[PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Guennadi Liakhovetski]

Many MMC capability flags are platform-dependent and are traditionally set
in platform data. With DT often each such capability requires a special
binding. Add bindings for MMC_CAP_SD_HIGHSPEED, MMC_CAP_MMC_HIGHSPEED and
MMC_CAP_POWER_OFF_CARD capabilities. Also add code to DT parser to look
up "keep-power-in-suspend" and "enable-sdio-wakeup" bindings and set
MMC_PM_KEEP_POWER and MMC_PM_WAKE_SDIO_IRQ respectively, if found.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---

Attention: contains new DT bindings, please, comment!

 Documentation/devicetree/bindings/mmc/mmc.txt |    5 ++++-
 drivers/mmc/core/host.c                       |   11 +++++++++++
 2 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index e180892..92ec534c 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -25,8 +25,11 @@ Optional properties:
 - max-frequency: maximum operating clock frequency
 - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
   this system, even if the controller claims it is.
+- cap-sd-highspeed: SD high-speed timing is supported
+- cap-mmc-highspeed: MMC high-speed timing is supported
+- cap-power-off-card: powering off the card is safe
 
-cd-inverted and wp-inverted properties are deprecated ans shouldn't be used,
+cd-inverted and wp-inverted properties are deprecated and shouldn't be used,
 instead pleaseuse the OF_GPIO_ACTIVE_LOW flag in respective GPIO bindings. Note,
 that the default (as defined by the SDHCI standard) CD and WP polarity is
 active-low, so, OF_GPIO_ACTIVE_LOW should normally be set, and only be left
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index e4c1cbd..f3ea268 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -372,6 +372,17 @@ void mmc_of_parse(struct mmc_host *host)
 			dev_err(host->parent,
 				"Failed to request WP GPIO: %d!\n", ret);
 	}
+
+	if (of_find_property(np, "cap-sd-highspeed", &len))
+		host->caps |= MMC_CAP_SD_HIGHSPEED;
+	if (of_find_property(np, "cap-mmc-highspeed", &len))
+		host->caps |= MMC_CAP_MMC_HIGHSPEED;
+	if (of_find_property(np, "cap-power-off-card", &len))
+		host->caps |= MMC_CAP_POWER_OFF_CARD;
+	if (of_find_property(np, "keep-power-in-suspend", &len))
+		host->pm_caps |= MMC_PM_KEEP_POWER;
+	if (of_find_property(np, "enable-sdio-wakeup", &len))
+		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
 }
 
 EXPORT_SYMBOL(mmc_of_parse);
-- 
1.7.2.5

Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Mark Rutland]

Hi,

On Wed, Jan 23, 2013 at 04:45:11PM +0000, Guennadi Liakhovetski wrote:
> Many MMC capability flags are platform-dependent and are traditionally set
> in platform data. With DT often each such capability requires a special
> binding. Add bindings for MMC_CAP_SD_HIGHSPEED, MMC_CAP_MMC_HIGHSPEED and
> MMC_CAP_POWER_OFF_CARD capabilities. Also add code to DT parser to look
> up "keep-power-in-suspend" and "enable-sdio-wakeup" bindings and set
> MMC_PM_KEEP_POWER and MMC_PM_WAKE_SDIO_IRQ respectively, if found.
> 

I've Cc'd Arnd, who had some related comments a while back:

https://lkml.org/lkml/2012/10/15/231

MMC_CAP_POWER_OFF_CARD sounds like something that can be selected in the driver
by checking the compatible string or probing the hardware revision, and not
something that should be taken directly from the dts where it could be
completely invalid for the hardware.

> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> ---
> 
> Attention: contains new DT bindings, please, comment!
> 
>  Documentation/devicetree/bindings/mmc/mmc.txt |    5 ++++-
>  drivers/mmc/core/host.c                       |   11 +++++++++++
>  2 files changed, 15 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
> index e180892..92ec534c 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> @@ -25,8 +25,11 @@ Optional properties:
>  - max-frequency: maximum operating clock frequency
>  - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
>    this system, even if the controller claims it is.
> +- cap-sd-highspeed: SD high-speed timing is supported
> +- cap-mmc-highspeed: MMC high-speed timing is supported
> +- cap-power-off-card: powering off the card is safe
>  
> -cd-inverted and wp-inverted properties are deprecated ans shouldn't be used,
> +cd-inverted and wp-inverted properties are deprecated and shouldn't be used,
>  instead pleaseuse the OF_GPIO_ACTIVE_LOW flag in respective GPIO bindings. Note,
>  that the default (as defined by the SDHCI standard) CD and WP polarity is
>  active-low, so, OF_GPIO_ACTIVE_LOW should normally be set, and only be left
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index e4c1cbd..f3ea268 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -372,6 +372,17 @@ void mmc_of_parse(struct mmc_host *host)
>  			dev_err(host->parent,
>  				"Failed to request WP GPIO: %d!\n", ret);
>  	}
> +
> +	if (of_find_property(np, "cap-sd-highspeed", &len))
> +		host->caps |= MMC_CAP_SD_HIGHSPEED;
> +	if (of_find_property(np, "cap-mmc-highspeed", &len))
> +		host->caps |= MMC_CAP_MMC_HIGHSPEED;
> +	if (of_find_property(np, "cap-power-off-card", &len))
> +		host->caps |= MMC_CAP_POWER_OFF_CARD;
> +	if (of_find_property(np, "keep-power-in-suspend", &len))
> +		host->pm_caps |= MMC_PM_KEEP_POWER;
> +	if (of_find_property(np, "enable-sdio-wakeup", &len))
> +		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
>  }
>  
>  EXPORT_SYMBOL(mmc_of_parse);
> -- 
> 1.7.2.5
> 
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss
> 

Thanks,
Mark.

Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Guennadi Liakhovetski]

Hi Mark

On Wed, 6 Feb 2013, Mark Rutland wrote:

> Hi,
> 
> On Wed, Jan 23, 2013 at 04:45:11PM +0000, Guennadi Liakhovetski wrote:
> > Many MMC capability flags are platform-dependent and are traditionally set
> > in platform data. With DT often each such capability requires a special
> > binding. Add bindings for MMC_CAP_SD_HIGHSPEED, MMC_CAP_MMC_HIGHSPEED and
> > MMC_CAP_POWER_OFF_CARD capabilities. Also add code to DT parser to look
> > up "keep-power-in-suspend" and "enable-sdio-wakeup" bindings and set
> > MMC_PM_KEEP_POWER and MMC_PM_WAKE_SDIO_IRQ respectively, if found.
> > 
> 
> I've Cc'd Arnd, who had some related comments a while back:
> 
> https://lkml.org/lkml/2012/10/15/231
> 
> MMC_CAP_POWER_OFF_CARD sounds like something that can be selected in the driver
> by checking the compatible string or probing the hardware revision, and not
> something that should be taken directly from the dts where it could be
> completely invalid for the hardware.

Thank for pointing me out at that thread. However, I don't think 
MMC_CAP_POWER_OFF_CARD has anything to do with compatibility or hardware 
revisions. At least I haven't yet come across any sd/mmc hosts, that also 
supply card power. You could "derive" this flag from the presence of a 
regulator, capable of changing its status (switching on / off), but even 
then you're not guaranteed, that you actually can (and want to) power the 
card off at run-time - the regulator can be shared etc. So, an explicit 
flag is needed.

Thanks
Guennadi

> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > ---
> > 
> > Attention: contains new DT bindings, please, comment!
> > 
> >  Documentation/devicetree/bindings/mmc/mmc.txt |    5 ++++-
> >  drivers/mmc/core/host.c                       |   11 +++++++++++
> >  2 files changed, 15 insertions(+), 1 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
> > index e180892..92ec534c 100644
> > --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> > @@ -25,8 +25,11 @@ Optional properties:
> >  - max-frequency: maximum operating clock frequency
> >  - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
> >    this system, even if the controller claims it is.
> > +- cap-sd-highspeed: SD high-speed timing is supported
> > +- cap-mmc-highspeed: MMC high-speed timing is supported
> > +- cap-power-off-card: powering off the card is safe
> >  
> > -cd-inverted and wp-inverted properties are deprecated ans shouldn't be used,
> > +cd-inverted and wp-inverted properties are deprecated and shouldn't be used,
> >  instead pleaseuse the OF_GPIO_ACTIVE_LOW flag in respective GPIO bindings. Note,
> >  that the default (as defined by the SDHCI standard) CD and WP polarity is
> >  active-low, so, OF_GPIO_ACTIVE_LOW should normally be set, and only be left
> > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> > index e4c1cbd..f3ea268 100644
> > --- a/drivers/mmc/core/host.c
> > +++ b/drivers/mmc/core/host.c
> > @@ -372,6 +372,17 @@ void mmc_of_parse(struct mmc_host *host)
> >  			dev_err(host->parent,
> >  				"Failed to request WP GPIO: %d!\n", ret);
> >  	}
> > +
> > +	if (of_find_property(np, "cap-sd-highspeed", &len))
> > +		host->caps |= MMC_CAP_SD_HIGHSPEED;
> > +	if (of_find_property(np, "cap-mmc-highspeed", &len))
> > +		host->caps |= MMC_CAP_MMC_HIGHSPEED;
> > +	if (of_find_property(np, "cap-power-off-card", &len))
> > +		host->caps |= MMC_CAP_POWER_OFF_CARD;
> > +	if (of_find_property(np, "keep-power-in-suspend", &len))
> > +		host->pm_caps |= MMC_PM_KEEP_POWER;
> > +	if (of_find_property(np, "enable-sdio-wakeup", &len))
> > +		host->pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
> >  }
> >  
> >  EXPORT_SYMBOL(mmc_of_parse);
> > -- 
> > 1.7.2.5
> > 
> > _______________________________________________
> > devicetree-discuss mailing list
> > devicetree-discuss@lists.ozlabs.org
> > https://lists.ozlabs.org/listinfo/devicetree-discuss
> > 
> 
> Thanks,
> Mark.
> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Arnd Bergmann]

On Wednesday 06 February 2013 17:25:42 Guennadi Liakhovetski wrote:
> 
> Thank for pointing me out at that thread. However, I don't think 
> MMC_CAP_POWER_OFF_CARD has anything to do with compatibility or hardware 
> revisions. At least I haven't yet come across any sd/mmc hosts, that also 
> supply card power. You could "derive" this flag from the presence of a 
> regulator, capable of changing its status (switching on / off), but even 
> then you're not guaranteed, that you actually can (and want to) power the 
> card off at run-time - the regulator can be shared etc. So, an explicit 
> flag is needed.

It sounds like something that should be handled in a controller specific
way I think. E.g. on SDHCI, there seems to always be a method to power
down the card using the SDHCI_POWER_CONTROL register, even without
any external regulators.

	Arnd

Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Guennadi Liakhovetski]

On Thu, 7 Feb 2013, Arnd Bergmann wrote:

> On Wednesday 06 February 2013 17:25:42 Guennadi Liakhovetski wrote:
> > 
> > Thank for pointing me out at that thread. However, I don't think 
> > MMC_CAP_POWER_OFF_CARD has anything to do with compatibility or hardware 
> > revisions. At least I haven't yet come across any sd/mmc hosts, that also 
> > supply card power. You could "derive" this flag from the presence of a 
> > regulator, capable of changing its status (switching on / off), but even 
> > then you're not guaranteed, that you actually can (and want to) power the 
> > card off at run-time - the regulator can be shared etc. So, an explicit 
> > flag is needed.
> 
> It sounds like something that should be handled in a controller specific
> way I think. E.g. on SDHCI, there seems to always be a method to power
> down the card using the SDHCI_POWER_CONTROL register, even without
> any external regulators.

If I understand correctly, that register only controls card bus power. 
Further sdhci.c uses regulators (host->vmmc) to power up and down the 
card.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: [PATCH/RFC] mmc: add DT bindings for more MMC capability flags

[Arnd Bergmann]

On Wednesday 06 February 2013, Guennadi Liakhovetski wrote:
> 
> On Thu, 7 Feb 2013, Arnd Bergmann wrote:
> 
> > On Wednesday 06 February 2013 17:25:42 Guennadi Liakhovetski wrote:
> > > 
> > > Thank for pointing me out at that thread. However, I don't think 
> > > MMC_CAP_POWER_OFF_CARD has anything to do with compatibility or hardware 
> > > revisions. At least I haven't yet come across any sd/mmc hosts, that also 
> > > supply card power. You could "derive" this flag from the presence of a 
> > > regulator, capable of changing its status (switching on / off), but even 
> > > then you're not guaranteed, that you actually can (and want to) power the 
> > > card off at run-time - the regulator can be shared etc. So, an explicit 
> > > flag is needed.
> > 
> > It sounds like something that should be handled in a controller specific
> > way I think. E.g. on SDHCI, there seems to always be a method to power
> > down the card using the SDHCI_POWER_CONTROL register, even without
> > any external regulators.
> 
> If I understand correctly, that register only controls card bus power. 
> Further sdhci.c uses regulators (host->vmmc) to power up and down the 
> card.

Ok, that may be true. So a device that can only power down the bus
but not the card itself should not set MMC_CAP_POWER_OFF_CARD
then? I only saw that it is set unconditionally for the PCI
case, which does not use regulators.

	Arnd