[PATCH 5/9] PM / Domains: dt: Allow power-domain property to be a list of phandles

[PATCH 5/9] PM / Domains: dt: Allow power-domain property to be a list of phandles

[Ulf Hansson]

To be able to describe topologies where devices are partitioned across
multiple power domains, let's extend the power-domain property to allow
being a list of phandles.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Suggested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 .../devicetree/bindings/power/power_domain.txt         | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
index 4733f76..b27ae7f 100644
--- a/Documentation/devicetree/bindings/power/power_domain.txt
+++ b/Documentation/devicetree/bindings/power/power_domain.txt
@@ -111,8 +111,9 @@ Example 3:
 ==PM domain consumers==
 
 Required properties:
- - power-domains : A phandle and PM domain specifier as defined by bindings of
-                   the power controller specified by phandle.
+ - power-domains : A phandle and PM domain specifier, or a list of phandles, as
+		   defined by bindings of the power controller specified by
+		   phandle.
 
 Example:
 
@@ -122,9 +123,16 @@ Example:
 		power-domains = <&power 0>;
 	};
 
-The node above defines a typical PM domain consumer device, which is located
-inside a PM domain with index 0 of a power controller represented by a node
-with the label "power".
+	leaky-device@12350000 {
+		compatible = "foo,i-leak-current";
+		reg = <0x12350000 0x1000>;
+		power-domains = <&power0 0>, <&power1 0> ;
+	};
+
+The first example above defines a typical PM domain consumer device, which is
+located inside a PM domain with index 0 of a power controller represented by a
+node with the label "power". In the second example the consumer device are
+partitioned across two PM domains.
 
 Optional properties:
 - required-opps: This contains phandle to an OPP node in another device's OPP
-- 
2.7.4

[PATCH 6/9] PM / Domains: Don't attach devices in genpd with multi PM domains

[Ulf Hansson]

The power-domain DT property may now contain a list of phandles, which
represents that a device are partitioned across multiple PM domains. This
leads to a new situation in genpd_dev_pm_attach(), as only one PM domain
can be attached per device.

To remain things simple for the most common configuration, when a single PM
domain is used, let's treat the multiple PM domain case as being specific.

In other words, let's change genpd_dev_pm_attach() to check for multiple PM
domains and prevent it from attach any PM domain for this case. Instead,
leave this to be managed separately, from following changes to genpd.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Suggested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 050ce07..4597e1c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2229,10 +2229,10 @@ static void genpd_dev_pm_sync(struct device *dev)
  * attaches the device to retrieved pm_domain ops.
  *
  * Returns 1 on successfully attached PM domain, 0 when the device don't need a
- * PM domain or a negative error code in case of failures. Note that if a
- * power-domain exists for the device, but it cannot be found or turned on,
- * then return -EPROBE_DEFER to ensure that the device is not probed and to
- * re-try again later.
+ * PM domain or when multiple power-domains exists for it, else a negative error
+ * code. Note that if a power-domain exists for the device, but it cannot be
+ * found or turned on, then return -EPROBE_DEFER to ensure that the device is
+ * not probed and to re-try again later.
  */
 int genpd_dev_pm_attach(struct device *dev)
 {
@@ -2243,10 +2243,18 @@ int genpd_dev_pm_attach(struct device *dev)
 	if (!dev->of_node)
 		return 0;
 
+	/*
+	 * Devices with multiple PM domains must be attached separately, as we
+	 * can only attach one PM domain per device.
+	 */
+	if (of_count_phandle_with_args(dev->of_node, "power-domains",
+				       "#power-domain-cells") != 1)
+		return 0;
+
 	ret = of_parse_phandle_with_args(dev->of_node, "power-domains",
 					"#power-domain-cells", 0, &pd_args);
 	if (ret < 0)
-		return 0;
+		return ret;
 
 	mutex_lock(&gpd_list_lock);
 	pd = genpd_get_from_provider(&pd_args);
-- 
2.7.4

Re: [PATCH 5/9] PM / Domains: dt: Allow power-domain property to be a list of phandles

[Geert Uytterhoeven]

Hi Ulf,

On Fri, May 18, 2018 at 12:31 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> To be able to describe topologies where devices are partitioned across
> multiple power domains, let's extend the power-domain property to allow
> being a list of phandles.
>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Suggested-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Thanks for your patch!

> --- a/Documentation/devicetree/bindings/power/power_domain.txt
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -111,8 +111,9 @@ Example 3:
>  ==PM domain consumers==
>
>  Required properties:
> - - power-domains : A phandle and PM domain specifier as defined by bindings of
> -                   the power controller specified by phandle.
> + - power-domains : A phandle and PM domain specifier, or a list of phandles, as

A list of PM domain specifiers?

(A PM domain specifier consists of a phandle, and zero or more indices)

> +                  defined by bindings of the power controller specified by
> +                  phandle.
>
>  Example:
>
> @@ -122,9 +123,16 @@ Example:
>                 power-domains = <&power 0>;
>         };
>
> -The node above defines a typical PM domain consumer device, which is located
> -inside a PM domain with index 0 of a power controller represented by a node
> -with the label "power".
> +       leaky-device@12350000 {

I know it's just an example, but this uses the same unit-address and
reg property
as the device node above.

There's a similar issue with the two other examples below, but they
use different
node names (leaky-device0 and leaky-device1).

> +               compatible = "foo,i-leak-current";
> +               reg = <0x12350000 0x1000>;
> +               power-domains = <&power0 0>, <&power1 0> ;
> +       };
> +
> +The first example above defines a typical PM domain consumer device, which is
> +located inside a PM domain with index 0 of a power controller represented by a
> +node with the label "power". In the second example the consumer device are
> +partitioned across two PM domains.
>
>  Optional properties:
>  - required-opps: This contains phandle to an OPP node in another device's OPP

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds