Re: [PATCH v2 2/5] PM / OPP: add support to specify phandle of another node for OPP

[Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha-5wv7dgnIgG8@public.gmane.org>]

On 01/10/13 14:32, Sudeep KarkadaNagesha wrote:
> From: Sudeep KarkadaNagesha <sudeep.karkadanagesha-5wv7dgnIgG8@public.gmane.org>
> 
> Currently we need to replicate the OPP entries in all the nodes even
> though they share OPPs being in the same clock domain.
> 
> Few drivers like cpufreq depend on physical cpu0 node to specify the
> OPPs and only that node is referred irrespective of the logical cpu
> accessing it. Alternatively to support cpuhotplug path, few drivers
> parse all the cpu nodes for OPPs. Instead we can specify the phandle
> of the node which contains the OPP tuples.
> 
> This patch adds support to the new property 'operating-points-phandle'
> which specifies the phandle pointing to another node which contains the
> actual OPP tuples.
> 
> Cc: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
> Cc: Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>
> Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
> Cc: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
> Cc: "Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>
> Cc: Nishanth Menon <nm-l0cyMroinI0@public.gmane.org>
> Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha-5wv7dgnIgG8@public.gmane.org>
> ---
>  drivers/base/power/opp.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index ef89897..bb6ff64 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -708,12 +708,20 @@ struct srcu_notifier_head *opp_get_notifier(struct device *dev)
>  int of_init_opp_table(struct device *dev)
>  {
>  	const struct property *prop;
> +	struct device_node *opp_node;
>  	const __be32 *val;
>  	int nr;
>  
> -	prop = of_find_property(dev->of_node, "operating-points", NULL);
> -	if (!prop)
> +	opp_node = of_parse_phandle(dev->of_node,
> +					"operating-points-phandle", 0);
> +	if (!opp_node) /* if no OPP phandle, search for OPPs in current node */
> +		opp_node = dev->of_node;
> +	prop = of_find_property(opp_node, "operating-points", NULL);
> +	if (!prop) {
> +		dev_warn(dev, "node %s missing operating-points property\n",
> +							opp_node->full_name);
>  		return -ENODEV;
> +	}
>  	if (!prop->value)
>  		return -ENODATA;
>  
> @@ -740,6 +748,9 @@ int of_init_opp_table(struct device *dev)
>  		nr -= 2;
>  	}
>  
> +	if (opp_node != dev->of_node)
> +		of_node_put(opp_node);
> +
There are several exit paths on error conditions where we need to do this.
I missed them all. Here is the updated patch:

-->8--

From: Sudeep KarkadaNagesha <sudeep.karkadanagesha-5wv7dgnIgG8@public.gmane.org>

Currently we need to replicate the OPP entries in all the nodes even
though they share OPPs being in the same clock domain.

Few drivers like cpufreq depend on physical cpu0 node to specify the
OPPs and only that node is referred irrespective of the logical cpu
accessing it. Alternatively to support cpuhotplug path, few drivers
parse all the cpu nodes for OPPs. Instead we can specify the phandle
of the node which contains the OPP tuples.

This patch adds support to the new property 'operating-points-phandle'
which specifies the phandle pointing to another node which contains the
actual OPP tuples.

Cc: Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
Cc: Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>
Cc: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Cc: "Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>
Cc: Nishanth Menon <nm-l0cyMroinI0@public.gmane.org>
Signed-off-by: Sudeep KarkadaNagesha <sudeep.karkadanagesha-5wv7dgnIgG8@public.gmane.org>
---
 drivers/base/power/opp.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index ef89897..cd4dbb3 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -708,14 +708,25 @@ struct srcu_notifier_head *opp_get_notifier(struct device
*dev)
 int of_init_opp_table(struct device *dev)
 {
 	const struct property *prop;
+	struct device_node *opp_node;
 	const __be32 *val;
-	int nr;
-
-	prop = of_find_property(dev->of_node, "operating-points", NULL);
-	if (!prop)
-		return -ENODEV;
-	if (!prop->value)
-		return -ENODATA;
+	int nr, ret = 0;
+
+	opp_node = of_parse_phandle(dev->of_node,
+					"operating-points-phandle", 0);
+	if (!opp_node) /* if no OPP phandle, search for OPPs in current node */
+		opp_node = dev->of_node;
+	prop = of_find_property(opp_node, "operating-points", NULL);
+	if (!prop) {
+		dev_warn(dev, "node %s missing operating-points property\n",
+							opp_node->full_name);
+		ret = -ENODEV;
+		goto put_node;
+	}
+	if (!prop->value) {
+		ret = -ENODATA;
+		goto put_node;
+	}

 	/*
 	 * Each OPP is a set of tuples consisting of frequency and
@@ -724,7 +735,8 @@ int of_init_opp_table(struct device *dev)
 	nr = prop->length / sizeof(u32);
 	if (nr % 2) {
 		dev_err(dev, "%s: Invalid OPP list\n", __func__);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto put_node;
 	}

 	val = prop->value;
@@ -740,7 +752,11 @@ int of_init_opp_table(struct device *dev)
 		nr -= 2;
 	}

-	return 0;
+put_node:
+	if (opp_node != dev->of_node)
+		of_node_put(opp_node);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(of_init_opp_table);
 #endif
-- 
1.8.1.2






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