[PATCH v3 4/5] soc: samsung: pm_domains: Read domain name from the new label property

[PATCH v3 4/5] soc: samsung: pm_domains: Read domain name from the new label property

[Marek Szyprowski]

Device tree nodes for each power domain should use generic "power-domain"
name, so using it as a domain name doesn't give much benefits. This patch
adds support for human readable names defined in 'label' property. Such
names are visible to userspace and makes debugging much easier. When no
'label' property is found, driver keeps using the name constructed from
full node name.

Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 Documentation/devicetree/bindings/power/pd-samsung.txt |  4 ++++
 drivers/soc/samsung/pm_domains.c                       | 12 ++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/power/pd-samsung.txt b/Documentation/devicetree/bindings/power/pd-samsung.txt
index fb08c8d62733..549f7dee9b9d 100644
--- a/Documentation/devicetree/bindings/power/pd-samsung.txt
+++ b/Documentation/devicetree/bindings/power/pd-samsung.txt
@@ -13,6 +13,8 @@ Required Properties:
     must be 0.
 
 Optional Properties:
+- label: Human readable string with domain name. Will be visible in userspace
+	to let user to distinguish between multiple domains in SoC.
 - clocks: List of clock handles. The parent clocks of the input clocks to the
 	devices in this power domain are set to oscclk before power gating
 	and restored back after powering on a domain. This is required for
@@ -39,6 +41,7 @@ Example:
 		compatible = "samsung,exynos4210-pd";
 		reg = <0x10023C00 0x10>;
 		#power-domain-cells = <0>;
+		label = "LCD0";
 	};
 
 	mfc_pd: power-domain@10044060 {
@@ -47,6 +50,7 @@ Example:
 		clocks = <&clock CLK_FIN_PLL>, <&clock CLK_MOUT_USER_ACLK333>;
 		clock-names = "oscclk", "clk0";
 		#power-domain-cells = <0>;
+		label = "MFC";
 	};
 
 See Documentation/devicetree/bindings/power/power_domain.txt for description
diff --git a/drivers/soc/samsung/pm_domains.c b/drivers/soc/samsung/pm_domains.c
index 5a0a46bcbe18..a6a5d807cc2b 100644
--- a/drivers/soc/samsung/pm_domains.c
+++ b/drivers/soc/samsung/pm_domains.c
@@ -142,6 +142,15 @@ static int exynos_pd_power_off(struct generic_pm_domain *domain)
 	{ },
 };
 
+static __init const char *exynos_get_domain_name(struct device_node *node)
+{
+	const char *name;
+
+	if (of_property_read_string(node, "label", &name) < 0)
+		name = strrchr(node->full_name, '/') + 1;
+	return kstrdup_const(name, GFP_KERNEL);
+}
+
 static __init int exynos4_pm_init_power_domain(void)
 {
 	struct device_node *np;
@@ -159,8 +168,7 @@ static __init int exynos4_pm_init_power_domain(void)
 			of_node_put(np);
 			return -ENOMEM;
 		}
-		pd->pd.name = kstrdup_const(strrchr(np->full_name, '/') + 1,
-					    GFP_KERNEL);
+		pd->pd.name = exynos_get_domain_name(np);
 		if (!pd->pd.name) {
 			kfree(pd);
 			of_node_put(np);
-- 
1.9.1

Re: [PATCH v3 4/5] soc: samsung: pm_domains: Read domain name from the new label property

[Krzysztof Kozlowski]

On Mon, Jan 30, 2017 at 01:18:59PM +0100, Marek Szyprowski wrote:
> Device tree nodes for each power domain should use generic "power-domain"
> name, so using it as a domain name doesn't give much benefits. This patch
> adds support for human readable names defined in 'label' property. Such
> names are visible to userspace and makes debugging much easier. When no
> 'label' property is found, driver keeps using the name constructed from
> full node name.
> 
> Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  Documentation/devicetree/bindings/power/pd-samsung.txt |  4 ++++
>  drivers/soc/samsung/pm_domains.c                       | 12 ++++++++++--
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 

Thanks, applied.

Best regards,
Krzysztof

Re: [PATCH v3 4/5] soc: samsung: pm_domains: Read domain name from the new label property

[Rob Herring]

On Mon, Jan 30, 2017 at 01:18:59PM +0100, Marek Szyprowski wrote:
> Device tree nodes for each power domain should use generic "power-domain"
> name, so using it as a domain name doesn't give much benefits. This patch
> adds support for human readable names defined in 'label' property. Such
> names are visible to userspace and makes debugging much easier. When no
> 'label' property is found, driver keeps using the name constructed from
> full node name.

I'm not sure this is really a good use of label. label is intended for 
end user visible things like ports/connectors on a board. It's fine 
here, but I wouldn't want to see it used everywhere.

> 
> Suggested-by: Krzysztof Kozlowski <krzk@kernel.org>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  Documentation/devicetree/bindings/power/pd-samsung.txt |  4 ++++
>  drivers/soc/samsung/pm_domains.c                       | 12 ++++++++++--
>  2 files changed, 14 insertions(+), 2 deletions(-)

Re: [PATCH v3 4/5] soc: samsung: pm_domains: Read domain name from the new label property

[Krzysztof Kozlowski]

On Wed, Feb 01, 2017 at 10:25:54AM -0600, Rob Herring wrote:
> On Mon, Jan 30, 2017 at 01:18:59PM +0100, Marek Szyprowski wrote:
> > Device tree nodes for each power domain should use generic "power-domain"
> > name, so using it as a domain name doesn't give much benefits. This patch
> > adds support for human readable names defined in 'label' property. Such
> > names are visible to userspace and makes debugging much easier. When no
> > 'label' property is found, driver keeps using the name constructed from
> > full node name.
> 
> I'm not sure this is really a good use of label. label is intended for 
> end user visible things like ports/connectors on a board. It's fine 
> here, but I wouldn't want to see it used everywhere.
>

Thanks for comments. We want to use the label here for user visible
output - through dmesg or debugfs. Otherwise, we would have to stick
(always) to more descriptive node names, like "lcd-power-domain@xxxxx".

Best regards,
Krzysztof