I've noticed that this driver has the following
> > dependencies:
> > 
> >         depends on ARCH_TANGO || COMPILE_TEST
> > 
> > which, last I checked, is probably going to fail on some architectures
> > because you need at least another one on HAS_IOMEM (for readl() and
> > writel()). That's a pre-existing problem, of course, so should be fixed
> > in a separate patch.
> 
> No need, we just merged a patch to no longer allow COMPILE_TEST on
> arch/um/, so we can safely rely on MMIO to be available for COMPILE_TEST.

I thought at least S390 didn't have readl() and writel() either, at
least when PCI wasn't enabled, or some such.

Thierry
Arnd Bergmann July 18, 2016, 11:10 a.m. UTC | #4
On Monday, July 18, 2016 12:13:38 PM CEST Thierry Reding wrote:
> On Mon, Jul 18, 2016 at 12:09:39PM +0200, Arnd Bergmann wrote:
> > On Monday, July 18, 2016 11:33:28 AM CEST Thierry Reding wrote:
> > 
> > > > +
> > > > +     return 0;
> > > > +}
> > > > +
> > > > +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
> > > > +
> > > > +#define DEV_PM_OPS   &tango_thermal_pm
> > > > +#else
> > > > +#define DEV_PM_OPS   NULL
> > > > +#endif
> > > 
> > > In my experience it's often not useful to #ifdef the struct pm_ops.
> > > These days you almost certainly want PM enabled, and the conditional
> > > doesn't save you all that much in the first place, because it's not
> > > unlikely for this to fit into some of the space that would be padded
> > > out anyway.
> > 
> > This will also generate a warning when CONFIG_PM_SLEEP is not set.
> > Better write this as
> > 
> > #define DEV_PM_OPS (IS_ENABLED(CONFIG_PM_SLEEP) ? &tango_thermal_pm : NULL)
> > 
> > so the compiler can drop the variable definition when it's not
> > needed.
> 
> My suggestion was to define tango_thermal_pm unconditionally to avoid
> any of these tricks. For any real use-case in which the 92 bytes for the
> struct dev_pm_ops would matter you most likely want PM_SLEEP anyway, so
> I don't really see why we would even want to make it optional.

Sure, leaving it unconditional works too. 

> > > As a side-note, I've noticed that this driver has the following
> > > dependencies:
> > > 
> > >         depends on ARCH_TANGO || COMPILE_TEST
> > > 
> > > which, last I checked, is probably going to fail on some architectures
> > > because you need at least another one on HAS_IOMEM (for readl() and
> > > writel()). That's a pre-existing problem, of course, so should be fixed
> > > in a separate patch.
> > 
> > No need, we just merged a patch to no longer allow COMPILE_TEST on
> > arch/um/, so we can safely rely on MMIO to be available for COMPILE_TEST.
> 
> I thought at least S390 didn't have readl() and writel() either, at
> least when PCI wasn't enabled, or some such.

Yes, but they've never complained about COMPILE_TEST breakage because
of that. Tile is in the same boat too in some configurations.

	Arnd

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Thierry Reding July 18, 2016, 11:28 a.m. UTC | #5
On Mon, Jul 18, 2016 at 01:10:07PM +0200, Arnd Bergmann wrote:
> On Monday, July 18, 2016 12:13:38 PM CEST Thierry Reding wrote:
> > On Mon, Jul 18, 2016 at 12:09:39PM +0200, Arnd Bergmann wrote:
> > > On Monday, July 18, 2016 11:33:28 AM CEST Thierry Reding wrote:
> > > 
> > > > > +
> > > > > +     return 0;
> > > > > +}
> > > > > +
> > > > > +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
> > > > > +
> > > > > +#define DEV_PM_OPS   &tango_thermal_pm
> > > > > +#else
> > > > > +#define DEV_PM_OPS   NULL
> > > > > +#endif
> > > > 
> > > > In my experience it's often not useful to #ifdef the struct pm_ops.
> > > > These days you almost certainly want PM enabled, and the conditional
> > > > doesn't save you all that much in the first place, because it's not
> > > > unlikely for this to fit into some of the space that would be padded
> > > > out anyway.
> > > 
> > > This will also generate a warning when CONFIG_PM_SLEEP is not set.
> > > Better write this as
> > > 
> > > #define DEV_PM_OPS (IS_ENABLED(CONFIG_PM_SLEEP) ? &tango_thermal_pm : NULL)
> > > 
> > > so the compiler can drop the variable definition when it's not
> > > needed.
> > 
> > My suggestion was to define tango_thermal_pm unconditionally to avoid
> > any of these tricks. For any real use-case in which the 92 bytes for the
> > struct dev_pm_ops would matter you most likely want PM_SLEEP anyway, so
> > I don't really see why we would even want to make it optional.
> 
> Sure, leaving it unconditional works too. 
> 
> > > > As a side-note, I've noticed that this driver has the following
> > > > dependencies:
> > > > 
> > > >         depends on ARCH_TANGO || COMPILE_TEST
> > > > 
> > > > which, last I checked, is probably going to fail on some architectures
> > > > because you need at least another one on HAS_IOMEM (for readl() and
> > > > writel()). That's a pre-existing problem, of course, so should be fixed
> > > > in a separate patch.
> > > 
> > > No need, we just merged a patch to no longer allow COMPILE_TEST on
> > > arch/um/, so we can safely rely on MMIO to be available for COMPILE_TEST.
> > 
> > I thought at least S390 didn't have readl() and writel() either, at
> > least when PCI wasn't enabled, or some such.
> 
> Yes, but they've never complained about COMPILE_TEST breakage because
> of that. Tile is in the same boat too in some configurations.

Ah, okay. I remember running into this occasionally when doing
randconfig builds on S390. That was many moons ago, so perhaps it's not
an issue anymore, and maybe I've become overly cautious about the
COMPILE_TEST dependency.

Thierry
diff mbox

Patch

diff --git a/drivers/thermal/tango_thermal.c b/drivers/thermal/tango_thermal.c
index 70e0d9f406e9..d571ce2f546d 100644
--- a/drivers/thermal/tango_thermal.c
+++ b/drivers/thermal/tango_thermal.c
@@ -64,6 +64,12 @@  static const struct thermal_zone_of_device_ops ops = {
 	.get_temp	= tango_get_temp,
 };
 
+static void tango_thermal_init(struct tango_thermal_priv *priv)
+{
+	writel(0, priv->base + TEMPSI_CFG);
+	writel(CMD_ON, priv->base + TEMPSI_CMD);
+}
+
 static int tango_thermal_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -79,14 +85,30 @@  static int tango_thermal_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
+	platform_set_drvdata(pdev, priv);
 	priv->thresh_idx = IDX_MIN;
-	writel(0, priv->base + TEMPSI_CFG);
-	writel(CMD_ON, priv->base + TEMPSI_CMD);
+	tango_thermal_init(priv);
 
 	tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &ops);
 	return PTR_ERR_OR_ZERO(tzdev);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int tango_thermal_resume(struct device *dev)
+{
+	struct tango_thermal_priv *priv = dev_get_drvdata(dev);
+	tango_thermal_init(priv);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
+
+#define DEV_PM_OPS	&tango_thermal_pm
+#else
+#define DEV_PM_OPS	NULL
+#endif
+
 static const struct of_device_id tango_sensor_ids[] = {
 	{
 		.compatible = "sigma,smp8758-thermal",
@@ -99,6 +121,7 @@  static struct platform_driver tango_thermal_driver = {
 	.driver	= {
 		.name		= "tango-thermal",
 		.of_match_table	= tango_sensor_ids,
+		.pm		= DEV_PM_OPS,
 	},
 };